Information processing system, lighting control device, lighting control method, and program

Abstract

To prevent exposure of strong light to a subject in close proximity.SOLUTION: An illuminator (300) emits light toward a moving subject. A controller (500) controls the light emitted from the illuminator (300) such that the amount of light applied to the subject is below a certain level. For example, when the illuminator (300) emits pulsed light, the controller (500) may control at least one of the pulse width and pulse intensity of the light, thereby controlling the amount of light radiated to the subject. The controller (500) may control the light emitted from the illuminator (300) according to, for example, the distance between the illuminator (300) and the subject.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a lighting control device, a method, a system, and a computer-readable medium, and in particular to a lighting control device, a method, a system, and a computer-readable medium that may be used in iris-based authentication applications. [Background technology]

[0002] Biometric authentication using irises is known. In this biometric authentication, an image of the subject's iris is captured using an imaging device, and features are extracted from the captured iris pattern. When authenticating a subject, the extracted features are compared with features registered in a database in advance, and pass / fail is determined based on the comparison score. On the other hand, when registering a subject to be authenticated, the extracted features are added to the database.

[0003] As described in Non-Patent Document 1, the iris, which is a doughnut-shaped tissue surrounding the pupil, has a very complex pattern and is unique to each individual. In addition, in imaging the iris, near-infrared light is irradiated onto the subject's eye.

[0004] As described in Non-Patent Document 2, in imaging an iris, an iris image is captured at a resolution that allows the radius of the iris to be expressed by 100 to 140 pixels. The wavelength of near-infrared light irradiated to the subject's eye is 700 nm to 900 nm. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Hosoya, "Iris-based authentication system," Biomedical Engineering 44(1), page 33-39, 2006 [Non-Patent Document 2] Daugman, "How Iris Recognition Works," https: / / www.cl.cam.ac.uk / ~jgd1000 / irisrecog.pdf Summary of the Invention [Problem to be solved by the invention]

[0006] The diameter of the iris is about 1 cm, and if its radius were to be expressed using 100 pixels, the granularity would be 50 μm. As the iris pattern is so fine, it is difficult to prevent strong light from being irradiated onto nearby subjects while maintaining brightness sufficient to capture an image of the iris pattern with sufficient quality for authentication and matching, especially when the subject is moving and the distance between the subject and the imaging means is long.

[0007] In view of the above circumstances, an object of the present disclosure is to provide a lighting control device, method, system, and computer-readable medium that can prevent strong light from being irradiated onto nearby subjects. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present disclosure provides, as a first aspect, a lighting control system including a guidance means for guiding a subject, a lighting means for shining light on the subject, an imaging means for imaging the subject, and a control means for controlling the amount of light irradiated to the subject to be equal to or less than a certain level.

[0009] In a second aspect, the present disclosure provides a lighting control device including a control means for controlling light emitted from a lighting means such that the amount of light irradiated onto a moving subject from the lighting means is equal to or less than a certain level.

[0010] In a third aspect, the present disclosure provides a lighting control method for controlling light emitted from a lighting means such that the amount of light irradiated onto a moving subject from the lighting means is equal to or less than a certain level.

[0011] In a fourth aspect, the present disclosure provides a computer-readable medium storing a program for causing a computer to execute a process of controlling light emitted from an illumination means such that the amount of light irradiated onto a moving subject from the illumination means is equal to or less than a certain level. Effect of the Invention

[0012] The lighting control device, method, system, and computer-readable medium according to the present disclosure can prevent strong light from being irradiated onto nearby subjects. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram illustrating an image processing system including a lighting control system according to an embodiment of the present disclosure. [Diagram 2] FIG. 4 is a diagram showing iris image capture control. [Diagram 3] 4 is a flowchart showing an operation procedure in the image processing system. [Figure 4] FIG. 1 is a block diagram showing an example of the configuration of a computer device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Prior to describing the embodiments of the present disclosure, the problem will be quantified. In the following, the following conditions assumed as operating conditions of automated border control systems (ABC) will be described as an example. The distance between the subject and the imaging means (the distance between the subject and the gate) is 2 m, and the horizontal field of view, i.e., the horizontal range that can cover both eyes of one subject, is 0.2 m. Also, the vertical field of view, i.e., the vertical range that can cover from the eyes of a tall subject, typically a male, to the eyes of a short subject, typically a female, is 0.4 m. Also, the walking speed (movement speed) of the subject relative to the gate is the average slow walking speed of an adult, for example, 1 m / s.

[0015] If a position 2 m away is set as the position (focus position) where the iris of a subject walking from that distance is focused and captured, it is necessary for the lighting means to irradiate the subject with light of a level that can capture an image of the iris pattern with a quality that allows for authentication and matching. For example, the amount of light irradiated on the subject at the focus position of 2 m away is 5 mW / cm2. 2 The amount of light irradiated to the subject is attenuated in proportion to the square of the distance between the subject and the light source, and the amount of light irradiated to the subject at a position 1 m away is 20 mW / cm 2 From the viewpoint of safety, it is not preferable to irradiate a strong light to a subject at a close distance.

[0016] On the other hand, the light intensity irradiated to the subject at a position 1 m away was 5 mW / cm 2 Then, the amount of light irradiated to the subject at a position 2 m away is 1.25 mW / cm 2 In imaging an iris pattern, for example, imaging may be performed with a short exposure time to prevent motion blurring of the iris pattern of a moving subject. Also, a large aperture value may be used in the imaging device to widen the depth of field to clearly capture the iris pattern of a moving subject, and a large amount of light may be lost in the optical system of the imaging device. For these reasons, if the amount of light is reduced, there is a possibility that the iris pattern cannot be imaged with a quality that can be used for authentication or matching.

[0017] Because the iris pattern is fine, it is difficult to prevent strong light from being shone on the subject close to the light while maintaining brightness sufficient to capture an image of the iris pattern with a quality sufficient for authentication and matching, when the distance between the subject and the light is long and the subject moves toward the light.

[0018] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 shows an image processing system including a lighting control system according to an embodiment of the present disclosure. The image processing system includes an overall image capturer 100, a guider 200, an illuminator 300, iris image capturers 401 to 404, and a controller 500. Note that, although the number of iris image capturers is four in FIG. 1, the number of iris image capturers is not particularly limited. The number of iris image capturers can be appropriately set according to the visual field range to be covered, the resolution of the available iris image capturers, and the like.

[0019] The whole image capturer (whole image capture means) 100 captures an image of the subject in a wide field of view so as to cover the whole subject from tall subjects to short subjects. The whole image capturer 100 may have a resolution capable of authenticating the subject by face.

[0020] The controller (control means) 500 monitors the overall image provided from the overall image capturer 100, and controls the guide (guiding means) 200, the illuminator (illumination means) 300, and the multiple iris image capturers (imaging means) 401-404. The functions of the controller 500 can be configured with hardware, but can also be realized with a computer program. The controller 500 determines the start of biometric authentication for the subject based on the overall image provided from the overall image capturer 100 or an external input.

[0021] The control performed by the controller 500 includes guidance control, lighting control, and iris image capture control. In the guidance control, the controller 500 supplies guidance control information for guiding the subject to the guider 200. The guider 200 guides the subject based on the guidance control information. The guider 200 includes, for example, a display and a speaker. The guider 200 presents, for example, an image or sound for notifying the start of biometric authentication on the display and the speaker. The guider 200 also presents, for example, an image or sound for guiding the subject's gaze to the iris image capturer on the display and the speaker.

[0022] In the illumination control, the controller 500 supplies the illumination device 300 with illumination control information for irradiating the subject with illumination light. The illumination device 300 irradiates the subject with light (e.g., near-infrared light) based on the illumination control information. The illumination device 300 includes an LED (Light Emitting Diode) as a light source and a synchronization signal generator. The amount of light irradiated from the illumination device 300 to the subject is determined by the value of the current supplied to the LED, the lighting time of the LED, and the lighting cycle, and the illumination control information includes these values. When the LED is not constantly lit, the lighting cycle of the LED is synchronized with the frame rate of the multiple iris imagers 401-404.

[0023] In the iris imaging control, the controller 500 determines an iris imager that can suitably image an area including the subject's eyes from among the multiple iris imagers 401-404, based on the overall video supplied from the overall imager 100. The controller 500 also determines the vertical position of the gaze area to be read out at high speed in the determined iris imager.

[0024] FIG. 2 is a diagram showing the state of iris imaging control. The details of iris imaging control will be described with reference to FIG. 2. Here, it is assumed that a general-purpose camera with 12M pixels (4000 pixels horizontally and 3000 pixels vertically) and 60 fps is used for the iris imagers 401 to 404. Such cameras are becoming popular as industrial cameras and the like. When capturing an image with a grain size of 50 μm that can be authenticated by iris, the horizontal and vertical fields of view of each iris imager are 0.2 m (4000×50 [μm]=0.2 [m]) and 0.15 m (3000×50 [μm]=0.15 [m]), respectively.

[0025] The iris imagers 401-404 are arranged so as to be stacked on top of each other in the vertical direction. At this time, the iris imagers 401-404 are arranged so that the image areas of the adjacent iris imagers partially overlap. The iris imagers 401-404 are arranged so that the image areas of the adjacent iris imagers overlap by 2.5 cm, for example. In this case, at a focusing position 2 m ahead, the four units can ensure a visual field of 0.2 m horizontally and 0.45 m vertically ((0.15-0.025)+(0.15-0.025-0.025)+(0.15-0.025-0.025)+(0.15-0.025)m). In other words, the required visual field of 0.2 m horizontally and 0.4 m vertically can be ensured. It is understood from the drawings and the above description that the iris imagers have the same visual field range and are arranged at different positions from each other.

[0026] If the frame rate of each iris imager is 60 fps, the required frame rate of 100 fps cannot be met as is. Here, industrial cameras and the like have a gaze area mode. In the gaze area mode, only a partial area set as the gaze area is read out, rather than the entire screen. By using this gaze area mode, the frame rate can be increased.

[0027] The controller 500 sets a gaze area in an arbitrary iris imager and reads out an image of the gaze area from the iris imager. In the example of FIG. 2, a partial area of ​​4000 pixels horizontally and 1500 pixels vertically, which is half of the screen, is set as the gaze area. In this case, the number of pixels per frame is half of the whole, so that the frame rate can be increased to 120 fps, which is twice the frame rate of 60 fps when the entire screen is read out. However, the horizontal and vertical fields of view of the partial area are 0.2 m and 0.75 m, respectively. Note that both eyes of a person are aligned horizontally. For this reason, in the gaze area mode, it is preferable to reduce the number of pixels vertically rather than horizontally so that both eyes can be imaged.

[0028] Under the condition that the eye region is not captured in the range where the image regions of the adjacent iris imagers overlap, only one of the four iris imagers 401-404 captures the eye region. The condition for reading out at 120 fps is a partial region within that iris imager. The controller 500 estimates an iris imager that can suitably capture the eye region among the multiple iris imagers 401-404, and estimates the vertical position of the gaze region to be read out at high speed within that iris imager.

[0029] The above estimation can be realized by the following method. The overall image capturer 100 has a resolution that allows the subject to be authenticated by face, and the controller 500 derives the subject's eye position in the overall image captured by the overall image capturer 100. The controller 500 derives the iris imager corresponding to the subject's eye position in the overall image and the eye position present within that imager, using the camera parameters and positional relationship of the overall image capturer 100 and each iris imager. By using the gaze area mode, a field of view wider than 0.2 m horizontally and 0.4 m vertically and a time resolution higher than 100 fps can be realized using a general-purpose camera.

[0030] Note that when the vertical position is changed in the above-mentioned gaze area mode, a delay occurs before imaging starts. Therefore, in the above estimation, an image captured of the subject at a distance of, for example, 3 m, beyond the 2 m distance that is the focal position of the iris imager, may be used. A camera with a resolution of about 2M pixels that can recognize the face of a subject at a distance of 3 m can be realized, and a camera with lower specifications than the iris imager can be used for the whole imager 100.

[0031] The controller 500 supplies iris imaging information to each of the iris imagers 401-404 based on the above-mentioned iris imaging control. The controller 500 supplies iris imaging information including the vertical position of the gaze area to the iris imager that captures the subject's eye area. The controller 500 may supply any iris imaging information to the other iris imagers. The controller 500 may supply iris imaging information including information on stopping the supply of iris images to the other iris imagers, for example, for the purpose of reducing the total data amount of iris images.

[0032] The iris imagers 401-404 each supply an iris image to the controller 500 based on iris imaging information supplied from the controller 500. At this time, the iris imagers 401-404 output an image (iris image) of the gaze area set by the controller 500 using the iris imaging information to the controller 500. The iris imagers 401-404 may apply lossy compression to the iris image of the gaze area and output the compressed iris image to the controller 500. For example, the iris imagers 401-404 compress the iris image of the gaze area using quantization (compression for each pixel), predictive coding and quantization (compression for a set of multiple pixels), or a combination of transform coding and quantization (compression for a set of multiple pixels). The controller 500 performs authentication and registration described in the background art using the iris images supplied from the iris imagers 401-404. If there is a next subject, or if authentication or enrollment fails, the controller 500 returns to the next process.

[0033] Here, in this embodiment, the controller 500 controls the light emitted from the illuminator 300 so that the amount of light irradiated from the illuminator 300 to the moving subject is equal to or less than a certain amount. The illuminator 300 emits light in a pulsed form, for example. In this case, the controller 500 controls the amount of light irradiated to the subject by controlling at least one of the pulse width and pulse intensity of the light emitted from the illuminator 300. The pulse width corresponds to the lighting time of an LED or the like, and the pulse intensity corresponds to the current supplied to the LED. The controller 500 controls the light emitted from the illuminator 300, for example, according to the distance between the illuminator 300 and the subject. The controller 500 calculates the amount of light emitted from the illuminator 300 using a predetermined calculation formula that is, for example, a function of the distance. Alternatively, the controller 500 may determine the amount of light emitted from the illuminator 300 according to the distance using a table that defines the relationship between the distance and the amount of light emitted from the illuminator 300.

[0034] In this embodiment, the illumination control performed by the controller 500 includes a first illumination control and a second illumination control. The controller 500 performs the first illumination control when the subject is located near or far from the focal position of the iris imager. The controller 500 performs the second illumination control after the subject passes the focal position of the iris imager. In this embodiment, the controller 500 also functions as an illumination control device that performs an illumination control method. Note that, although an example in which the iris imagers 401 to 404 are used as the imaging means has been described in this embodiment, the imaging means may be any means that captures an image of the subject, and is not particularly limited to only the iris imagers 401 to 404.

[0035] In the first illumination control, the controller 500 causes the illuminator 300 to emit an amount of light that illuminates the subject with light of a brightness that can capture the iris pattern of the subject at the focusing position of the iris image capturer with a quality that can be used for authentication and matching. In the first illumination control, the controller 500, for example, sets the amount of light emitted from the illuminator 300 to a maximum value under control. The amount of light irradiated to the subject during the first illumination control is, for example, an amount of light that satisfies a predetermined safety standard.

[0036] In the second lighting control, the controller 500 controls the amount of light emitted from the illuminator 300 through the lighting control information so that the amount of light irradiated to the subject is equal to or less than a certain amount. In the second lighting control, the controller 500 reduces the amount of light emitted from the illuminator 300 from the maximum value under control. For example, in the second lighting control, the controller 500 reduces the value of the current supplied to the LED of the illuminator 300 compared to that in the first lighting control, thereby reducing the light emission intensity of the illuminator 300. Alternatively, in the second lighting control, the controller 500 shortens the lighting time (light emission time) of the LED of the illuminator 300 compared to that in the first lighting control. In the second lighting control, the controller 500 may reduce the value of the current supplied to the LED of the illuminator 300 and shorten the lighting time of the LED compared to that in the first lighting control. In the second lighting control, the controller 500 may turn off the illuminator 300. In other words, the light irradiation to the subject may be stopped.

[0037] Note that the subject passing the focus position of the iris imager means that the subject moves forward of the focus position and approaches the illuminator 300 and the iris imagers 401-404. If the authentication or registration operates at a sufficiently high speed, the controller 500 may regard the time at which the authentication or registration is completed as the time at which the subject passed the focus position, and may determine that the subject has already passed the focus position. If the controller 500 determines that the subject has already passed the focus position, it may switch the illumination control from the first illumination control to the second illumination control.

[0038] The method by which the controller 500 judges whether the subject has passed the focus position is not particularly limited. For example, the controller 500 may judge whether the subject has already passed the focus position by using position information of the subject obtained by using the overall image capturer 100 having a distance measurement function such as Time of Flight (ToF). Alternatively, the controller 500 may monitor the brightness of the iris image supplied from the iris image capturer and judge whether the subject has already passed the focus position based on the brightness of the iris image. The brightness of the iris image changes depending on the amount of light irradiated to the subject. The closer the subject is to the illuminator 300, the brighter the iris image becomes, so that it is possible to judge the position of the subject to some extent based on the brightness of the iris image.

[0039] Next, the operation procedure will be described. FIG. 3 shows the operation procedure in the image processing system. The controller 500 performs guidance control and guides the subject using the guide 200 (step S1001). The controller 500 performs first illumination control and irradiates the subject with infrared light using the illuminator 300 (step S1002). The controller 500 performs the above-mentioned iris imaging control and acquires an image of the iris (iris video) captured using the multiple iris imagers 401-404 (step S1003). The iris video acquired in step S1003 is used for iris authentication and registration. In step S1003, the controller 500 does not need to obtain iris videos from all of the iris imagers 401-404 for a given subject, as described above. The controller 500 acquires the iris video from the iris imager capturing an image of the subject's eye area.

[0040] The controller 500 performs iris authentication using the iris image acquired in step S1003, or registers the iris image (step S1004). The controller 500 performs second illumination control to keep the amount of light irradiated from the illuminator 300 to the subject below a certain level (step S1005). Note that the second illumination control is not necessarily performed after authentication or registration. For example, if the authentication or registration does not operate at a sufficiently high speed, step S1005 may be performed prior to step S1004, and the second illumination control may be performed before the authentication or registration is completed.

[0041] The controller 500 determines whether there is a next subject or whether re-authentication or re-registration is to be performed (step S1006). If there is a next subject or it is determined that re-authentication or re-registration is to be performed, the process returns to step S1001, and the process is performed from the guidance control.

[0042] In addition, when the whole image capturer 100 of the present embodiment has a resolution capable of performing face authentication, the database holds features for performing face authentication of the subject, and the database does not hold features for performing iris authentication of the subject, the device according to the present disclosure can also be used to identify the subject based on face authentication and register the extracted iris features in the database. The device according to the present disclosure can also be used to estimate height information of the subject based on eye position information obtained by iris imaging control or eye position information obtained when authenticating or registering an iris image obtained by an iris image capturer, and register the information in the database. Furthermore, the device according to the present disclosure can be used to determine or calibrate the vertical position of an iris image capturer that can suitably capture eye regions from multiple iris image capturers and a gaze region that is read out at high speed within the image capturer, using the estimated height information.

[0043] In this embodiment, the controller 500 causes the illuminator 300 to emit an amount of light with a brightness that allows the subject to capture an iris pattern of the subject at the focusing position of the iris imager with a quality that can be used for authentication and matching. After the subject passes the focusing position, the controller 500 controls the amount of light emitted from the illuminator 300 so that the amount of light irradiated to the subject is equal to or less than a certain level. In this way, it is possible to prevent strong light from being irradiated to a subject close to the illumination while maintaining brightness for capturing an iris pattern with a quality that can be used for authentication and matching under conditions where the distance between the subject and the image capturing means is long and the subject is moving.

[0044] In addition, in FIG. 2, an example is shown in which a partial region of 4000 pixels horizontally by 1500 pixels vertically is set as the gaze region, but the present disclosure is not limited to this. The shape of the gaze region is not limited to a rectangle, and the number of gaze regions is not limited to one. The controller 500 may derive the positions of the subject's right eye and left eye from the overall image (bird's-eye view image) captured by the overall image capturer 100, for example, and set the gaze region corresponding to the position of the right eye and the gaze region corresponding to the position of the left eye in the iris imager. In this case, the iris imager supplies the iris image of the right eye and the iris image of the left eye to the controller 500. The shape of the gaze region may be rectangular or elliptical. The controller 500 may derive the positions of the subject's right eye and left eye based on the iris image captured by the iris imager instead of the bird's-eye view image. 2 as the gaze area, and derive the positions of the right eye and the left eye from the image of the gaze area. In this case, the controller 500 may set the partial area corresponding to the position of the right eye and the partial area corresponding to the position of the left eye as the gaze areas in the iris imager, based on the derived positions of the right eye and the left eye.

[0045] In the above embodiment, the controller 500 may be configured as a computer device. Fig. 4 shows a configuration example of an information processing device (computer device) that may be used for the controller 500. The information processing device 600 includes a control unit (CPU: Central Processing Unit) 610, a storage unit 620, a ROM (Read Only Memory) 630, a RAM (Random Access Memory) 640, a communication interface (IF: Interface) 650, and a user interface 660.

[0046] The communication interface 650 is an interface for connecting the information processing device 600 to a communication network via a wired communication means or a wireless communication means, etc. The user interface 660 includes a display unit such as a display, and an input unit such as a keyboard, a mouse, and a touch panel.

[0047] The storage unit 620 is an auxiliary storage device capable of holding various data. The storage unit 620 does not necessarily need to be a part of the information processing device 600, and may be an external storage device or a cloud storage connected to the information processing device 600 via a network. The ROM 630 is a non-volatile storage device. For example, a semiconductor storage device having a relatively small capacity, such as a flash memory, is used for the ROM 630. The programs executed by the CPU 610 may be stored in the storage unit 620 or the ROM 630.

[0048] The above program can be stored using various types of non-transitory computer-readable media and can be supplied to the information processing device 600. The non-transitory computer-readable medium includes various types of tangible storage media. Examples of the non-transitory computer-readable medium include magnetic recording media such as a flexible disk, a magnetic tape, or a hard disk, magneto-optical recording media such as a magneto-optical disk, optical disk media such as a compact disc (CD) or a digital versatile disk (DVD), and semiconductor memories such as a mask ROM, a programmable ROM (PROM), an erasable PROM (EPROM), a flash ROM, or a RAM. The program may also be supplied to the computer using various types of temporary computer-readable media. Examples of the temporary computer-readable medium include an electric signal, an optical signal, and an electromagnetic wave. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or via a wireless communication path.

[0049] The RAM 640 is a volatile storage device. Various semiconductor memory devices such as a dynamic random access memory (DRAM) or a static random access memory (SRAM) are used for the RAM 640. The RAM 640 can be used as an internal buffer for temporarily storing data and the like. The CPU 610 loads a program stored in the storage unit 620 or the ROM 630 into the RAM 640 and executes it. By the CPU 610 executing the program, various controls including, for example, guidance control, lighting control, and iris imaging control are executed.

[0050] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above-described embodiments, and changes and modifications to the above-described embodiments that do not deviate from the spirit of the present disclosure are also included in the present disclosure.

[0051] This application claims priority based on Japanese Patent Application No. 2019-026940, filed on February 18, 2019, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0052] 100: Overall imager 200: Inductor 300: Illuminator 401~404: Iris imager 500:Controller 600: Information processing device

Claims

1. a lighting means for shining light on the subject; imaging means for imaging the subject at or near a predetermined focusing position; a control means for controlling the illumination means to perform a first illumination control for irradiating the subject at or near the focusing position with a first amount of light, and a second illumination control for irradiating the subject at a position closer to the illumination means than the focusing position or near the focusing position with a second amount of light that is set based on a distance to the subject, The control means determines whether or not the subject has passed the focusing position based on the brightness of the image supplied from the imaging means, and when it is determined that the subject has passed the focusing position, switches the lighting control from the first lighting control to the second lighting control.

2. The illumination means emits light in a pulsed manner, The information processing system according to claim 1 , wherein the control means controls at least one of a pulse width and a pulse intensity of the light, thereby controlling the amount of light irradiated to the subject.

3. the imaging means has a plurality of iris cameras, the plurality of iris cameras are arranged such that image areas of adjacent iris cameras overlap, and focal positions of the plurality of iris cameras are positions where the iris of the subject is imaged; 3. The information processing system according to claim 1, wherein, when controlling the light emitted from the lighting means to irradiate the subject with the second amount of light, the control means controls the lighting means so that light having a lower emission intensity, a shorter emission time, or a lower emission intensity and a shorter emission time is emitted from the lighting means, compared to when controlling the light emitted from the lighting means to irradiate the subject with the first amount of light.

4. A control means for controlling a lighting means to perform a first lighting control for irradiating a first amount of light to a subject at or near a focus position of an imaging means for photographing the subject, and a second lighting control for irradiating a second amount of light, the second amount being set based on a distance to the subject, to the subject at or near the focus position of the imaging means; The control means determines whether or not the subject has passed the focusing position based on the brightness of the image supplied from the imaging means, and when it determines that the subject has passed the focusing position, switches the lighting control from the first lighting control to the second lighting control.

5. The illumination means emits light in a pulsed manner, The lighting control device according to claim 4 , wherein the control means controls at least one of a pulse width and a pulse intensity of the light, thereby controlling the amount of light irradiated to the subject.

6. the imaging means has a plurality of iris cameras, the plurality of iris cameras are arranged such that image areas of adjacent iris cameras overlap, and focal positions of the plurality of iris cameras are positions where the iris of the subject is imaged; 6. The lighting control device according to claim 4 or 5, wherein, when controlling the light emitted from the lighting means to irradiate the subject with the second amount of light, the control means controls the lighting means so that light with a lower emission intensity, a shorter emission time, or a lower emission intensity and a shorter emission time is emitted from the lighting means, compared to when controlling the light emitted from the lighting means to irradiate the subject with the first amount of light.

7. The imaging means captures an iris image of the subject, The lighting control device according to claim 4 , wherein the first light amount is a light amount at which an iris image of the subject is captured with a predetermined quality at the focusing position.

8. A first lighting control is performed by controlling a lighting means to irradiate a first amount of light onto a subject at or near a focus position of an imaging means for photographing the subject, and a second lighting control is performed to irradiate a second amount of light onto a subject at a position closer to the lighting means than the focus position or near the focus position, the second amount of light being set based on a distance to the subject; A lighting control method comprising: determining whether or not the subject has passed the focusing position based on the brightness of the image supplied from the imaging means; and switching lighting control from the first lighting control to the second lighting control when it is determined that the subject has passed the focusing position.

9. A first lighting control is performed by controlling a lighting means to irradiate a first amount of light onto a subject at or near a focus position of an imaging means for photographing the subject, and a second lighting control is performed to irradiate a second amount of light onto a subject at a position closer to the lighting means than the focus position or near the focus position, the second amount of light being set based on a distance to the subject; A program for causing a processor to execute a process of determining whether or not the subject has passed the focusing position based on the brightness of the image supplied from the imaging means, and switching lighting control from the first lighting control to the second lighting control when it is determined that the subject has passed the focusing position.

Images