JP7619032B2 - Fingerprint processing device, fingerprint processing method and computer program - Google Patents

Description

This disclosure relates to the technical fields of a fingerprint processing device, a fingerprint processing method, and a computer program capable of performing fingerprint-related processing.

In recent years, biometric authentication for authenticating a user using the user's biometric information has been utilized in various situations. One example of biometric authentication is fingerprint authentication, which authenticates a user using the user's fingerprint. For example, Patent Document 1 describes a personal authentication system that uses a scanner to generate a fingerprint image containing the user's fingerprint, and authenticates the user using the fingerprint image.

Other prior art documents related to this disclosure include Patent Documents 2 to 5.

JP 2001-084371 A JP 2009-053842 A JP 2006-072554 A JP 2003-044857 A JP 2001-014462 A

When performing fingerprint authentication, it is necessary to extract features for authentication from a fingerprint image. Here, fingerprint features can be extracted using various fingerprint feature extraction methods. In this case, a technical problem arises in that, depending on the fingerprint feature extraction method used to extract features from a fingerprint image, fingerprint features that are not suitable for a desired application may be extracted. In other words, a fingerprint image may not be suitable for fingerprint authentication, which is performed using fingerprint features extracted using a particular fingerprint feature extraction method.

Alternatively, the fingerprint image may be used for fingerprint analysis in addition to or instead of fingerprint authentication. Fingerprint analysis is usually performed by an examiner. In this case, a technical problem occurs that the fingerprint image may not be suitable for the fingerprint analysis performed by the examiner. Alternatively, fingerprint analysis may be performed by a fingerprint analysis device (e.g., a computer) that can perform fingerprint analysis without the intervention of an examiner. In this case, the fingerprint analysis device usually extracts features for analysis from the fingerprint image and performs fingerprint analysis using the extracted features. As a result, as in the case of fingerprint authentication, a technical problem occurs that fingerprint features that are not suitable for the desired application may be extracted depending on the fingerprint feature extraction method for extracting features from the fingerprint image. In other words, the fingerprint image may not be suitable for the fingerprint analysis performed using fingerprint features extracted using a certain fingerprint feature extraction method.

The objective of this disclosure is to provide a fingerprint processing device, a fingerprint processing method, and a computer program that can solve the above-mentioned technical problems. As an example, the objective of this disclosure is to provide a fingerprint processing device, a fingerprint processing method, and a computer program that can generate a fingerprint image suitable for a desired application (e.g., fingerprint authentication application or fingerprint identification application).

A first aspect of the fingerprint processing device disclosed herein includes an acquisition means for acquiring a first fingerprint image that represents a fingerprint in a three-dimensional coordinate space, and a generation means for generating, from the first fingerprint image, a second fingerprint image that represents the fingerprint in a two-dimensional coordinate plane and in which the fingerprint is captured with desired image characteristics.

A second aspect of the fingerprint processing device disclosed herein includes an acquisition means for acquiring a fingerprint image representing a first fingerprint, and a display means for displaying the fingerprint image in which the first fingerprint is captured in a manner that allows a distinction to be made between a first portion of the first fingerprint corresponding to a portion of a second fingerprint captured in another fingerprint image different from the first fingerprint image, and a second portion of the first fingerprint that is different from the first portion.

A first aspect of the fingerprint processing method disclosed herein involves obtaining a first fingerprint image that represents a fingerprint in a three-dimensional coordinate space, and generating from the first fingerprint image a second fingerprint image that represents the fingerprint in a two-dimensional coordinate plane and in which the fingerprint is captured with desired image characteristics.

A second aspect of the fingerprint processing method disclosed herein is to obtain a fingerprint image representing a first fingerprint, and display the fingerprint image in which the first fingerprint is captured in such a manner that a first portion of the first fingerprint corresponding to a portion of a second fingerprint captured in another fingerprint image different from the first fingerprint image can be distinguished from a second portion of the first fingerprint that is different from the first portion.

A first aspect of the computer program disclosed herein causes a computer to execute a fingerprint processing method that acquires a first fingerprint image that represents a fingerprint in a three-dimensional coordinate space, and generates, from the first fingerprint image, a second fingerprint image that represents the fingerprint in a two-dimensional coordinate plane and in which the fingerprint is captured with desired image characteristics.

A second aspect of the computer program of this disclosure causes a computer to execute a fingerprint processing method that acquires a fingerprint image representing a first fingerprint, and displays the fingerprint image in which the first fingerprint is captured in a manner that allows a first portion of the first fingerprint corresponding to a portion of a second fingerprint captured in another fingerprint image different from the first fingerprint image to be distinguished from a second portion of the first fingerprint that is different from the first portion.

FIG. 1 is a block diagram showing the overall configuration of a fingerprint processing system according to the present embodiment. FIG. 2 is a block diagram showing the configuration of the fingerprint processing device of this embodiment. FIG. 3 is a flowchart showing the flow of the first fingerprint processing according to this embodiment. FIG. 4 shows an example of a fingerprint image. FIG. 5 shows an example of a fingerprint image. FIG. 6 is a flowchart showing the flow of the second fingerprint process of this embodiment. FIG. 7 shows an example of a fingerprint image and an identification target image displayed by the output device. FIG. 8 shows an example of a fingerprint image and an identification target image displayed by the output device. FIG. 9 shows an example of a fingerprint image and an identification target image displayed by the output device. FIG. 10 shows an example of a fingerprint image and an authentication target image displayed by the output device. FIG. 11 is a flowchart showing the flow of the third fingerprint process of this embodiment. FIG. 12 shows the same area of interest in the acquired fingerprint as in the fingerprint to be identified. FIG. 13 is a flowchart showing the flow of the fourth fingerprint process of this embodiment. FIG. 14 shows a display example in which an acquired fingerprint image is displayed in a display mode in which a target area and a non-target area can be distinguished from each other. FIG. 15 shows a display example in which an acquired fingerprint image is displayed in a display mode in which a target area and a non-target area can be distinguished from each other. FIG. 16 shows a display example in which an acquired fingerprint image is displayed in a display mode in which a target area and a non-target area can be distinguished. FIG. 17 is a block diagram showing the configuration of a fingerprint sensor according to a modified example.

Below, embodiments of a fingerprint processing device, a fingerprint processing method, and a computer program are described with reference to the drawings. Below, a fingerprint processing system SYS to which the embodiments of a fingerprint processing device, a fingerprint processing method, and a computer program are applied is described.

(1) Overview of the Fingerprint Processing System SYS The fingerprint processing system SYS performs a predetermined process using a fingerprint image in which a fingerprint is captured. To perform the predetermined process, the fingerprint processing system SYS typically extracts fingerprint features from a fingerprint image using a desired fingerprint feature extraction method. There are various fingerprint feature extraction methods. In this case, a fingerprint feature detected by a first fingerprint feature extraction method (hereinafter referred to as a "first feature") and a fingerprint feature extracted by a second fingerprint feature extraction method different from the first fingerprint feature extraction method (hereinafter referred to as a "second feature") may differ depending on the image properties of the original fingerprint image and the characteristics of the fingerprint feature extraction method. As a result, when the first feature and the second feature are compared, the similarity between the first and second features may not be sufficiently high even if the first and second features are extracted from fingerprint images taken from the same finger of the same person.

As an example, the fingerprint processing system SYS may perform a fingerprint authentication process to authenticate a user using a fingerprint image. In this case, when a fingerprint feature is extracted from a first fingerprint image using a first fingerprint feature extraction method in the fingerprint authentication process, a technical problem occurs in that the fingerprint authentication may be performed with a relatively high degree of accuracy, while when a fingerprint feature is extracted from the same first fingerprint image using a second fingerprint feature extraction method in the fingerprint authentication process, a technical problem occurs in that the fingerprint authentication may not be performed with a relatively high degree of accuracy. Conversely, when a fingerprint feature is extracted from a second fingerprint image having image characteristics different from those of the first fingerprint image using the first fingerprint feature extraction method, a technical problem occurs in that the fingerprint authentication may not be performed with a relatively high degree of accuracy, while when a fingerprint feature is extracted from the same second fingerprint image using the second fingerprint feature extraction method in the fingerprint authentication process, a technical problem occurs in that the fingerprint authentication may be performed with a relatively high degree of accuracy. One of the causes of such technical problems is that the fingerprint extraction method used in the fingerprint authentication process is usually tuned to match the image characteristics of the fingerprint image. As a result, a technical problem arises in that the accuracy of fingerprint authentication processing may vary depending on the combination of the type of fingerprint feature extraction method used in the fingerprint authentication processing and the image characteristics of the fingerprint image.

As another example, the fingerprint images may be used by an examiner performing fingerprint analysis. In this case, the first fingerprint image may be an image that the examiner is familiar with, while the second fingerprint image, which has different image characteristics from the first fingerprint image, may be an image that the examiner is not familiar with. As a result, a technical problem arises in that the efficiency of fingerprint analysis by the examiner may vary depending on the image characteristics of the fingerprint images.

Alternatively, as another example, the fingerprint image may be used by a fingerprint identification device (e.g., a computer) that performs fingerprint identification. In this case, the fingerprint identification device typically extracts fingerprint features from the fingerprint image using a desired fingerprint feature extraction method, and performs fingerprint identification using the extracted features. As a result, as in the case of fingerprint authentication, a technical problem occurs in that, depending on the fingerprint feature extraction method used to extract features from a fingerprint image, fingerprint features that are not suitable for the desired application may be extracted. As a result, a technical problem occurs in that, depending on the combination of the type of fingerprint feature extraction method used in fingerprint identification and the image characteristics of the fingerprint image, there may be variations in the accuracy of the fingerprint identification.

The fingerprint processing system SYS of this embodiment is capable of solving the technical problems described above. In other words, the fingerprint processing system SYS of this embodiment is a fingerprint processing system to which an embodiment of a fingerprint processing device, a fingerprint processing method, and a computer program capable of solving the technical problems described above is applied. The configuration and operation of such a fingerprint processing system SYS will be described below in order.

(2) Configuration of Fingerprint Processing System SYS First, the configuration of the fingerprint processing system SYS of this embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of the fingerprint processing system SYS of this embodiment.

As shown in FIG. 1, the fingerprint processing system SYS includes a fingerprint sensor 1 and a fingerprint processing device 2. The fingerprint sensor 1 and the fingerprint processing device 2 can communicate with each other via a communication network 3. The communication network 3 may include a wired communication network. The communication network 3 may include a wireless communication network.

The fingerprint sensor 1 is a detection device capable of detecting a fingerprint. In this embodiment, the fingerprint sensor 1 is a detection device capable of detecting the three-dimensional shape of a fingerprint (i.e., the three-dimensional shape of the unevenness of the finger surface and the three-dimensional shape of the ridges formed on the finger surface). The fingerprint sensor 1 is a detection device capable of detecting a fingerprint three-dimensionally. One example of such a fingerprint sensor 1 is a 3D scanner (i.e., a three-dimensional measuring device) that can optically detect the three-dimensional shape of a fingerprint.

The fingerprint sensor 1 detects a fingerprint and generates a fingerprint image IMG_3D that represents the detected fingerprint in a three-dimensional coordinate space. The fingerprint image IMG_3D may be, for example, point group data (so-called point cloud) that includes a plurality of points that indicate the positions of each part of the unevenness (e.g., ridges) on the surface of the finger in a three-dimensional coordinate space. The fingerprint image IMG_3D generated by the fingerprint sensor 1 is transmitted from the fingerprint sensor 1 to the fingerprint processing device 2 via the communication network 3.

However, the fingerprint sensor 1 does not have to be a detection device capable of detecting the three-dimensional shape of a fingerprint. For example, the fingerprint sensor 1 may be a detection device capable of detecting the two-dimensional shape of a fingerprint (i.e., the shape of the fingerprint's uneven pattern obtained by projecting the uneven pattern of the fingerprint's surface onto a specified plane). In this case, the fingerprint sensor 1 may detect the fingerprint and generate an image that represents the fingerprint in a two-dimensional coordinate plane.

The fingerprint processing device 2 receives the fingerprint image IMG_3D transmitted from the fingerprint sensor 1. The fingerprint processing device 2 uses the fingerprint image IMG_3D to perform desired processing related to the fingerprint. In the following description, the desired processing related to the fingerprint is referred to as "fingerprint processing."

The fingerprint processing device 2 may perform an image generation process for generating a fingerprint image IMG_2D from a fingerprint image IMG_3D as at least a part of the fingerprint processing. The operation of generating a fingerprint image IMG_2D from a fingerprint image IMG_3D may be considered equivalent to the operation of converting the fingerprint image IMG_3D into a fingerprint image IMG_2D. In this case, the image generation process may be referred to as an image conversion process.

The fingerprint image IMG_2D is an image that represents the fingerprint represented by the fingerprint image IMG_3D (i.e., the fingerprint captured in the fingerprint image IMG_3D) in a two-dimensional coordinate plane. In other words, the fingerprint image IMG_2D is an image that represents the fingerprint using a plurality of pixels (typically, a plurality of pixels distributed in a matrix) distributed in a two-dimensional coordinate plane. As described above, the fingerprint image IMG_3D is an image (e.g., point cloud data) that represents the fingerprint in a three-dimensional coordinate space. For this reason, the operation of generating the fingerprint image IMG_2D from the fingerprint image IMG_3D may be considered equivalent to the operation of converting three-dimensional data of the fingerprint into two-dimensional data of the fingerprint. The operation of generating the fingerprint image IMG_2D from the fingerprint image IMG_3D may be considered equivalent to the operation of calculating the shape of the fingerprint in the two-dimensional coordinate plane by projecting (in other words, projecting) the fingerprint represented in the three-dimensional coordinate space by the fingerprint image IMG_3D onto a specified plane.

Fingerprint image IMG_2D is further an image in which the fingerprint captured in fingerprint image IMG_3D is captured with desired image characteristics (in other words, tendency). In other words, fingerprint image IMG_2D is an image in which the captured fingerprint has desired image characteristics. The image characteristics of the fingerprint may include, for example, at least one of the brightness, saturation, luminance, resolution, and gradation of each part of the fingerprint (for example, each pixel that constitutes the fingerprint). The image characteristics of the fingerprint may include the number of pixels representing the fingerprint (so-called pixel count). The image characteristics of the fingerprint may include characteristics related to noise superimposed on the pixels representing the fingerprint. The image characteristics of the fingerprint may include characteristics related to the position of the fingerprint within the image.

In this embodiment, the image characteristics of a fingerprint may include characteristics that vary depending on the type of fingerprint detection method available for detecting a fingerprint. For example, examples of methods for detecting a fingerprint include at least one of the following: an ink imprinting method in which a fingerprint is collected by pressing a finger against ink; an optical detection method in which a fingerprint is detected by optically measuring the surface of a finger; a capacitance detection method in which a fingerprint is detected by measuring the capacitance between the surface of a finger and an electrode; an electric field detection method in which a fingerprint is detected by measuring the electric field generated when an electromagnetic wave injected into a finger from an electrode is emitted from the finger; a pressure sensing method in which a fingerprint is detected by measuring the pressure from a finger pressed against a detection surface; and a heat sensing method in which a fingerprint is detected by measuring the temperature of a finger pressed against a detection surface. In this case, the operation of generating a fingerprint image IMG_2D may include at least one of an operation of generating a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by an ink imprint method, an operation of generating a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by an optical detection method, an operation of generating a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by a capacitance detection method, an operation of generating a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by an electric field detection method, an operation of generating a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by a pressure sensitive method, and an operation of generating a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by a thermal sensitive method. The operation of generating the fingerprint image IMG_2D may include at least one of the following operations: generating a fingerprint image IMG_2D in which a fingerprint having image characteristics specific to the ink imprinting method is captured, generating a fingerprint image IMG_2D in which a fingerprint having image characteristics specific to the optical detection method is captured, generating a fingerprint image IMG_2D in which a fingerprint having image characteristics specific to the capacitance detection method is captured, generating a fingerprint image IMG_2D in which a fingerprint having image characteristics specific to the electric field detection method is captured, generating a fingerprint image IMG_2D in which a fingerprint having image characteristics specific to the pressure sensitive method is captured, and generating a fingerprint image IMG_2D in which a fingerprint having image characteristics specific to the thermal sensitive method is captured. In other words, the operation of generating the fingerprint image IMG_2D may include an operation of generating the same fingerprint image IMG_2D as an image representing a fingerprint detected by a desired fingerprint detection method (i.e., a fingerprint image IMG_2D in which a fingerprint having image characteristics specific to the desired fingerprint detection method is captured). The operation of generating the fingerprint image IMG_2D may include an operation of simulating or pseudo-generating the fingerprint image IMG_2D that would be generated if it were assumed that the fingerprint captured in the fingerprint image IMG_3D was detected using a desired fingerprint detection method.

The fingerprint processing device 2 may perform fingerprint authentication processing using a fingerprint captured in the fingerprint image IMG_2D as at least a part of the fingerprint processing. The fingerprint authentication processing may include processing for authenticating a person to be authenticated whose fingerprint is captured in the fingerprint image IMG_2D. To perform the fingerprint authentication processing, the fingerprint processing device 2 typically extracts fingerprint features from the fingerprint image IMG_2D using a desired fingerprint feature extraction method, and authenticates the person to be authenticated using the extracted fingerprint features.

The fingerprint processing device 2 may perform fingerprint identification processing using a fingerprint captured in the fingerprint image IMG_2D as at least a part of the fingerprint processing. The fingerprint identification processing may include processing to determine whether or not the fingerprint captured in the fingerprint image IMG_2D matches the fingerprint to be identified. As an example, the fingerprint identification processing may include processing to determine whether or not the fingerprint captured in the fingerprint image IMG_2D matches a latent fingerprint left at the crime scene. To perform the fingerprint identification processing, the fingerprint processing device 2 typically extracts fingerprint features from the fingerprint image IMG_2D using a desired fingerprint feature extraction method, and uses the extracted fingerprint features to determine whether or not the fingerprint captured in the fingerprint image IMG_2D matches a latent fingerprint left at the crime scene.

In addition, in the fingerprint authentication process, the fingerprint processing device 2 normally determines whether or not the fingerprint captured in the fingerprint image IMG_2D matches a fingerprint registered in a fingerprint database for fingerprint authentication. For this reason, the fingerprint identification process may be considered to be a process included in the fingerprint authentication process. In other words, in this embodiment, the fingerprint authentication process may include not only a process for authenticating a person whose fingerprint is captured in the fingerprint image IMG_2D, but also a process for determining whether or not the fingerprint captured in the fingerprint image IMG_2D matches the fingerprint to be identified.

The fingerprint processing device 2 may perform, as at least a part of the fingerprint processing, an identification support process that supports an examiner performing fingerprint identification using the fingerprint image IMG_2D. The identification support process may include a process for improving the efficiency of fingerprint identification by the examiner. The identification support process may include a process for improving the accuracy of fingerprint identification by the examiner. As an example, the identification support process may include a process for displaying a fingerprint captured in the fingerprint image IMG_2D and a fingerprint to be identified (e.g., a latent fingerprint left at a crime scene) side by side. As an example, the identification support process may include a process for displaying a fingerprint captured in the fingerprint image IMG_2D superimposed on a fingerprint to be identified (e.g., a latent fingerprint left at a crime scene).

The configuration of the fingerprint processing device 2 that performs fingerprint processing is shown in FIG. 2. As shown in FIG. 2, the fingerprint processing device 2 includes a calculation device 21, a storage device 22, and a communication device 23. Furthermore, the fingerprint processing device 2 may include an input device 24 and an output device 25. However, the fingerprint processing device 2 does not have to include at least one of the input device 24 and the output device 25. The calculation device 21, the storage device 22, the communication device 23, the input device 24, and the output device 25 may be connected via a data bus 26.

The arithmetic device 21 may include at least one of, for example, a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), an FPGA (Field Programmable Gate Array), a DSP (Demand-Side Platform), and an ASIC (Application Specific Integrated Circuit). A plurality of these may also be used in parallel. The arithmetic device 21 reads a computer program. For example, the arithmetic device 21 may read a computer program stored in the storage device 22. For example, the arithmetic device 21 may read a computer program stored in a computer-readable and non-transitory recording medium using a recording medium reading device (not shown). The arithmetic device 21 may acquire (i.e., download or read) a computer program from a device (not shown) disposed outside the fingerprint processing device 2 via the communication device 23. The arithmetic device 21 executes the read computer program. As a result, a logical functional block for executing the processing to be performed by the fingerprint processing device 2 (e.g., at least a part of the fingerprint processing) is realized within the arithmetic device 21. In other words, the arithmetic device 21 can function as a controller for realizing a logical functional block for executing the processing to be performed by the fingerprint processing device 2.

2 shows an example of a logical functional block realized in the calculation device 21 to execute at least a part of the fingerprint processing. As shown in FIG. 2, the calculation device 21 realizes an image acquisition unit 211, which is a specific example of an "acquisition means", an image generation unit 212, which is a specific example of a "generation means", an output control unit 213, which is a specific example of a "display means", and a fingerprint authentication unit 214. The image acquisition unit 211 acquires a fingerprint image IMG_3D from the fingerprint sensor 1 using the communication device 23. The image generation unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_3D acquired by the image acquisition unit 211. The output control unit 213 controls the output device 25 to output (e.g., display) the fingerprint image IMG_2D generated by the image generation unit 212. The fingerprint authentication unit 214 performs fingerprint authentication processing using the fingerprint image IMG_2D (or the fingerprint image IMG_3D) generated by the image generation unit 212.

The storage device 22 can store desired data. For example, the storage device 22 may temporarily store a computer program executed by the arithmetic device 21. The storage device 22 may temporarily store data that is temporarily used by the arithmetic device 21 when the arithmetic device 21 is executing a computer program. The storage device 22 may store data that is to be stored long-term by the fingerprint processing device 2. The storage device 22 may include at least one of a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device. In other words, the storage device 22 may include a non-temporary recording medium.

In this embodiment, the storage device 22 may store a fingerprint database (DB: DataBase) 221. The fingerprint database 221 is a database that stores data (information) related to fingerprints. For example, the fingerprint database 221 may store a fingerprint image IMG_3D generated by the fingerprint sensor 1. For example, the fingerprint database 221 may store a fingerprint image IMG_2D generated by the fingerprint processing device 2. For example, the fingerprint database 221 may store any fingerprint image (i.e., any image in which any fingerprint is captured).

The communication device 23 is capable of receiving information transmitted from the fingerprint sensor 1 via the communication network 3. In this embodiment, as described above, the communication device 23 is capable of receiving (i.e., acquiring) the fingerprint image IMG_3D transmitted from the fingerprint sensor 1.

The input device 24 is a device that accepts information input to the fingerprint processing device 2 from outside the fingerprint processing device 2. For example, the input device 24 may include an operation device (e.g., at least one of a keyboard, a mouse, and a touch panel) that can be operated by a user of the fingerprint processing device 2. For example, the input device 24 may include a reading device that can read information recorded as data on a recording medium that can be attached externally to the fingerprint processing device 2.

The fingerprint sensor 1 may be used as the input device 24 of the fingerprint processing device 2. For example, the fingerprint sensor 1 may be used as the input device 24 for inputting the fingerprint image IMG_3D to the fingerprint processing device 2.

The output device 25 is a device that outputs information to the outside of the fingerprint processing device 2. For example, the output device 25 may output information as an image. That is, the output device 25 may include a display device (so-called a display) capable of displaying an image showing the information to be output. For example, the output device 25 may output information as sound. That is, the output device 25 may include an audio output device (so-called a speaker) capable of outputting sound. For example, the output device 25 may output information on paper. That is, the output device 25 may include a printing device (so-called a printer) capable of printing desired information on paper.

(3) Specific examples of fingerprint processing performed by the fingerprint processing device 2 Next, specific examples of fingerprint processing performed by the fingerprint processing device 2 will be described. In this embodiment, the fingerprint processing device 2 may perform at least one of the first fingerprint processing to the fourth fingerprint processing. The first fingerprint processing to the fourth fingerprint processing will be described in order below.

(3-1) First Fingerprint Processing First, the first fingerprint processing will be described. The first fingerprint processing includes a first image generation processing for generating a fingerprint image IMG_2D from a fingerprint image IMG_3D based on the contents of a fingerprint feature extraction method used in the fingerprint authentication processing. For this reason, the fingerprint processing device 2 typically performs the first image generation processing when performing the fingerprint authentication processing. In other words, the fingerprint processing device 2 typically performs the first fingerprint processing including the first image generation processing and the fingerprint authentication processing. The flow of the first fingerprint processing will be described below with reference to FIG. 3. FIG. 3 is a flowchart showing the flow of the first fingerprint processing.

As shown in FIG. 3, the image acquisition unit 211 acquires a fingerprint image IMG_3D from the fingerprint sensor 1 using the communication device 23 (step S11). Note that the fingerprint image IMG_3D acquired in step S11 may be stored in the fingerprint database 221 stored in the storage device 22.

However, in step S11, the image acquisition unit 211 may acquire the fingerprint image IMG_3D from a device other than the fingerprint sensor 1. For example, the image acquisition unit 211 may acquire the fingerprint image IMG_3D from the storage device 22 (specifically, from the fingerprint database 221 stored in the storage device 22). For example, the image acquisition unit 211 may acquire the fingerprint image IMG_3D from a cloud server that can communicate with the fingerprint processing device 2 via the communication network 3. For example, the image acquisition unit 211 may acquire the fingerprint image IMG_3D input to the fingerprint processing device 2 via the input device 24.

Then, the image generating unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_3D acquired in step S11 (step S12). In the first fingerprint processing, the image generating unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_3D based on the content of the fingerprint feature extraction method used in the fingerprint authentication processing. Specifically, the content of the fingerprint feature extraction method is determined by the type of fingerprint authentication algorithm adopted by the fingerprint processing device 2 to perform the fingerprint authentication processing. Therefore, the image generating unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_3D based on the type of fingerprint authentication algorithm.

As an example, a fingerprint authentication algorithm is usually designed (or tuned) to extract fingerprint features from a fingerprint image in which a fingerprint detected by a specific fingerprint detection method is captured. In this case, the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by a specific fingerprint detection method corresponding to the fingerprint authentication algorithm. For example, when the fingerprint processing device 2 performs fingerprint authentication processing using a fingerprint authentication algorithm designed to extract fingerprint features from a fingerprint image in which a fingerprint detected by an ink imprinting method is captured, the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by the ink imprinting method (i.e., a fingerprint image IMG_2D in which a fingerprint is captured with image characteristics specific to the ink imprinting method). For example, when the fingerprint processing device 2 performs fingerprint authentication processing using a fingerprint authentication algorithm designed to extract fingerprint features from a fingerprint image that includes a fingerprint detected by an optical detection method, the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image that represents a fingerprint detected by an optical detection method (i.e., a fingerprint image IMG_2D that includes a fingerprint with image characteristics specific to optical detection).

In step S12, the image generating unit 212 may generate the fingerprint image IMG_2D using an image generation model that outputs the fingerprint image IMG_2D when the fingerprint image IMG_3D is input. An example of such an image generation model is an image generation model using a neural network. An example of an image generation model using a neural network is an image generation model using a GAN (Generative Adversarial Network). When the fingerprint image IMG_2D is generated using an image generation model using a neural network in this way, the image generating unit 212 may adjust the parameters of the neural network (e.g., at least one of the weight and bias) based on the contents of the fingerprint feature extraction method (e.g., the type of fingerprint authentication algorithm, and essentially, the type of fingerprint detection method corresponding to the fingerprint authentication algorithm). As a result, the image generating unit 212 can generate the fingerprint image IMG_2D corresponding to the fingerprint authentication algorithm relatively easily. However, the image generation unit 212 may generate the fingerprint image IMG_2D from the fingerprint image IMG_3D using any image generation method (or any image conversion method).

In step S12, the image generating unit 212 may generate a fingerprint image IMG_2D_real from the fingerprint image IMG_3D by faithfully projecting the three-dimensional shape of the fingerprint represented by the fingerprint image IMG_3D onto a predetermined plane. After that, the image generating unit 212 may generate a fingerprint image IMG_2D from the fingerprint image IMG_2D_real. The fingerprint image IMG_2D_real may be, for example, a binary image in which pixels corresponding to a region on a predetermined plane onto which the point cloud included in the fingerprint image IMG_3D is projected are either white pixels or black pixels, while pixels corresponding to a region on a predetermined plane onto which the point cloud included in the fingerprint image IMG_3D is not projected are either white pixels or black pixels. An example of the fingerprint image IMG_2D_real is shown in FIG. 4. On the other hand, an example of the fingerprint image IMG_2D is shown in FIG. 5. 5 shows an example of a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by the ink imprinting method (i.e., a fingerprint image IMG_2D that captures a fingerprint having image characteristics specific to the ink imprinting method). Alternatively, the image generating unit 212 may generate the fingerprint image IMG_2D directly from the fingerprint image IMG_3D. In other words, the image generating unit 212 may generate the fingerprint image IMG_2D from the fingerprint image IMG_3D without generating the fingerprint image IMG_2D_real.

The fingerprint image IMG_2D generated by the image generation unit 212 in step S12 may be stored in the fingerprint database 221 stored in the storage device 22. In addition, when the image generation unit 212 generates a fingerprint image IMG_2D_real, the fingerprint image IMG_2D_real generated by the image generation unit 212 may be stored in the fingerprint database 221 stored in the storage device 22.

Then, the fingerprint authentication unit 214 performs fingerprint authentication processing using the fingerprint image IMG_2D generated in step S12 (step S13).

As described above, the fingerprint authentication algorithm used by the fingerprint authentication unit 214 is designed to extract fingerprint features from a fingerprint image IMG_2D in which a fingerprint detected by a specific fingerprint detection method is captured. For this reason, the accuracy of a fingerprint authentication process performed using a fingerprint image IMG_2D in which a fingerprint detected by a specific fingerprint detection method is captured is usually higher than the accuracy of a fingerprint authentication process performed using a fingerprint image IMG_2D in which a fingerprint detected by a fingerprint detection method other than the specific fingerprint detection method is captured. For example, if a fingerprint authentication algorithm is designed to extract fingerprint features from a fingerprint image IMG_2D in which a fingerprint detected by an ink imprinting method is captured, the accuracy of a fingerprint authentication process performed using a fingerprint image IMG_2D in which a fingerprint detected by an ink imprinting method is captured is higher than the accuracy of a fingerprint authentication process performed using a fingerprint image IMG_2D in which a fingerprint detected by a fingerprint detection method other than the ink imprinting method (for example, an optical detection method) is captured.

Under such circumstances, in the first fingerprint processing, the image generating unit 212 generates a fingerprint image IMG_2D that is the same as the image representing a fingerprint detected by a specific fingerprint detection method corresponding to the fingerprint authentication algorithm. In other words, if the accuracy of the fingerprint authentication processing performed using the fingerprint image IMG_2D in which a fingerprint detected by the first fingerprint detection method is captured is higher than the accuracy of the fingerprint authentication processing performed using the fingerprint image IMG_2D in which a fingerprint detected by a second fingerprint detection method different from the first fingerprint detection method is captured, the image generating unit 212 generates the image in which the fingerprint detected by the first fingerprint detection method is captured as the fingerprint image IMG_2D. As a result, the fingerprint authentication unit 214 performs the fingerprint authentication processing using the fingerprint image IMG_2D that is the same as the image representing a fingerprint detected by a specific fingerprint detection method corresponding to the fingerprint authentication algorithm. Therefore, the accuracy of the fingerprint authentication processing is higher than when using the fingerprint image IMG_2D in which a fingerprint detected by a fingerprint detection method different from the specific fingerprint detection method corresponding to the fingerprint authentication algorithm.

In this way, according to the first fingerprint processing, a fingerprint image IMG_2D is generated based on the contents of the fingerprint feature extraction method. Therefore, according to the first fingerprint processing, it is possible to enjoy the effect of increasing the accuracy of the fingerprint authentication processing compared to a case where the fingerprint image IMG_2D is not generated based on the contents of the fingerprint feature extraction method. In other words, according to the first fingerprint processing, it is possible to enjoy the effect of increasing the accuracy of the fingerprint authentication processing compared to a case where the fingerprint authentication processing is performed using a fingerprint image IMG_2D_real in which the contents of the fingerprint feature extraction method are not taken into consideration at all (i.e., the type of a specific fingerprint detection method corresponding to the fingerprint authentication algorithm is not taken into consideration at all). In this way, according to the first fingerprint processing, a fingerprint image IMG_2D suitable for the application of fingerprint authentication processing (including fingerprint identification processing) is generated.

In addition, in the first fingerprint processing, the output control unit 213 does not have to control the output device 25 to output (e.g., display) the fingerprint image IMG_2D generated by the image generation unit 212. In this case, the calculation device 21 does not have to be equipped with the output control unit 213. Also, the fingerprint processing device 2 does not have to be equipped with the output device 25. However, the output control unit 213 may control the output device 25 to output (e.g., display) the fingerprint image IMG_2D generated by the image generation unit 212.

(3-2) Second Fingerprint Processing Next, the second fingerprint processing will be described. The second fingerprint processing includes a second image generation processing for generating a fingerprint image IMG_2D from a fingerprint image IMG_3D based on information about an examiner who performs fingerprint analysis using the fingerprint image IMG_2D. For this reason, the fingerprint processing device 2 typically performs the second image generation processing when an examiner performs fingerprint analysis. Also, as described above, when an examiner performs fingerprint analysis, the fingerprint processing device 2 may perform analysis support processing. For this reason, the fingerprint processing device 2 typically performs the second fingerprint processing including the second image generation processing and analysis support processing. Hereinafter, the flow of the second fingerprint processing will be described with reference to FIG. 6. FIG. 6 is a flowchart showing the flow of the second fingerprint processing. Note that the operations that have already been described will be given the same step numbers and detailed descriptions thereof will be omitted.

As shown in FIG. 6, in the second fingerprint process, as in the first fingerprint process, the image acquisition unit 211 acquires a fingerprint image IMG_3D (step S11).

Then, the image generating unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_3D acquired in step S11 (step S22). In the second fingerprint process, the image generating unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_3D based on information about the examiner.

The information on the examiner may include information on a fingerprint detection method corresponding to the examiner. The information on the fingerprint detection method corresponding to the examiner may include information on a fingerprint detection method preferred by the examiner. The fingerprint detection method preferred by the examiner may include a fingerprint detection method with which the examiner is familiar. The fingerprint detection method preferred by the examiner may include a fingerprint detection method that is often or normally used when the examiner performs fingerprint analysis. The fingerprint detection method preferred by the examiner may include a fingerprint detection method that is often used when the examiner performs fingerprint analysis. In this case, the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by a fingerprint detection method corresponding to the examiner. For example, if the ink imprinting method is preferred by the examiner (i.e., the examiner often performs fingerprint analysis using a fingerprint detected by the ink imprinting method), the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by the ink imprinting method (i.e., a fingerprint image IMG_2D in which a fingerprint is captured with image characteristics specific to the ink imprinting method). For example, if an examiner prefers an optical detection method (i.e., an examiner often performs fingerprint identification using a fingerprint detected by an optical detection method), the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by an optical detection method (i.e., a fingerprint image IMG_2D in which the fingerprint is captured with image characteristics unique to the optical detection method).

The image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by a specific fingerprint detection method that is preset as a fingerprint detection method corresponding to the examiner. For example, if an ink imprinting method is preset as a fingerprint detection method corresponding to the examiner, the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by the ink imprinting method. For example, if an optical detection method is preset as a fingerprint detection method corresponding to the examiner, the image generating unit 212 may generate a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by the optical detection method. In this case, the image generating unit 212 does not necessarily need to obtain information about the examiner (for example, information about the fingerprint detection method corresponding to the examiner) each time it generates a fingerprint image IMG_2D. Even if the image generating unit 212 does not acquire information about the examiner, as long as it generates a fingerprint image IMG_2D that is the same as an image representing a fingerprint detected by a specific fingerprint detection method that is preset as a fingerprint detection method corresponding to the examiner, it can be said that the image generating unit 212 generates a fingerprint image IMG_2D based on information about the examiner (e.g., information about the fingerprint detection method corresponding to the examiner).

The image generating unit 212 may obtain information on the fingerprint detection method corresponding to the examiner, and generate a fingerprint image IMG_2D based on the obtained information. For example, the image generating unit 212 may obtain information on the fingerprint detection method corresponding to the examiner based on an instruction from the examiner specifying the fingerprint detection method corresponding to the examiner. In this case, the examiner may specify the fingerprint detection method corresponding to the examiner using the input device 24. Alternatively, the image generating unit 212 may obtain identification information for identifying the examiner, and obtain information on the fingerprint detection method corresponding to the examiner from a table or the like that records the fingerprint detection method corresponding to the examiner based on the identification information. In this case, the image generating unit 212 may obtain a login ID or the like used when the examiner logs in to the fingerprint processing device 2 (or any information processing device used by the examiner for fingerprint analysis) as identification information for identifying the examiner.

In the second fingerprint processing, similarly to the first fingerprint processing, the image generating unit 212 may generate the fingerprint image IMG_2D using an image generation model (or any image generation method). The image generating unit 212 may generate a fingerprint image IMG_2D_real from the fingerprint image IMG_3D, and generate the fingerprint image IMG_2D from the fingerprint image IMG_2D_real. The image generating unit 212 may generate the fingerprint image IMG_2D directly from the fingerprint image IMG_3D. The fingerprint image IMG_2D generated by the image generating unit 212 in step S22 may be stored in the fingerprint database 221 stored in the storage device 22.

Then, the fingerprint processing device 2 performs an examination support process that supports the examiner in performing the fingerprint examination using the fingerprint image IMG_2D generated in step S22. Specifically, the output control unit 213 presents the fingerprint image IMG_2D generated in step S22 to the examiner (step S23). For example, the output control unit 213 controls the output device 25 to output (typically display) the fingerprint image IMG_2D generated in step S22. As a result, the examiner can recognize the fingerprint image IMG_2D output by the output device 25.

When performing fingerprint analysis, the examiner usually determines whether the fingerprint captured in the fingerprint image IMG_2D matches the fingerprint to be analyzed (for example, a latent fingerprint left at a crime scene, hereinafter referred to as the "fingerprint to be analyzed"). For this reason, the output control unit 213 may present the examiner with an image to be analyzed IMG_target, which is an image representing the fingerprint to be analyzed, in addition to or instead of the fingerprint image IMG_2D. For example, the output control unit 213 may control the output device 25 to output (typically display) the image to be analyzed IMG_target. As a result, the examiner can recognize the image to be analyzed IMG_target output by the output device 25. In other words, the examiner can determine whether the fingerprint captured in the fingerprint image IMG_2D matches the fingerprint to be analyzed captured in the image to be analyzed IMG_target by comparing the fingerprint image IMG_2D output by the output device 25 with the image to be analyzed IMG_target.

FIG. 7 shows an example of the display of fingerprint image IMG_2D and the target image IMG_target by the output device 25. As shown in FIG. 7, the output control unit 213 may control the output device 25 to display (i.e., output) the fingerprint image IMG_2D and the target image IMG_target side by side. As a result, the examiner can relatively easily compare the fingerprint image IMG_2D and the target image IMG_target.

The output control unit 213 may select at least one fingerprint image IMG_2D to be displayed by the output device 25 from among multiple fingerprint images IMG_2D in which the same fingerprint, each having different image characteristics, is captured, and control the output device 25 to display the selected at least one fingerprint image IMG_2D. For example, the output control unit 213 may select either a first fingerprint image IMG_2D that is the same as the image representing the fingerprint detected by the ink imprinting method, or a second fingerprint image IMG_2D that is the same as the image representing the fingerprint detected by the optical detection method, as the fingerprint image IMG_2D to be displayed by the output device 25, and control the output device 25 to display the selected fingerprint image IMG_2D.

In this case, the output control unit 213 may select at least one fingerprint image IMG_2D to be displayed by the output device 25 based on the examiner's instruction to specify the fingerprint image IMG_2D to be displayed by the output device 25. The examiner may input the examiner's instruction to specify the fingerprint image IMG_2D to be displayed by the output device 25 to the fingerprint processing device 2 using the input device 24. In addition, when the examiner's instruction to specify the fingerprint image IMG_2D to be displayed by the output device 25 is input, the output control unit 213 may control the output device 25 to display a GUI (Graphical User Interface) for the examiner to specify the fingerprint image IMG_2D to be displayed by the output device 25. For example, as shown in FIG. 8, the output control unit 213 may control the output device 25 to display a text box TXT in which the examiner can input text specifying the fingerprint image IMG_2D to be displayed by the output device 25. For example, as shown in FIG. 9, the output control unit 213 may control the output device 25 to display a button BTN that the examiner can press to switch the fingerprint image IMG_2D displayed by the output device 25.

As described above, when the image generating unit 212 generates a fingerprint image IMG_2D after generating a fingerprint image IMG_2D_real, the output control unit 213 may control the output device 25 to display the fingerprint image IMG_2D_real in addition to the fingerprint image IMG_2D. As a result, the examiner can recognize the fingerprint image IMG_2D_real output by the output device 25. Furthermore, the examiner can perform fingerprint identification while also referring to the fingerprint image IMG_2D_real.

When the fingerprint image IMG_2D_real is displayed in addition to the fingerprint image IMG_2D, the output control unit 213 may control the output device 25 to display a composite image IMG_COM obtained by combining the fingerprint image IMG_2D and the fingerprint image IMG_2D_real. The composite image IMG_COM may be, for example, as shown in FIG. 10, an image in which an area in which the fingerprint image IMG_2D represents a part of the fingerprint and an area in which the fingerprint image IMG_2D_real represents a part of the remaining fingerprint are adjacent to each other across a boundary BD set in the composite image IMG_COM. In this case, the examiner may use the input device 24 to change the position of the boundary BD in the composite image IMG_COM. As a result, the proportion of the fingerprint image IMG_2D to the composite image IMG_COM and the proportion of the fingerprint image IMG_2D_real to the composite image IMG_COM change. In other words, the part of the fingerprint represented by the fingerprint image IMG_2D and the part of the fingerprint represented by the fingerprint image IMG_2D_real change.

In this way, according to the second fingerprint processing, a fingerprint image IMG_2D is generated based on information about the examiner (particularly, information about the fingerprint detection method corresponding to the examiner). As a result, a fingerprint image IMG_2D is generated in which a fingerprint having image characteristics corresponding to the examiner (for example, a fingerprint with an appearance familiar to the examiner) is captured. Therefore, according to the second fingerprint processing, it is possible to enjoy the effect of increasing the efficiency of fingerprint identification by the examiner compared to a case in which the fingerprint image IMG_2D is not generated based on information about the examiner. In other words, according to the second fingerprint processing, it is possible to enjoy the effect of increasing the efficiency of fingerprint identification by the examiner compared to a case in which the examiner performs fingerprint identification using a fingerprint image IMG_2D that represents a fingerprint detected by a fingerprint detection method different from the fingerprint detection method corresponding to the examiner. In other words, according to the second fingerprint processing, it is possible to enjoy the effect of increasing the efficiency of fingerprint identification by the examiner compared to a case in which fingerprint identification is performed using a fingerprint image IMG_2D that does not take into account any information about the examiner (i.e., the type of fingerprint detection method corresponding to the examiner is not taken into account at all). Therefore, in the second fingerprint processing, in effect, if the efficiency of fingerprint analysis performed by an expert using a fingerprint image IMG_2D that includes a fingerprint detected using the first fingerprint detection method is higher than the efficiency of fingerprint analysis performed by an expert using a fingerprint image IMG_2D that includes a fingerprint detected using a second fingerprint detection method that is different from the first fingerprint detection method, then the image generating unit 212 can be said to generate an image that includes a fingerprint detected using the first fingerprint detection method as the fingerprint image IMG_2D. In this way, according to the second fingerprint processing, a fingerprint image IMG_2D that is suitable for use in fingerprint analysis by an expert is generated.

On the other hand, the results of fingerprint analysis are used for various purposes. For example, the results of fingerprint analysis may be used as evidence in court. In this case, in order to increase the credibility of the results of fingerprint analysis, the results of fingerprint analysis may include, instead of fingerprint image IMG_2D, a fingerprint image IMG_2D_real obtained by faithfully projecting the three-dimensional shape of the fingerprint represented by fingerprint image IMG_3D onto a specified plane. This is because fingerprint image IMG_2D is considered by the court to be an image that has been subjected to a certain amount of processing, and as a result, the credibility of fingerprint image IMG_2D as evidence may be considered by the court to be lower than the credibility of fingerprint image IMG_2D_real as evidence.

In addition, in the second fingerprint process, the fingerprint authentication unit 214 does not have to perform the fingerprint authentication process. In this case, the computing device 21 does not have to be equipped with the fingerprint authentication unit 214. However, the fingerprint authentication unit 214 may perform the fingerprint authentication process.

(3-3) Third Fingerprint Processing Next, the third fingerprint processing will be described. The third fingerprint processing includes a third image generation processing for generating a fingerprint image IMG_2D from a fingerprint image IMG_3D based on information on the fingerprint to be identified that is captured in the identification target image IMG_target. For this reason, the fingerprint processing device 2 typically performs the third image generation processing when at least one of the fingerprint processing device 2 and an examiner performs fingerprint identification. When the third image generation processing is performed under a situation in which the fingerprint processing device 2 performs fingerprint identification, the fingerprint processing device 2 may typically perform the third fingerprint processing including the third image generation processing and a fingerprint identification processing. When the third image generation processing is performed under a situation in which an examiner performs fingerprint identification, the fingerprint processing device 2 may typically perform the third fingerprint processing including the third image generation processing and an identification support processing. Hereinafter, the flow of the third fingerprint processing will be described with reference to FIG. 11. FIG. 11 is a flowchart showing the flow of the third fingerprint processing.

As shown in FIG. 11, the image acquisition unit 211 acquires the target image IMG_target in which the target fingerprint is captured (step S31). For example, if the target image IMG_target is stored in the fingerprint database 221 stored in the storage device 22, the image acquisition unit 211 may acquire the target image IMG_target from the fingerprint database 221 stored in the storage device 22. For example, the image acquisition unit 211 may acquire the target image IMG_target from a cloud server that can communicate with the fingerprint processing device 2 via the communication network 3. For example, the image acquisition unit 211 may acquire the target image IMG_target input to the fingerprint processing device 2 via the input device 24.

Then, the image generating unit 212 extracts feature points of the identification target image IMG_target acquired in step S31 (step S32). Specifically, the image generating unit 212 extracts features of the identification target fingerprint reflected in the identification target image IMG_target acquired in step S11 (step S32). In this embodiment, as an example, the image generating unit 212 extracts feature points of the identification target fingerprint reflected in the identification target image IMG_target as the features of the identification target fingerprint. For example, the image generating unit 212 may extract points where ridges of the identification target fingerprint are cut (these points may be referred to as "end points") as feature points. For example, the image generating unit 212 may extract points where ridges of the identification target fingerprint are branched (these points may be referred to as "branch points") as feature points. For example, the image generating unit 212 may extract a point where the ridges of the fingerprint to be analyzed join (this point may be referred to as a "joining point") as a feature point.

In parallel with or before or after the processing from step S31 to step S32, the image acquisition unit 211 acquires a fingerprint image IMG_3D (step S11). After that, the image generation unit 212 generates a fingerprint image IMG_2D_real from the fingerprint image IMG_3D acquired in step S11 (step S33). After that, the image generation unit 212 extracts features of the fingerprint image IMG_2D_real generated in step S33 (step S34). Specifically, the image generation unit 212 extracts features of the fingerprint (hereinafter referred to as the "acquired fingerprint") that appears in the fingerprint image IMG_2D_real generated in step S33 (step S34). In this embodiment, as an example, the image generation unit 212 extracts feature points of the acquired fingerprint as features of the acquired fingerprint. For example, the image generation unit 212 may extract points where ridges of the acquired fingerprint are cut (these points may be referred to as "end points") as feature points. For example, the image generating unit 212 may extract a point where the ridges of the acquired fingerprint branch off (this point may be referred to as a "branching point") as a feature point. For example, the image generating unit 212 may extract a point where the ridges of the acquired fingerprint join (this point may be referred to as a "joining point") as a feature point.

Then, the image generating unit 212 calculates a portion of interest in the acquired fingerprint that corresponds to the fingerprint to be identified (typically the same portion as the portion of the fingerprint to be identified) based on the feature points of the fingerprint to be identified extracted in step S32 and the feature points of the acquired fingerprint extracted in step S34 (step S35). For example, as shown in Fig. 12, the image generating unit 212 may calculate the portion of interest by performing pattern matching to compare the distribution pattern of the feature points of the fingerprint to be identified with the distribution pattern of the feature points of the acquired fingerprint.

Then, the image generating unit 212 regenerates the fingerprint image IMG_2D_real (step S36). Specifically, the image generating unit 212 generates a fingerprint image IMG_2D_real in which the part of interest calculated in step S35 is reflected in the same orientation as the fingerprint to be identified (step S36). For example, if the fingerprint to be identified is collected under a condition in which the finger is pressed in a direction facing the pressing surface against which the finger is presumed to be pressed, the image generating unit 212 may generate a fingerprint image IMG_2D_real in which the part of interest of the acquired fingerprint that is presumed to be collected when the finger having the acquired fingerprint is pressed in a direction facing the pressing surface is reflected. For example, if the fingerprint to be analyzed is collected under conditions in which the finger is pressed at a predetermined angle relative to the pressing surface against which the finger is presumed to be pressed, the image generating unit 212 may generate a fingerprint image IMG_2D_real that includes a portion of interest in the acquired fingerprint that is presumed to be collected when the finger having the acquired fingerprint is pressed at the same predetermined angle relative to the pressing surface.

The degree of correspondence between the orientation of the fingerprint to be identified and the orientation of the acquired fingerprint including the portion of interest may be considered to be equivalent to the degree of correspondence between the distribution pattern of the minutiae of the fingerprint to be identified and the distribution pattern of the minutiae of the acquired fingerprint. For this reason, the image generating unit 212 may generate a fingerprint image IMG_2D_real in which the acquired fingerprint (particularly the portion of interest) is captured in the same orientation as the fingerprint to be identified by image transforming (e.g., translating, enlarging, reducing, and/or rotating) at least a portion of the acquired fingerprint so that the distribution pattern of the minutiae of the acquired fingerprint becomes the same as the distribution pattern of the minutiae of the fingerprint to be identified.

The fingerprint image IMG_2D_real generated in step S36 may be an image in which the portion of interest in the acquired fingerprint is captured, but a portion of the acquired fingerprint other than the portion of interest is not captured. Alternatively, the fingerprint image IMG_2D_real generated in step S36 may be an image in which the portion of interest in the acquired fingerprint is captured, and a portion of the acquired fingerprint other than the portion of interest is captured. The fingerprint image IMG_2D_real generated in step S36 may be stored in the fingerprint database 221 stored in the storage device 22.

Then, the image generating unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_2D_real generated in step S36 (step S37). Note that the process of generating the fingerprint image IMG_2D in step S37 may be the same as the process of generating the fingerprint image IMG_2D in step S22 of FIG. 6. That is, in step S37 of FIG. 11, the image generating unit 212 may generate the fingerprint image IMG_2D based on information about the examiner performing the fingerprint analysis (for example, information about the type of fingerprint detection method preferred by the examiner).

Then, the fingerprint processing device 2 performs an authentication support process using the fingerprint image IMG_2D generated in step S37 (step S38). For example, the fingerprint processing device 2 (particularly the output control unit 213) may perform an authentication support process that controls the output device 25 to output the fingerprint image IMG_2D, similar to the second fingerprint process. In this case, the authentication support process performed in step S38 may be the same as the authentication support process performed in step S23 of FIG. 6.

Alternatively, in step S38, the fingerprint processing device 2 may use the fingerprint image IMG_2D generated in step S37 to perform a fingerprint identification process in addition to or instead of the identification support process. For example, the fingerprint processing device 2 may perform a fingerprint identification process using the acquired fingerprint captured in the fingerprint image IMG_2D. That is, the fingerprint processing device 2 may perform a fingerprint identification process to determine whether the acquired fingerprint captured in the fingerprint image IMG_2D matches the fingerprint to be identified captured in the identification target image IMG_target. In this case, the process of generating the fingerprint image IMG_2D in step S37 may be the same as the process of generating the fingerprint image IMG_2D in step S12 of FIG. 3. That is, in step S37 of FIG. 11, the image generating unit 212 may generate the fingerprint image IMG_2D based on the contents of the fingerprint authentication process (for example, the type of fingerprint authentication algorithm).

However, the fingerprint processing device 2 may perform the identification support process (or the fingerprint identification process) using the fingerprint image IMG_2D_real generated in step S36 in addition to or instead of the fingerprint image IMG_2D generated in step S37. Furthermore, not only when the third fingerprint process is performed, the fingerprint processing device 2 may perform the identification support process (or the fingerprint identification process) using the fingerprint image IMG_2D_real in addition to or instead of the fingerprint image IMG_2D. Similarly, the fingerprint processing device 2 may perform the fingerprint authentication process using the fingerprint image IMG_2D_real in addition to or instead of the fingerprint image IMG_2D.

In this way, the third fingerprint processing generates a fingerprint image IMG_2D in which a portion of the acquired fingerprint that corresponds to a portion of the fingerprint to be identified is captured in the same orientation as the fingerprint to be identified. As a result, an examiner can use the fingerprint image IMG_2D to compare the fingerprint to be identified that is captured in the target image IMG_target with a portion of the acquired fingerprint that corresponds to a portion of the fingerprint to be identified that is captured in the fingerprint image IMG_2D in the same orientation as the fingerprint to be identified. As a result, the third fingerprint processing has the effect of increasing the efficiency of fingerprint identification by an examiner. In this way, the third fingerprint processing generates a fingerprint image IMG_2D that is suitable for use in fingerprint identification by an examiner.

When the output device 25 is equipped with a projection device (so-called projector), the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D generated in step S37 of FIG. 11 onto a projection surface on which the fingerprint to be identified is captured. For example, the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D onto a projection surface that is a paper surface on which the fingerprint to be identified is drawn (or printed). For example, the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D onto a projection surface that is a display surface of a display device on which the fingerprint to be identified is displayed. For example, the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D onto a projection surface that is a projection screen on which the fingerprint to be identified is projected. Alternatively, the output control unit 213 may display the fingerprint image IMG_2D generated in step S37 of Fig. 11 superimposed on the target image IMG_target in which the target fingerprint is captured. For example, the output control unit 213 may display the fingerprint image IMG_2D and the target image IMG_target superimposed so that the acquired fingerprint (particularly, the portion of interest) is superimposed on the target fingerprint (particularly, the portion corresponding to the portion of interest).

In the above description, the image generating unit 212 generates a fingerprint image IMG_2D_real in which the portion of interest in the acquired fingerprint is captured in the same orientation as the fingerprint to be identified in step S36 of FIG. 11. However, if the acquired fingerprint can be redetected, the fingerprint processing device 2 may redetect the acquired fingerprint using the fingerprint sensor 1. Specifically, the fingerprint processing device 2 may use the output device 25 (or any other output device) to notify the subject of the fingerprint redetection that the fingerprint will be redetected using the fingerprint sensor 1. At this time, the fingerprint processing device 2 may instruct the subject of the fingerprint redetection on the orientation of the finger at the time of redetection so that the fingerprint can be redetected in the same orientation as the fingerprint to be identified. Thereafter, the fingerprint processing device 2 may redetect the fingerprint using the fingerprint sensor 1. In particular, the fingerprint processing device 2 may redetect the portion of interest in the fingerprint using the fingerprint sensor 1. As a result, the fingerprint sensor 1 generates a fingerprint image IMG_3D in which the portion of interest in the fingerprint is captured in the same orientation as the fingerprint to be identified. In this case, the fingerprint processing device 2 may generate the fingerprint image IMG_2D directly from the fingerprint image IMG_3D. The fingerprint image IMG_2D generated in this manner is an image in which the part of interest in the acquired fingerprint is captured in the same orientation as the fingerprint to be identified.

(3-4) Fourth Fingerprint Processing Next, the fourth fingerprint processing will be described. The fourth fingerprint processing includes an image display processing for displaying the fingerprint image IMG_2D in such a manner that a portion of interest corresponding to a portion of a fingerprint to be identified among acquired fingerprints captured in the fingerprint image IMG_2D can be distinguished from a portion of the acquired fingerprint captured in the fingerprint image IMG_2D that is different from the portion of interest (hereinafter, the portion different from the portion of interest is referred to as a "non-part of interest"). The displayed fingerprint image IMG_2D may typically be referred to by an examiner when the examiner performs fingerprint identification. For this reason, the fingerprint processing device 2 typically performs an image display processing when the examiner performs fingerprint identification. In this case, the fingerprint processing device 2 may perform the image display processing as at least a part of the identification support processing. Hereinafter, the flow of the fourth fingerprint processing will be described with reference to FIG. 13. FIG. 13 is a flowchart showing the flow of the fourth fingerprint processing.

As shown in FIG. 13, in the fourth fingerprint process, as in the third fingerprint process, the image acquisition unit 211 acquires an identification target image IMG_target in which the identification target fingerprint appears (step S31). After that, the image generation unit 212 extracts feature points of the identification target image IMG_target acquired in step S31 (step S32).

In parallel with or before or after the processing of steps S31 and S32, the image acquisition unit 211 acquires a fingerprint image IMG_3D (step S11). After that, the image generation unit 212 generates a fingerprint image IMG_2D from the fingerprint image IMG_3D acquired in step S11 (step S43). The process of generating the fingerprint image IMG_2D in step S43 may be the same as the process of generating the fingerprint image IMG_2D in step S22 of FIG. 6. That is, in step S43 of FIG. 13, the image generation unit 212 may generate the fingerprint image IMG_2D based on information about the examiner performing the fingerprint analysis (for example, information about the type of fingerprint detection method preferred by the examiner). However, in step S43, the image generation unit 212 may generate a fingerprint image IMG_2D_real, as in the third fingerprint process.

Then, the image generating unit 212 extracts feature points of the fingerprint image IMG_2D generated in step S43 (step S44). Note that the process of extracting feature points of the fingerprint image IMG_2D in step S44 may be the same as the process of extracting feature points of the fingerprint image IMG_2D_real in step S34 of FIG. 11. In other words, the image generating unit 212 extracts feature points of the acquired fingerprint that are captured in the fingerprint image IMG_2D generated in step S43.

Then, the image generating unit 212 calculates a portion of the acquired fingerprint that corresponds to the fingerprint to be identified (typically the same portion as the portion of the fingerprint to be identified) based on the feature points of the fingerprint to be identified extracted in step S32 and the feature points of the acquired fingerprint extracted in step S44 (step S45). Note that the process of calculating the portion of interest of the acquired fingerprint in step S45 may be the same as the process of calculating the portion of interest of the acquired fingerprint in step S35 of FIG. 11.

Thereafter, the output control unit 213 controls the output device 25 to display the fingerprint image IMG_2D in a display mode in which the part of interest in the acquired fingerprint and the non-interest part different from the part of interest in the acquired fingerprint are visually distinguishable (step S46). For example, as shown in FIG. 14, the output control unit 213 may control the output device 25 to display the fingerprint image IMG_2D together with a frame F surrounding the part of interest. In this case, the part of interest and the non-interest part are visually distinguishable by the frame F. For example, as shown in FIG. 15, the output control unit 213 may control the output device 25 to display a fingerprint image IMG_2D in which the ridges in the part of interest are shown by a first type of line (solid lines in the example shown in FIG. 15), while the ridges in the non-interest part are shown by a second type of line different from the first type (dotted lines in the example shown in FIG. 15). In this case, the part of interest and the non-interest part are distinguishable by the type of line showing the ridges. For example, as shown in FIG. 16, the output control unit 213 may control the output device 25 to display a fingerprint image IMG_2D that includes a region of interest but does not include a region of non-interest. In this case, the region of interest and the region of non-interest can be distinguished by whether or not the region is displayed.

In this way, according to the fourth fingerprint processing, the fingerprint image IMG_2D is displayed in such a manner that the portion of the acquired fingerprint that corresponds to the portion of the fingerprint to be identified and the portion of the acquired fingerprint that is not of interest and that is different from the portion of interest can be distinguished. As a result, the examiner can use the fingerprint image IMG_2D to compare the fingerprint to be identified that appears in the target image IMG_target with the portion of the acquired fingerprint that corresponds to the portion of the fingerprint to be identified that appears in the fingerprint image IMG_2D. As a result, according to the fourth fingerprint processing, it is possible to enjoy the effect of increasing the efficiency of fingerprint identification by the examiner. In this way, according to the fourth fingerprint processing, a fingerprint image IMG_2D that is suitable for the purpose of fingerprint identification by an examiner is generated.

When the output device 25 is equipped with a projection device (so-called projector), the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D (particularly, the image related to the part of interest calculated in step S45 of FIG. 13) generated in step S43 of FIG. 13 onto a projection surface on which the fingerprint to be identified is captured. For example, the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D (particularly, the image related to the part of interest) onto a projection surface that is a paper surface on which the fingerprint to be identified is drawn (or printed). For example, the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D (particularly, the image related to the part of interest) onto a projection surface that is a display surface of a display device on which the fingerprint to be identified is displayed. For example, the output control unit 213 may control the output device 25 to project the fingerprint image IMG_2D (particularly, the image related to the part of interest) onto a projection surface that is a projection screen on which the fingerprint to be identified is projected. Alternatively, the output control unit 213 may display the fingerprint image IMG_2D generated in step S43 of FIG. 13 (particularly, the image relating to the portion of interest calculated in step S45 of FIG. 13) superimposed on the target image IMG_target in which the fingerprint to be identified is captured. For example, the output control unit 213 may display the fingerprint image IMG_2D and the target image IMG_target superimposed so that the acquired fingerprint (particularly, the portion of interest) is superimposed on the fingerprint to be identified (particularly, the portion corresponding to the portion of interest).

(4) Modification In the above description, the fingerprint processing device 2 generates the fingerprint image IMG_2D from the fingerprint image IMG_3D generated by the fingerprint sensor 1. However, the fingerprint sensor 1 may generate the fingerprint image IMG_2D from the fingerprint image IMG_3D generated by the fingerprint sensor 1. That is, as shown in FIG. 17, the fingerprint sensor 1 may include a calculation device 11, and a processing block (e.g., an image generation unit 212) for generating the fingerprint image IMG_2D from the fingerprint image IMG_3D may be realized inside the calculation device 11. In this case, the fingerprint sensor 1 may transmit the fingerprint image IMG_2D to the fingerprint processing device 2 in addition to or instead of the fingerprint image IMG_3D. The fingerprint processing device 2 may perform fingerprint authentication processing using the fingerprint image IMG_2D.

In the above description, the fingerprint sensor 1 and the fingerprint processing device 2 are separate devices. However, the fingerprint sensor 1 and the fingerprint processing device 2 may be integrated. In other words, the fingerprint processing device 2 may include the fingerprint sensor 1 as a part of the components of the fingerprint processing device 2.

(5) Supplementary Notes The following supplementary notes are further disclosed with respect to the embodiment described above.
[Appendix 1]
an acquisition means for acquiring a first fingerprint image representing a fingerprint in a three-dimensional coordinate space;
a generating means for generating, from the first fingerprint image, a second fingerprint image which represents the fingerprint in a two-dimensional coordinate plane and in which the fingerprint is captured with desired image characteristics.
[Appendix 2]
and an authentication unit that extracts fingerprint features from the second fingerprint image by using a desired fingerprint feature extraction method and performs fingerprint authentication processing using the extracted fingerprint features.
The fingerprint processing device according to claim 1, wherein the generating means generates the second fingerprint image from the first fingerprint image based on the content of the fingerprint feature extraction method.
[Appendix 3]
The fingerprint processing device described in Appendix 2, wherein when the accuracy of the fingerprint authentication processing performed using the features extracted by the desired fingerprint feature extraction method from an image containing the fingerprint detected using a first fingerprint detection method is higher than the accuracy of the fingerprint authentication processing performed using the features extracted by the desired fingerprint feature extraction method from an image containing the fingerprint detected using a second fingerprint detection method different from the first fingerprint detection method, the generation means generates the image containing the fingerprint detected using the first fingerprint detection method as the second fingerprint image.
[Appendix 4]
providing the second fingerprint image to a fingerprint examiner;
The fingerprint processing device according to any one of claims 1 to 3, wherein the generating means generates the second fingerprint image from the first fingerprint image based on information about the examiner.
[Appendix 5]
The information about the examiner includes information about a fingerprint detection method corresponding to the examiner,
The fingerprint processing device according to claim 4, wherein the generating means generates, as the second fingerprint image, an image in which the fingerprint detected by the fingerprint detection method corresponding to the examiner is captured.
[Appendix 6]
The fingerprint processing device described in Appendix 4 or 5, wherein if the efficiency of the fingerprint analysis performed by the examiner using an image containing the fingerprint detected using a first fingerprint detection method is higher than the efficiency of the fingerprint analysis performed by the examiner using an image containing the fingerprint detected using a second fingerprint detection method different from the first fingerprint detection method, the generation means generates the image containing the fingerprint detected using the first fingerprint detection method as the second fingerprint image.
[Appendix 7]
a first fingerprint is captured in each of the first and second fingerprint images;
The fingerprint processing device according to any one of claims 1 to 6, wherein the generation means generates the second fingerprint image from the first fingerprint image based on fingerprint information regarding a second fingerprint that appears in a third fingerprint image different from the first fingerprint image.
[Appendix 8]
The fingerprint processing device according to claim 7, wherein the generating means generates, as the second fingerprint image, an image in which a portion of the first fingerprint that corresponds to a portion of the second fingerprint is captured in the same orientation as the second fingerprint.
[Appendix 9]
the generating means generates an image including the fingerprint detected using a desired fingerprint detection method as the second fingerprint image;
The fingerprint processing device according to any one of appendixes 1 to 8, wherein the image characteristics include characteristics that change depending on the type of the fingerprint detection method.
[Appendix 10]
The fingerprint processing device according to any one of claims 1 to 9, further comprising a display means for displaying the second fingerprint image in which the fingerprint is captured in a manner that allows a first portion of the fingerprint to be distinguished from a second portion of the fingerprint that is different from the first portion.
[Appendix 11]
a first fingerprint is captured in each of the first and second fingerprint images;
11. The fingerprint processing device according to claim 10, wherein the first portion of the first fingerprint includes a portion corresponding to a portion of a second fingerprint that appears in a third fingerprint image different from the first fingerprint image.
[Appendix 12]
a first fingerprint is captured in each of the first and second fingerprint images;
The fingerprint authentication device according to claim 10 or 11, further comprising a projection means capable of projecting the second fingerprint image onto a projection surface on which the second fingerprint is captured.
[Appendix 13]
an acquisition means for acquiring a fingerprint image representative of a fingerprint;
a display means for displaying the fingerprint image in which the fingerprint is captured in a manner that allows a first portion of the fingerprint and a second portion of the fingerprint that is different from the first portion to be distinguished from each other.
[Appendix 14]
a first fingerprint is captured in the fingerprint image;
14. The fingerprint processing device according to claim 13, wherein the first portion of the first fingerprint includes a portion corresponding to a portion of a second fingerprint that appears in another fingerprint image different from the fingerprint image.
[Appendix 15]
obtaining a first fingerprint image representing the fingerprint in three-dimensional coordinate space;
generating, from said first fingerprint image, a second fingerprint image which represents said fingerprint in a two-dimensional coordinate plane and in which said fingerprint is captured with desired image characteristics;
[Appendix 16]
obtaining a fingerprint image representative of a fingerprint;
displaying the fingerprint image in which the fingerprint is captured such that a first portion of the fingerprint can be distinguished from a second portion of the fingerprint.
[Appendix 17]
obtaining a first fingerprint image representing the fingerprint in three-dimensional coordinate space;
a second fingerprint image that represents the fingerprint in a two-dimensional coordinate plane and captures the fingerprint with desired image characteristics from the first fingerprint image;
[Appendix 18]
obtaining a fingerprint image representative of a fingerprint;
a fingerprint image including a first portion of the fingerprint and a second portion of the fingerprint that are distinguishable from each other;
[Appendix 19]
obtaining a first fingerprint image representing the fingerprint in three-dimensional coordinate space;
A recording medium having a computer program recorded thereon that causes a computer to execute a fingerprint processing method for generating, from the first fingerprint image, a second fingerprint image that represents the fingerprint in a two-dimensional coordinate plane and in which the fingerprint is captured with desired image characteristics.
[Appendix 20]
obtaining a fingerprint image representative of a fingerprint;
a fingerprint image in which the fingerprint is captured in a manner that allows a first portion of the fingerprint to be distinguished from a second portion of the fingerprint;

This disclosure may be modified as appropriate within the scope of the claims and the entire specification without violating the gist or concept of this disclosure, and the fingerprint processing device, fingerprint processing method, computer program, and recording medium that incorporate such modifications are also included in the technical concept of this disclosure.

SYS Fingerprint processing system 1 Fingerprint sensor 2 Fingerprint processing device 21 Arithmetic unit 211 Image acquisition unit 212 Image generation unit 213 Output control unit 214 Fingerprint authentication unit 22 Storage device 221 Fingerprint database IMG_3D Fingerprint image IMG_2D Fingerprint image IMG_2D_real Fingerprint image IMG_target Image to be identified

Claims (5)

an acquisition means for acquiring a first fingerprint image representing a fingerprint in a three-dimensional coordinate space;
a generating means for generating a second fingerprint image from the first fingerprint image, the second fingerprint image representing the fingerprint in a two-dimensional coordinate plane and including the fingerprint with desired image characteristics ;
an authentication means for extracting fingerprint features from the second fingerprint image by using a desired fingerprint feature extraction method and performing fingerprint authentication processing using the extracted features;
Equipped with
when the accuracy of the fingerprint authentication process performed using the features extracted by the desired fingerprint feature extraction method from an image into which the fingerprint detected using a first fingerprint detection method appears is higher than the accuracy of the fingerprint authentication process performed using the features extracted by the desired fingerprint feature extraction method from an image into which the fingerprint detected using a second fingerprint detection method different from the first fingerprint detection method appears, the generation means generates the image into which the fingerprint detected using the first fingerprint detection method appears as the second fingerprint image,
providing the second fingerprint image to a fingerprint examiner;
the generating means generates, as the second fingerprint image, an image in which the fingerprint detected by the fingerprint detection method corresponding to the examiner is captured;
The fingerprint detection method includes at least one of an ink imprinting method for capturing a fingerprint by pressing a finger against ink, an optical detection method for detecting a fingerprint by optically measuring the surface of a finger, a capacitance detection method for detecting a fingerprint by measuring the capacitance between the surface of a finger and an electrode, an electric field detection method for detecting a fingerprint by measuring an electric field generated when an electromagnetic wave injected into a finger from an electrode is emitted from the finger, a pressure sensing method for detecting a fingerprint by measuring the pressure from a finger pressed against a detection surface, and a heat sensing method for detecting a fingerprint by measuring the temperature of a finger pressed against a detection surface.
Fingerprint processing device. 2. The fingerprint processing device of claim 1, wherein when the efficiency of the fingerprint analysis performed by the examiner using an image containing the fingerprint detected using a first fingerprint detection method is higher than the efficiency of the fingerprint analysis performed by the examiner using an image containing the fingerprint detected using a second fingerprint detection method different from the first fingerprint detection method, the generation means generates the image containing the fingerprint detected using the first fingerprint detection method as the second fingerprint image. a first fingerprint is captured in each of the first and second fingerprint images;
3. The fingerprint processing device according to claim 1, wherein the generating means generates, as the second fingerprint image, an image in which a portion of the first fingerprint that corresponds to a portion of a second fingerprint that appears in a third fingerprint image different from the first fingerprint image is reflected in the same orientation as the second fingerprint. acquiring a first fingerprint image representing the fingerprint in three-dimensional coordinate space;
generating a second fingerprint image from the first fingerprint image, the second fingerprint image representing the fingerprint in a two-dimensional coordinate plane and including the fingerprint with desired image characteristics ;
extracting fingerprint features from the second fingerprint image using a desired fingerprint feature extraction method, and performing fingerprint authentication processing using the extracted fingerprint features.
Including,
generating, as the second fingerprint image, the image containing the fingerprint detected using the first fingerprint detection method, when the accuracy of the fingerprint authentication process performed using the features extracted by the desired fingerprint feature extraction method from an image containing the fingerprint detected using a first fingerprint detection method is higher than the accuracy of the fingerprint authentication process performed using the features extracted by the desired fingerprint feature extraction method from an image containing the fingerprint detected using a second fingerprint detection method different from the first fingerprint detection method;
The second fingerprint image is provided to an examiner who performs fingerprint identification, and an image in which the fingerprint detected by a fingerprint detection method corresponding to the examiner is captured is generated as the second fingerprint image, and the fingerprint detection method includes at least one of an ink imprinting method in which a fingerprint is collected by pressing a finger against ink, an optical detection method in which a fingerprint is detected by optically measuring the surface of a finger, a capacitance detection method in which a fingerprint is detected by measuring the capacitance between the surface of a finger and an electrode, an electric field detection method in which a fingerprint is detected by measuring an electric field generated when an electromagnetic wave injected into a finger from an electrode is emitted from the finger, a pressure sensing method in which a fingerprint is detected by measuring the pressure from a finger pressed against a detection surface, and a heat sensing method in which a fingerprint is detected by measuring the temperature of a finger pressed against a detection surface.
A fingerprint processing method using a fingerprint processing device . acquiring a first fingerprint image representing the fingerprint in three-dimensional coordinate space;
generating a second fingerprint image from the first fingerprint image, the second fingerprint image representing the fingerprint in a two-dimensional coordinate plane and including the fingerprint with desired image characteristics ;
extracting fingerprint features from the second fingerprint image using a desired fingerprint feature extraction method, and performing fingerprint authentication processing using the extracted fingerprint features.
Including,
generating, as the second fingerprint image, the image containing the fingerprint detected using the first fingerprint detection method, when the accuracy of the fingerprint authentication process performed using the features extracted by the desired fingerprint feature extraction method from an image containing the fingerprint detected using a first fingerprint detection method is higher than the accuracy of the fingerprint authentication process performed using the features extracted by the desired fingerprint feature extraction method from an image containing the fingerprint detected using a second fingerprint detection method different from the first fingerprint detection method;
The second fingerprint image is provided to an examiner who performs fingerprint identification, and an image in which the fingerprint detected by a fingerprint detection method corresponding to the examiner is captured is generated as the second fingerprint image, and the fingerprint detection method includes at least one of an ink imprinting method in which a fingerprint is collected by pressing a finger against ink, an optical detection method in which a fingerprint is detected by optically measuring the surface of a finger, a capacitance detection method in which a fingerprint is detected by measuring the capacitance between the surface of a finger and an electrode, an electric field detection method in which a fingerprint is detected by measuring an electric field generated when an electromagnetic wave injected into a finger from an electrode is emitted from the finger, a pressure sensing method in which a fingerprint is detected by measuring the pressure from a finger pressed against a detection surface, and a heat sensing method in which a fingerprint is detected by measuring the temperature of a finger pressed against a detection surface.
A computer program causing a computer to execute a fingerprint processing method.

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