Information processing system, information processing apparatus, information processing method, and recording medium

Abstract

An information processing system (10) comprises: a distance acquisition means (110) for identifying an iris region including an iris of a subject from a visible light image of the subject and acquiring an iris distance that is a distance to the iris region; an iris image acquisition means (120) for changing a focal distance in accordance with the iris distance and acquiring the iris image of the subject; a score calculation means (130) for calculating, on the basis of the iris image, a score regarding a deviation of focus in the iris image; and a correspondence update means (140) for updating, on the basis of the score, a correspondence between the iris distance and focal distance at the time of acquiring the iris image. According to such an information processing system, the correspondence can be updated with high accuracy and hence an appropriate iris image can be acquired.

Description

Technical Field

[0001] This disclosure relates to the technical field of information processing systems, information processing apparatuses, information processing methods, and recording media.

Background Art

[0002] As this type of system, one that automatically adjusts the focal length of a camera is known. For example, in Patent Document 1, a technique is disclosed in which the distance to a subject is measured using an external light AF sensor, and the in-focus position of a digital still camera is changed based on the distance measurement result. In Patent Document 2, a technique is disclosed in which the position of a focus lens group is moved based on the measurement result of the subject distance. In Patent Document 3, a technique is disclosed in which the correspondence relationship between the focal length of a liquid lens and the applied voltage is stored and focus adjustment is performed. In Patent Document 4, a technique is disclosed in which the voltage applied to a variable focus lens is corrected. In Patent Document 5, a technique is disclosed in which the relationship between the distance and the applied voltage in a liquid lens is stored as a table. In Patent Document 6, a technique is disclosed in which imaging is performed while gradually changing the focus position in an iris camera.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0004] This disclosure aims to improve upon the techniques disclosed in the prior art documents. [Means for solving the problem]

[0005] One aspect of the information processing system disclosed herein comprises a distance acquisition means that identifies an iris region including the iris of a subject from a visible light image of the subject and acquires an iris distance, which is the distance to the iris region; an iris image acquisition means that acquires an iris image of the subject by changing a focal length according to the iris distance; a score calculation means that calculates a score related to a focus shift in the iris image based on the iris image; and a correspondence update means that updates the correspondence between the iris distance and the focal length when acquiring the iris image based on the score.

[0006] One aspect of the information processing device disclosed herein comprises a distance acquisition means that identifies an iris region including the iris of a subject from a visible light image of the subject and acquires an iris distance, which is the distance to the iris region; an iris image acquisition means that acquires an iris image of the subject by changing a focal length according to the iris distance; a score calculation means that calculates a score related to a focus shift in the iris image based on the iris image; and a correspondence update means that updates the correspondence between the iris distance and the focal length when acquiring the iris image based on the score.

[0007] One aspect of the information processing method disclosed herein is an information processing method executed by at least one computer, which identifies an iris region including an iris of a subject from a visible light image of the subject, obtains an iris distance, which is the distance to the iris region, changes a focal length according to the iris distance, obtains an iris image of the subject, calculates a score related to a focus shift in the iris image based on the iris image, and updates the correspondence between the iris distance and the focal length when obtaining the iris image based on the score.

[0008] One aspect of the recording medium of this disclosure has recorded thereon a computer program that causes at least one computer to execute an information processing method, which includes identifying an iris region including the iris of a subject from a visible light image of the subject, obtaining an iris distance that is the distance to the iris region, changing a focal length according to the iris distance to obtain an iris image of the subject, calculating a score related to a focus shift in the iris image based on the iris image, and updating the correspondence between the iris distance and the focal length when obtaining the iris image based on the score. [Brief explanation of the drawings]

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of an information processing system, an information processing apparatus, an information processing method, and a recording medium will be described with reference to the drawings.

[0011] <First Embodiment> The information processing system according to the first embodiment will be described with reference to FIGS. 1 to 3.

[0012] (Hardware Configuration) First, with reference to FIG. 1, the hardware configuration of the information processing system according to the first embodiment will be described. FIG. 1 is a block diagram showing the hardware configuration of the information processing system according to the first embodiment.

[0013] 1, an information processing 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 information processing system 10 may further include an input device 15 and an output device 16. The information processing system 10 may also include a camera 18. The processor 11, RAM 12, ROM 13, storage device 14, input device 15, output device 16, and camera 18 are connected via a data bus 17.

[0014] The processor 11 loads a computer program. For example, the processor 11 is configured to load 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 load 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., load) the computer program from a device (not shown) located outside the information processing 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 loaded computer program. In particular, in this embodiment, when the processor 11 executes the loaded computer program, a functional block for updating the correspondence between the iris distance and the control voltage is realized within the processor 11.

[0015] The processor 11 may be configured as, for example, a central processing unit (CPU), a graphics processing unit (GPU), a field-programmable gate array (FPGA), a demand-side platform (DSP), or an application-specific integrated circuit (ASIC). The processor 11 may be configured as one of these, or may be configured to use multiple processors in parallel.

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

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

[0018] The storage device 14 stores the data that the information processing system 10 stores in the long term. The storage device 14 may operate as a temporary storage device of 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 an input instruction from a user of the information processing system 10. The input device 15 may include, for example, at least one of a keyboard, a mouse, and a touch panel. The input device 15 may be configured as a portable terminal such as a smartphone or a tablet.

[0020] The output device 16 is a device that outputs information regarding the information processing system 10 to the outside. For example, the output device 16 may be a display device (e.g., a display) capable of displaying information regarding the information processing system 10. Also, the output device 16 may be a speaker or the like capable of outputting information regarding the information processing system 10 as sound. The output device 16 may be configured as a portable terminal such as a smartphone or a tablet.

[0021] Camera 18 is a camera installed in a location capable of capturing an image of the target (for example, an image including the target's face and iris). Camera 18 may be a camera mounted on a terminal (for example, a smartphone) owned by the target. Note that the target here is not limited to humans, but may also include animals such as dogs and snakes, robots, etc. Camera 20 may be a camera that captures still images or a camera that captures video. Camera 20 may be configured as a visible light camera or a near-infrared camera.

[0022] 1 shows an example of information processing system 10 including a plurality of devices, but all or some of the functions may be realized by a single device (information processing device). This information processing device may be configured to include only processor 11, RAM 12, and ROM 13 described above, and the other components (i.e., storage device 14, input device 15, output device 16, camera 18) may be provided by an external device connected to the information processing device. Furthermore, some of the calculation functions of the information processing device may be realized by an external device (e.g., an external server, a cloud, etc.).

[0023] (Functional configuration) Next, the functional configuration of the information processing 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 information processing system according to the first embodiment.

[0024] 2, the information processing system 10 according to the first embodiment is configured to include, as components for realizing its functions, an iris distance acquisition unit 110, an iris image acquisition unit 120, a score calculation unit 130, and a correspondence update unit 140. Each of the iris distance acquisition unit 110, the iris image acquisition unit 120, the score calculation unit 130, and the correspondence update unit 140 may be a processing block realized by, for example, the above-mentioned processor 11 (see FIG. 1). Furthermore, the iris image acquisition unit 120 may acquire an iris image using the above-mentioned camera 18.

[0025] The iris distance acquisition unit 110 is configured to be able to identify an iris region including the iris of the target from the visible light image of the target. Regarding the method of identifying the iris region, since existing technologies can be appropriately adopted, detailed description here is omitted. Also, the iris distance acquisition unit 110 is configured to be able to acquire an iris distance, which is the distance to the identified iris region. The iris distance acquisition unit 110 may be configured to be able to acquire the iris distance, for example, using the image of the identified iris distance and a calibrated distance sensor. Note that the iris distance may be acquired as the distance from the distance sensor to the iris region, or may be acquired as the distance from the camera that captures the visible light image or the iris image to be described later to the iris region. Information regarding the iris distance acquired by the iris distance acquisition unit 110 is configured to be output to the iris image acquisition unit 120.

[0026] The iris image acquisition unit 120 is configured to be able to acquire an iris image of the target (that is, an image including the iris of the target). The iris image may be acquired, for example, as a near-infrared image. In this case, the iris image acquisition unit 120 may be configured to be able to irradiate the target with near-infrared light. The iris image acquisition unit 120 is configured to be able to change the focal length based on the iris distance acquired by the iris distance acquisition unit 110. More specifically, the iris image acquisition unit 120 is configured to be able to change the focal length when capturing the iris image by applying a control voltage corresponding to the iris distance. The iris image acquisition unit 120 may be configured to be able to acquire the iris image, for example, using a camera equipped with a liquid lens, a variable focus lens, or the like. The iris image acquisition unit 120 includes a distance voltage conversion unit 121 and a voltage application unit 122 as components for changing the focal length.

[0027] The distance-voltage conversion unit 121 is configured to be able to convert the iris distance acquired by the iris distance acquisition unit 110 into the voltage value of a control voltage. That is, the distance-voltage conversion unit 121 is configured to be able to acquire, from the iris distance acquired by the iris distance acquisition unit 110, the voltage value for realizing an appropriate focal length corresponding to that iris distance. The distance-voltage conversion unit 121 stores the correspondence between the iris distance and the control voltage, and acquires the voltage value of the control voltage corresponding to the iris distance from that correspondence. The correspondence between the iris distance and the control voltage may be stored, for example, as a mathematical formula, or may be stored as a look-up table or a map. Note that, as will be described later, the correspondence between the iris distance and the control voltage is stored as being updatable. The distance-voltage conversion unit 121 is configured to be able to output information regarding the voltage value of the control voltage corresponding to the iris distance to the voltage application unit 122.

[0028] The voltage application unit 122 is configured to be able to output the control voltage of the voltage value acquired by the distance-voltage conversion unit 121. The control voltage output by the voltage application unit 122 is applied to a lens system including a liquid lens, a variable focal length lens, or the like, and thereby the focal length when imaging an iris image will change.

[0029] The score calculation unit 130 is configured to calculate a score based on the iris image acquired by the iris image acquisition unit 120. The "score" here refers to a score related to the defocus of the iris image. For example, a high score may be calculated when the image is captured in an in-focus state (i.e., a state with a small defocus), and a low score may be calculated when the image is captured out-of-focus (i.e., a state with a large defocus). The defocus indicated by the score may not be the defocus as seen by the human eye, but may be the defocus as seen by the device. Therefore, even if an iris image is in-focus as seen by the human eye, a low score may be calculated for an iris image that is out-of-focus as seen by the device (i.e., an iris image that causes problems when handled by the device). Similarly, even if an iris image is out-of-focus as seen by the human eye, a high score may be calculated for an iris image that is in-focus as seen by the device (i.e., an iris image that does not cause problems when handled by the device). In such a case, the score calculation unit 130 may calculate, for example, an authentication score to be used in iris authentication (that is, a score for determining whether authentication is successful or unsuccessful).

[0030] The specific method for calculating the score is not particularly limited, and the score calculation unit 130 may calculate the score by appropriately adopting existing technology. The score calculation unit 130 may calculate the score from the iris image itself, or may calculate the score based on feature amounts extracted from the iris image. The score calculation unit 130 may also calculate the score from multiple iris images. For example, the score calculation unit 130 may calculate the score by extracting feature amounts from multiple images captured in succession and matching the feature amounts of previous and next images. In this case, matching out-of-focus images will result in a low calculated score. On the other hand, matching in-focus images will result in a high calculated score.

[0031] The correspondence relationship update unit 140 is configured to be able to update the correspondence relationship between the iris distance and the control voltage stored by the distance-voltage conversion unit 121. That is, the correspondence relationship update unit 140 is configured to be able to rewrite the pre-stored correspondence relationship with a new one. Therefore, after the correspondence relationship update unit 140 updates the correspondence relationship, the conversion from the iris distance to the voltage value is performed based on the updated correspondence relationship. In particular, the correspondence relationship update unit 140 is configured to be able to update the correspondence relationship based on the score calculated by the score calculation unit 130. The correspondence relationship update unit 140 may update the correspondence relationship so that, for example, the score calculated by the score calculation unit 130 becomes higher. That is, the correspondence relationship update unit 140 may update the correspondence relationship between the iris distance and the control voltage so that a focused iris image can be obtained by the iris image acquisition unit 120. A specific example of updating the correspondence relationship will be described in detail in other embodiments described later.

[0032] (Flow of operations) Next, with reference to FIG. 3, the flow of operations by the information processing system 10 according to the first embodiment will be described. FIG. 3 is a flowchart showing the flow of operations by the information processing system according to the first embodiment.

[0033] As shown in FIG. 3, when the information processing system 10 according to the first embodiment operates, first, the iris distance acquisition unit 110 acquires a visible light image of the target (step S101). After that, the iris distance acquisition unit 110 identifies the iris region from the visible light image of the target (step S102). Then, the iris distance acquisition unit 110 acquires the iris distance, which is the distance to the identified iris region (step S103).

[0034] Subsequently, the distance-voltage conversion unit 121 converts the iris distance acquired by the iris distance acquisition unit 110 into a voltage value of the control voltage (step S104). Then, the voltage application unit 122 applies the control voltage of the voltage value converted by the distance-voltage conversion unit 121 (step S105). The iris image acquisition unit 120 acquires the iris image of the target in a state where the focal distance is changed by the application of the control voltage (step S106).

[0035] Subsequently, the score calculation unit 130 calculates a score based on the iris image acquired by the iris image acquisition unit 120 (step S107). Then, the correspondence relationship update unit 140 updates the correspondence relationship between the iris distance and the control voltage based on the score calculated by the score calculation unit 130 (step S108).

[0036] (Technical effect) Next, the technical effect obtained by the information processing system 10 according to the first embodiment will be described.

[0037] As described with reference to FIGS. 1 to 5, in the information processing system 10 according to the first embodiment, the correspondence relationship between the iris distance and the control voltage is updated based on the score calculated from the iris image. In this way, even if the correspondence relationship when adjusting the focal distance is inappropriate, it can be updated to an appropriate one, and an appropriate iris image can be acquired. Note that the correspondence relationship between the iris distance and the control voltage changes due to individual differences in lenses and environmental changes (for example, temperature changes in the lenses themselves), etc., so it is difficult to set an optimal correspondence relationship in advance for all lenses. However, according to the information processing system 10 according to the present embodiment, since the correspondence relationship is updated based on the actually acquired iris image, it becomes possible to acquire an appropriate iris image from the next time.

[0038] <Second Embodiment> The information processing system 10 according to the second embodiment will be described with reference to FIGS. 4 and 5. Note that the second embodiment is only different from the above-described first embodiment in some configurations and operations, and the other parts may be the same as those of the first embodiment. Therefore, hereinafter, the parts different from the already described first embodiment will be described in detail, and the description of the other overlapping parts will be omitted as appropriate.

[0039] (Functional configuration) First, with reference to FIG. 4, the functional configuration of the information processing system 10 according to the second embodiment will be described. FIG. 4 is a block diagram showing the functional configuration of the information processing system according to the second embodiment. In FIG. 4, the same reference numerals are assigned to the same elements as those shown in FIG. 2.

[0040] As shown in FIG. 4, the information processing system 10 according to the second embodiment includes, as components for realizing its functions, an iris distance acquisition unit 110, an iris image acquisition unit 120, a score calculation unit 130, and a correspondence relationship update unit 140. In particular, the score calculation unit 130 according to the second embodiment includes an image evaluation unit 131. Further, the correspondence relationship update unit 140 according to the second embodiment includes an update determination unit 141.

[0041] The image evaluation unit 131 is configured to be able to evaluate whether the iris image acquired by the iris image acquisition unit 120 is appropriate. Specifically, the image evaluation unit 131 is configured to be able to evaluate whether the iris image acquired by the iris image acquisition unit 120 is an image suitable for use in updating the correspondence relationship. The image evaluation unit 131 may evaluate whether the iris image is appropriate using the score calculated by the score calculation unit 131. For example, the image evaluation unit 131 may evaluate that the image is appropriate when the score is equal to or greater than a predetermined threshold, and evaluate that the image is not appropriate when the score is less than the predetermined threshold. The image evaluation unit 131 may be configured to issue an instruction to the iris image acquisition unit 120 to acquire a new iris image when it evaluates that the iris image is not appropriate. In this case, the image evaluation unit 131 may output an instruction to change the voltage value of the control voltage to acquire a new iris image.

[0042] The update determination unit 141 is configured to be able to determine whether it is necessary to update the correspondence relationship. The update determination unit 141 may determine whether it is necessary to update the correspondence relationship, for example, by comparing the voltage value calculated from the correspondence relationship pre-stored in the distance-voltage conversion unit 121 with the voltage value corresponding to the image determined to be appropriate by the image evaluation unit 131 (for example, the image with the highest score). Specifically, when the difference between the voltage value calculated from the original correspondence relationship and the voltage value corresponding to the image determined to be appropriate exceeds a predetermined value, the update determination unit 141 may determine that it is necessary to update the correspondence relationship. On the other hand, when the difference between the voltage value calculated from the original correspondence relationship and the voltage value corresponding to the image determined to be appropriate does not exceed the predetermined value, the update determination unit 141 may determine that it is not necessary to update the correspondence relationship.

[0043] (Flow of operations) Next, with reference to FIG. 5, the flow of operations of the information processing system 10 according to the second embodiment will be described. FIG. 5 is a flowchart showing the flow of operations of the information processing system according to the second embodiment. In FIG. 5, the same reference numerals are given to the same processes as those described in FIG. 3.

[0044] As shown in FIG. 5, when the information processing system 10 according to the second embodiment operates, first, the iris distance acquisition unit 110 acquires a visible light image of the target (step S101). After that, the iris distance acquisition unit 110 specifies the iris region from the acquired visible light image of the target (step S102). Then, the iris distance acquisition unit 110 acquires the iris distance, which is the distance to the specified iris region (step S103).

[0045] Subsequently, the distance-voltage conversion unit 121 converts the iris distance acquired by the iris distance acquisition unit 110 into a voltage value of a control voltage (step S104). Then, the voltage application unit 122 applies the control voltage of the voltage value converted by the distance-voltage conversion unit 121 (step S105). The iris image acquisition unit 120 acquires the iris image of the target in a state where the focal distance is changed by the application of the control voltage (step S106).

[0046] Subsequently, the score calculation unit 130 calculates a score based on the iris image acquired by the iris image acquisition unit 120 (step S107). Here, in the second embodiment, the image evaluation unit 131 evaluates whether an appropriate image has been acquired by the iris image acquisition unit 120 (step S201). If it is evaluated that an appropriate image has not been acquired (step S201: NO), the voltage value of the control voltage applied by the voltage application unit 122 is updated (step S202), and the process starts again from step S105. The update of the voltage value may be performed so that the variation value is within a predetermined range (for example, a value smaller than the width of the depth of field).

[0047] On the other hand, if it is evaluated that an appropriate image has not been acquired (step S201: YES), the update determination unit 141 determines whether it is necessary to update the correspondence relationship (step S203). If it is determined that the correspondence relationship needs to be updated (step S203: YES), the correspondence relationship update unit 140 updates the correspondence relationship between the iris distance and the control voltage based on the score calculated by the score calculation unit 130 (step S108). On the other hand, if it is determined that there is no need to update the correspondence relationship (step S203: NO), the correspondence relationship update unit 140 does not update the correspondence relationship between the iris distance and the control voltage (that is, the process of step S108 is omitted).

[0048] (Technical Effect) Next, the technical effect obtained by the information processing system 10 according to the second embodiment will be described.

[0049] As described with reference to FIGS. 4 and 5, in the information processing system 10 according to the second embodiment, capturing of iris images is repeated until an appropriate iris image is acquired. This prevents a situation in which only an inappropriate iris image is captured, resulting in the inability to update the correspondence relationship. Furthermore, in the information processing system 10 according to the second embodiment, the correspondence relationship is updated only when it is determined that an update is necessary. This prevents the correspondence relationship from being updated even when there is no need to update it. Therefore, the processing load required for updating the correspondence relationship can be reduced.

[0050] Third Embodiment An information processing system 10 according to the third embodiment will be described with reference to Figures 6 and 7. The third embodiment differs from the first and second embodiments in some configurations and operations, but other parts may be the same as the first and second embodiments. Therefore, the following will describe in detail the parts that differ from the embodiments already described, and will omit a description of other overlapping parts as appropriate.

[0051] (Functional configuration) First, the functional configuration of the information processing system 10 according to the third embodiment will be described with reference to Fig. 6. Fig. 6 is a block diagram showing the functional configuration of the information processing system according to the third embodiment. Note that in Fig. 6, the same elements as those shown in Fig. 2 are denoted by the same reference numerals.

[0052] As shown in FIG. 6, the information processing system 10 according to the third embodiment includes, as components for realizing its functions, an iris distance acquisition unit 110, an iris image acquisition unit 120, a score calculation unit 130, a correspondence relationship update unit 140, an object information acquisition unit 150, and an iris distance correction unit 160. That is, the information processing system 10 according to the third embodiment is further configured to include an object information acquisition unit 150 and an iris distance correction unit 160 in addition to the configuration of the first embodiment (see FIG. 2). Each of the object information acquisition unit 150 and the iris distance correction unit 160 may be a processing block realized by, for example, the above-described processor 11 (see FIG. 1).

[0053] The object information acquisition unit 150 is configured to be able to acquire object information from an object that acquires a visible light image. The "object information" here is information regarding elements that affect the acquisition of the iris distance by the iris distance acquisition unit 110 (for example, the presence or absence of glasses, the thickness and length of eyelashes, the depth of facial carving, etc.). The object information acquisition unit 150 may acquire object information by, for example, analyzing a visible light image, or may acquire object information from various sensors or the like. Alternatively, the object information acquisition unit 150 may acquire object information by an operation input by the object. The object information acquisition unit 150 may acquire multiple types of object information. The object information acquired by the object information acquisition unit 150 is configured to be output to the iris distance correction unit 160.

[0054] The iris distance correction unit 160 is configured to be able to correct the distance obtained by the iris distance acquisition unit 110 based on the target information acquired by the target information acquisition unit 150. Specifically, the iris distance correction unit 160 is configured to be able to correct the iris distance to a more accurate value based on the target information. Note that the iris distance correction unit 160 may be configured to correct the iris distance at a stage after the iris distance acquisition unit 110 has acquired it, or may substantially correct the acquired iris distance at the stage when the iris distance acquisition unit 110 acquires it (for example, by changing the method of acquiring the iris distance). For example, when target information indicating that the target is wearing glasses is acquired, the iris distance correction unit 160 may correct the iris distance so that it is the distance to the iris behind the glasses (for example, several centimeters corresponding to the depth from the glasses may be added to the acquired iris distance). In this way, it is possible to prevent the glasses position from being recognized as the iris position.

[0055] (Flow of operations) Next, with reference to FIG. 7, the flow of operations of the information processing system 10 according to the third embodiment will be described. FIG. 7 is a flowchart showing the flow of operations of the information processing system according to the third embodiment. In FIG. 7, the same reference numerals are given to the same processes as those shown in FIG. 3.

[0056] As shown in FIG. 7, when the information processing system 10 according to the third embodiment operates, first, the iris distance acquisition unit 110 acquires a visible light image of the target (step S10). Then, the iris distance acquisition unit 110 identifies the iris region from the visible light image of the target (step S102). And the iris distance acquisition unit 110 acquires the iris distance, which is the distance to the identified iris region (step S103).

[0057] Subsequently, the target information acquisition unit 150 acquires target information (step S301). Then, the iris distance correction unit 160 corrects the iris distance acquired by the iris distance acquisition unit 110 based on the target information acquired by the target information acquisition unit 150 (step S302). Note that the processes of steps S301 and S302 may be executed simultaneously and in parallel with the processes of steps S101 to S103 described above, or may be executed successively.

[0058] Subsequently, the distance-voltage conversion unit 121 converts the corrected iris distance into a voltage value of a control voltage (step S104). Then, the voltage application unit 122 applies the control voltage of the voltage value converted by the distance-voltage conversion unit 121 (step S105). The iris image acquisition unit 120 acquires an iris image of the target in a state where the focal length is changed by the application of the control voltage (step S106).

[0059] Subsequently, the score calculation unit 130 calculates a score based on the iris image acquired by the iris image acquisition unit 120 (step S107). Then, the correspondence relationship update unit 140 updates the correspondence relationship between the iris distance and the control voltage based on the score calculated by the score calculation unit 130 (step S108).

[0060] (Technical effect) Next, the technical effect obtained by the information processing system 10 according to the third embodiment will be described.

[0061] As described with reference to FIGS. 6 and 7, in the information processing system 10 according to the third embodiment, the iris distance is corrected based on the target information. By doing so, an accurate iris distance can be used as compared with the case where no correction is performed, and thus the correspondence relationship can be updated more appropriately.

[0062] <Fourth Embodiment> An information processing system 10 according to the fourth embodiment will be described with reference to Figures 8 and 9. The fourth embodiment differs only in part of the configuration and operation from the first to third embodiments described above, and other parts may be the same as the first to third embodiments. Therefore, the following will describe in detail the parts that differ from the embodiments already described, and will omit a description of other overlapping parts as appropriate.

[0063] (Functional configuration) First, the functional configuration of the information processing system 10 according to the fourth embodiment will be described with reference to Fig. 8. Fig. 8 is a block diagram showing the functional configuration of the information processing system according to the fourth embodiment. Note that in Fig. 8, the same elements as those shown in Fig. 2 are denoted by the same reference numerals.

[0064] 8, the information processing system 10 according to the fourth embodiment is configured to include, as components for realizing its functions, an iris distance acquisition unit 110, an iris image acquisition unit 120, a score calculation unit 130, a correspondence update unit 140, an environment information acquisition unit 170, and a correspondence change unit 180. That is, the information processing system 10 according to the fourth embodiment is configured to further include, in addition to the configuration of the first embodiment (see FIG. 2), an environment information acquisition unit 170 and a correspondence change unit 180. Each of the environment information acquisition unit 170 and the correspondence change unit 180 may be a processing block realized by, for example, the above-mentioned processor 11 (see FIG. 1).

[0065] The environmental information acquisition unit 170 is configured to be able to acquire environmental information relating to the environment when acquiring an iris image. Here, "environmental information" refers to information relating to the environment that may affect the correspondence between the iris distance and the control voltage, and examples thereof include information indicating the temperature around the lens and information indicating the temperature of the lens itself. The environmental information acquisition unit 170 may acquire environmental information using, for example, various sensors. The environmental information acquisition unit 170 may acquire multiple types of environmental information. The environmental information acquired by the environmental information acquisition unit 170 is configured to be output to the correspondence change unit 180.

[0066] Based on the environmental information acquired by the environmental information acquisition unit 170, the correspondence change unit 180 is configured to be able to change the correspondence used to convert the iris distance into the voltage value of the control voltage. Here, the "change" is temporary, different from the "update" performed by the correspondence update unit 140. Specifically, the correspondence change unit 180 only changes the correspondence used to convert the iris distance into the voltage value of the control voltage for the current target, and does not newly rewrite the correspondence stored in the distance-voltage conversion unit 121. Therefore, when the target changes, basically the correspondence returns to the one stored in advance. For example, when the distance-voltage conversion unit 121 stores a plurality of correspondences, the correspondence change unit 180 may perform an operation of selecting the correspondence to be used this time from among the plurality of correspondences. More specifically, when the distance-voltage conversion unit 121 stores a table indicating the correspondence when the temperature is high and a table indicating the correspondence when the temperature is low, the correspondence change unit 180 may perform an operation of selecting which table to use based on the environmental information (here, the information indicating the temperature).

[0067] (Flow of operations) Next, with reference to FIG. 9, the flow of operations by the information processing system 10 according to the fourth embodiment will be described. FIG. 9 is a flowchart showing the flow of operations by the information processing system according to the fourth embodiment. In FIG. 9, the same reference numerals are given to the same processes as those shown in FIG. 3.

[0068] As shown in FIG. 9, when the information processing system 10 according to the fourth embodiment operates, first, the iris distance acquisition unit 110 acquires a visible light image of the target (step S101). After that, the iris distance acquisition unit 110 identifies the iris region from the visible light image of the target (step S102). Then, the iris distance acquisition unit 110 acquires the iris distance, which is the distance to the identified iris region (step S103).

[0069] Subsequently, the environmental information acquisition unit 170 acquires environmental information (step S401). Then, the correspondence change unit 180 changes the correspondence based on the environmental information acquired by the environmental information acquisition unit 170 (step S402). Note that the processes of steps S401 and S402 may be executed in parallel simultaneously with the processes of steps S101 to S103 described above, or may be executed successively.

[0070] Subsequently, the distance-voltage conversion unit 121 converts the iris distance acquired by the iris distance acquisition unit 110 into a voltage value of a control voltage (step S104). Then, the voltage application unit 122 applies the control voltage of the voltage value converted by the distance-voltage conversion unit 121 (step S105). The iris image acquisition unit 120 acquires an iris image of an object in a state where the focal length is changed by the application of the control voltage (step S106).

[0071] Subsequently, the score calculation unit 130 calculates a score based on the iris image acquired by the iris image acquisition unit 120 (step S107). Then, the correspondence update unit 140 updates the correspondence between the iris distance and the control voltage based on the score calculated by the score calculation unit 130 (step S108).

[0072] (Technical effect) Next, the technical effect obtained by the information processing system 10 according to the fourth embodiment will be described.

[0073] As described with reference to FIGS. 8 and 9, in the information processing system 10 according to the fourth embodiment, the correspondence is changed based on environmental information. In this way, an appropriate correspondence is used in consideration of the influence of environmental changes. As a result, it becomes possible to acquire a more appropriate iris image as compared with the case where environmental information is not used.

[0074] <Fifth Embodiment> The information processing system 10 according to the fifth embodiment will be described with reference to FIGS. 10 to 12. Note that the fifth embodiment is only different from the first to fourth embodiments described above in some configurations and operations, and the other parts may be the same as those of the first to fourth embodiments. Therefore, hereinafter, the parts different from the embodiments already described will be described in detail, and the description of the other overlapping parts will be omitted as appropriate.

[0075] (Functional configuration) First, with reference to FIG. 10, the functional configuration of the information processing system 10 according to the fifth embodiment will be described. FIG. 10 is a block diagram showing the functional configuration of the information processing system according to the fifth embodiment. Note that in FIG. 10, the same reference numerals are given to the elements similar to those shown in FIG. 2.

[0076] As shown in FIG. 10, the information processing system 10 according to the fifth embodiment includes, as components for realizing its functions, an iris distance acquisition unit 110, an iris image acquisition unit 120, a score calculation unit 130, and a correspondence relationship update unit 140. In particular, the correspondence relationship update unit 140 according to the fifth embodiment includes a depth of field setting unit 142.

[0077] The depth of field setting unit 142 is configured to be able to set the depth of field to be considered when updating the correspondence relationship. More specifically, the depth of field setting unit 142 sets the depth of field required in iris authentication using the iris image as the depth of field to be considered when updating the correspondence relationship. The depth of field setting unit 142 may store in advance the depth of field required in iris authentication, or may appropriately acquire it from outside the system. Note that the depth of field required in iris authentication may be a different value depending on the authentication type. For example, the depth of field required for 1:1 authentication may be a narrower range than the depth of field required for 1:N authentication. When different depths of field are required depending on the authentication type, the depth of field setting unit 142 may select the depth of field corresponding to the iris authentication to be executed this time from those different depths of field. The method of updating the correspondence relationship considering the depth of field will be described in detail later.

[0078] (Flow of operations) Next, with reference to FIG. 11, the flow of operations by the information processing system 10 according to the fifth embodiment will be described. FIG. 11 is a flowchart showing the flow of operations by the information processing system according to the fifth embodiment. In FIG. 11, the same reference numerals are given to the same processes as those shown in FIG. 3.

[0079] As shown in FIG. 11, when the information processing system 10 according to the fifth embodiment operates, first, the iris distance acquisition unit 110 acquires a visible light image of the target (step S101). After that, the iris distance acquisition unit 110 identifies the iris region from the visible light image of the target (step S102). Then, the iris distance acquisition unit 110 acquires the iris distance, which is the distance to the identified iris region (step S103).

[0080] Subsequently, the distance-voltage conversion unit 121 converts the iris distance acquired by the iris distance acquisition unit 110 into a voltage value of a control voltage (step S104). Then, the voltage application unit 122 applies the control voltage of the voltage value converted by the distance-voltage conversion unit 121 (step S105). The iris image acquisition unit 120 acquires an iris image of the subject in a state where the focal length is changed by the application of the control voltage (step S106).

[0081] Subsequently, the score calculation unit 130 calculates a score based on the iris image acquired by the iris image acquisition unit 120 (step S107). Then, the depth of field setting unit 142 acquires information regarding the depth of field required in iris authentication using the iris image acquired this time (step S501). Note that the process of step S501 may be executed in parallel with the processes up to this point (the processes of steps S101 to S107), or may be executed successively.

[0082] Subsequently, the correspondence relationship update unit 140 updates the correspondence relationship between the iris distance and the control voltage based on the score calculated by the score calculation unit 130. At this time, the correspondence relationship update unit 140 updates the correspondence relationship in consideration of the depth of field acquired by the depth of field setting unit 142. Specifically, the correspondence relationship is updated so that the deviation of the updated focal length falls within the range of the depth of field acquired by the depth of field setting unit 142 (step S502).

[0083] (Example of updating the correspondence relationship) Next, with reference to FIG. 12, the operation when the correspondence relationship update unit 140 according to the fifth embodiment updates the correspondence relationship will be specifically described with examples. FIG. 12 is a graph showing a specific change example of the correspondence relationship by the information processing system according to the fifth embodiment.

[0084] As shown in FIG. 12, according to the correspondence relationship between the iris distance and the control voltage stored in advance (refer to the straight line in the figure), when a voltage value V0 corresponding to the subject distance d0 is applied as the control voltage, the subject (i.e., the target iris) falls within the depth of field range. However, if this correspondence relationship changes, even if the voltage value V0 is applied as the control voltage, the subject will not fall within the depth of field range. Therefore, when the correspondence relationship changes, the correspondence relationship update unit 140 updates the stored correspondence relationship so that it becomes the correct correspondence relationship.

[0085] The correspondence relationship update unit 140 may update the correspondence relationship, for example, by adding an offset to the voltage value. Specifically, when the stored correspondence relationship is represented by V = f(d), the correspondence relationship is updated so that V = f(d)+ΔV. Here, V is the voltage value, d is the distance, f() is a function of the distance and the voltage value, and ΔV is the offset. The value of the offset ΔV can be calculated, for example, as the difference between the voltage value V0 calculated from the original correspondence relationship corresponding to the iris distance acquired by the iris distance acquisition unit 110 and the voltage value Vm corresponding to the iris image with the highest score among the iris images acquired by the iris image acquisition unit 120.

[0086] In particular, in the present embodiment, after the update, the correspondence relationship is updated so that the subject falls within the depth of field range required for iris authentication (refer to the broken line in the figure).

[0087] (Technical Effect) Next, the technical effect obtained by the information processing system 10 according to the fifth embodiment will be described.

[0088] As described with reference to FIGS. 10 to 12, in the information processing system 10 according to the fifth embodiment, the correspondence relationship is updated in consideration of the depth of field required for iris authentication. Since the depth of field required for iris authentication may vary depending on the authentication type and the like as already described, by updating the correspondence relationship so that it falls within the depth of field required for the actual iris authentication, it becomes possible to acquire a more appropriate iris image (i.e., an iris image suitable for that iris authentication).

[0089] <Sixth Embodiment> The information processing system 10 according to the sixth embodiment will be described with reference to FIGS. 13 to 15. Note that the sixth embodiment shows specific display examples in the first to fifth embodiments described above, and the configuration and operation thereof may be the same as those in the first to fifth embodiments. For this reason, in the following, parts different from the embodiments already described will be described in detail, and other overlapping parts will be omitted as appropriate.

[0090] (Display example before update) First, with reference to FIG. 13, a display example before the correspondence relationship update by the information processing system 10 according to the sixth embodiment will be described. FIG. 13 is a plan view showing a display example before the correspondence relationship update by the information system according to the sixth embodiment.

[0091] As shown in FIG. 13, before updating the correspondence relationship, the information processing system 10 according to the sixth embodiment may display a message for the user to determine whether to update the correspondence relationship. Here, a message "Do you want to update the correspondence relationship?" is displayed, together with a button "Yes (update)" and a button "No (do not update)". When the user presses the "Yes" button in this state, the correspondence relationship is updated. On the other hand, when the user presses the "No" button, the correspondence relationship is not updated. In this way, it is possible to leave the decision of whether to execute the update of the correspondence relationship to the user. In addition to the display shown in FIG. 13, an iris image captured in the state before the update (that is, an out-of-focus iris image) and a score corresponding to the image may be displayed.

[0092] (Display example during update) Next, with reference to FIG. 14, a display example during the correspondence relationship update by the information processing system 10 according to the sixth embodiment will be described. FIG. 14 is a plan view showing a display example during the correspondence relationship update by the information system according to the sixth embodiment.

[0093] As shown in FIG. 14, the information processing system 10 according to the sixth embodiment may display a notification indicating that the correspondence relationship is being updated during the update of the correspondence relationship. Here, a message "The correspondence relationship is being updated..." is displayed together with a message "Please do not move." By doing so, it is possible to suppress the user from moving and appropriately capture the iris image used for updating the correspondence relationship. In addition to the display shown in FIG. 14, the time required or the remaining time for updating the correspondence relationship and the number of captured iris images may be displayed. Alternatively, an iris image or the like captured for updating the correspondence relationship may be displayed.

[0094] (Display example after update) Next, with reference to FIG. 15, a display example after the update of the correspondence relationship by the information processing system 10 according to the sixth embodiment will be described. FIG. 15 is a plan view showing a display example after the update of the correspondence relationship by the information system according to the sixth embodiment.

[0095] As shown in FIG. 15, the information processing system 10 according to the sixth embodiment may display a notification indicating that the update of the correspondence relationship has been completed after the update of the correspondence relationship. Here, a message "The correspondence relationship has been updated" is displayed together with a button "Accept" and a button "Restore the correspondence relationship". When the user presses the "Accept" button in this state, the update of the correspondence relationship is confirmed. On the other hand, when the user presses the "Restore the correspondence relationship" button, the correspondence relationship is restored to the state before the update. By doing so, it is possible to prevent the update of the correspondence relationship that the user does not desire from being executed. In addition to the display shown in FIG. 15, an iris image captured after the update (i.e., a focused iris image), a score after the update, etc. may be displayed. Also, images and scores before and after the update may be arranged and displayed to perform a display that allows comparison of the changes due to the update of the correspondence relationship.

[0096] (Technical effect) Next, the technical effect obtained by the information processing system 10 according to the sixth embodiment will be described.

[0097] As described with reference to FIGS. 13 to 15, according to the information processing system 10 according to the sixth embodiment, it is possible to notify various information related to the update of the correspondence relationship to the user of the system (for example, the target, the system administrator, etc.) in an easy-to-understand manner.

[0098] <Seventh Embodiment> The information processing system 10 according to the seventh embodiment will be described with reference to FIGS. 16 and 17. Note that the seventh embodiment is only different from the first to sixth embodiments described above in some configurations and operations, and the other parts may be the same as those of the first to sixth embodiments. For this reason, hereinafter, the parts different from the embodiments already described will be described in detail, and the description of the other overlapping parts will be omitted as appropriate.

[0099] (Functional Configuration) First, with reference to FIG. 16, the functional configuration of the information processing system 10 according to the seventh embodiment will be described. FIG. 16 is a block diagram showing the functional configuration of the information processing system according to the seventh embodiment. In FIG. 16, the same reference numerals are given to the elements similar to those shown in FIG. 2.

[0100] As shown in FIG. 16, the information processing system 10 according to the seventh embodiment includes, as components for realizing its functions, an iris distance acquisition unit 110, an iris image acquisition unit 120, a score calculation unit 130, and a correspondence relationship update unit 140. In particular, the iris image acquisition unit 120 according to the seventh embodiment includes a focal length acquisition unit 125 and a focal length control unit 126.

[0101] The focal length acquisition unit 125 is configured to be able to acquire an appropriate focal length corresponding to the iris distance acquired by the iris distance acquisition unit 110. The focal length acquisition unit 125 stores a correspondence relationship between the iris distance and the focal length, and acquires the focal length corresponding to the iris distance from the correspondence relationship. The correspondence relationship between the iris distance and the focal length may be stored, for example, as a mathematical formula, or may be stored as a look-up table or a map. The correspondence relationship between the iris distance and the focal length is stored so as to be updateable as appropriate. The focal length acquisition unit 125 is configured to be able to output information regarding the focal length corresponding to the iris distance to the focal length control unit 126.

[0102] The focal length control unit 126 is configured to be able to change the focal length when capturing an iris image so that it becomes the value acquired by the focal length acquisition unit 125. Note that the method of controlling the focal length here is not limited to, for example, using the control voltage described in the first to sixth embodiments, and the focal length control unit 126 may control the focal length using various methods including existing technologies.

[0103] The correspondence relationship updating unit 140 according to the seventh embodiment is configured to be able to update the correspondence relationship between the iris distance and the focal length stored in the focal length acquisition unit 125. Therefore, after the correspondence relationship updating unit 140 updates the correspondence relationship, a focal length corresponding to the iris distance is acquired based on the updated correspondence relationship. The correspondence relationship updating unit 140 is particularly configured to be able to update the correspondence relationship based on the score calculated by the score calculation unit 130. The correspondence relationship updating unit 140 may update the correspondence relationship, for example, so that the score calculated by the score calculation unit 130 becomes higher. In other words, the correspondence relationship updating unit 140 may update the correspondence relationship between the iris distance and the focal length so that the iris image acquisition unit 120 can acquire an iris image that is in focus.

[0104] (Operation flow) Next, with reference to FIG. 17, the operation flow of the information processing system 10 according to the seventh embodiment will be described. FIG. 17 is a flowchart showing the operation flow of the information processing system according to the seventh embodiment. In FIG. 17, the same reference numerals are given to the processes similar to those shown in FIG. 3.

[0105] As shown in FIG. 17, when the information processing system 10 according to the seventh embodiment operates, first, the iris distance acquisition unit 110 acquires a visible light image of the target (step S101). Then, the iris distance acquisition unit 110 identifies the iris region from the visible light image of the target (step S102). And the iris distance acquisition unit 110 acquires the iris distance, which is the distance to the identified iris region (step S103).

[0106] Subsequently, the focal length acquisition unit 125 acquires a focal length corresponding to the iris distance acquired by the iris distance acquisition unit 110 (step S701). Then, the focal length control unit 126 controls the focal length so as to be the value acquired by the focal length acquisition unit 125 (step S702). After the focal length is controlled by the focal length control unit 126 (that is, in a state where the focal length is the focal length acquired by the focal length acquisition unit 125), the iris image acquisition unit 120 acquires an iris image of the target (step S703).

[0107] Subsequently, the score calculation unit 130 calculates a score based on the iris image acquired by the iris image acquisition unit 120 (step S107). And the correspondence relationship update unit 140 updates the correspondence relationship between the iris distance and the focal length based on the score calculated by the score calculation unit 130 (step S704).

[0108] (Technical effects) Next, the technical effects obtained by the information processing system 10 according to the seventh embodiment will be described.

[0109] As described with reference to FIGS. 16 and 17 , in the information processing system 10 according to the seventh embodiment, the correspondence between the iris distance and the focal length is updated based on the score calculated from the iris image. In this way, even if the correspondence between the iris distance and the focal length is inappropriate, it can be updated to an appropriate one, making it possible to acquire an appropriate iris image. Note that the correspondence between the iris distance and the focal length changes depending on individual differences in lenses and environmental changes (e.g., temperature changes in the lens itself), making it difficult to set an optimal correspondence for all lenses in advance. However, according to the information processing system 10 according to the present embodiment, the correspondence is updated based on an actually acquired iris image, making it possible to acquire an appropriate iris image from the next time.

[0110] The scope of each embodiment also includes a processing method in which a program that operates the configuration of each embodiment to realize the functions of the above-described embodiments is recorded on a recording medium, the program recorded on the recording medium is read as code, and the program is executed on a computer. In other words, a computer-readable recording medium is also included in the scope of each embodiment. Furthermore, each embodiment includes not only a recording medium on which the above-described program is recorded, but also the program itself.

[0111] Examples of recording media that can be used include floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, magnetic tapes, non-volatile memory cards, and ROMs. The scope of each embodiment is not limited to programs recorded on the recording media that execute processing by themselves, but also includes programs that run on an OS in cooperation with other software and functions of an expansion board to execute processing. <Additional Notes> The above-described embodiment may be further described as follows, but is not limited to the following.

[0112] (Appendix 1) The information processing system described in Supplementary Note 1 identifies an iris region including the iris of the target from a visible light image of the target, and includes distance acquisition means for acquiring an iris distance which is the distance to the iris region, iris image acquisition means for changing a focal length according to the iris distance and acquiring an iris image of the target, score calculation means for calculating a score regarding a focus deviation in the iris image based on the iris image, and correspondence relationship update means for updating a correspondence relationship between the iris distance and the focal length when acquiring the iris image based on the score.

[0113] (Supplementary Note 2) The information processing system described in Supplementary Note 2 is the information processing system described in Supplementary Note 1, further including target information acquisition means for acquiring target information regarding an element that affects when acquiring the iris distance of the target by applying a control voltage corresponding to the iris distance to change the focal length, and iris distance correction means for correcting the iris distance based on the target information.

[0114] (Supplementary Note 3) The information processing system described in Supplementary Note 3 is the information processing system described in Supplementary Note 1 or 2, further including environment information acquisition means for acquiring environment information regarding an environment when acquiring the iris image, and correspondence relationship change means for changing the correspondence relationship based on the environment information.

[0115] (Supplementary Note 4) The information processing system described in Supplementary Note 4 is the information processing system according to any one of Supplementary Notes 1 to 3, wherein the correspondence relationship update means updates the correspondence relationship based on a depth of field required in iris authentication using the iris image.

[0116] (Supplementary Note 5) The information processing apparatus according to Supplementary Note 5 identifies an iris region including the iris of the target from a visible light image of the target, and acquires an iris distance which is the distance to the iris region; an iris image acquisition means for changing a focal length according to the iris distance to acquire an iris image of the target; a score calculation means for calculating a score related to a focus deviation in the iris image based on the iris image; and a correspondence relationship update means for updating a correspondence relationship between the iris distance and the focal length when acquiring the iris image based on the score.

[0117] (Supplementary Note 6) The information processing method according to Supplementary Note 6 is an information processing method executed by at least one computer, which identifies an iris region including the iris of the target from a visible light image of the target, acquires an iris distance which is the distance to the iris region, changes a focal length according to the iris distance to acquire an iris image of the target, calculates a score related to a focus deviation in the iris image based on the iris image, and updates a correspondence relationship between the iris distance and the focal length when acquiring the iris image based on the score.

[0118] (Supplementary Note 7) The recording medium according to Supplementary Note 7 is a recording medium in which a computer program for causing at least one computer to execute an information processing method is recorded, the information processing method including: identifying an iris region including the iris of the target from a visible light image of the target; acquiring an iris distance which is the distance to the iris region; changing a focal length according to the iris distance to acquire an iris image of the target; calculating a score related to a focus deviation in the iris image based on the iris image; and updating a correspondence relationship between the iris distance and the focal length when acquiring the iris image based on the score.

[0119] (Supplementary Note 8) The computer program described in Appendix 8 is a computer program that causes at least one computer to execute an information processing method of identifying an iris region that includes an iris of a subject from a visible light image of the subject, acquiring an iris distance that is the distance to the iris region, changing a focal length according to the iris distance to acquire an iris image of the subject, calculating a score related to a defocus in the iris image based on the iris image, and updating a correspondence relationship between the iris distance and the focal length when acquiring the iris image based on the score.

[0120] This disclosure may be modified as appropriate within the scope that does not contradict the gist or idea of the invention that can be read from the claims and the entire specification, and information processing systems, information processing devices, information processing methods, and recording media that involve such modifications are also included in the technical idea of this disclosure. [Explanation of symbols]

[0121] 10 Information Processing Systems 11 processors 18 Camera 110 Iris distance acquisition unit 120 Iris image acquisition unit 121 Distance-voltage conversion unit 122 Voltage application section 125 Focal length acquisition section 126 Focal length control unit 130 Score Calculation Section 131 Image Evaluation Unit 140 Correspondence Update Section 141 Update determination section 142 Depth of field setting section 150 Target information acquisition unit 160 Iris distance correction section 170 Environmental Information Acquisition Department 180 Correspondence change section

Claims

1. Distance acquisition means for identifying an iris region including the iris of the subject from a visible light image of the subject and acquiring an iris distance that is the distance to the iris region; Based on the correspondence relationship between the iris distance and the voltage value for realizing an appropriate focal length corresponding to the iris distance, an iris image acquisition means for outputting a control voltage of the voltage value corresponding to the iris distance to change the focal length and acquiring a plurality of iris images of the subject; Score calculation means for calculating a score related to the focus deviation in the iris image by matching a plurality of the iris images; Correspondence relationship update means for updating the correspondence relationship based on the score; An information processing system comprising:

2. Target information acquisition means for acquiring target information which is information on an element that affects the iris distance acquired by the distance acquisition means in the target; Iris distance correction means for correcting the iris distance based on the target information; The information processing system according to claim 1, further comprising:

3. Environment information acquisition means for acquiring environment information regarding the environment when acquiring the iris image; Correspondence relationship change means for changing the correspondence relationship based on the environment information; The information processing system according to claim 1 or 2, further comprising:

4. The correspondence relationship update means updates the correspondence relationship based on the depth of field required in iris authentication using the iris image. The information processing system according to any one of claims 1 to 3.

5. Distance acquisition means for identifying an iris region including the iris of the subject from a visible light image of the subject and acquiring an iris distance that is the distance to the iris region; Based on the correspondence relationship between the iris distance and the voltage value for realizing an appropriate focal length corresponding to the iris distance, an iris image acquisition means for outputting a control voltage of the voltage value corresponding to the iris distance to change the focal length and acquiring a plurality of iris images of the subject; Score calculation means for calculating a score related to the focus deviation in the iris image by matching a plurality of the iris images; Correspondence relationship update means for updating the correspondence relationship based on the score; An information processing apparatus comprising:

6. An information processing method executed by at least one computer, comprising: Identifying an iris region including the iris of the subject from a visible light image of the subject and acquiring an iris distance that is the distance to the iris region; Based on the correspondence relationship between the iris distance and the voltage value for realizing an appropriate focal length corresponding to the iris distance, output a control voltage of the voltage value corresponding to the iris distance to change the focal length, and acquire a plurality of iris images of the object, calculate a score regarding the focus deviation in the iris image by matching the plurality of iris images with each other, update the correspondence relationship based on the score, information processing method.

7. at least one computer, specify an iris region including the iris of the object from a visible light image of the object, and acquire an iris distance which is the distance to the iris region, Based on the correspondence relationship between the iris distance and the voltage value for realizing an appropriate focal length corresponding to the iris distance, output a control voltage of the voltage value corresponding to the iris distance to change the focal length, and acquire a plurality of iris images of the object, calculate a score regarding the focus deviation in the iris image by matching the plurality of iris images with each other, update the correspondence relationship based on the score, A computer program for executing an information processing method.

Images