JP5438089B2 - Background image concealment method, background image concealment device, and computer-executable program - Google Patents

Description

  The present invention relates to a background image concealment method, a background image concealment device, and a program executable by a computer.

  In recent years, many information processing apparatuses such as personal computers equipped with cameras have become widespread. It is common to shoot a user with a camera mounted on an information processing apparatus and transfer the captured image to hold a TV conference. In such a TV conference or the like, since an image captured of the user is transferred to the other party, a background image when the user is captured is also transferred. However, there are cases where it is desirable to hide the background from the viewpoint of privacy.

  As a method of hiding the background, for example, a person is detected by image processing, and the other area (background) is replaced with another image, or a person image as a foreground is used by using a depth sensor represented by Kinect. There is a method of detecting the image and replacing the other area with another image.

  However, since the above method requires large-scale image processing for all image frames, there is a problem that cost (hardware cost, processing cost) increases.

Japanese Patent Laid-Open No. 5-91504 JP 2009-124264 A

  The present invention has been made in view of the above, and a background image concealment method capable of concealing the background of a person with a low-cost configuration when the person is photographed and the image data is transmitted. An object of the present invention is to provide a background image concealment device and a computer-executable program.

  In order to solve the above-described problems and achieve the object, the present invention provides an imaging process in which an imaging unit images a subject and outputs image data, and face detection in which a face detection unit detects a face area from the image data. And a brightness comparison unit compares the brightness of the detected face area of the image data with the background area, and determines whether the brightness of the background area is greater than a predetermined amount than the brightness of the face area. A comparing step of determining, an exposure amount setting step of setting the exposure amount of the imaging unit high when the lightness of the background region is greater than the lightness of the face region by a predetermined amount or more, and a communication unit, The imaging step includes a transmission step in which the imaging means transmits image data captured with the set exposure amount to the other party.

  Further, according to a preferred aspect of the present invention, the brightness adjustment means further performs an adjustment process for performing adjustment to lower the brightness of the image data captured by the imaging means with the set exposure amount in the imaging process. In the transmission step, the image data adjusted in the adjustment step is preferably transmitted to the other party.

  According to a preferred aspect of the present invention, it is desirable that in the adjustment step, adjustment is performed to lower the brightness of image data captured by the imaging unit with the set exposure amount by a specified amount.

  According to a preferred aspect of the present invention, in the adjustment step, the brightness of the image data captured by the imaging unit with the set exposure amount is lowered so that the facial appearance evaluation value of the face region is maximized. In addition, it is desirable to adjust the contrast high.

Further, according to a preferred aspect of the present invention, in the exposure amount setting step, it is desirable that the exposure amount is increased by a specified amount when the brightness of the background region is larger than the brightness of the face region by a predetermined amount or more.

Also, according to a preferred aspect of the present invention, in the exposure amount setting step, when the brightness of the background area is greater than the brightness of the face area by a predetermined amount or more, the facial appearance evaluation value of the face area becomes a lower limit It is desirable to increase the exposure amount until the amount of change in background information with respect to the background region of the image data before setting the exposure amount in the exposure amount setting step becomes a predetermined value or more.

  In order to solve the above-described problems and achieve the object, the present invention provides an imaging unit that images a subject and outputs image data, a face detection unit that detects a face area from the image data, and the image Brightness comparison means for comparing the brightness of the detected face area and background area of data to determine whether the brightness of the background area is greater than or equal to a predetermined amount than the brightness of the face area; and the background area Exposure control means for setting the exposure amount of the imaging means high when the brightness of the face area is greater than the brightness of the face area, and image data captured by the imaging means with the set exposure amount to the other party And a communication means for transmitting.

  According to a preferred aspect of the present invention, there is provided a program installed in the information processing apparatus, the face detecting step for detecting a face area from the image data captured by the imaging unit, and the detected face of the image data A comparison step of comparing the brightness of the area and the background area to determine whether the brightness of the background area is greater than or equal to a predetermined amount than the brightness of the face area; and the brightness of the background area is the brightness of the face area An exposure amount setting step for setting the exposure amount of the imaging unit to be higher, and a transmission step for transmitting image data captured by the imaging unit with the set exposure amount to the other party. The computer is executed.

  According to the present invention, when a person is photographed and the image data is transmitted, the background of the person can be concealed with a low-cost configuration.

FIG. 1 is a diagram for explaining the principle of the background image concealment method according to the present embodiment. FIG. 2 is a conceptual diagram of the background image concealment device according to the present embodiment. FIG. 3 is a diagram illustrating an example of schematic image data before the background image concealment process is performed. FIG. 4 is a diagram illustrating an example of schematic image data after the background image concealment process is performed. FIG. 5 is a schematic external view of a notebook PC to which the background image concealment device according to the present embodiment is applied. FIG. 6 is a diagram illustrating a schematic hardware configuration example of the notebook PC. FIG. 7 is a diagram showing a functional configuration related to processing in a case where image data captured by a camera is transmitted to a communication partner when image data captured by a camera is transmitted to a communication partner. FIG. 8 is a flowchart for explaining the background image concealment process when the videophone application transmits image data captured by the camera to the communication partner.

  Hereinafter, a background image concealment method, a background image concealment device, and a computer-executable program according to the present invention will be described in detail with reference to the drawings. Although the components of the present invention are generally illustrated in the drawings herein, it can be readily understood that they may be arranged and designed in a wide variety of configurations with various configurations. Accordingly, the following more detailed description of the apparatus, system and method embodiments of the present invention is not intended to limit the scope of the invention as set forth in the claims, but merely as an example of selected embodiments of the invention. It is intended merely to illustrate selected embodiments of apparatus, systems and methods consistent with the present invention as set forth in the claims herein. Those skilled in the art will appreciate that the present invention may be implemented without one or more of the specific details or with other methods, components, and materials. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same.

(Embodiment)
FIG. 1 is a diagram for explaining the principle of the background image concealment method according to the present embodiment. In FIG. 1, when a camera is mounted on an information processing apparatus such as a personal computer, the camera is mounted on the display and a user working in front of the display is photographed. In general, bright colors are used for the ceiling, walls, curtains, and the like. In many cases, when the user is imaged by a camera, the background area BA is imaged as a brighter color than the face area FA. Therefore, the brightness of the face area FA is lower than that of the background area BA (FIG. 1A).

  In such a general environment, the exposure amount of the camera is increased, and the background area BA is blurred by using the “whiteout” effect (FIG. 1B). Further, as post-processing, the brightness of the face area FA is returned to the original appropriate level by adjusting the brightness and contrast (FIG. 1C). As a result, the captured image has an effect in which a filter of white or similar color is applied except for the face area FA, and most of the background area BA can be erased or blurred.

  FIG. 2 is a conceptual diagram of the background image concealment device according to the present embodiment. The background image concealment device shown in FIG. 2 can be configured with hardware or software modules, or a combination thereof. As illustrated in FIG. 2, the background image concealment device includes an imaging unit 1, a face detection unit 2, a brightness comparison unit 3, an exposure amount control unit 4, a brightness adjustment unit 5, and a communication unit 6. Yes. The process of concealing the background area of the image data is referred to as background image concealment process.

  The imaging unit 1 outputs image data (moving image) obtained by imaging the subject to the face detection unit 2, the brightness comparison unit 3, and the exposure amount control unit 4. The imaging means 1 can be composed of, for example, a CCD camera or a CMOS camera.

  The face detection unit 2 detects a face area from the image data input from the imaging unit 1 and outputs a face detection result (information indicating the face area) to the brightness comparison unit 3. A well-known face detection algorithm can be used, and for example, a face detection method described in Japanese Patent Application Laid-Open No. 2006-508463 can be used.

  Based on the face detection result of the face detection unit 2, the brightness comparison unit 3 determines the brightness (luminance) of each of the face area and the background area other than the face area in the image data input from the imaging unit 1. ) Is calculated as the average value, and it is determined whether the brightness of the background area ≧ the brightness of the face area + the predetermined value A (where A> 0). Then, the brightness comparison unit 3 outputs a comparison result indicating whether or not the brightness of the background area ≧ the brightness of the face area + the predetermined value A to the exposure amount control unit 4.

  The exposure amount control unit 4 controls the exposure amount of the imaging unit 1. Based on the comparison result inputted from the brightness comparison means 3, the exposure amount control means 4 makes the background area of the image data white out when the brightness of the background area ≧ the brightness of the face area + the predetermined value A. In addition, the exposure amount of the imaging means 1 is set high. Then, the exposure amount control unit 4 outputs the image data captured with the high exposure amount set by the imaging unit 1 to the brightness adjustment unit 5. Note that the exposure amount control means 4 may set the exposure amount higher by a specified amount. Further, the exposure amount control means 4 may increase the exposure amount until the lower limit of the facial appearance evaluation value is reached or until the amount of change in the background information of the background area due to the exposure amount change becomes a predetermined value or more. Good.

  Here, the amount of change in the background information of the background area means the amount of change in the background information for the background area of the image data taken after setting the exposure amount high and the image data before the exposure amount is changed. For example, the background information can be an edge amount or a frequency component distribution. Moreover, a well-known thing can be used for a facial appearance evaluation value, For example, what was described in Unexamined-Japanese-Patent No. 2008-263478 or Unexamined-Japanese-Patent No. 2008-079055 can be used. Further, the exposure amount control unit 4 may set the exposure amount of the imaging unit 2 high so that the background region of the image data is overexposed even when the face detection unit 2 does not detect the face region.

  The brightness adjustment means 5 adjusts the brightness of the image data captured with a high exposure amount (decreases the brightness), desirably adjusts the brightness and contrast (decreases the brightness and increases the contrast), and originally adjusts the brightness of the face area. To the appropriate level (original level), and the adjusted image data is output to the communication means 6. The lightness adjusting means 5 may reduce the lightness by a specified amount. Further, the lightness adjusting means 5 may be adjusted so as to lower the lightness and increase the contrast so that the facial appearance evaluation value of the face area of the image data is maximized.

  The communication means 6 is connected to the network and configured to be able to communicate with the counterpart terminal, and transmits the image data input from the brightness adjustment means 5 to the communication counterpart. This makes it possible to send image data whose background is concealed and whose face can be recognized to the other party.

  FIG. 3 shows an example of schematic image data before performing background image concealment processing, and FIG. 4 shows an example of schematic image data after performing background image concealment processing. As shown in FIG. 3, the content of the background area BA is visible in the image data before the background concealment process is performed. On the other hand, as shown in FIG. 4, in the image data after the background concealment processing is performed, the background area BA is overexposed, and the contents of the background area BA cannot be visually recognized.

  As described above, according to the present embodiment, the imaging unit 1 images a subject and outputs image data, the face detection unit 2 detects a face area from the image data, and the brightness comparison unit 3 uses the image data. The brightness of the detected face area and the background area are compared to determine whether the brightness of the background area is greater than the brightness of the face area by a predetermined amount or more. When the brightness is greater than the brightness of the face area by a predetermined amount or more, the exposure amount of the imaging unit 1 is set high, and the communication unit 6 transmits image data captured by the imaging unit 1 with the set exposure amount to the other party. Therefore, the background image in the image data can be concealed by a simple and low-cost method. Thereby, secrecy and privacy can be maintained. In addition, since it is a simple method, it can be realized at a low realization cost (hardware cost and processing cost (including power consumption)), and can be implemented in a system with low processing capability.

  Further, according to the present embodiment, the lightness adjusting means 5 adjusts to lower the lightness of the image data picked up with the exposure amount set by the image pickup means 1, and the communication means 6 adjusts the adjusted image data. Is transmitted to the other party, so that the face of the person in the image data can be made appropriate (clearly).

  Further, according to the present embodiment, the brightness adjustment unit 5 performs the adjustment to lower the brightness of the image data captured by the imaging unit 1 with the set exposure amount, so that it is simple and low-cost. It becomes possible to make the face of the person in the image data appropriate by the method.

  Further, according to the present embodiment, the brightness adjustment unit 5 lowers the brightness of the image data captured by the imaging unit 1 with the set exposure amount so that the facial appearance evaluation value of the face area is maximized. Since the contrast is adjusted to be high, the human face in the image data can be made as appropriate as possible.

  Further, according to the present embodiment, the exposure amount control means 4 increases the exposure amount by a prescribed amount when the brightness of the background region is greater than the brightness of the face region by a predetermined amount, so that it is simple and low-cost. The background image in the image data can be concealed by a simple method.

  In addition, according to the present embodiment, the exposure amount control unit 4 is configured until the face-likeness evaluation value of the face area reaches the lower limit when the brightness of the background area is greater than the brightness of the face area by a predetermined amount or Since the exposure amount is increased until the amount of change in the background information with respect to the background area of the image data before setting the exposure amount becomes a predetermined value or more, the background image in the image data can be more effectively concealed. It becomes possible.

(Example)
FIG. 5 is a schematic external view of a notebook PC 10 that is an information processing apparatus to which the background image concealment apparatus according to the present embodiment is applied. As shown in FIG. 1, the notebook PC 10 includes a main body side housing 12 and a display side housing 13 which are substantially rectangular parallelepipeds. The main body side housing 12 includes an input unit 14 having a keyboard, a touch pad, and the like, a microphone 15, and speakers 16a and 16b. The display-side housing 13 includes an LCD (liquid crystal display) 17 and a camera 18 that is disposed on the display surface side of the LCD 17 at a substantially central position above the LCD 17 and can image a front subject.

  The main body side case 12 and the display side case 13 are connected to each other by a pair of left and right connecting parts (hinge parts) 19a and 19b, and the connecting parts 19a and 19b open and close these cases. Supports freely.

  FIG. 6 is a diagram illustrating a schematic hardware configuration example of the notebook PC 1 of FIG. As shown in the figure, the notebook PC 1 includes a CPU 31, ROM 32, memory 33, HDD (hard disk) 34, LCD 17, input unit 14, camera device 25, audio device 27, communication device 21, battery 22, DC-DC converter 23. , An AC adapter 24, and a USB port 39, and each unit is connected directly or indirectly via a bus.

  The CPU 31 controls the notebook PC 10 as a whole by the OS 35 stored in the HDD 34 connected via the bus, and manages the function of executing processing based on various programs stored in the HDD 34. The ROM 32 stores a BIOS (Basic Input / Output System: basic input / output system) 32a, data, and the like.

  The memory 33 is composed of a cache memory and a RAM, and is a writable memory used as a work area for writing processing data of the execution program as a read area for the execution program of the CPU 31.

  An HDD (hard disk) 34 includes, for example, an OS 35 for controlling the notebook PC 1 as a whole, such as Windows (registered trademark) XP, Vista, 7, etc., various drivers 36 for hardware operation of peripheral devices, video conferencing and chat For storing a videophone application program (hereinafter referred to as “videophone application”) 37 such as Skype, and another application program 38 directed to a specific business.

  The OS 35 controls basic operations of the notebook PC 1, manages various resources, and transmits, for example, commands generated by application programs to the various drivers 36 and the BIOS 32a. The OS 35 has a multi-task function and a multi-window function, and also manages software resources such as an application program execution context (register set, main memory image, file handle, etc. used by a certain application program) and GUI parts. Configured to do.

  The various drivers 36 are, for example, a display driver that controls the LCD 17 according to an instruction from the OS 35, a camera driver (see FIG. 7) that controls the camera device 25 according to an instruction from the OS 35, an audio driver that controls the audio device 27 according to an instruction from the OS 35, and the OS 35. The communication driver or the like controls the communication device 21 in accordance with the instruction.

  The videophone application 37 causes the communication device 21 to establish a link with the counterpart terminal via the OS 35 and transmit an image captured by the camera 18 or sound collected by the microphone 15 or transmitted from the counterpart terminal. Images and sounds are displayed on the LCD 17 and sound is emitted from the speakers 16a and 16b.

  The other application program 38 is a program such as a browser, mail, word processor, or spreadsheet.

  The LCD 17 converts display information into a video signal under the control of the CPU 31, and displays various information corresponding to the converted video signal on the display screen.

  In this embodiment, an LCD is used as a display. However, the present invention is not limited to this, and another display such as an organic EL display or a CRT may be used.

  The input unit 14 is a user interface for a user to perform an input operation. The input unit 14 is a keyboard configured by various keys for inputting characters, commands, etc., a touch for moving a cursor on the screen, and selecting various menus. A pad is provided.

  The camera device 25 is a USB camera device connected to the USB port 39, and includes a camera 18 and a camera processing circuit 26. The camera 18 includes a lens and an imaging unit (CCD or CMOS). The lens forms subject light, and the imaging unit outputs the imaged subject light as R, G, and B image signals. The camera processing circuit 26 includes an A / D converter, an image processing LSI, a memory, and the like, performs drive timing and exposure control of the imaging unit, and performs data processing (A / D conversion, etc.) and output to the CPU 31. When the power of the camera device 25 is turned on, the camera device 25 is configured to perform initial processing such as white balance adjustment and exposure adjustment, and output a captured image after the imaging conditions and signal processing are stabilized.

  The audio device 27 includes a microphone 15, speakers 16 a and 16 b, and an audio processing circuit 28. The microphone 25 collects sound and outputs the sound data to the sound processing circuit 28. The speakers 16 a and 16 b output sound corresponding to the sound data output from the sound processing circuit 28. The audio processing circuit 28 includes an A / D converter, a D / A converter, an audio processing LSI, a memory, and the like, and processes audio data input from the microphone 15 (A / D conversion, etc.) Audio data (digital data) after data processing is output to the CPU 11 or audio data (digital) input from the CPU 31 is D / A converted and emitted from the speakers 16a and 16b.

  The communication device 21 is for transmitting and receiving data via a network, transmits image data and audio data to the network, and receives image data and audio data transmitted via the network. Note that the communication device 21 may encode and transmit image data and audio data, and may decode the encoded image data and audio data when received.

  The AC adapter 24 is connected to a commercial power supply, converts an AC voltage into a DC voltage, and outputs the DC voltage to the DC-DC converter 23. The DC-DC converter 23 converts the DC voltage supplied from the AC adapter 24 into a predetermined voltage, supplies power to each unit, and charges the battery 22. The battery 22 is charged by the DC-DC converter 23 and supplies the charged voltage to each unit. The battery 23 is used when the AC adapter 24 is not connected to a commercial power source.

  FIG. 7 is a diagram showing a functional configuration related to processing in the case where the video phone application 37 transmits image data captured by the camera 18 to a communication partner when transmitting image data in which the background to be imaged is hidden.

  The videophone application 37 is an application program that is executed on the OS 35, and implements a videophone function for making a call with an opponent terminal using an image and voice. The videophone application 37 functions as the communication means 6 in FIG. The OS 35 intervenes in transmission / reception of data or commands between the videophone application 37 and each device driver.

  The camera device 25 functions as the imaging unit 1 in FIG. The camera driver 36 a controls the camera device 25 in accordance with an instruction from the videophone application 37 via the OS 35. The camera driver 36a functions as the face detection unit 2, the brightness comparison unit 3, the exposure amount control unit 4, and the brightness adjustment unit 5 of FIG.

  The camera driver 36 a includes an image analysis unit 40, an exposure control unit 50, and a brightness / contrast adjustment unit 60. Furthermore, the image analysis unit 40 includes a face recognition unit 41, a face lightness detection unit 42, a background lightness detection unit 43, a background concealment control unit 44, a faceness evaluation unit 45, and a background change detection unit 45. ing.

  The camera device 25 outputs the image data captured by the camera 18 to the image analysis unit 40, the exposure control unit 50, and the brightness / contrast adjustment unit 60.

  In the image analysis unit 40, the face recognition unit 41 detects a face area from the image data input from the camera device 25, and outputs a face detection result (information indicating the face area). The face brightness detection unit 42 calculates the brightness of the face area in the image data input from the camera device 25 based on the face detection result of the face recognition unit 41. The background lightness detection unit 43 calculates the lightness of a region other than the face region of the image data input from the camera device 25, that is, the background region based on the face detection result of the face recognition unit 41.

  Based on the brightness of the face area calculated by the face brightness detection unit 42 and the brightness of the background area calculated by the background brightness detection unit 43, the background concealment control unit 44 determines the brightness of the background area ≧ the brightness of the face area + It is determined whether or not the value is a predetermined value A, and a comparison result indicating whether the lightness of the background region ≧ the lightness of the face region + the predetermined value A (where A> 0) is output to the exposure control unit 50.

  The face-likeness evaluation unit 45 calculates the face-likeness evaluation value of the face area of the image data captured by the camera device 25 after the exposure amount is set high by the exposure control unit 50, and outputs it to the exposure control unit 50. Further, the facial appearance evaluation unit 45 calculates a facial appearance evaluation value of the face area of the image data after the lightness / contrast adjustment unit 60 has adjusted the lightness / contrast, and outputs the facial appearance evaluation value to the lightness / contrast adjustment unit 60.

  The background change evaluation unit 46 determines whether or not the background area has been blown out, image data captured by the camera device 25 after the exposure control unit 50 sets the exposure amount high, and before the exposure amount is changed. The amount of change in the background information of the background area is calculated and output to the exposure control unit 50. For example, an edge amount or a frequency component distribution can be used to calculate the amount of change in background information.

  The exposure control unit 50 controls the exposure amount of the camera 18 of the camera device 25 and instructs the camera processing circuit 26 about the exposure amount. When the brightness of the background region ≧ the brightness of the face region + the predetermined value A, the exposure control unit 50 determines whether the facial appearance evaluation value calculated by the facial appearance evaluation unit 45 reaches the lower limit or the background change evaluation unit The exposure amount of the camera 18 is increased until the change amount of the background information of the background area calculated in 46 becomes equal to or greater than the predetermined value C. As a result, the image is overexposed and the background area is overexposed.

  If the face area is not detected in the image data, the exposure control unit 50 determines that the amount of change in the background information of the background area calculated by the background change evaluation unit 46 is equal to or greater than the predetermined value C. Increase the exposure amount. This is because the background is kept secret even when no person is shown.

  The brightness / contrast adjustment unit 60 sets the brightness until the facial appearance evaluation value calculated by the facial appearance evaluation unit 45 is maximized for the image data captured by the camera device 25 after the exposure control unit 50 sets the exposure amount high. And adjust the contrast (decrease brightness and increase contrast). Thus, the face of the image data that is overexposed is appropriate. The brightness / contrast adjustment unit 60 restores image data after adjustment, that is, image data in which the background area is concealed and the face area can be recognized as much as possible, and outputs the image data to the videophone application 37.

  The videophone application 37 transmits the adjusted image data input from the brightness / contrast adjustment unit 60 to the counterpart terminal.

  FIG. 8 is a flowchart for explaining the background image concealment process in the case where the notebook PC 10 having the configuration shown in FIG. 7 transmits image data captured by the video phone application 37 to the communication partner. The process shown in FIG. 8 is executed when the videophone application 37 starts videophone communication or at a predetermined cycle.

  In FIG. 8, when the camera driver 36a starts shooting with the camera 18 and inputs image data (step S11), the face recognition unit 41 detects a face area of the input image data (step S12). . When the face area is not detected (“No” in step S12), the process proceeds to step S17.

  When the face area is detected (“Yes” in step S12), the background concealment control unit 44 determines whether or not the brightness of the background area ≧ the brightness of the face area + the predetermined value A (step S13). If the brightness of the background area ≧ the brightness of the face area + the predetermined value A is not satisfied (“No” in step S13), the image data is transferred to the videophone application 37 (step S21).

  If the brightness of the background area ≧ the brightness of the face area + the predetermined value A (“Yes” in step S13), the exposure control unit 50 sets the exposure amount higher by a predetermined amount, and the exposure amount Vexp = exposure amount. Vexp + predetermined amount B (step S14). Subsequently, the exposure control unit 50 determines whether or not the facial appearance evaluation value calculated by the facial appearance evaluation unit 45 is a lower limit (step S15). When the facial appearance evaluation value is the lower limit (“Yes” in step S15), the process proceeds to step S19. On the other hand, when the facial appearance evaluation value is not the lower limit (“No” in step S15), the exposure control unit 50 determines whether or not the amount of change in the background information of the background area calculated by the background change detection unit 46 ≧ predetermined value C. It is determined whether or not (step S16). When the amount of change in the background information is equal to or greater than the predetermined value C (“Yes” in step S16), the process proceeds to step S19. If the change amount of the background information is not greater than or equal to the predetermined value C (“No” in step S16), the process returns to step S14, and the exposure control unit 50 sets the exposure amount higher by the predetermined amount B and the facial appearance evaluation value is The processes in steps S14 to S16 are repeated until the lower limit (“Yes” in step S15) or the amount of change in background information ≧ predetermined value C (“Yes” in step S16). Here, it is expected that the evaluation values are compared while finely controlling the exposure change amount B so that the facial appearance evaluation value does not greatly exceed the lower limit value. Note that the reason for increasing the exposure amount to the lower limit of the facial appearance evaluation value is to maximize the exposure amount so that the background information can be concealed as much as possible, while the face region can be normally recognized as a face. This is because the upper limit of the exposure amount is estimated by the facial appearance evaluation value.

  Instead of the processing in steps S14 to S16, the exposure control unit 50 sets the exposure amount to a predetermined amount higher, determines whether the facial appearance evaluation value is the lower limit (step S15), and the amount of change in the background information. ≧ The determination of the predetermined value C (step S16) may not be executed. Thereby, the processing speed can be improved.

  In step S19, the brightness / contrast adjustment unit 60 performs a process of adjusting the brightness and contrast (lowering the brightness and increasing the contrast) in order to return the face area of the image data to the brightness before increasing the exposure amount. . The brightness / contrast adjustment unit 60 determines whether or not the facial appearance evaluation value calculated by the facial appearance evaluation unit 45 is maximum (step S20). If the facial appearance evaluation value is the maximum (“Yes” in step S20), the image data is transferred to the videophone application 37 (step S21). As a result, the videophone application 37 transmits the image data that can be recognized and the face can be recognized to the counterpart terminal. If the facial appearance evaluation value is not the maximum (“No” in step S20), the process returns to step S19, and the brightness / contrast adjustment unit 60 further adjusts the brightness and contrast until the facial appearance evaluation value reaches the maximum ( “Yes” in step S20), the processing in steps S19 and S20 is repeated.

  Instead of the processing in steps S19 and S20, the brightness / contrast adjustment unit 60 may lower the prescribed amount brightness and not execute the determination (step S20) as to whether or not the facial appearance evaluation value is the maximum. Good. Thereby, the processing speed can be improved.

  In step S17, the exposure control unit 50 sets the exposure amount higher by a predetermined amount and sets the exposure amount Vexp = exposure amount Vexp + predetermined amount B (step S17). Subsequently, the exposure control unit 50 determines whether or not the amount of change in the background information of the background region calculated by the background change detection unit 46 ≧ predetermined value C (step S18). If the change amount of the background information ≧ the predetermined value C (“Yes” in step S18), the image data is transferred to the videophone application 37 (step S21). If the change amount of the background information is not greater than or equal to the predetermined value C (“No” in step S18), the process returns to step S17, and the exposure control unit 50 sets the exposure amount to be higher by the predetermined amount B and changes the change amount of the background information. The processes of step S17 and step S18 are repeated until ≧ predetermined value C (“Yes” in step S16).

  Instead of the processing in steps S17 and S18, the exposure control unit 50 may set the exposure amount to be higher by a predetermined amount and not execute the determination of change in background information ≧ predetermined value C (step S18). . Thereby, the processing speed can be improved.

  When the detection of the face is confirmed, when the background image concealment process is completed, the image data photographed with the exposure amount finally set in steps S14 to S16 is finally obtained in steps S19 and S20. The determined brightness / contrast adjustment is performed and transmitted from the videophone application 37 to the other party.

  In the present embodiment, the background image concealment process is executed by the camera driver 36a, but may be executed by an application program, a utility program, or an OS. Furthermore, the camera device 25 may execute part or all of the background image concealment process.

  In the present embodiment, the image data with the background hidden is transmitted by the videophone application 37. However, the present invention is not limited to this. For example, the mail application attaches the image data. It can also be applied to the case of transmission.

  In this embodiment, a notebook PC is exemplified as the information processing apparatus. However, the present invention is not limited to this, and can be applied to a desktop PC, a PDA, a mobile phone, and the like.

  As described above, the background image concealment method, the background image concealment device, and the computer-executable program according to the present invention are suitable for concealing the background of the subject to be imaged when transferring captured image data.

DESCRIPTION OF SYMBOLS 1 Imaging means 2 Face detection means 3 Lightness comparison means 4 Exposure amount control means 5 Lightness adjustment means 6 Communication means 10 Notebook PC
DESCRIPTION OF SYMBOLS 12 Main body side housing | casing 13 Display side housing | casing 14 Input part 15 Microphone 16a, 16b Speaker 17 LCD (liquid crystal display)
18 Camera 19a, 19b Connecting part (hinge part)
25 Camera Device 26 Camera Processing Circuit 31 CPU
32 ROM
33 Memory 34 HDD (Hard Disk)
35 OS
36 Driver 36a Camera Driver 37 Videophone Application Program (Videophone Application)
DESCRIPTION OF SYMBOLS 40 Image analysis part 41 Face recognition part 42 Face lightness detection part 43 Background lightness detection part 44 Background secrecy control part 45 Face-likeness evaluation part 46 Background change detection part

Claims (8)

An imaging step in which the imaging means images a subject and outputs image data;
A face detection step in which a face detection means detects a face region from the image data;
Comparison in which brightness comparison means compares the brightness of the detected face area of the image data with the background area to determine whether the brightness of the background area is greater than the brightness of the face area by a predetermined amount or more. Process,
An exposure amount setting step in which the exposure control means sets the exposure amount of the imaging means to be high when the brightness of the background area is greater than the brightness of the face area by a predetermined amount;
A transmission step in which the communication means transmits image data captured by the imaging means at the set exposure amount to the other party in the imaging step;
A background image concealing method characterized by comprising: Furthermore, an adjustment step in which the brightness adjustment unit performs an adjustment to lower the brightness of the image data captured by the imaging unit with the set exposure amount in the imaging step;
Including
The background image concealment method according to claim 1, wherein in the transmission step, the image data adjusted in the adjustment step is transmitted to the other party.   The background image concealment method according to claim 2, wherein in the adjustment step, adjustment is performed to lower the brightness of image data captured by the imaging unit with the set exposure amount by a predetermined amount.   In the adjustment step, the imaging unit adjusts the brightness of the image data captured with the set exposure amount to be low and the contrast to be high so that the facial appearance evaluation value of the face region is maximized. The background image concealment method according to claim 2. 5. The exposure amount setting step of increasing the exposure amount by a specified amount when the brightness of the background region is greater than the brightness of the face region by a predetermined amount or more. The background image concealment method described in 1. In the exposure amount setting step, when the lightness of the background region is larger than the lightness of the face region by a predetermined amount or more, exposure is performed until the facial appearance evaluation value of the face region becomes a lower limit or in the exposure amount setting step 5. The exposure amount according to claim 1, wherein the exposure amount is increased until a change amount of background information with respect to a background region of the image data before setting the amount becomes a predetermined value or more. Background image concealment method. Imaging means for imaging a subject and outputting image data;
Face detection means for detecting a face area from the image data;
Brightness comparison means for comparing the brightness of the detected face area and background area of the image data to determine whether the brightness of the background area is greater than a predetermined amount than the brightness of the face area;
Exposure control means for setting the exposure amount of the imaging means high when the brightness of the background area is a predetermined amount or more greater than the brightness of the face area;
Communication means for transmitting image data captured by the imaging means with the set exposure amount to the other party; and
A background image concealing device comprising: A program installed in an information processing apparatus,
A face detection step of detecting a face region from the image data captured by the imaging means;
A comparison step of comparing the brightness of the detected face area and background area of the image data to determine whether the brightness of the background area is greater than a predetermined amount than the brightness of the face area;
An exposure amount setting step of setting the exposure amount of the imaging means high when the brightness of the background region is larger than the brightness of the face region by a predetermined amount;
A transmission step in which the imaging means transmits image data captured with the set exposure amount to the other party;
A computer-executable program characterized by causing a computer to execute.

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