Imaging system, imaging method, and computer program

Abstract

To appropriately capture an image around the eyes of a subject.SOLUTION: An imaging system (10) includes first control means (110) that controls imaging means (20) to capture a first image of a subject (500) at a first pixel density, detection means (120) that detects the position of the subject's eyes from the first image, setting means (130) that sets a peripheral area around the subject's eyes on the basis of the position of the eyes, and second control means (140) that controls the imaging means to capture a second image of the peripheral area at a second pixel density higher than the first pixel density. According to such an imaging system, it is possible to appropriately capture an image around the eyes of the subject.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to the technical fields of an imaging system, an imaging method, and a computer program for imaging a subject. [Background technology]

[0002] Known systems of this type capture images to be used for iris authentication. For example, Patent Document 1 discloses a technology for detecting the face and eyes of a subject and identifying an iris region of interest. Patent Document 2 discloses a technology for generating a low-resolution image from a high-resolution image and performing pupil detection from the low-resolution image.

[0003] As another related technique, Patent Document 3 discloses a technique for generating a composite image with a wide angle of view by synthesizing a plurality of images. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2007-504562 [Patent Document 2] JP 2017-134542 A [Patent Document 3] JP 2012-191486 A Summary of the Invention [Problem to be solved by the invention]

[0005] Iris cameras that capture images for iris authentication are generally set to have high pixel counts and a narrow angle of view. For this reason, due to restrictions on communication speed and angle of view, it is difficult for an iris camera to capture a wide-angle image that can detect the subject's eye position. The above cited documents do not mention such problems, and there is room for improvement.

[0006] This disclosure has been made in consideration of the above-mentioned problems, and an object of the disclosure is to provide an imaging system, an imaging method, and a computer program capable of appropriately capturing an image of the area around the eyes of a subject. [Means for solving the problem]

[0007] One aspect of the imaging system of this disclosure includes a first control means for controlling the imaging means to capture a first image of a subject at a first pixel density, a detection means for detecting the position of the subject's eyes from the first image, a setting means for setting a peripheral area around the subject's eyes based on the position of the eyes, and a second control means for controlling the imaging means to capture a second image of the peripheral area at a second pixel density higher than the first pixel density.

[0008] One aspect of the imaging method of this disclosure includes controlling an imaging means to capture a first image of a subject at a first pixel density, detecting the position of the subject's eyes from the first image, setting a peripheral region around the subject's eyes based on the position of the eyes, and controlling the imaging means to capture a second image of the peripheral region at a second pixel density higher than the first pixel density.

[0009] One aspect of the computer program of the disclosure operates a computer to control an imaging means to capture a first image of a subject at a first pixel density, detect the position of the subject's eyes from the first image, set a peripheral region around the subject's eyes based on the position of the eyes, and control the imaging means to capture a second image of the peripheral region at a second pixel density higher than the first pixel density. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a hardware configuration of an imaging system according to a first embodiment. [Diagram 2] 1 is a block diagram showing a functional configuration of an imaging system according to a first embodiment. [Diagram 3]4 is a flowchart showing the flow of operations of the imaging system according to the first embodiment. [Figure 4] 4A to 4C are conceptual diagrams showing imaging timings and imaging ranges of a first image and a second image according to the first embodiment. [Diagram 5] FIG. 11 is a block diagram showing a functional configuration of an imaging system according to a second embodiment. [Figure 6] 10 is a flowchart showing the flow of operations of the imaging system according to the second embodiment. [Figure 7] 13 is a conceptual diagram showing the imaging timing and imaging range of a first image and a second image according to the second embodiment. FIG. [Figure 8] FIG. 11 is a block diagram showing a functional configuration of an imaging system according to a third embodiment. [Figure 9] 13 is a flowchart showing the flow of operations of the imaging system according to the third embodiment. [Figure 10] FIG. 13 is a block diagram showing a functional configuration of an imaging system according to a fourth embodiment. [Figure 11] 13 is a flowchart showing the flow of operations of the imaging system according to the fourth embodiment. [Figure 12] 13 is a conceptual diagram showing the imaging timing and imaging range of a first image and a second image according to the fifth embodiment. FIG. [Figure 13] 11 is a conceptual diagram showing an operation when capturing a first image with a low resolution by thinning out pixels. FIG. [Figure 14] 11 is a conceptual diagram showing an operation when capturing a first image by restricting an imaging area to a small size. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of an imaging system, an imaging method, and a computer program will be described with reference to the drawings.

[0012] First Embodiment An imaging system according to a first embodiment will be described with reference to FIGS. 1 to 4. FIG.

[0013] (Hardware configuration) First, the hardware configuration of an imaging system 10 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the hardware configuration of the imaging system according to the first embodiment.

[0014] 1, an imaging system 10 according to the first embodiment includes a processor 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, and a storage device 14. The imaging system 10 may further include an input device 15 and an output device 16. The processor 11, the RAM 12, the ROM 13, the storage device 14, the input device 15, and the output device 16 are connected via a data bus 17.

[0015] The processor 11 reads a computer program. For example, the processor 11 is configured to read a computer program stored in at least one of the RAM 12, the ROM 13, and the storage device 14. Alternatively, the processor 11 may read a computer program stored in a computer-readable storage medium using a storage medium reading device (not shown). The processor 11 may acquire (i.e., read) a computer program from a device (not shown) disposed outside the imaging system 10 via a network interface. The processor 11 controls the RAM 12, the storage device 14, the input device 15, and the output device 16 by executing the computer program that the processor 11 reads. In particular, in this embodiment, when the processor 11 executes the computer program that the processor 11 reads, a functional block for imaging a subject is realized in the processor 11. In addition, the processor 11 may be one of a central processing unit (CPU), a graphics processing unit (GPU), a field-programmable gate array (FPGA), a demand-side platform (DSP), and an application specific integrated circuit (ASIC), or may be a plurality of devices in parallel.

[0016] The RAM 12 temporarily stores a computer program executed by the processor 11. The RAM 12 temporarily stores data that is temporarily used by the processor 11 when the processor 11 is executing the computer program. The RAM 12 may be, for example, a D-RAM (Dynamic RAM).

[0017] The ROM 13 stores computer programs executed by the processor 11. The ROM 13 may also store other fixed data. The ROM 13 may be, for example, a programmable ROM (P-ROM).

[0018] The storage device 14 stores data to be stored long-term by the imaging system 10. The storage device 14 may operate as a temporary storage device for the processor 11. The storage device 14 may include, for example, at least one of a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device.

[0019] The input device 15 is a device that receives input instructions from a user of the imaging system 10. The input device 15 may include, for example, at least one of a keyboard, a mouse, and a touch panel.

[0020] The output device 16 is a device that outputs information related to the imaging system 10 to the outside. For example, the output device 16 may be a display device (for example, a display) that can display information related to the imaging system 10.

[0021] (Functional configuration) Next, the functional configuration of the imaging system 10 according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the functional configuration of the imaging system according to the first embodiment.

[0022] 2, the imaging system 10 according to the first embodiment is connected to an iris camera 20. The imaging system 10 includes, as processing blocks for realizing its functions, a first control unit 110, an eye position detection unit 120, an ROI setting unit 130, and a second control unit 140. The first control unit 110, the eye position detection unit 120, the ROI setting unit 130, and the second control unit 140 may be realized, for example, in the above-mentioned processor 11 (see FIG. 1).

[0023] The first control unit 110 is configured to be able to control the iris camera 20 to capture a first image of the subject. The first image is an image used to detect the position of the subject's eyes, and is captured at a relatively low first pixel density. The first image is captured so that, for example, the entire subject fits within the imaging range.

[0024] The eye position detection unit 120 detects the subject's eye position (i.e., where the eyes are located) using the first image captured under the control of the first control unit 110. Note that a method for detecting the subject's eye position from an image can be appropriately adopted from existing technologies, so a detailed description will be omitted here. Information regarding the subject's eye position detected by the eye position detection unit 120 is configured to be output to the ROI setting unit.

[0025] The ROI setting unit 130 is configured to be able to set an ROI (Region Of Interest) for capturing an image of the iris of the subject based on the eye position of the subject detected by the eye position detection unit 120. The ROI is set as a region through which the subject's eyes are likely to pass at the focal point of the iris camera 20. Note that a method for setting the ROI from the eye position can be appropriately adopted from existing techniques, so a more detailed description will be omitted here. Information regarding the ROI set by the ROI setting unit 130 is configured to be output to the second control unit 140.

[0026] The second control unit 140 is configured to be able to control the iris camera 20 to capture a second image of the subject. The second image is an image captured as an image of the area set by the ROI setting unit 130, and is captured at a second pixel density higher than the first pixel density (i.e., the pixel density when the first image is captured). As a result, the second image is an image of the area around the subject's eyes captured at a high resolution.

[0027] (Operation flow) Next, the flow of operations of the imaging system 10 according to the first embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the flow of operations of the imaging system according to the first embodiment.

[0028] 3, when the imaging system 10 according to the first embodiment operates, the first control unit 110 first controls the iris camera 20 to capture a first image of a subject (step S101). The first image is captured at a first pixel density.

[0029] Next, the eye position detection unit 120 detects the eye positions of the subject from the first image (step S102), and the ROI setting unit 130 sets an ROI based on the detected eye positions (step S103).

[0030] Next, the second control unit 140 controls the iris camera 20 to capture a second image in the set ROI (step S104). The second image is captured at a second pixel density higher than the first pixel density.

[0031] (Technical effect) Next, technical effects obtained by the imaging system 10 according to the first embodiment will be described with reference to Fig. 4. Fig. 4 is a conceptual diagram showing the imaging timing and imaging range of the first image and the second image according to the first embodiment.

[0032] As shown in FIG. 4, in the imaging system 10 according to the first embodiment, after a first image is captured at a first pixel density, a second image is captured at a second pixel density. Here, in particular, since the first pixel density is lower than the second pixel density, the amount of data of the first image can be relatively small. Therefore, it is possible to prevent the amount of data of the first image, which requires a relatively wide angle of view, from becoming large. As a result, it is possible to shorten the time required for communication and processing of the first image, and it is possible to smoothly execute the processes from capturing the first image to capturing the second image (for example, the process of detecting the eye position, the process of setting the ROI, etc.).

[0033] It should be noted that a method of separately installing a dedicated camera (i.e., a low-resolution camera) for capturing the first image can be considered, but in that case, the increase in cost and the high level of complexity of the system can become problems. However, according to the imaging system of the first embodiment, the iris camera 20 can capture the first image (i.e., an image for detecting the eye position and setting the ROI) and the second image (i.e., a high-resolution image of the iris). Therefore, the iris image of the subject can be captured appropriately without incurring the above-mentioned increase in cost and high level of complexity of the system. Furthermore, if there are multiple types of cameras, the user needs to face each camera, which may make the user aware of the presence of the cameras and may be troublesome for the user. According to the imaging system 10 of the first embodiment, the eye position can be identified and the iris area can be identified with a low-quality image even with an iris camera with a narrow angle of view. In addition, it is not necessary for the user to be aware of the camera.

[0034] <Modification> The following describes modified examples of the first embodiment. Note that the following modified examples can be combined with each other.

[0035] (First Modification) For example, the first control unit 110 may capture the first image when the subject reaches a predetermined trigger position. The timing when the subject reaches the trigger position may be detected by various sensors installed around the trigger position.

[0036] (Second Modification) For example, the second control unit 140 may capture the second image at the timing when the subject reaches a preset focus point of the iris camera 20. The second control unit 140 may predict the timing when the subject reaches the focus point, and capture a plurality of second images consecutively around that timing.

[0037] (Third Modification) The second image captured under the control of the second control unit 140 may be input to a biometric authentication unit (not shown) and used for iris authentication of the subject. This biometric authentication unit may be provided as a part of the imaging system 10, or may be provided outside the imaging system 10 (for example, an external server or cloud). Since existing technology can be appropriately adopted for authentication processing using the iris image (i.e., the second image), a detailed description thereof will be omitted here.

[0038] <Second embodiment> An imaging system 10 according to the second embodiment will be described with reference to Fig. 5 to Fig. 7. The second embodiment differs from the first embodiment described above only in some configurations and operations, and other parts are generally similar. Therefore, hereinafter, parts that differ from the first embodiment will be described in detail, and descriptions of other overlapping parts will be omitted as appropriate.

[0039] (Hardware configuration) The hardware configuration of the imaging system 10 according to the second embodiment may be the same as the hardware configuration of the first embodiment described in Fig. 1. Therefore, a description of the hardware configuration of the imaging system 10 according to the second embodiment will be omitted.

[0040] (Functional configuration) Next, the functional configuration of the imaging system 10 according to the second embodiment will be described with reference to Fig. 5. Fig. 5 is a block diagram showing the functional configuration of the imaging system according to the second embodiment. In Fig. 5, the same components as those shown in Fig. 2 are denoted by the same reference numerals.

[0041] 5, the imaging system 10 according to the second embodiment is connected to each of a first iris camera 21, a second iris camera 22, and a third iris camera 23 (hereinafter, these may be collectively referred to as "iris camera 20"). That is, the imaging system 10 according to the second embodiment is configured to be able to control imaging by the multiple iris cameras 20. The imaging system 10 also includes a first control unit 110, an eye position detection unit 120, an ROI setting unit 130, and a second control unit 140 as processing blocks for realizing the functions of the imaging system 10.

[0042] (Operation flow) Next, the flow of operations of the imaging system 10 according to the second embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the flow of operations of the imaging system according to the second embodiment. In Fig. 6, the same processes as those shown in Fig. 3 are denoted by the same reference numerals.

[0043] 6, when the imaging system 10 according to the second embodiment operates, the first control unit 110 first controls each of the first iris camera 21, the second iris camera 22, and the third iris camera 23 to capture a first image of the subject (step S201). Note that it is preferable that the first image is captured at the same timing in each iris camera 20, but there may be some lag in the capture timing.

[0044] Next, the eye position detection unit 120 detects the eye positions of the subject from the multiple first images (step S102).Then, the ROI setting unit 130 sets an ROI based on the detected eye positions (step S103).

[0045] Next, the second control unit 140 controls the iris camera 20 to capture the second image in the set ROI (step S104). The second image may be captured by one of the first iris camera 21, the second iris camera 22, and the third iris camera 23. That is, it is not necessary for all the iris cameras 20 to capture the second image separately. The iris camera 20 that captures the second image may be determined according to the ROI set by the ROI setting unit 130, for example. Specifically, the second image may be captured by the iris camera 20 that includes the ROI in its imaging range.

[0046] (Technical effect) Next, technical effects obtained by the imaging system 10 according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a conceptual diagram showing the imaging timing and imaging range of the first and second images according to the second embodiment. In Fig. 7, the same reference symbols are used for the same components as those shown in Fig. 4.

[0047] As shown in FIG. 7, in the imaging system 10 according to the second embodiment, first images are captured by multiple iris cameras 20, and eye positions are detected and ROIs are set from the first images. Here, particularly when the first image is captured only once, depending on the situation, the eyes may not be included in the imaging range. However, if multiple first images are captured, a wider range can be captured, and as a result, the possibility of capturing the eye positions increases. Therefore, an appropriate ROI can be set from the eye positions, and the second image (i.e., a high-definition iris image) can be captured more appropriately.

[0048] Note that the multiple first images do not have to be captured using multiple iris cameras 20, and multiple first images may be captured by one iris camera 20. Specifically, for example, the position of one camera may be appropriately moved to capture the first images from multiple angles. Even in this case, the above-mentioned technical effect can be obtained by synthesizing the multiple first images to generate a wide-angle image.

[0049] <Third embodiment> An imaging system 10 according to the third embodiment will be described with reference to Fig. 8 and Fig. 9. The third embodiment differs from the first and second embodiments in some configurations and operations, and other parts are generally similar. Therefore, hereinafter, parts that differ from the first and second embodiments will be described in detail, and descriptions of other overlapping parts will be omitted as appropriate.

[0050] (Hardware configuration) The hardware configuration of the imaging system 10 according to the third embodiment may be the same as the hardware configuration of the first embodiment described with reference to Fig. 1. Therefore, a description of the hardware configuration of the imaging system 10 according to the third embodiment will be omitted.

[0051] (Functional configuration) Next, a functional configuration of an imaging system 10 according to a third embodiment will be described with reference to Fig. 8. Fig. 8 is a block diagram showing the functional configuration of the imaging system according to the second embodiment. In Fig. 8, the same components as those shown in Figs. 2 and 5 are denoted by the same reference numerals.

[0052] 8, the imaging system 10 according to the third embodiment includes, as processing blocks for realizing the functions thereof, a first control unit 110, an eye position detection unit 120, an ROI setting unit 130, a second control unit 140, and an image synthesis unit 210. That is, the imaging system 10 according to the second embodiment is configured to further include an image synthesis unit 210 in addition to the configuration of the second embodiment (see FIG. 5).

[0053] The image synthesis unit 210 is configured to be able to synthesize the first images captured by the first iris camera 21, the second iris camera 22, and the third iris camera 23. The first iris camera 21, the second iris camera 22, and the third iris camera 23 are installed so that their imaging ranges do not overlap significantly. Therefore, when the first images captured by the iris cameras 20 are synthesized, a single wide-angle image can be generated. The wide-angle image generated by the image synthesis unit 210 is configured to be output to the eye position detection unit 110. The image synthesis unit 210 may be realized, for example, in the above-mentioned processor 11 (see FIG. 1).

[0054] (Operation flow) Next, the flow of operations of the imaging system 10 according to the third embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing the flow of operations of the imaging system according to the third embodiment. In Fig. 9, the same processes as those shown in Figs. 3 and 6 are denoted by the same reference numerals.

[0055] As shown in FIG. 9, when the imaging system 10 according to the third embodiment operates, first, the first control unit 110 controls each of the first iris camera 21, the second iris camera 22, and the third iris camera 23 to capture a first image of the subject (step S201).

[0056] Next, the image synthesis unit 210 synthesizes the multiple first images captured by the first iris camera 21, the second iris camera 22, and the third iris camera 23 (step S202). Then, the eye position detection unit 120 detects the eye position of the subject from the wide-angle image obtained by synthesizing the multiple first images (step S102). Then, the ROI setting unit 130 sets the ROI based on the detected eye position (step S103).

[0057] Next, the second control unit 140 controls the iris camera 20 to capture a second image in the set ROI (step S104).

[0058] (Technical effect) Next, technical effects obtained by the imaging system 10 according to the third embodiment will be described.

[0059] As described in Fig. 8 and Fig. 9, in the imaging system 10 according to the third embodiment, images captured by the multiple iris cameras 20 are combined to generate one wide-angle image. Here, the iris camera 20 is often set to have a relatively narrow angle of view since it is required to capture an image of the iris of the subject with high resolution. However, according to the imaging system 10 according to the third embodiment, a wide-angle image is generated from the first images captured by the multiple iris cameras 20. Therefore, even if the angle of view of each iris camera is narrow, a wide-angle image suitable for detecting the eye position can be obtained.

[0060] <Fourth embodiment> An imaging system 10 according to the fourth embodiment will be described with reference to Fig. 10 and Fig. 11. The fourth embodiment differs from the first to third embodiments in some configurations and operations, and other parts are generally similar. Therefore, hereinafter, parts that differ from the first to third embodiments will be described in detail, and descriptions of other overlapping parts will be omitted as appropriate.

[0061] (Hardware configuration) The hardware configuration of the imaging system 10 according to the fourth embodiment may be the same as the hardware configuration of the first embodiment described in Fig. 1. Therefore, a description of the hardware configuration of the imaging system 10 according to the fourth embodiment will be omitted.

[0062] (Functional configuration) Next, a functional configuration of the imaging system 10 according to the fourth embodiment will be described with reference to Fig. 10. Fig. 10 is a block diagram showing the functional configuration of the imaging system according to the fourth embodiment. In Fig. 10, the same components as those shown in Figs. 2, 5, and 8 are denoted by the same reference numerals.

[0063] 10, the imaging system 10 according to the fourth embodiment includes, as processing blocks for realizing its functions, a first control unit 110, an eye position detection unit 120, an ROI setting unit 130, a second control unit 140, and an eye region determination unit 220. That is, the imaging system 10 according to the fourth embodiment is configured to further include an eye region determination unit 220 in addition to the configuration of the second embodiment (see FIG. 5).

[0064] The eye region determination unit 220 is configured to be able to determine whether or not an eye region is included in each of the first images captured by the first iris camera 21, the second iris camera 22, and the third iris camera 23. In other words, the eye region determination unit 220 is configured to be able to determine which image, among the multiple first images captured by the second iris camera 22 and the third iris camera 23, includes an eye region. The determination result of the eye region determination unit 220 (i.e., information on the first image including the eye region) is configured to be output to the eye position detection unit 110. Note that the eye region determination unit 220 may be realized, for example, in the above-mentioned processor 11 (see FIG. 1).

[0065] (Operation flow) Next, the flow of operations of the imaging system 10 according to the fourth embodiment will be described with reference to Fig. 11. Fig. 11 is a flowchart showing the flow of operations of the imaging system according to the fourth embodiment. In Fig. 11, the same processes as those shown in Figs. 3, 6, and 9 are denoted by the same reference numerals.

[0066] As shown in FIG. 11, when the imaging system 10 according to the fourth embodiment operates, first, the first control unit 110 controls each of the first iris camera 21, the second iris camera 22, and the third iris camera 23 to capture a first image of the subject (step S201).

[0067] Next, the eye region determination unit determines whether or not an eye region is present in the first images captured by the first iris camera 21, the second iris camera 22, and the third iris camera 23 (step S203). Then, the eye position detection unit 120 detects the subject's eye position from the first images determined to contain an eye region (step S102). Then, the ROI setting unit 130 sets an ROI based on the detected eye position (step S103).

[0068] Next, the second control unit 140 controls the iris camera 20 to capture a second image in the set ROI (step S104).

[0069] (Technical effect) Next, technical effects obtained by the imaging system 10 according to the fourth embodiment will be described.

[0070] 10 and 11, in the imaging system 10 according to the fourth embodiment, it is determined whether or not the first images captured by the multiple iris cameras 20 include eye regions, and eye positions are detected from the first images that include eye regions. This makes it possible to detect eye positions more efficiently than when eye positions are detected from all of the first images.

[0071] <Fifth embodiment> An imaging system 10 according to a fifth embodiment will be described with reference to Fig. 12. The fifth embodiment specifically describes another method for capturing a first image, and the hardware configuration, functional configuration, and operation flow of the system may be the same as those of the first to fifth embodiments described above. Therefore, in the following, only the parts that differ from the first to fifth embodiments will be described in detail, and the description of the other overlapping parts will be omitted as appropriate.

[0072] (Multiple captures of the first image) First, the timing of capturing a first image by the imaging system 10 according to the fifth embodiment will be described in detail with reference to Fig. 12. Fig. 12 is a conceptual diagram showing the timing of capturing a first image and a second image and the imaging range according to the fifth embodiment. In Fig. 12, the same reference numerals are used for the same components as those shown in Figs. 4 and 7.

[0073] As shown in Fig. 12, in the imaging system according to the fifth embodiment, the first iris camera 21, the second iris camera 22, and the third iris camera 23 each capture a first image at a different timing. Specifically, the first iris camera 21 captures the first image at the timing when the subject 500 reaches the first trigger point. The second iris camera 22 captures the first image at the timing when the subject 500 reaches the second trigger point. The third iris camera 23 captures the first image at the timing when the subject 500 reaches the third trigger point. In this way, if multiple trigger points are installed at different times, multiple first images are captured at different times.

[0074] The eye positions of subject 500 may be detected from each of the plurality of first images captured as described above. For example, the eye positions may be detected using all of the plurality of first images, or the eye positions may be detected using only the first images that include the eye regions by determining the first images that include the eye regions from the plurality of first images.

[0075] It is preferable that the multiple iris cameras 20 are set so that the overlapping areas of their imaging ranges are sufficiently large. In this way, even if subjects 500 are of different heights, at least one iris camera 20 can capture an image of the face of subject 500 without interruption.

[0076] (Technical effect) Next, technical effects obtained by the imaging system 10 according to the fifth embodiment will be described.

[0077] 12, in the imaging system 10 according to the fifth embodiment, a plurality of first images are captured at different timings. Even in this case, it is possible to detect the eye position of the subject 500, as in the case where a plurality of first images are captured simultaneously.

[0078] Sixth Embodiment An imaging system 10 according to the sixth embodiment will be described with reference to Fig. 13. The third embodiment specifically describes a method for reducing the resolution when capturing a first image, and the hardware configuration, functional configuration, and operation flow of the system may be the same as those of the first to fifth embodiments described above. Therefore, in the following, only the parts that differ from the first to fifth embodiments will be described in detail, and the description of the other overlapping parts will be omitted as appropriate.

[0079] (Reducing resolution by thinning out pixels) First, the image quality reduction of the first image in the imaging system 10 according to the sixth embodiment will be described with reference to Fig. 13. Fig. 13 is a conceptual diagram showing the operation when capturing a first image with a low resolution by thinning out pixels.

[0080] As shown in FIG. 13, in the imaging system 10 according to the sixth embodiment, the resolution of the first image is reduced by thinning out the pixels of the iris camera 20. Specifically, the first control unit 110 reduces the number of pixels read out when capturing the first image, for example, using a technique such as binning. This reduces the pixel density of the first image. On the other hand, the second control unit 140 prevents the pixels from being thinned out when capturing the second image (however, the captured area is limited to the ROI). In this way, the pixel density of the second image is higher than that of the first image.

[0081] The amount of pixel thinning may vary depending on the location of the image capture area. That is, the amount of pixel thinning may not be uniform throughout the entire image capture area. For example, the amount of pixel thinning may be small in areas where eye regions are likely to exist, and large in areas where eye regions are unlikely to exist.

[0082] (Technical effect) Next, technical effects obtained by the imaging system 10 according to the sixth embodiment will be described.

[0083] 13, in the imaging system 10 according to the sixth embodiment, the resolution of the first image is reduced by thinning out pixels. This prevents the amount of data of the first image from becoming large, and shortens the time required for communication and processing of the first image.

[0084] Seventh embodiment An imaging system 10 according to the seventh embodiment will be described with reference to Fig. 14. The seventh embodiment specifically describes a method for reducing the amount of data when capturing a first image, and the hardware configuration, functional configuration, and operation flow of the system may be the same as those of the first to sixth embodiments described above. Therefore, in the following, only the parts that differ from the first to sixth embodiments will be described in detail, and explanations of other overlapping parts will be omitted as appropriate.

[0085] (Limitation of imaging area) First, data amount reduction of the first image in the imaging system 10 according to the seventh embodiment will be described with reference to Fig. 14. Fig. 14 is a conceptual diagram showing the operation when the imaging area is restricted to a small size and the first image is captured.

[0086] As shown in Fig. 14, in the imaging system 10 according to the seventh embodiment, the amount of data of the first image is reduced by restricting (i.e. narrowing) the imaging area of ​​the iris camera 20. Specifically, the first control unit 110 does not read out pixels from at least one of the upper and lower end parts of the imaging area (e.g., an area where it is estimated that the subject's eyes are unlikely to be located) when capturing the first image. This reduces the amount of data of the first image. Note that the first image is captured with the pixels thinned out as described in the sixth embodiment, and therefore the pixel density is also reduced. Therefore, the amount of data of the first image is significantly reduced.

[0087] In addition to or instead of the above-mentioned upper end portion and lower end portion, pixels of at least one of the right end portion and the left end portion of the imaging area may not be read. For example, when the subject passes through the center of the passage (when an arrow is painted on the floor and the subject is guided to the center of the passage, etc.), the right end portion and the left end portion of the imaging area are unlikely to include the subject's eyes. Therefore, by not reading pixels of at least one of the right end portion and the left end portion of the imaging area, the data amount of the first image can be efficiently reduced.

[0088] (Technical effect) Next, technical effects obtained by the imaging system 10 according to the seventh embodiment will be described.

[0089] 14, in the imaging system 10 according to the seventh embodiment, the data amount of the first image is further reduced by narrowing the imaging area of ​​the iris camera 20. This prevents the data amount of the first image from becoming large, and makes it possible to shorten the time required for communication and processing of the first image.

[0090] <Additional Notes> The above-described embodiment may be further described as follows, but is not limited to the following.

[0091] (Appendix 1) The imaging system described in Appendix 1 is an imaging system characterized by comprising a first control means for controlling the imaging means to capture a first image of a subject at a first pixel density, a detection means for detecting the position of the subject's eyes from the first image, a setting means for setting a peripheral area around the subject's eyes based on the position of the eyes, and a second control means for controlling the imaging means to capture a second image of the peripheral area at a second pixel density higher than the first pixel density.

[0092] (Appendix 2) The imaging system described in Appendix 2 is the imaging system described in Appendix 1, characterized in that the first control means processes the pixels of the imaging means to thin out, thereby making the first pixel density lower than the second pixel density.

[0093] (Appendix 3) The imaging system described in Appendix 3 is the imaging system described in Appendix 1 or 2, characterized in that the first control means reduces the amount of data of the first image by limiting the imaging area of ​​the imaging means to a small size.

[0094] (Appendix 4) The imaging system described in Appendix 4 is the imaging system described in any one of Appendixes 1 to 3, characterized in that the imaging means includes a plurality of cameras, and the first control means controls the imaging means to capture the first image with each of the plurality of cameras.

[0095] (Appendix 5) The imaging system described in Appendix 5 is the imaging system described in any one of Appendixes 1 to 4, characterized in that the detection means detects the position of the subject's eyes from a composite image formed by combining a plurality of the first images.

[0096] (Appendix 6) The imaging system described in Appendix 6 is the imaging system described in any one of Appendixes 1 to 5, characterized in that the first control means controls the imaging means to capture the first image when the subject reaches a predetermined trigger position.

[0097] (Appendix 7) The imaging system described in Appendix 7 is the imaging system described in any one of Appendixes 1 to 6, characterized in that the second imaging means controls the imaging means to capture the second image when the subject reaches a predetermined focus point.

[0098] (Appendix 8) The imaging system described in Supplementary Note 8 is the imaging system according to any one of claims 1 to 7, further comprising an authentication unit that performs iris authentication of the subject by using the second image.

[0099] (Appendix 9) The imaging method described in Appendix 9 is an imaging method characterized by controlling an imaging means to capture a first image of a subject at a first pixel density, detecting the position of the subject's eyes from the first image, setting a peripheral region around the subject's eyes based on the position of the eyes, and controlling the imaging means to capture a second image of the peripheral region at a second pixel density higher than the first pixel density.

[0100] (Appendix 10) The computer program described in Appendix 10 is a computer program characterized by operating a computer to control an imaging means to capture a first image of a subject at a first pixel density, detect the position of the subject's eyes from the first image, set a peripheral region around the subject's eyes based on the position of the eyes, and control the imaging means to capture a second image of the peripheral region at a second pixel density higher than the first pixel density.

[0101] This disclosure may be modified as appropriate within the scope that does not contradict the gist or concept of the invention that can be read from the claims and the entire specification, and imaging systems, imaging methods, and computer programs incorporating such modifications are also included in the technical concept of this disclosure. [Explanation of symbols]

[0102] 10. Imaging System 20. Iris Camera 21 First Iris Camera 22 Second Iris Camera 23 3rd Iris Camera 110 First Control Section 120 Eye position detection unit 130 ROI setting section 140 Second Control Section 210 Image synthesis department 220 Target Area Judgment Department 500 written type

Claims

1. a first control means for controlling the imaging means to capture a first image of a subject at a first pixel density when the subject is in a first position; a detection means for detecting an eye position of the subject from the first image captured when the subject is in the first position; a setting means for setting a peripheral area that is a predicted peripheral area of ​​the subject's eyes when the subject is in the second position, based on the position of the eyes of the subject when the subject is in the first position; a second control means for controlling the imaging means to capture a second image of the surrounding area at a second pixel density higher than the first pixel density when the subject is at the second position; Equipped with the first control means controls the plurality of imaging means to capture, when the subject is at the first position, the first images including different regions of the subject at the first pixel density, respectively; The detection means detects the position of the eyes of the subject from a composite image obtained by combining a plurality of the first images.

1. An imaging system comprising:

2. The first control means limits the imaging area to a small size by a first operation that does not read out pixels in at least one of an upper end portion and a lower end portion of the imaging area of ​​the imaging means, thereby reducing the amount of data of the first image.

2. The imaging system according to claim 1 .

3. The first control means limits the imaging area to a small size by a second operation of not reading out pixels in at least one of a right end portion and a left end portion of the imaging area of ​​the imaging means, thereby reducing the amount of data of the first image.

2. The imaging system according to claim 1 .

4. The second control means, when the subject is at the second position, causes one of the plurality of image capturing means that is capable of capturing an image of the surrounding area to capture an image of the surrounding area at the second pixel density.

2. The imaging system according to claim 1 .

5. controlling an imaging means to capture a first image of a subject at a first pixel density when the subject is in a first position; detecting an eye position of the subject from the first image captured when the subject is in the first position; setting a peripheral region that is a predicted peripheral area of ​​the eye of the subject when the subject is in the second position based on a position of the eye of the subject when the subject is in the first position; controlling the imaging means to capture a second image of the surrounding area at a second pixel density higher than the first pixel density; controlling the plurality of imaging means to capture, when the subject is at the first position, the first images including different regions of the subject at the first pixel density; Detecting the position of the subject's eyes from a composite image obtained by combining a plurality of the first images.

13. An imaging method comprising:

6. controlling an imaging means to capture a first image of a subject at a first pixel density when the subject is in a first position; detecting an eye position of the subject from the first image captured when the subject is in the first position; setting a peripheral region that is a predicted peripheral area of ​​the eye of the subject when the subject is in the second position based on a position of the eye of the subject when the subject is in the first position; controlling the imaging means to capture a second image of the surrounding area at a second pixel density higher than the first pixel density when the subject is at the second position; controlling the plurality of imaging means to capture, when the subject is at the first position, the first images including different regions of the subject at the first pixel density; Detecting the position of the subject's eyes from a composite image obtained by combining a plurality of the first images. A computer program for causing a computer to operate in such a manner.

Images