JP3250461B2 - Imprint fingerprint image input device and input method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fingerprint collating apparatus for identifying an individual using a fingerprint, which is a collection of sweat glands on the surface of a finger of a human body, and more particularly to inputting a fingerprint image up to the side of a finger into a computer or the like. Fingerprint image input device and input method for the same.

[0002]

2. Description of the Related Art An impression fingerprint including a fingerprint up to the side of a finger is
In the old days, it was collected by applying ink to a finger and pressing one side of the finger on the paper, and then rotating the finger on the paper until the other side touches the paper. However, this classical method requires a separate digitization operation to mechanically process the imprinted fingerprint.
Therefore, various fingerprint image input devices have been proposed in which an imprinted fingerprint image can be obtained at the sampling stage.

[0003] In most cases, the input of an imprinted fingerprint image used in conventional fingerprint collation focuses on the difference in the reflectance due to the unevenness of the fingerprint, and obtains the unevenness of the fingerprint as a grayscale image by receiving the light reflected by the finger. In inputting an imprint fingerprint image including a fingerprint up to the side of the finger, most of the methods take in an image when the finger is rotated on the finger rest.

For example, referring to FIG. 20, a fingerprint image input device in a conventional typical fingerprint collation device has a light projecting unit 171 using white light as a light source and a total reflection condition at a contact surface with a finger. A prism 172 for reflecting the white light incident from the light projecting unit 171 to the light source, and an image sensor 173 for receiving the reflected light from the prism 172 to obtain a fingerprint image (for example, Japanese Patent Application Laid-Open No. 54-85600). .

That is, when a finger is not in contact with the prism 172, the white light incident from the light projecting unit 171 is totally reflected by the upper surface of the prism 172, and the image obtained by the image sensor 173 becomes a bright image over the entire surface. . When a finger is pressed against the upper surface of the prism 172 during fingerprint input, the skin is not in contact with the prism 172 at the convex portion of the fingerprint, so that the condition of total reflection is not satisfied, and the amount of white light from the light projecting unit 171 is large. A part will be absorbed by the skin and a part will be reflected by the contact surface. On the other hand, since the skin and the prism 172 are not in contact with each other in the fingerprint concave portion, the total reflection condition is satisfied, and the white light from the light projecting unit 171 is totally reflected by the contact surface and input to the image sensor 173. Will be. As a result, the concave portions of the fingerprint are bright and the convex portions are dark, and a fingerprint image with contrast is obtained.

[0006] When collecting an imprint fingerprint including the side of the finger, the finger is rotated on the prism 172, and image data is recorded for each area where the finger is in contact with the prism 172, and the entire area is recorded. A method of synthesizing an imprint fingerprint image from each image data after rotating, or a method of always collecting images of the entire area on the prism 172 at a fixed time interval and recording the maximum value of the image data at each interval. A stamped fingerprint is input by a method such as forming a stamped fingerprint image (for example, US Pat. No. 5,233,404).

As an example of collecting a fingerprint near the side surface of a finger, a finger is placed on the inner surface of a transparent body whose inner surface and outer surface are curved so as to form a concentric cylinder, and the finger is placed from the outer surface of the transparent body toward the inner surface. A technique of inputting a fingerprint image by moving an illuminator that irradiates light and an image sensor that receives light reflected from the inner surface of the transparent body along the outer circumference of the transparent body has also been proposed (for example, Japanese Patent Laid-Open No. 2-146991). No.).

[0008]

As a technique for collecting a fingerprint including the side surface of a finger, the above-mentioned technique has been known, but a transparent body which is curved so that the inner and outer surfaces are concentric cylinders is used. With this technique, it is difficult to collect a fingerprint over a wide area on the side of the finger. This is because although the inner surface is curved, only a small area of the side surface portion contacts the inner surface when the finger is placed on the inner surface, and the contact pressure is reduced. Therefore, it is basically unsuitable for input of an imprint fingerprint including a fingerprint up to a wide area on the side surface of the finger.

On the other hand, in the technique of inputting a fingerprint image by rotating a finger on a prism, a large sampling area as large as a classic method of collecting a fingerprint by rotating an inked finger on a sheet of paper is used. Can be secured. However,
This method has the following problems.

(1) The input fingerprint image may be discontinuous or the image may be blurred. The reason is that the finger slips when the finger is pressed against the prism and rotated. (2) The density of the input fingerprint image is likely to be uneven.
The reason is that the act of rotating the finger is artificial, and the pressure applied during rotation of the finger changes. (3) A blank area may be generated in the input fingerprint image. The reason is that, since the finger is artificially rotated, the rotation of the finger and the timing of image capturing by the input device cannot be synchronized.

SUMMARY OF THE INVENTION It is an object of the present invention to enable a fingerprint of a wide area on the side of a finger to be accurately input so as not to cause blurring of an image, uneven shading, or a blank area. It is in.

[0012]

According to a first aspect of the present invention, there is provided an imprinted fingerprint image input device comprising: a contact surface between a light incident surface and a finger; and a derivation surface for deriving a light beam incident from the incident surface and reflected by the contact surface. Integrated with a transparent polyhedron having a planar light source for irradiating the transparent polyhedron with light rays from the incident surface, and a two-dimensional image sensor for receiving reflected light derived from the derived surface and converting the reflected light intensity into an electric signal. Unit and the transparent
Finger with the contact surface of the light polyhedron fixed for fingerprint collection
The contact surface at a plurality of predetermined angles.
Set and detect each and measure the shape of the fixed finger
Measuring means, and the shape of the finger measured by the measuring means
The contact pressure between the contact surface and the finger based on the shape
While the position of the unit until reaching the said contact surface of the transparent polyhedra via the ball of the finger from a position in contact with one side surface of the fixed finger contact with the other side surface position
A drive unit for moving a predetermined distance at a time, and a control unit for converting an electric signal from the two-dimensional image sensor into digital image data for each position of the unit, taking in the digital image data, and synthesizing an imprint fingerprint image therefrom. It is characterized by the following.

[0013]

In another configuration, the control section converts the electric signals from all the light receiving elements of the two-dimensional image sensor obtained at the initial position of the unit into digital image data, When an electric signal is obtained from the two-dimensional image sensor at a later position of the unit, the electric signals of all the light receiving elements are converted into digital image data, and then the digital image recorded in the internal memory is obtained. It is characterized in that the data and the value are compared in pixel units, and the larger value is left in the internal memory.

[0015]

In the imprint fingerprint image input method according to the present invention, a transparent polyhedron having a contact surface between a light incident surface and a finger and a derivation surface for deriving a light beam incident from the incident surface and reflected by the contact surface is derived. The contact surface is fixed for fingerprinting
The contact surface with a finger at a predetermined angle
Each time set and detected, the shape of the fixed finger
A first step of measuring the transparent polyhedron, a planar light source for irradiating light from the incident surface to the transparent polyhedron,
And a unit in which a two-dimensional image sensor that receives reflected light derived from the derived surface and converts the reflected light intensity into an electric signal is integrated with a finger on which the contact surface of the transparent polyhedron is fixed for collecting a fingerprint. A second step of moving to a position in contact with one side of the unit with a certain contact pressure, and corresponding to a rectangular area in the contact surface of the electric signal from the two-dimensional image sensor determined by the current position of the unit. A third step of converting only the electric signal of the light receiving element to be converted into digital image data and recording the digital image data;
It is determined whether or not the contact surface of the transparent polyhedron has been moved until it reaches a position in contact with the other side surface of the finger, and if not moved, the process proceeds to the following fifth step. A fourth step for moving to a sixth step described below, and a finger shape determined in the first step.
The contact pressure between the contact surface of the transparent polyhedron and the finger
While maintaining the unit constant, the unit is oriented in a direction in which the contact surface reaches a position in contact with the other side surface via the pad of a finger.
A fifth step of moving the position of the unit by a predetermined distance and returning to the third step; and a sixth step of combining the digital image data recorded at each position of the unit to synthesize an imprint fingerprint image. It is characterized by including.

In another imprinted fingerprint image input method of the present invention, a contact surface between a light incident surface and a finger and a derivation surface for deriving a light beam incident from the incident surface and reflected by the contact surface are derived. The contact surface of the transparent polyhedron having a fingerprint
The position of contact with the finger fixed to the
Detected by setting each to a plurality of angles, the fixed
A first step of measuring the shape of a finger, the transparent polyhedron, a planar light source for irradiating a light beam from the incident surface to the transparent polyhedron, and receiving reflected light derived from the derivation surface and measuring reflected light intensity. A unit in which a two-dimensional image sensor for converting into a signal is integrated is moved to an initial position in which the contact surface of the transparent polyhedron comes in contact with one side of a finger fixed for fingerprint acquisition with a certain contact pressure. a second step, a third step of recording in the internal memory the electrical signals from all the light receiving elements of the two-dimensional image sensor is converted into digital image data when the unit is positioned in the initial position, the first Determined in one step
The contact between the contact surface of the transparent polyhedron and the finger is determined based on the shape of the finger.
While keeping the contact pressure almost constant, in the direction in which the contact surface reaches a position in contact with the other side surface via the pad of the finger.
Wherein moving the position of the unit by a predetermined distance a
4 and steps to convert the electrical signals from all the light receiving elements of the two-dimensional image sensor after the movement of the unit according to the steps of the fourth to the digital image data, and the digital image data recorded in the internal memory compares the values for each pixel, a fifth leaving the larger value in the internal memory
And determining whether or not the unit has been moved until the contact surface of the transparent polyhedron reaches a position in contact with the other side surface of the finger.
Returns to fourth step, a seventh below if you have moved
A sixth step of operation proceeds to the step for, characterized in that it comprises a seventh step of the inked fingerprint image digital image data recorded in the internal memory.

In the imprinted fingerprint image input apparatus and the input method of the present invention configured as described above, the transparent polyhedron and the finger using the fiber collecting member in which the light emitted by the planar light source bundles a large number of optical fibers are used. The light reflected from the contact surface is directly imaged by the two-dimensional image sensor without passing through an optical system such as a lens.
The unit in which the planar light source, the transparent polyhedron, and the two-dimensional image sensor are integrated is one step by the driving unit such that the contact surface of the transparent polyhedron contacts the fixed finger with almost constant pressure and without slipping. It is moved by one. At each position of the unit, the control unit captures an image of each rectangular area of the contact surface of the transparent polyhedron in contact with the finger and combines them to form an imprint fingerprint image, or the contact surface of the transparent polyhedron Each time, the whole area including the area in contact with the finger and the area not in contact with the finger is imaged, and the maximum pixel value of each pixel is recorded to form an imprint fingerprint image. As described above, by making the pressure on the finger in contact with the contact surface of the transparent polyhedron substantially constant, it is possible to obtain an imprinted fingerprint image having a uniform density, and the transparent polyhedron can be formed without slipping the contact surface with the finger. Since the image is rotated around the finger, the images between the rectangular area images do not become discontinuous, and even when the image data values are compared and the maximum value is recorded, the images are not blurred and blurred. Further, the finger is fixed, the unit including the transparent polyhedron is moved around the finger, and the fingerprint area of the finger pressed against the contact surface is imaged at each position. Will not be out of position,
Blank areas can be eliminated.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram of an imprint fingerprint image input device according to one embodiment of the present invention. Referring to FIG. 1, the imprinted fingerprint image input device of the present embodiment includes a light incident surface 2a, a contact surface 2b between a finger, and a derivation surface 2c for deriving a light beam incident from the incident surface 2a and reflected by the contact surface 2b. Transparent polyhedron 2, L
A flat light source 1 that irradiates a light beam having a uniform illuminance (for example, a parallel light beam) into the inside of the transparent polyhedron 2 from the incident surface 2a using the ED or the like as a light source, and receives and reflects reflected light derived from the derived surface 2c of the transparent polyhedron 2 C to convert light intensity into electric signal
A unit U in which a two-dimensional image sensor 3 such as a CD is integrated, and a drive unit that rotates the unit U by one step around a finger fixed on a finger fixing base 6 for collecting a fingerprint to be stamped. And a control unit 5 for converting an electric signal from the two-dimensional image sensor 3 for each position of the unit U into digital image data and taking in the digital image data, and forming an imprint fingerprint image from the digital image data for each step. I have.

Here, the transparent polyhedron 2 in this embodiment
Is composed of a fiber collecting member in which a large number of optical fibers are bundled. One end of the optical fiber in the longitudinal direction is a contact surface 2b, the other end is a lead-out surface 2c, and a side orthogonal to the optical fiber is an incident surface 2a. I have.

Next, a more detailed configuration and operation of the embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is an explanatory view of the positional relationship between the optical fibers constituting the transparent polyhedron 2 and the light receiving elements constituting the two-dimensional image sensor 2. As shown in the figure, a cross section of a fiber collecting member in which optical fibers are regularly collected is exposed on a contact surface 2b of the transparent polyhedron 2 with which a finger contacts. The optical fiber in a certain area 21 of the contact surface 2b is connected to a light receiving element 31 corresponding to the area 21 on the two-dimensional image sensor 3, and the light receiving element 31 detects reflected light in the area 21. It has become.

FIG. 3 is a side view of the connection between the optical fiber constituting the transparent polyhedron 2 and the light receiving element constituting the two-dimensional image sensor 3 as viewed from the lateral direction. As shown in the figure, the end of the optical fiber on the side of the lead-out surface 2c is cut vertically and connected to the light receiving element 31 vertically. On the other hand, the end of the optical fiber on the side of the contact surface 2b is cut obliquely, and a group of the cut surfaces forms the contact surface 2b. From the incident surface 2a of the transparent polyhedron 2, light rays enter the cut surfaces of all the optical fibers forming the contact surface 2b by the planar light source 1, and among these optical fibers,
Since the total reflection condition is not satisfied at the cut surface of the optical fiber in contact with the convex portion of the fingerprint on the contact surface 2b, the incident light is scattered. On the other hand, the cut surface of the optical fiber in contact with the concave portion of the fingerprint satisfies the condition of total reflection, the incident light is totally reflected, and propagates in the optical fiber in the direction of the output surface 2c.

FIG. 4 focuses on one optical fiber 22 constituting the transparent polyhedron 2, and a light beam incident from the planar light source 1 is applied to a cut surface forming a part of the contact surface 2 b of the optical fiber 22. 2 shows that light is totally reflected, and the reflected light propagates through the optical fiber 22 and enters the light receiving element 31. That is, the light beam totally reflected by the cut surface of the optical fiber 22 in contact with the concave portion of the fingerprint of the finger placed on the contact surface 2b enters the light receiving element 31 while repeating total reflection on the wall inside the optical fiber 22.

In the two-dimensional image sensor 3, each light receiving element converts the reflected light into an electric signal proportional to the intensity of the reflected light by photoelectric conversion, and sends it to the control unit 5. The control unit 5 converts the electric signal from each light receiving element into digital image data (for example, density image data in which each pixel has a gradation from 0 to 125).
And stored in the internal memory 50 having a storage area corresponding to each light receiving element of the two-dimensional image sensor 3 on a one-to-one basis.

The unit U, in which the planar light source 1, the transparent polyhedron 2, and the two-dimensional image sensor 3 are integrated, moves to the next imaging position after completing the fingerprint image at a certain position. Is moved to the next position by one step by the drive unit 4 controlled by the controller.

FIG. 5 shows an example of possible positions of the unit U. The illustration of the planar light source 1 and the two-dimensional image sensor 3 is omitted, and only the positional relationship between the transparent polyhedron 2 and the finger 7 is shown. . FIG. 2A shows a state in which the unit U is positioned at a position where the contact surface 2b of the transparent polyhedron 2 contacts one side surface of the finger 7 fixed for fingerprint collection with a certain contact pressure. In this state, since the left area of the contact surface 2b is pressed against one side of the finger 7, a fingerprint near the one side of the finger 7 can be collected. FIG. 2B is a view similar to FIG.
3 shows the positional relationship between the transparent polyhedron 2 and the finger 7 after the unit U at the position of (1) has been moved by one step. In this state,
Since the central region of the contact surface 2b is pressed against the belly of the finger 7, the fingerprint of the belly of the finger 7 can be collected. FIG. 3C shows that the unit U at the position shown in FIG.
The positional relationship between the transparent polyhedron 2 and the finger 7 after the step movement is shown. In this state, since the area on the right side of the contact surface 2b is pressed against the other side of the finger 7, a fingerprint near the other side of the finger 7 can be collected.

From the position shown in FIG. 5A to the position shown in FIG.
When the unit U is moved from the position (b) to the position (c), the unit is moved between the transparent polyhedron 2 and the finger 7 in order to prevent the fingerprint image from being discontinuous or blurred. It is important that no slip occur. That is, for example, in the state of FIG. 5A, when a certain part 51 of the finger 7 shown in FIG. 5A contacts a certain part 52 on the contact surface 2b, the finger 7 in the state of FIG. Even when the point 51 is in contact with the contact surface 2b, the contact position must be the same point 52. The same applies when the unit U is moved from the position (b) to the position (c). Also, in order to avoid uneven density of the fingerprint image, FIG.
It is desired that the contact pressure applied to the finger 7 of the transparent polyhedron 2 be substantially equal in each of the states (b) and (c).

Although the unit U is moved from the initial position to the final position in two steps in the example of FIG. 5, it is needless to say that the unit U may be moved to the final position in a larger number of steps. is there.

An example of the configuration of the drive unit 4 that drives the unit U so as to satisfy the above conditions will be described later. Next, an impression fingerprint image is formed from images taken at each position of the unit U. The method will be described with reference to FIGS. First, the forming method shown in FIG. 6 will be described.

FIG. 6 shows, for each position of the unit U, of the light receiving element corresponding to a rectangular area in the contact surface 2b predetermined for each position of the unit U in the electric signal from the two-dimensional image sensor 3. A method of converting only an electric signal into digital image data and recording the digital image data, and finally combining the digital image data at each position to synthesize an imprint fingerprint image will be described. FIG. 6 shows an example in which the fingerprint image 9 on the contact surface 2b of the transparent polyhedron 2 is imaged in three regions, but this is for matching with the example in FIG. Needless to say, an image may be taken.

The rectangular area 91 in FIG. 6 is the first imaging area. When the unit U is at the position shown in FIG. 5A, the control unit 5 controls only the rectangular area 91 located on the left side of the contact surface 2b. Digital image data of two-dimensional image sensor 3
Is generated by selecting from the output of. The control unit 5
When the image data of the rectangular area 91 is recorded in the internal memory 50, a control signal for moving the unit U by one step is sent to the drive unit 4.

The rectangular area 92 shown in FIG. 6 is the second image pickup area, and when the unit U is at the position shown in FIG. 5B, the control unit 5 operates in a portion of the rectangular area 92 located at the center of the contact surface 2b. The digital image data is generated by selecting only digital image data from the output of the two-dimensional image sensor 3. Control unit 5
Sends the control signal to the drive unit 4 to move the unit U by one step when the image data of the rectangular area 92 is recorded in the internal memory 50.

The rectangular area 93 in FIG. 6 is the third imaging area, and when the unit U is at the position shown in FIG. 5C, the control unit 5 operates the part of the rectangular area 93 located on the right side of the contact surface 2b. The digital image data is generated by selecting only digital image data from the output of the two-dimensional image sensor 3. Control unit 5
When the image data of the rectangular area 93 is recorded in the internal memory 50, the unit U has been moved to the final position.
The image data of the rectangular areas 91, 92, and 93 are combined (joined) and recorded in the internal memory 50 as the fingerprint combined image 10 of FIG. The fingerprint composite image 10 becomes the collected fingerprint image.

FIG. 8 is a flowchart showing a processing example of the control section 5 when the method for forming an imprint fingerprint image described in FIG. 6 is employed. First, the control unit 5 sends a control signal for moving the unit U to an initial position where the contact surface 2b of the transparent polyhedron 2 contacts one side surface of the finger to the driving unit 4, and moves the unit U to the initial position. (Step S81). next,
The control unit 5 includes a contact surface 2b corresponding to the current position of the unit U among the electric signals detected by the two-dimensional image sensor 3.
An electric signal for each pixel corresponding to the intensity of the reflected light from the rectangular area 91 is fetched, the electric signal is converted into digital image data, and recorded in the internal memory 50 as digital image data of the rectangular area 91 (step S82). ).
Next, the control unit 5 determines whether or not the unit U has been moved to the final position (Step S83). Here, whether or not the control signal has been moved to the final position is determined by the number of control signals transmitted after transmitting the movement to the initial position to the drive unit 4. In the example of FIG. 5, if the control signal is transmitted twice. It is determined that it has been moved to the final position. In this example, since the unit U has not been moved to the final position, the control unit 5 outputs a control signal for moving the unit U by one step to the driving unit 4 and returns to step S82 to image the next rectangular area 92. The digital image data is stored in the internal memory 50. Hereinafter, similarly, the digital image data of the next rectangular area 93 is recorded in the internal memory 50, and the digital image data of the rectangular areas 91, 92, and 93 at the respective positions up to the final position of the unit U are obtained. These are combined to form an imprint fingerprint image (step S85), and the control related to the current imprint fingerprint collection ends.

Next, the method of forming an imprint fingerprint image shown in FIG. 7 will be described.

FIG. 7 shows that the electric signal from the two-dimensional image sensor 3 obtained at the initial position of the unit U is converted into digital image data and recorded in the internal memory 50. When an electric signal is obtained from the image sensor 3, the electric signal is converted into digital image data, and the digital image data recorded in the internal memory 50 is compared with a value in pixel units. This is a method of forming an imprint fingerprint image by leaving the image. FIG. 7 shows an example in which the contact surface 2b of the transparent polyhedron 2 is imaged three times. However, this is for the purpose of matching with the example in FIG. 5, and it goes without saying that imaging may be performed more times. is there.

The frame 11 shown in FIG. 7 is the first captured image. When the unit U is at the position shown in FIG. 5A, the control unit 5 converts the digital image data of the entire area of the contact surface 2b into a two-dimensional image. It is generated from the output of the image sensor 3. In this example, since the location of the contact area 111 is touching a finger, digital image data including a fingerprint image of the location is obtained. In the case of the first imaging, the control unit 5
Records the obtained digital image data in the internal memory 50 as it is. As a result, as shown in FIG.
Is recorded. Next, the control unit 5 sends a control signal to the drive unit 4 to move the unit U by one step.

The frame 12 in FIG. 7 is a second captured image. When the unit U is at the position shown in FIG. 5B, the control unit 5 converts the digital image data of the entire area of the contact surface 2b into a two-dimensional image. It is generated from the output of the sensor 3. In this example, since the position of the contact area 121 is touching a finger, digital image data including a fingerprint image of the portion is obtained. In the case of the second or subsequent imaging, unlike the first imaging, the pixel values of the digital image data obtained this time and the digital image data already recorded in the internal memory 50 are compared in pixel units, and the pixel values are compared. The larger value is left in the internal memory 50. As a result, the digital image data in the internal memory 50 is an image in which the image data 14 and the frame 12 are combined like the image data 15 in FIG. When the control unit 5 generates the image data 15 by comparing the image data 14 and the frame 12, the control unit 5 sends a control signal for moving the unit U by one step further.
To send to.

The frame 13 in FIG. 7 is the third captured image. When the unit U is at the position shown in FIG. 5C, the control unit 5 converts the digital image data of the entire area of the contact surface 2b into a two-dimensional image. It is generated from the output of the sensor 3. In this example, since the portion of the contact area 131 is touching a finger, digital image data including a fingerprint image of the portion is obtained. In the case of the third imaging, similarly to the second imaging, the pixel value of the digital image data obtained this time is compared with the digital image data already recorded in the internal memory 50 in pixel units, and the pixel value is large. One is left in the internal memory 50. As a result, the internal memory 50
The digital image data therein is an image obtained by combining the image data 15 and the frame 13 like the image data 16 in FIG. Then, the image data 16 becomes the collected impression fingerprint image.

FIG. 9 is a flowchart showing a processing example of the control unit 5 in the case where the imprint fingerprint image forming method described with reference to FIG. 7 is employed. First, the control unit 5 sends a control signal for moving the unit U to an initial position where the contact surface 2b of the transparent polyhedron 2 contacts one side surface of the finger to the driving unit 4, and moves the unit U to the initial position. (Step S91). next,
The control unit 5 captures an electric signal for each pixel corresponding to the intensity of the reflected light from the entire area of the contact surface 2b of the transparent polyhedron 2 detected by the two-dimensional image sensor 3, converts the electric signal into digital image data. To the internal memory 50 (step S92). Then, the control unit 5 controls the unit U
Is output to the drive unit 4 to move the unit 1 by one step (step S9).
3). Then, an electric signal for each pixel corresponding to the intensity of the reflected light from the entire area of the contact surface 2b of the transparent polyhedron 2 is taken in, the electric signal is converted into digital image data, and the digital image data recorded in the internal memory 50 is stored. And the pixel value is compared for each pixel, and the larger pixel value is left in the internal memory 50 (step S94). Next, the controller 5 determines whether or not the unit U has been moved to the final position (step S95). If the unit U has not been moved to the final position, the process returns to step S93. The same processing is performed. On the other hand, if it has been moved to the final position, the digital image data recorded in the internal memory 50 is taken as the collected fingerprint image, and the control relating to the current collection of the fingerprint is ended.

Next, an example of the configuration of the driving section 4 for driving the unit U will be described.

FIG. 10 is an external perspective view showing an example of the configuration of the driving section 4, and FIG. 11 is a side view seen from the direction of arrow A in FIG. As shown in FIGS. 10 and 11, two guide bars 101a,
102 a, 101 b, and 102 b are provided, and are loosely inserted into guide lines 103 opened on support plates 104 and 105 erected on the drive unit 4. The driving unit 4
Is provided with a lever 107 that is moved back and forth along a groove 106 by a motor (not shown), and a tip of the lever 107 is rotatably supported by a shaft 108 attached to the lower surface of the planar light source 1. . This lever 107 is
The cylinder 107a moving back and forth along the line 06 and the cylinder 1
The shaft 107 b is loosely inserted into the shaft 107 a, and the tip of the shaft 107 b is attached to the shaft 108. The position of the unit U shown in FIGS. 10 and 11 is shown in FIG.
It corresponds to the state of. From this position, the lever 107 is moved as shown in FIG.
Move to the right, the shaft 107 of the lever 107
b pulls the lower end of the unit U rightward in FIG. 10 while slightly sinking. Unit U has guide bars 101a, 102a, 101b loosely inserted into guide line 103,
102b, the unit U satisfies the guidelines 10
3 and the distance between the guide bars 101a and 102a (the distance between the guide bars 101b and 102b is
And the distance between the contact surfaces 102a and 102a) and changes the direction of the contact surface 2b. Here, the shape of the guide line 103 and the guide bars 101a, 102
The interval between a, 101b, and 102b is such that, for a standard finger, the contact surface 2b of the transparent polyhedron 2 is in contact with one side of the finger 7 fixed for fingerprint collection via the belly of the finger. Unit U until it reaches the position where it touches the side
When the unit moves, the position and posture of the unit U are guided so that the contact pressure between the contact surface 2b and the finger 7 is substantially constant and no slip occurs between the contact surface 2b and the finger 7. Have been.

FIG. 12 is an external perspective view showing another example of the configuration of the driving section 4, and FIG. 13 is a side view seen from the direction of arrow A in FIG. As shown in FIGS. 12 and 13, two guide bars 201 are provided at symmetrical positions on both sides of the unit U.
a, 202a, 201b and 202b are provided,
Each upper end of a support bar 204 having a shape in which an upper end is processed into a substantially U-shape and one rod is connected to the upper end is formed by a guide bar 201.
a, 201b so as to be rotatable,
Each upper end of the support bar 205 having the same shape as the guide bar 202
a and 202b, and the unit U is supported by these two indicator rods 204 and 205.
The lower rods of the support rods 204 and 205 are loosely inserted into horizontal grooves 206 and 207 provided in the drive unit 4.

FIG. 14 shows that the support rods 204 and 205 are
A configuration example of a mechanism for horizontally moving in the direction of 6,207 (hereinafter, referred to as an X-axis direction) and moving in a vertical direction perpendicular to the direction (hereinafter, referred to as a Z-axis direction) and a control unit thereof are shown.
These are provided in the drive unit 4 of FIG. In FIG. 14, reference numeral 301 denotes a flat board, and X
An X-axis table 302 is provided that can move back and forth in the axial direction. A Z-axis table 303 is provided on the X-axis table 302 so as to be able to advance and retreat in the Z-axis direction. An end of a support rod 204 loosely inserted into the groove 206 is fixed to the Z-axis table 303. . Also, the X-axis table 302, Z
There are an X-axis motor 304 and a Z-axis motor 305 such as a pulse motor for moving the axis table 303. A mechanism similar to the mechanism for moving the support rod 204 in the X-axis direction and the Z-axis direction is provided for the other support rod 205 as well, but is not shown in FIG. On the other hand,
An MPU 306 that operates according to a predetermined program, and an X-axis motor 304,
A motor driver 307 for driving the Z-axis motor 305;
A motor drive unit 308 that drives a motor for moving the other support rod 205 (not shown) in the X-axis direction and the Z-axis direction according to a command from the PU 306, and an electric signal from the two-dimensional image sensor 3 in FIG. And an A / D converter 309 for converting the data into an MPU 306.

The driving unit 4 having the structure shown in FIGS.
, Two support rods 20 supporting the unit U
4, 205 can be independently moved in the X-axis direction and the Y-axis direction, so that the position and posture of the unit U are changed so that the contact surface 2b of the transparent polyhedron 2 follows an optimal path for fingerprint collection. be able to. FIG. 15 shows two support rods 2
A state in which the position and the posture of the transparent polyhedron 2 are changed by moving 04 and 205 in the X-axis direction and the Z-axis direction is shown. FIG. 15A shows a state in which the support bar 204 is raised higher than the support bar 205 and the interval between them is narrowed.
This corresponds to the case (a). FIG. 15B shows a state where the heights of the two support rods 204 and 205 are the same, and FIG.
This corresponds to the case (b). FIG. 15C shows the support rod 20.
5 is higher than the support rod 204 and the distance between the two is narrowed, which corresponds to the case of FIG. Also,
If the size and position of the finger 7 are extremely different, the transparent polyhedron 2
Of the contact surface 2b must also be changed. Therefore, in this example, the shape and position of the finger 7 are measured by using the fact that the electric signal of the two-dimensional image sensor 3 changes when the contact surface 2b of the transparent polyhedron 2 touches the finger 7, and this measured value is used. The optimum movement route of the unit U is calculated on the basis of the calculation result. Hereinafter, the operation of this example will be described with reference to the flowchart of FIG.

Upon receiving a control signal for moving the unit U to the initial position from the control unit 5 of FIG. 1, the MPU 306 of the drive unit 4 starts the processing shown in FIG. The measurement is performed (step S1601). This is performed, for example, as follows.

First, a command is issued to the motor driving units 307 and 308 to make the heights of the two support rods 204 and 205 the same, and the intermediate position between the support rods 204 and 205 is right below the finger fixing base 6. The support rods 204 and 205 are moved so as to come up, and from that state, the support rods 204 and 205 are raised upward while maintaining the same height. When the output of any one of the light receiving elements of the two-dimensional image sensor 3 changes, the movement of the support bars 204 and 205 is stopped. This stop position is a place where the contact surface 2b is lightly in contact with the belly of the finger 7 while the contact surface 2b is horizontal. The length of the support rods 204 and 205 and the unit U
The shape and size of the contact surface 2b are known, and the contact surface 2b of the light receiving element whose output of the two-dimensional image sensor 3 has changed
Since the region inside is also known, the position p of the lowest point of the belly portion of the finger 7 can be calculated from the stop position by calculation. When the levels of the plurality of light receiving elements of the two-dimensional image sensor 3 have changed, the position of the light receiving element at the center is used.

Next, the MPU 306 controls the motor drive unit 30
7 and 308, the support rods 204 and 205 are once lowered and, as shown in FIG.
Is tilted at a certain angle (for example, 45 degrees), and the support bars 204 and 205 are raised upward while maintaining the tilt. When the output of any one of the light receiving elements of the two-dimensional image sensor 3 changes as in the previous case,
The movement of the finger 4 is stopped, and the position q of the finger 7 (a certain position on one side surface of the finger 7) with which the contact surface 2b is in contact is obtained by calculation based on the stop position. Similarly, MPU30
6 issues a command to the motor drive units 307 and 308 to lower the support rods 204 and 205 once and
As shown in (c), the contact surface 2b is set at an angle (for example, -45).
Degree) The support rods 204 and 205 are raised while keeping the inclination. When the output of any one of the light receiving elements of the two-dimensional image sensor 3 changes in the same manner as the previous time, the movement of the support rods 204 and 205 is stopped, and the finger on which the contact surface 2b is in contact is calculated based on the stop position. 7 position r (a certain position on the other side of the finger 7)
Ask for.

Then, the MPU 306 recognizes the shape and position of the finger from which the fingerprint is to be collected, based on the positions p, q, and r obtained above. FIG. 17 shows an example of recognizing the shape and position of the finger based on the positions p, q, and r. FIG. 17 (a), (b)
In each case, a substantially elliptical line passing through the positions p, q, and r is defined as the contour of the finger. Here, in FIGS. 17A and 17B,
Line segment q with respect to the length of the perpendicular drawn from p to line segment qr
The length ratio of -r is different. FIG. 17A shows a shape often seen on the thumb and the like, and FIG. 17B shows a shape often seen on the little finger and the like.

When the MPU 306 measures the shape and position of the finger, the MPU 306 then moves from the position where the contact surface 2b of the transparent polyhedron 2 contacts one side of the finger 7 via the belly of the finger based on the measurement result. Until reaching the position in contact with the other side surface, the contact pressure between the contact surface 2b and the finger 7 is kept substantially constant and without causing a slip between the contact surface 2b and the finger 7.
A route for moving the unit U is calculated (step S1602). This is performed, for example, as follows.

Assuming that a contour line indicating the measured shape and position of the finger is indicated by a solid line 1800 in FIG. 18, FIG.
As shown in FIG. 17, a tangent 1801 of the contour 1800 is drawn at a point at the position q detected as shown in FIG.
Line segment 1 parallel to 01 and separated by a predetermined length Δ on the back side of the finger
802 is drawn, and the position where the contact surface 2b of the transparent polyhedron 2 overlaps this line segment 1802 is set as the initial position of the unit U. Here, the predetermined length Δ is predetermined according to the contact pressure required between the finger and the contact surface 2b. Next, as shown in FIG. 18B, a tangent 1803 of the contour 1800 passing through the intersection x1 on the ventral side of the finger where the line segment 1802 intersects the contour 1800 is drawn.
A line segment 1804 parallel to the tangent line 1803 and separated by a predetermined length Δ is drawn on the back side of the finger. Then, a point x1 ′ on the line segment 1804 separated from the intersection x1 by a predetermined length Δ is considered, and FIG.
The point of the contact surface 2b in contact with the intersection x1
A position in contact with 1 ′ and where the contact surface 2b of the transparent polyhedron 2 overlaps with the line segment 1804 is defined as a middle position of the unit U. Similarly, the middle position of the unit U is sequentially obtained toward the opposite side surface of the finger. The process of obtaining the position and orientation of the intermediate unit U between adjacent positions among a plurality of intermediate positions obtained in this way by interpolation and further obtaining the intermediate position and orientation by interpolation is repeated as shown in FIG. As shown in FIG.
X and Z of the two support rods 204 and 205
MPU3 uses the position information that is finely defined in time series with coordinate axes.
06 is stored in the memory. The moving path defined by the stored position information is the optimum moving path of the unit U.

When the MPU 306 calculates the optimal movement path of the unit U as described above, the initial position indicated by the movement path (the X and Z coordinate values of the support rod 204 in FIG. 19 are x11, z11, the support rod X and Z coordinate values of 205 are x2
1 and z21) by controlling the motor driving units 307 and 308 to move the unit U to the two support rods 20.
4, 205, and notifies the controller 5 of FIG. 1 after the movement is completed (step S1063).

Thereafter, when a control signal for moving the unit U by one step is received from the control unit 5 of FIG.
In step 06, the unit U is moved by one step (steps S1604 and S1606). Here, since the number of steps to complete the movement on the entire movement route is determined in advance, the MPU 306 reads out the position information of one step ahead from the position information in FIG.
08 is controlled to move the two support rods 204 and 205. For example, in the example of FIG. 5, the unit U is moved to the final position in two steps. At this time, control is performed using a plurality of pieces of position information up to the center position information of the position information in FIG. That is, first, the X and Z coordinate values of the support bar 204 are x12 and z12, and the X and Z coordinate values of the support bar 205 are x2 and z2.
2, the unit U is moved to the position where
The control to move the unit U to the position where the X and Z coordinate values of the support bar 204 are x13 and z13 and the X and Z coordinate values of the support bar 205 are x23 and z23 is continued until the position information of one step ahead. .

As described above, the MPU 306 moves the unit U by one step each time it receives a control signal for moving one step from the control unit 5 in FIG. End (step 160)
5).

In the example of the driving section 4 shown in FIG.
Although the shape and position of the finger are measured and the movement path of the unit U is dynamically calculated, programming may be performed so as to move a predetermined movement path for a standard finger. .

[0058]

As described above, according to the present invention, the following effects can be obtained.

When inputting an imprint fingerprint image for collecting a fingerprint up to the side of the finger, discontinuity of the fingerprint image and blurring of the image can be prevented. The reason is that there is no artificial fluctuation of the finger position such as inputting the imprint fingerprint image by rotating the finger itself. For this reason, in the method of imaging a predetermined rectangular area on the contact surface at each unit position and finally combining them, discontinuity due to a finger shift between the rectangular area images is eliminated, and the contact surface at each unit position is eliminated. In the method of capturing the entire upper region, recording the data of the maximum pixel value, and synthesizing the imprint fingerprint image, blurring of image overlap due to a finger shift between images at each unit position is eliminated.

When inputting an imprint fingerprint image for collecting a fingerprint up to the side of the finger, the density of the fingerprint image can be made uniform over the entire area. The reason for this is that there is no artificial contact pressure fluctuation such as inputting a fingerprint image by rotating the finger itself, and the shading change due to the contact pressure change of the image data is reduced.

In a case where a method of imaging a predetermined rectangular area on the contact surface at each unit position and finally synthesizing them is adopted, a blank area is not generated in the input fingerprint image. The reason is that there is no artificial rotation measurement fluctuation such as inputting a fingerprint image by rotating the finger itself, and the contact position of the finger coincides with the imaging position. This is because it does not exist.

Since the transparent polyhedron is constituted by an optical fiber collecting member and a unit in which the collecting member is integrated with a planar light source and a two-dimensional image sensor, the unit can be miniaturized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an imprint fingerprint image input device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a positional relationship between an optical fiber constituting a transparent polyhedron and a light receiving element of a two-dimensional image sensor.

FIG. 3 is a side view when a state of connection between an optical fiber constituting a transparent polyhedron and a light receiving element of the two-dimensional image sensor 3 is viewed from a lateral direction.

FIG. 4 pays attention to one optical fiber constituting a transparent polyhedron, and a ray incident on a cut surface constituting a part of a contact surface of the optical fiber is totally reflected at the cut surface and propagates through the optical fiber. It is a figure showing signs that it enters into a light receiving element.

FIG. 5 is an explanatory diagram showing a state in which a unit is rotated by a driving unit while a contact surface is in contact with a fixed finger.

FIG. 6 is an explanatory diagram of an example of a process of forming an imprint fingerprint image from digital image density data for each position of a unit.

FIG. 7 is an explanatory diagram of another example of a process of forming an imprint fingerprint image from digital image density data for each position of a unit.

FIG. 8 is a flowchart illustrating a processing example of a control unit when the imprint fingerprint image forming method described with reference to FIG. 6 is employed.

9 is a flowchart illustrating a processing example of a control unit when the imprint fingerprint image forming method described with reference to FIG. 7 is employed.

FIG. 10 is an external perspective view illustrating a configuration example of a driving unit.

FIG. 11 is a side view as seen from the direction of arrow A in FIG. 10;

FIG. 12 is an external perspective view illustrating another example of the configuration of the driving unit.

FIG. 13 is a side view as seen from the direction of arrow A in FIG. 12;

FIG. 14 is a view showing a configuration example of a mechanism for horizontally moving two support rods and a vertical direction perpendicular thereto, and a configuration example of a control unit thereof.

FIG. 15 is a diagram illustrating a state in which the position and orientation of a transparent polyhedron are changed by movement of two support rods.

FIG. 16 is a flowchart illustrating a processing example of an MPU.

FIG. 17 is a diagram illustrating an example of recognizing the shape and position of a finger based on a measurement position.

FIG. 18 is an explanatory diagram of a method of obtaining an optimum movement path of a unit from a measured finger shape and position.

FIG. 19 is a diagram showing a configuration example of position information for determining a movement route.

FIG. 20 is a diagram showing a configuration of a conventional fingerprint image input device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Planar light source 2 ... Transparent polyhedron 2a ... Incident surface 2b ... Contact surface 2c ... Derivation surface 3 ... 2D image sensor 4 ... Drive part 5 ... Control part 51 ... Internal memory 6 ... Finger fixing stand 7 ... Finger U ... Unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G06T 1/00, 7/00 A61B 5/10

Claims (4)

(57) [Claims] 1. A light incident surface and a contact surface between a finger and said incident surface.
Derivation of light rays incident from a surface and reflected by the contact surface
A transparent polyhedron having a light-transmitting surface,
From a planar light source that illuminates the light polyhedron, and from the exit surface
Receives reflected light and converts reflected light intensity to electrical signals
A unit integrating a two-dimensional image sensorThe contact surface of the transparent polyhedron is fixed for fingerprint collection.
The contact surface with a finger at a predetermined angle
Each time set and detected, the shape of the fixed finger
Measuring means for measuring The contact based on the shape of the finger measured by the measuring means
While keeping the contact pressure between the surface and the finger almost constant, The transparent poly
The contact surface of the facepiece isSaidTouch one side of the fixed finger
From the point of contact with the other side via the pad of the finger
Until you reachThe position of the unit is a predetermined distanceMove by
A driving unit to be moved; and the two-dimensional image sensor for each position of the unit.
Electrical signals from the
And a control unit that synthesizes an imprinted fingerprint image from them.
An imprinted fingerprint image input device, characterized in that: 2. The control section converts an electric signal from all light receiving elements of the two-dimensional image sensor obtained at an initial position of the unit into digital image data and records the digital image data in an internal memory. When electric signals are obtained from the two-dimensional image sensor at the subsequent positions, the electric signals of all the light receiving elements are converted into digital image data, and the values are compared with the digital image data recorded in the internal memory in pixel units. 2. The imprinted fingerprint image input device according to claim 1, wherein the device having a larger value is left in an internal memory. 3. A light incident surface and a contact surface between a finger and said incident surface.
Derivation of light rays incident from a surface and reflected by the contact surface
Transparent polyhedron having surfacesof,The contact surface has a fingerprint
The contact surface with the fixed finger
The angle is set at each of a plurality of angles and detected,
A first step of measuring the shape of the finger The transparent polyhedron, The light is transmitted from the incident surface to the transparent polyhedron.
A planar light source for irradiating the
Secondary to receive reflected light and convert reflected light intensity to electrical signal
The unit integrating the original image sensor is
The contact surface of the facepiece is one of the fingers fixed for fingerprinting.
To a position where it touches the side with a certain contact pressure.
First2Step of the electric signal from the two-dimensional image sensor.
For the rectangular area within the contact surface determined by the current position of the knit,
Only the electric signal of the corresponding light receiving element is converted to digital image data.
Convert to and record3The contacting of the transparent polyhedron with the finger
Whether or not it has been moved until it reaches a position that touches the side
And if not moved, the following5Step
If you have moved to6Steps
Move to the first4Steps andBased on the shape of the finger determined in the first step,
The contact pressure between the contact surface of the light polyhedron and the finger is kept almost constant.
While The contact surface contacts the other side via the pad of the finger.
In the direction to reach the positionThe position of the unit
Predetermined distanceJust move the said3Step back to the step
5Step; and each digital image recorded at each position of the unit.
Stitching image data together to synthesize an imprint fingerprint image6
Fingerprint image input comprising the steps of:
Method. 4. A light incident surface and a contact surface between a finger and said incident surface.
Derivation of light rays incident from a surface and reflected by the contact surface
Transparent polyhedron having surfacesof,The contact surface has a fingerprint
The contact surface with the fixed finger
The angle is set at each of a plurality of angles and detected,
A first step of measuring the shape of the finger Said A transparent polyhedron, a light beam from the incident surface to the transparent polyhedron
A planar light source for irradiating the
Secondary to receive reflected light and convert reflected light intensity to electrical signal
The unit integrating the original image sensor is
The contact surface of the facepiece is one of the fingers fixed for fingerprinting.
Move to the initial position where it comes in contact with the other side with some contact pressure
Let2And the two-dimensional image when the unit is located at the initial position.
Digitally converts electrical signals from all light receiving elements of the image sensor
Convert to image data and record to internal memory3No
AndBased on the shape of the finger determined in the first step,
The contact pressure between the contact surface of the light polyhedron and the finger is kept almost constant.
While The contact surface contacts the other side via the pad of the finger.
In the direction to reach the positionThe position of the unit
Predetermined distanceJust moveLet the fourthSteps and the4
The two-dimensional image after the movement of the unit by the step of
Digitally converts electrical signals from all light receiving elements of the image sensor
Converted to image data and recorded in the internal memory
Compares the digital image data with the value in pixel units.
Keep the key in the internal memory5The contact surface of the transparent polyhedron is the other of the finger
Whether it has been moved until it reaches the position
Judgment, and if not moved,4The steps
Return and move7Go to step
First6And pressing digital image data recorded in the internal memory.
The fingerprint image7And a step of
How to input a fingerprint image.