Information processing device, information processing method, and recording medium

Abstract

This information processing device comprises: an acquisition means for acquiring a fingerprint image including a fingerprint; a calculation means for calculating, for each finger, a certainty factor indicating the fingerprint likeness of the fingerprint included in the fingerprint image; a fingerprint frame determination means for determining, for each finger on the basis of the certainty factor, the size of a fingerprint frame corresponding to a region where the fingerprint is present in the fingerprint image; and a superimposition means for superimposing the fingerprint frame on the corresponding position on the fingerprint image. According to such an information processing device, it is possible to appropriately determine a region in which a fingerprint is present in a fingerprint image.

Description

Information processing device, information processing method, and recording medium

[0001] The present disclosure relates to the technical fields of an information processing device, an information processing method, and a recording medium.

[0002] Known devices of this type perform various processes on images containing fingerprints. For example, Patent Document 1 discloses using a classifier to find key regions (such as the entire hand or four fingers) from an image, and using a classifier to find fingertips from an image.

[0003] Japanese Patent Application Laid-Open No. 2020-074174

[0004] An object of this disclosure is to provide an information processing device, an information processing method, and a recording medium that aim to improve upon the techniques disclosed in prior art documents.

[0005] One aspect of the information processing device disclosed herein comprises an acquisition means for acquiring a fingerprint image including a fingerprint, a calculation means for calculating, for each finger, a degree of certainty indicating the likelihood that the fingerprint included in the fingerprint image is a fingerprint, a fingerprint frame determination means for determining, for each finger, the size of a fingerprint frame corresponding to an area in the fingerprint image where the fingerprint exists based on the degree of certainty, and a superimposition means for superimposing the fingerprint frame on a corresponding position on the fingerprint image.

[0006] One aspect of the information processing method disclosed herein is to use at least one computer to acquire a fingerprint image containing a fingerprint, calculate a degree of certainty for each finger indicating the likelihood that the fingerprint contained in the fingerprint image is a fingerprint, determine a size of a fingerprint frame for each finger that corresponds to an area in the fingerprint image where the fingerprint exists based on the degree of certainty, and superimpose the fingerprint frame on the corresponding position on the fingerprint image.

[0007] One aspect of a recording medium of this disclosure is a computer program recorded on at least one computer that causes the computer to execute an information processing method, which includes acquiring a fingerprint image containing a fingerprint, calculating a degree of certainty for each finger that indicates the likelihood that the fingerprint contained in the fingerprint image is a fingerprint, determining, for each finger, a size of a fingerprint frame corresponding to an area in the fingerprint image where the fingerprint exists based on the degree of certainty, and superimposing the fingerprint frame on a corresponding position on the fingerprint image.

[0008] 1 is a block diagram showing a hardware configuration of a first information processing device. FIG. 2 is a block diagram showing a functional configuration of the first information processing device. FIG. 3 is a flowchart showing a flow of operations performed by the first information processing device. FIG. 4 is a schematic diagram showing an example of a superimposition operation performed by the first information processing device. FIG. 5 is a block diagram showing a functional configuration of a second information processing device. FIG. 6 is a flowchart showing a flow of operations performed by the second information processing device. FIG. 7 is a schematic diagram showing an example of a frame determination operation performed by the second information processing device. FIG. 8 is a flowchart showing a modified example of the operation performed by the second information processing device. FIG. 9 is a block diagram showing a functional configuration of a third information processing device. FIG. 10 is a flowchart showing a flow of operations performed by the third information processing device. FIG. 11 is a schematic diagram showing an example of a cut-out operation performed by the third information processing device.

[0009] Hereinafter, embodiments of an information processing device, an information processing method, and a recording medium will be described with reference to the drawings.

[0010] First Embodiment A first information processing apparatus will be described with reference to FIGS. 1 to 4. FIG.

[0011] (Hardware Configuration) First, the hardware configuration of the first information processing apparatus will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the hardware configuration of the first information processing apparatus.

[0012] 1, the first information processing device 1 includes a processor 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, a storage device 14, an input device 15, and an output device 16. The processor 11, RAM 12, ROM 13, storage device 14, input device 15, and output device 16 are connected to each other via a data bus 17. The data bus 17 may be an interface other than a data bus (for example, a LAN, a USB, etc.).

[0013] 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 first information processing device 1 via a network interface. The processor 11 executes the loaded computer program to perform various processes. When the processor 11 executes the loaded computer program, functional blocks related to the processes performed by the first information processing device 1 are realized within the processor 11. In other words, the processor 11 may function as a controller that executes each control in the first information processing device 1.

[0014] 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 digital signal processor (DSP), an application-specific integrated circuit (ASIC), or a quantum processor. The processor 11 may be configured as one of these, or may be configured to use multiple processors in parallel.

[0015] The RAM 12 temporarily stores computer programs executed by the processor 11. The RAM 12 temporarily stores data that the processor 11 temporarily uses while it is executing the computer programs. The RAM 12 may be, for example, a dynamic random access memory (D-RAM) or a static random access memory (SRAM). Alternatively, other types of volatile memory may be used instead of the RAM 12.

[0016] The ROM 13 stores computer programs executed by the processor 11. The ROM 13 may also store fixed data. The ROM 13 may be, for example, a programmable read-only memory (PROM) or an erasable read-only memory (EPROM). Alternatively, other types of non-volatile memory may be used instead of the ROM 13.

[0017] The storage device 14 stores data that is to be saved long-term by the information processing device 1. The storage device 14 may operate as a temporary storage device for the processor 11. The storage device 14 may store computer programs executed by 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.

[0018] The input device 15 is a device that receives input instructions from a user of the information processing device 1. 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 also be, for example, a device that includes a microphone and is capable of voice input.

[0019] The output device 16 is a device that outputs information related to the information processing device 1 to the outside. For example, the output device 16 may be a display device (e.g., a display or a monitor) that can display information related to the information processing device 1. The output device 16 may also be a speaker or the like that can output information related to the information processing device 1 as audio.

[0020] The first information processing device 1 may be configured to include some of the components described in Fig. 1. For example, the first information processing device 1 may be configured to include only the processor 11, RAM 12, and ROM 13 among the above-mentioned components. In this case, the storage device 14, input device 15, and output device 16 may each be provided as a device external to the first information processing device 1. Furthermore, some of the calculation functions of the first information processing device 1 may be realized by an external server, a cloud, or the like.

[0021] (Functional Configuration) Next, the functional configuration of the first information processing device 1 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the functional configuration of the first information processing device.

[0022] 2, the first information processing device 1 is configured to be able to execute processing on a fingerprint image including a fingerprint. The first information processing device 1 is configured to include, as components for realizing its functions, an image acquisition unit 110, a certainty factor calculation unit 120, a fingerprint frame determination unit 130, and a superimposition unit 140. Note that each of the image acquisition unit 110, the certainty factor calculation unit 120, the fingerprint frame determination unit 130, and the superimposition unit 140 may be a processing block realized by the above-mentioned processor 11 (see FIG. 1).

[0023] The image acquisition unit 110 is configured to acquire a fingerprint image including a fingerprint. The fingerprint image may be an image including fingerprints of multiple fingers. For example, the fingerprint image may be an image including fingerprints of the thumb, index finger, middle finger, ring finger, and little finger. Alternatively, the fingerprint image may be an image including fingerprints of some of multiple fingers. The fingerprint image may also be an image including the entire palm (i.e., a palmprint image). The fingerprint image may be acquired by, for example, photographing the subject's hand using a camera. Alternatively, the fingerprint image may be read from a database that stores multiple fingerprint images. The fingerprint image acquired by the image acquisition unit 110 is configured to be output to each of the certainty calculation unit 120 and the superposition unit 140.

[0024] The certainty calculation unit 120 is configured to be able to calculate the certainty of a fingerprint included in the fingerprint image acquired by the image acquisition unit 110. The certainty is a value indicating the likelihood that a fingerprint is a fingerprint. The certainty calculation unit 120 may estimate an area including a fingerprint from the fingerprint image and calculate the certainty based on the quality of the estimated area, etc. The certainty calculation unit 120 calculates the certainty of the fingerprint included in the fingerprint image for each finger. In other words, when the fingerprints of multiple fingers are included in the fingerprint image, the certainty calculation unit 120 calculates the certainty for each of the multiple fingerprints. The certainty calculated by the certainty calculation unit 120 is configured to be output to the fingerprint frame determination unit 130.

[0025] The fingerprint frame determination unit 130 is configured to determine a fingerprint frame corresponding to an area in a fingerprint image where a fingerprint exists (hereinafter referred to as the "fingerprint area" as appropriate). The fingerprint frame may be, for example, a rectangular frame corresponding to the fingerprint area. Alternatively, the fingerprint frame may be a frame shaped to fit the fingerprint area (for example, a frame shaped like the outline of a finger). However, the shape of the fingerprint frame is not particularly limited. The fingerprint frame determination unit 130 determines the fingerprint frame based on the fingerprint image acquired by the image acquisition unit 110 and the certainty calculated by the certainty calculation unit 120. More specifically, the fingerprint frame determination unit 130 determines the size of the fingerprint frame for each finger based on the certainty calculated by the certainty calculation unit 120. The fingerprint frame determination unit 130 may increase the size of the fingerprint frame as the certainty decreases. For example, the certainty calculation unit 120 may increase the size of the fingerprint frame for a finger calculated to have a relatively low certainty value. The certainty calculation unit 120 may increase the size of the fingerprint frame for a finger calculated to have a relatively low certainty value, compared to a preset initial value. The certainty calculation unit 120 may also decrease the size of the fingerprint frame for a finger calculated to have a relatively high certainty value. The certainty calculation unit 120 may decrease the size of the fingerprint frame for a finger calculated to have a relatively high certainty value, compared to the initial value, or set the enlargement rate relative to the initial value to zero. The fingerprint frame determination unit 130 may calculate the fingerprint frame using, for example, a machine learning model. This model may be configured as a neural network trained by deep learning. Information regarding the fingerprint frame determined by the fingerprint frame determination unit 130 is configured to be output to the superposition unit 140.

[0026] The superimposing unit 140 is configured to superimpose the fingerprint frame determined by the fingerprint frame determining unit 130 onto the fingerprint image acquired by the image acquiring unit 110. Specifically, the superimposing unit 140 superimposes the fingerprint frame at a corresponding position in the fingerprint image (e.g., a position surrounding the fingerprint area). If the fingerprint image includes multiple fingerprints, the superimposing unit 140 may superimpose a fingerprint frame for each finger. For example, a fingerprint frame determined based on the certainty of the index finger may be superimposed on the fingerprint area of ​​the index finger, and a fingerprint frame determined based on the certainty of the middle finger may be superimposed on the fingerprint area of ​​the middle finger. The superimposing unit 140 may have a function to output a fingerprint image with a fingerprint frame superimposed thereon (hereinafter referred to as a "superimposed image"), for example. The superimposed image may be used to cut out the fingerprint area. The process of cutting out the fingerprint area will be described in detail in another embodiment described later.

[0027] (Flow of Operation) Next, the flow of operation by the first information processing device 1 will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the flow of operation by the first information processing device.

[0028] 3, when the operation of the first information processing device 1 starts, the image acquisition unit 110 first acquires a fingerprint image (step S101). Then, the certainty factor calculation unit 120 calculates the certainty factor for each finger regarding the fingerprint included in the fingerprint image acquired by the image acquisition unit 110 (step S102).

[0029] Next, the fingerprint frame determination unit 130 determines a fingerprint frame for each finger based on the fingerprint image acquired by the image acquisition unit 110 and the certainty calculated by the certainty calculation unit 120 (step S103). Then, the superimposition unit 140 superimposes the fingerprint frame determined by the fingerprint frame determination unit 130 on the fingerprint image acquired by the image acquisition unit 110 (step S104).

[0030] The above-described series of operations may be repeatedly executed. For example, the operations from step S101 to step S104 may be executed each time a new fingerprint image is captured by a camera or the like. Alternatively, the operations from step S101 to step S104 may be executed for each of a plurality of fingerprint images stored in the database.

[0031] (Superimposition Operation) Next, the superimposition operation (i.e., the operation of superimposing a fingerprint frame on a fingerprint image) performed by the first information processing device 1 will be specifically described with reference to FIG. 4. FIG. 4 is a schematic diagram showing an example of the superimposition operation performed by the first information processing device. Note that, in the following description, an image including fingerprints of four fingers will be used as an example of a fingerprint image, but the scope of application of this embodiment is not limited to such fingerprint images. Also, in the following description, an example will be used in which a rectangular fingerprint frame is superimposed on a fingerprint image, but the shape of the fingerprint frame is not particularly limited.

[0032] 4, the superimposing unit 140 in the first information processing device 1 first calculates the center position of the fingerprint when superimposing a fingerprint frame. The superimposing unit 140 may, for example, extract a fingerprint area from a fingerprint image and calculate a position corresponding to the center of the fingerprint area (for example, the center point in the vertical and horizontal directions) as the center position of the fingerprint.

[0033] 4 includes a fingerprint F1 of the index finger, a fingerprint F2 of the middle finger, a fingerprint F3 of the ring finger, and a fingerprint F4 of the little finger. The superimposition unit 140 calculates the center position of each of these fingerprints F1 to F4. Specifically, the superimposition unit 140 calculates the center position C1 of the fingerprint F1 of the index finger, the center position C2 of the fingerprint F2 of the middle finger, the center position C3 of the fingerprint F3 of the ring finger, and the center position C4 of the fingerprint F4 of the little finger.

[0034] The superimposition unit 140 then performs a fingerprint frame superimposition process based on the calculated center positions C1 to C4. Specifically, the superimposition unit 140 performs the superimposition process so that the center position C1 of the index finger fingerprint F1 coincides with the center position of the index finger fingerprint frame X1. The superimposition unit 140 performs the superimposition process so that the center position C2 of the middle finger fingerprint F2 coincides with the center position of the middle finger fingerprint frame X2. The superimposition unit 140 performs the superimposition process so that the center position C3 of the ring finger fingerprint F3 coincides with the center position of the ring finger fingerprint frame X3. The superimposition unit 140 performs the superimposition process so that the center position C4 of the little finger fingerprint F4 coincides with the center position of the little finger fingerprint frame X4.

[0035] According to the above-described superimposing operation, it is possible to appropriately superimpose the fingerprint frame on the fingerprint image. Specifically, it is possible to prevent the fingerprint frame from being superimposed at a position that is misaligned with the fingerprint.

[0036] (Technical Effects) Next, technical effects obtained by the first information processing device 1 will be described.

[0037] As described with reference to FIGS. 1 to 4 , in the first information processing device 1, a fingerprint frame is determined based on the certainty of the fingerprint, and the fingerprint frame is superimposed on the fingerprint image. In this way, it is possible to appropriately determine the fingerprint area in the fingerprint image. That is, it is possible to appropriately determine which part of the fingerprint image is the fingerprint. Furthermore, if the size of the fingerprint frame is increased as the certainty decreases when determining the fingerprint frame, it is possible to generate a superimposed image so that the fingerprint fits within the fingerprint frame. For example, it is possible to prevent the fingerprint from extending beyond the fingerprint frame in the superimposed image.

[0038] When attempting to recognize a fingerprint in a fingerprint image, situations may arise in which the fingerprint area cannot be accurately determined due to the condition of the fingerprint. For example, wear of ridges due to aging, loss of contrast due to dryness, or stains due to residual hand sweat or hand cream may cause the fingerprint area to not be detected or a non-fingerprint area to be detected as the fingerprint area. Furthermore, situations may arise in which the fingerprint area cannot be accurately determined due to the way the hand is positioned when photographing the hand. For example, if the hand is placed at an angle to the scanning table when photographing the hand (in an extreme example, if the hand is placed at a 90-degree angle), it becomes difficult to determine the fingerprint area. Alternatively, if the fingers are placed too close together when photographing multiple fingers (for example, if the fingers are placed close together), it becomes difficult to determine the fingerprint area.

[0039] However, in this embodiment, as described above, a fingerprint frame is determined based on the degree of certainty of the fingerprint (i.e., the likelihood of it being a fingerprint), and the fingerprint frame is superimposed on the fingerprint image. Therefore, even in cases where it is difficult to determine the fingerprint area, it is possible to appropriately determine the fingerprint area.

[0040] Second Embodiment A second information processing device 1 will be described with reference to Figures 5 to 8. The second information processing device 1 differs in some configurations and operations from the first information processing device 1 described above, but other parts may be similar to the first information processing device 1. Therefore, the following will describe in detail the parts that differ from the first embodiment, and will omit explanations of other overlapping parts as appropriate.

[0041] (Functional Configuration) First, the functional configuration of the second information processing device 1 will be described with reference to Fig. 5. Fig. 5 is a block diagram showing the functional configuration of the second information processing device. Note that in Fig. 5, the same elements as those shown in Fig. 2 are denoted by the same reference numerals.

[0042] 5, the second information processing device 1 is configured to include, as components for realizing its functions, an image acquisition unit 110, a certainty factor calculation unit 120, a fingerprint frame determination unit 130, a superimposition unit 140, and a provisional frame determination unit 150. That is, the second information processing device 1 further includes the provisional frame determination unit 150 in addition to the configuration described in the first embodiment (see FIG. 2). Note that the provisional frame determination unit 150 may be a processing block realized by the above-mentioned processor 11 (see FIG. 1).

[0043] The temporary frame determination unit 150 is configured to be able to determine, for each finger, a temporary frame corresponding to a fingerprint region included in the fingerprint image based on the fingerprint image acquired by the image acquisition unit 110. The temporary frame is a frame that is temporarily determined in order to determine the fingerprint frame. The temporary frame may be, for example, a rectangular frame corresponding to the fingerprint region. However, the shape of the temporary frame is not particularly limited. The temporary frame determination unit 150 may calculate the temporary frame using a machine learning model, similar to the fingerprint frame determination unit 130 already described. This model may be configured as a neural network trained by deep learning. Information regarding the temporary frame determined by the temporary frame determination unit 150 is configured to be output to the certainty calculation unit 120.

[0044] The certainty factor calculation unit 120 in the second information processing device 1 calculates the certainty factor based on the provisional quota determined by the provisional quota determination unit 150. The certainty factor calculation unit 120 may calculate the certainty factor based on, for example, the quality of the fingerprints included in the provisional quota. Note that the certainty factor based on the provisional quota may be calculated all at once when the provisional quota determination unit 150 determines the provisional quota. In other words, the provisional quota determination unit 150 may be configured to have the function of the certainty factor calculation unit 120.

[0045] The fingerprint frame determination unit 130 in the second information processing device 1 determines a fingerprint frame using the temporary frame determined by the temporary frame determination unit 150 and the certainty calculated based on the certainty calculation unit 120. Specifically, the fingerprint frame determination unit 130 determines a fingerprint frame by changing the size of the temporary frame according to the certainty calculated based on the temporary frame. For example, when the certainty is calculated to be a relatively low value, the fingerprint frame determination unit 130 determines a fingerprint frame with a significantly enlarged size of the temporary frame. Furthermore, when the certainty is calculated to be a relatively high value, the fingerprint frame determination unit 130 determines a fingerprint frame with a slightly enlarged size of the temporary frame. Alternatively, when the certainty is calculated to be a relatively high value, the fingerprint frame determination unit 130 may determine a fingerprint frame with a reduced size of the temporary frame.

[0046] (Operation Flow) Next, the operation flow of the second information processing device 1 will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the operation flow of the second information processing device. Note that in Fig. 6, the same processes as those shown in Fig. 3 are denoted by the same reference numerals.

[0047] 6, when the operation of the second information processing device 1 is started, the image acquisition unit 110 first acquires a fingerprint image (step S101). Then, the temporary frame determination unit 150 determines, for each finger, a temporary frame corresponding to a fingerprint region included in the fingerprint image based on the fingerprint image acquired by the image acquisition unit 110 (step S201).

[0048] Next, the certainty factor calculation unit 120 calculates the certainty factor of the fingerprint included in the fingerprint image for each finger based on the temporary frame determined by the temporary frame determination unit 150 (step S202). As described above, the process of calculating the certainty factor may be executed simultaneously with the process of determining the temporary frame. That is, the processes of steps S201 and S202 may be executed simultaneously.

[0049] Next, the fingerprint frame determination unit 130 determines a fingerprint frame by changing the size of the temporary frame determined by the temporary frame determination unit 150 based on the certainty calculated by the certainty calculation unit 120 (step S203). Then, the superimposition unit 140 superimposes the fingerprint frame determined by the fingerprint frame determination unit 130 on the fingerprint image acquired by the image acquisition unit 110 (step S104).

[0050] As described above, the process of determining a frame corresponding to a fingerprint area is executed in two stages in the second information processing device 1. That is, in the first stage, the process of determining a provisional frame is executed by the provisional frame determination unit 150, and then in the second stage, the process of determining a fingerprint frame is executed by the fingerprint frame determination unit 130.

[0051] In particular, the first stage of processing executed by the temporary frame determination unit 150 to determine the temporary frame may have a smaller processing load than the second stage of processing executed by the fingerprint frame determination unit 130 to determine the fingerprint frame. For example, the model used by the temporary frame determination unit 150 to determine the temporary frame may be lighter than the model used by the fingerprint frame determination unit 130 to determine the fingerprint frame. In this way, it is possible to prevent the processing load related to the frame determination process from increasing. Note that reducing the processing load of the process to determine the temporary frame may result in a decrease in the accuracy of the frame determination. However, because the temporary frame is merely a temporary frame (i.e., a frame temporarily determined to determine the fingerprint frame), there is no problem even if the accuracy is lower than that of the process to determine the fingerprint frame.

[0052] (Frame Determination Operation) Next, the frame determination operation (i.e., the operation when determining the provisional frame and fingerprint frame) by the second information processing device 1 will be specifically described with reference to Fig. 7. Fig. 7 is a schematic diagram showing an example of the frame determination operation by the second information processing device. Note that in Fig. 7, the same elements as those shown in Fig. 4 are assigned the same reference numerals.

[0053] 7, in the frame determination operation by the second information processing device 1, first, the temporary frame determination unit 150 determines a temporary frame based on a fingerprint image. Then, the certainty factor calculation unit 120 calculates the certainty factor based on the temporary frame.

[0054] 7 includes a fingerprint F1 of the index finger, a fingerprint F2 of the middle finger, a fingerprint F3 of the ring finger, and a fingerprint F4 of the little finger. The temporary frame determination unit 150 determines a temporary frame for each of these fingerprints F1 to F4. Specifically, the temporary frame determination unit 150 determines a temporary frame Y1 corresponding to the fingerprint F1 of the index finger, a temporary frame Y2 corresponding to the fingerprint F2 of the middle finger, a temporary frame Y3 corresponding to the fingerprint F3 of the ring finger, and a temporary frame Y4 corresponding to the fingerprint F4 of the little finger.

[0055] The certainty calculation unit 120 then calculates certainty based on the determined temporary frames Y1 to Y4. Specifically, the certainty calculation unit 120 calculates a certainty factor (here, "50") for the index finger fingerprint F1 based on the temporary frame Y1 corresponding to the index finger fingerprint F1. The certainty calculation unit 120 calculates a certainty factor (here, "70") for the middle finger fingerprint F2 based on the temporary frame Y2 corresponding to the middle finger fingerprint F2. The certainty calculation unit 120 calculates a certainty factor (here, "60") for the ring finger fingerprint F3 based on the temporary frame Y3 corresponding to the ring finger fingerprint F3. The certainty calculation unit 120 calculates a certainty factor (here, "80") for the little finger fingerprint F4 based on the temporary frame Y4 corresponding to the little finger fingerprint F4.

[0056] Thereafter, the fingerprint frame determination unit 130 determines a fingerprint frame based on the temporary frame and the certainty factor. Specifically, the fingerprint frame determination unit 130 determines a fingerprint frame X1 corresponding to the index finger fingerprint F1 by enlarging the temporary frame Y1 corresponding to the index finger fingerprint F1 based on the certainty factor for the index finger fingerprint F1. The fingerprint frame determination unit 130 determines a fingerprint frame X2 corresponding to the middle finger fingerprint F2 by enlarging the temporary frame Y2 corresponding to the middle finger fingerprint F2 based on the certainty factor for the middle finger fingerprint F2. The fingerprint frame determination unit 130 determines a fingerprint frame X3 corresponding to the ring finger fingerprint F3 by enlarging the temporary frame Y3 corresponding to the ring finger fingerprint F3 based on the certainty factor for the ring finger fingerprint F3. The fingerprint frame determination unit 130 determines a fingerprint frame X4 corresponding to the little finger fingerprint F4 by enlarging the temporary frame Y4 corresponding to the little finger fingerprint F4 based on the certainty factor for the little finger fingerprint F4.

[0057] 7, the fingerprint frame determination unit 130 determines fingerprint frames X1 to X4 by enlarging the provisional frames Y1 to Y4 more as the certainty level becomes lower. For example, for the index finger fingerprint F1, which has a low certainty level, the fingerprint frame X1 is determined by significantly enlarging the provisional frame Y1. On the other hand, for the little finger fingerprint F4, which has a high certainty level, the fingerprint frame X4 is determined by slightly enlarging the provisional frame Y4.

[0058] (Modification) Next, a modification of the operation of the second information processing device 1 will be described with reference to Fig. 8. Fig. 8 is a flowchart showing a modification of the operation of the second information processing device. Note that in Fig. 8, the same processes as those shown in Fig. 6 are denoted by the same reference numerals.

[0059] 8 , first, image acquisition unit 110 acquires a fingerprint image (step S101). Then, temporary frame determination unit 150 determines, for each finger, a temporary frame corresponding to a fingerprint area included in the fingerprint image based on the fingerprint image acquired by image acquisition unit 110 (step S201). Thereafter, certainty factor calculation unit 120 calculates, for each finger, a certainty factor of the fingerprint included in the fingerprint image based on the temporary frame determined by temporary frame determination unit 150 (step S202).

[0060] Next, the fingerprint frame determination unit 130 determines the amount of size correction to be used when determining the designated frame (i.e., the amount of correction to be used when enlarging the size of the temporary frame) based on the density distribution within the temporary frame (step S251). For example, the fingerprint frame determination unit 130 may determine a larger amount of size correction as the deviation between the density distribution within the temporary frame and the density distribution of a preset fingerprint increases.

[0061] Then, the designated frame determination unit 130 determines a fingerprint frame by changing the size of the temporary frame determined by the temporary frame determination unit 150 based on the certainty calculated by the certainty calculation unit 120 and the determined size correction amount (step S252). That is, the fingerprint frame determination unit 130 changes the size of the temporary frame by taking into account both the size change amount determined according to the certainty and the size correction amount determined according to the density distribution. After changing the size of the temporary frame based on the size change amount determined according to the certainty, the fingerprint frame determination unit 130 may further change the size of the temporary frame based on the size correction amount determined according to the density distribution. Alternatively, the fingerprint frame determination unit 130 may change the size of the temporary frame all at once based on the combined value of the size change amount determined according to the certainty and the size correction amount determined according to the density distribution.

[0062] As described above, if the amount of size correction is determined based on the density distribution within the temporary frame, the size of the temporary frame can be changed more appropriately, and as a result, the fingerprint frame can be made to a more appropriate size.

[0063] Next, the superimposing unit 140 calculates the center position of the fingerprint region based on the density distribution within the temporary frame (step S253). For example, the fingerprint frame determination unit 130 calculates the center position of the fingerprint region by comparing the density distribution within the temporary frame with the density distribution of a preset fingerprint. Note that the superimposing unit 140 may correct the center position that has already been calculated based on the density distribution within the temporary frame.

[0064] Thereafter, the superimposing unit 140 superimposes the fingerprint frame determined by the fingerprint frame determining unit 130 onto the fingerprint image based on the center position calculated in step S253 (step S254). The superimposing process of the fingerprint frame based on the center position may be performed in the same manner as the process described with reference to FIG.

[0065] As described above, by using the density distribution within the provisional frame, the center position of the fingerprint area can be calculated more accurately, and as a result, the fingerprint frame can be superimposed at a more appropriate position.

[0066] (Technical Effects) Next, technical effects obtained by the second information processing device 1 will be described.

[0067] As described with reference to Figures 5 to 8, in the second information processing device 1, a temporary frame is determined based on a fingerprint image, and a confidence level is calculated based on the temporary frame. The fingerprint frame is then determined by changing the size of the temporary frame based on the confidence level. In this way, it is possible to determine the fingerprint area more accurately compared to determining the fingerprint frame directly from the fingerprint image (i.e., without determining a temporary frame). For example, by determining the temporary frame to give an estimate of the fingerprint area, and then estimating the fingerprint area in detail when determining the fingerprint frame, it is possible to determine the fingerprint area more appropriately.

[0068] <Third embodiment> A third information processing device 1 will be described with reference to Figures 9 to 11. The third information processing device 1 differs in some configurations and operations from the first and second information processing devices 1 described above, but other parts may be similar to the first and second information processing devices 1. Therefore, the following will describe in detail the parts that differ from the embodiments already described, and will omit explanations of other overlapping parts as appropriate.

[0069] (Functional Configuration) First, the functional configuration of the third information processing device 1 will be described with reference to Fig. 9. Fig. 9 is a block diagram showing the functional configuration of the third information processing device. Note that in Fig. 9, the same elements as those shown in Fig. 5 are denoted by the same reference numerals.

[0070] 9, the third information processing device 1 is configured to include, as components for realizing its functions, an image acquisition unit 110, a certainty calculation unit 120, a fingerprint frame determination unit 130, a superposition unit 140, a temporary frame determination unit 150, and a cutout unit 160. That is, the third information processing device 1 further includes the cutout unit 160 in addition to the configuration described in the second embodiment (see FIG. 5). Note that the cutout unit 160 may be a processing block realized by the above-mentioned processor 11 (see FIG. 1).

[0071] The cutout unit 160 is configured to be able to cut out a fingerprint area from the fingerprint image based on a fingerprint frame superimposed on the fingerprint image. The cutout unit 160 may cut out the fingerprint area along the fingerprint frame. The cutout unit 160 may have a function to output an image of the cut-out fingerprint area (hereinafter referred to as a "cut-out image" as appropriate). The cut-out image cut out by the cutout unit 160 may be registered as a registered image in a fingerprint matching database, for example. When the fingerprint image includes multiple fingerprints, the cutout unit 160 may cut out a cut-out image for each finger.

[0072] (Operation Flow) Next, the operation flow of the third information processing device 1 will be described with reference to Fig. 10. Fig. 10 is a flowchart showing the operation flow of the third information processing device. Note that in Fig. 10, the same processes as those shown in Fig. 6 are denoted by the same reference numerals.

[0073] 10 , when the operation of the third information processing device 1 is started, the image acquisition unit 110 first acquires a fingerprint image (step S101). Then, the temporary frame determination unit 150 determines, for each finger, a temporary frame corresponding to a fingerprint area included in the fingerprint image based on the fingerprint image acquired by the image acquisition unit 110 (step S201). Then, the certainty calculation unit 120 calculates, for each finger, the certainty of the fingerprint included in the fingerprint image based on the temporary frame determined by the temporary frame determination unit 150 (step S202).

[0074] Next, the fingerprint frame determination unit 130 determines a fingerprint frame by changing the size of the temporary frame determined by the temporary frame determination unit 150 based on the certainty calculated by the certainty calculation unit 120 (step S203). Then, the superimposition unit 140 superimposes the fingerprint frame determined by the fingerprint frame determination unit 130 on the fingerprint image acquired by the image acquisition unit 110 (step S104). Thereafter, the cutout unit 160 cuts out a fingerprint region from the fingerprint image based on the fingerprint frame (step S301).

[0075] (Cutting-out operation) Next, the cutting-out operation by the third information processing device 1 (i.e., the operation when cutting out a fingerprint area based on a fingerprint frame) will be specifically described with reference to Fig. 11. Fig. 11 is a schematic diagram showing an example of the cutting-out operation by the third information processing device. Note that in Fig. 11, the same elements as those shown in Fig. 7 are assigned the same reference numerals.

[0076] 11 includes a fingerprint F1 of the index finger, a fingerprint F2 of the middle finger, a fingerprint F3 of the ring finger, and a fingerprint F4 of the little finger. The temporary frame determination unit 150 determines temporary frames Y1 to Y4 for each of these fingerprints F1 to F4. The fingerprint frame determination unit 130 then determines fingerprint frames X1 to X4 based on the temporary frames Y1 to Y4 and their certainty factors.

[0077] The cropping unit 160 crops out a fingerprint region based on the determined fingerprint frames X1 to X4. Specifically, the cropping unit 160 crops out a cropped image P1 of the index finger along the fingerprint frame X1 corresponding to the index finger fingerprint F1. The cropping unit 160 crops out a cropped image P2 of the middle finger along the fingerprint frame X2 corresponding to the middle finger fingerprint F2. The cropping unit 160 crops out a cropped image P3 of the ring finger along the fingerprint frame X3 corresponding to the ring finger fingerprint F3. The cropping unit 160 crops out a cropped image P4 of the little finger along the fingerprint frame X4 corresponding to the little finger fingerprint F4.

[0078] 11, when the fingerprint frames X1 to X4 have different sizes, the sizes of the cut-out images P1 to P4 cut out by the cut-out unit 160 also differ. In this case, the cut-out unit 160 may execute a process to make the sizes of the cut-out images P1 to P4 uniform.

[0079] (Technical Effects) Next, technical effects obtained by the third information processing device 1 will be described.

[0080] 9 to 11, in the third information processing device 1, a fingerprint area is cut out from a fingerprint image based on a fingerprint frame. In this way, it is possible to appropriately cut out only the part of the fingerprint image where the fingerprint exists.

[0081] 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.

[0082] 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. Furthermore, the scope of each embodiment is not limited to programs that execute processes by themselves, but also includes programs that execute processes by operating on an OS in conjunction with other software or expansion board functions. Furthermore, the program itself may be stored on a server, and part or all of the program may be downloadable from the server to a user terminal. The program may be provided to the user in, for example, a SaaS (Software as a Service) format.

[0083] <Supplementary Notes> The above-described embodiment may be further described as in the following supplementary notes, but is not limited to the following.

[0084] (Supplementary Note 1) The information processing device described in Supplementary Note 1 is an information processing device that includes an acquisition means for acquiring a fingerprint image including a fingerprint, a calculation means for calculating, for each finger, a degree of certainty indicating the likelihood that the fingerprint included in the fingerprint image is a fingerprint, a fingerprint frame determination means for determining, for each finger, the size of a fingerprint frame corresponding to an area in the fingerprint image where the fingerprint exists based on the degree of certainty, and a superimposition means for superimposing the fingerprint frame on a corresponding position on the fingerprint image.

[0085] (Supplementary Note 2) The information processing device according to Supplementary Note 2 is the information processing device according to Supplementary Note 1, wherein the fingerprint frame determination means increases the size of the fingerprint frame as the certainty factor decreases.

[0086] (Supplementary Note 3) The information processing device according to Supplementary Note 3 is the information processing device according to Supplementary Note 1 or 2, wherein the superimposing means calculates a center position of the fingerprint for each finger and superimposes the fingerprint frame based on the center position.

[0087] (Appendix 4) The information processing device described in Appendix 4 is an information processing device described in any one of Appendices 1 to 3, further comprising a temporary frame determination means for determining a temporary frame corresponding to an area in which the fingerprint contained in the fingerprint image is present, the calculation means calculates the certainty factor based on the temporary frame, and the fingerprint frame determination means determines the fingerprint frame by changing the size of the temporary frame according to the certainty factor.

[0088] (Appendix 5) The information processing device described in Appendix 5 is the information processing device described in Appendix 4, in which the process of determining the temporary frame by the temporary frame determination means has a smaller processing load than the process of determining the fingerprint frame by the fingerprint frame determination means.

[0089] (Appendix 6) The information processing device described in Appendix 6 is the information processing device described in Appendix 4 or 5, in which the fingerprint frame determination means corrects at least one of the size of the fingerprint frame or the center position of the area in which the fingerprint exists based on the distribution of shading within the temporary frame.

[0090] (Appendix 7) The information processing device described in Appendix 7 is the information processing device described in any one of Appendices 4 to 6, wherein the superimposing means calculates the center position of the area where the fingerprint exists based on the distribution of shading within the temporary frame, and superimposes the fingerprint frame based on the center position.

[0091] (Appendix 8) The information processing device described in Appendix 8 is the information processing device described in any one of Appendices 1 to 7, further comprising an extraction means for extracting an area in which the fingerprint exists from the fingerprint image based on the fingerprint frame superimposed on the fingerprint image.

[0092] (Supplementary Note 9) The information processing method described in Supplementary Note 9 is an information processing method that, by using at least one computer, acquires a fingerprint image containing a fingerprint, calculates a certainty factor indicating the likelihood that the fingerprint contained in the fingerprint image is a fingerprint for each finger, determines a fingerprint frame size for each finger that corresponds to an area in the fingerprint image where the fingerprint exists based on the certainty factor, and superimposes the fingerprint frame on the corresponding position on the fingerprint image.

[0093] (Supplementary Note 10) The recording medium described in Supplementary Note 10 is a recording medium having recorded thereon a computer program for causing at least one computer to execute an information processing method of acquiring a fingerprint image including a fingerprint, calculating for each finger a degree of certainty indicating the likelihood that the fingerprint included in the fingerprint image is a fingerprint, determining for each finger a size of a fingerprint frame corresponding to an area in the fingerprint image where the fingerprint exists based on the degree of certainty, and superimposing the fingerprint frame on a corresponding position on the fingerprint image.

[0094] (Appendix 11) The computer program described in Appendix 11 is a computer program that causes at least one computer to execute an information processing method of acquiring a fingerprint image including a fingerprint, calculating a certainty factor for each finger that indicates the likelihood that the fingerprint included in the fingerprint image is a fingerprint, determining a size of a fingerprint frame for each finger that corresponds to an area in the fingerprint image where the fingerprint exists based on the certainty factor, and superimposing the fingerprint frame on a corresponding position on the fingerprint image.

[0095] 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 devices, information processing methods, and recording media that involve such modifications are also included in the technical idea of ​​this disclosure.

[0096] 10 Information processing device 11 Processor 12 RAM 13 ROM 14 Storage device 15 Input device 16 Output device 17 Data bus 110 Image acquisition unit 120 Certainty factor calculation unit 130 Fingerprint frame determination unit 140 Superposition unit 150 Temporary frame determination unit 160 Cutout unit F1 to F4 Fingerprints C1 to C4 Center position X1 to X4 Fingerprint frame Y1 to Y2 Temporary frame P1 to P4 Cutout image

Claims

1. An information processing device comprising: an acquisition means for acquiring a fingerprint image including a fingerprint; a calculation means for calculating, for each finger, a degree of certainty indicating the likelihood that the fingerprint included in the fingerprint image is a fingerprint; a fingerprint frame determination means for determining, for each finger, the size of a fingerprint frame corresponding to an area in the fingerprint image where the fingerprint exists based on the degree of certainty; and a superimposition means for superimposing the fingerprint frame on a corresponding position on the fingerprint image.

2. The information processing device according to claim 1, wherein said fingerprint frame determination means increases the size of said fingerprint frame as said certainty level decreases.

3. The information processing device according to claim 1 or 2, wherein the superimposing means calculates a center position of the fingerprint for each finger and superimposes the fingerprint frame based on the center position.

4. An information processing device as described in claim 1 or 2, further comprising a temporary frame determination means for determining a temporary frame corresponding to an area in the fingerprint image where the fingerprint is present, wherein the calculation means calculates the certainty factor based on the temporary frame, and the fingerprint frame determination means determines the fingerprint frame by changing the size of the temporary frame according to the certainty factor.

5. The information processing device according to claim 4, wherein the processing of determining the temporary frame by the temporary frame determining means has a smaller processing load than the processing of determining the fingerprint frame by the fingerprint frame determining means.

6. The information processing device according to claim 4, wherein said fingerprint frame determination means corrects the size of said fingerprint frame based on the distribution of shading within said temporary frame.

7. The information processing device according to claim 4, wherein the superimposing means calculates the center position of the area where the fingerprint exists based on the distribution of shading within the temporary frame, and superimposes the fingerprint frame based on the center position.

8. The information processing apparatus according to claim 1, further comprising: cutting means for cutting out an area in which the fingerprint exists from the fingerprint image based on the fingerprint frame superimposed on the fingerprint image.

9. An information processing method comprising: acquiring a fingerprint image containing a fingerprint by at least one computer; calculating a degree of certainty for each finger indicating the likelihood that the fingerprint contained in the fingerprint image is a fingerprint; determining, for each finger, the size of a fingerprint frame corresponding to the area in the fingerprint image where the fingerprint exists based on the degree of certainty; and superimposing the fingerprint frame on the corresponding position on the fingerprint image.

10. A recording medium having recorded thereon a computer program for causing at least one computer to execute an information processing method, which comprises acquiring a fingerprint image containing a fingerprint, calculating for each finger a degree of certainty indicating the likelihood that the fingerprint contained in the fingerprint image is a fingerprint, determining for each finger a size of a fingerprint frame corresponding to an area in the fingerprint image where the fingerprint exists based on the degree of certainty, and superimposing the fingerprint frame on the corresponding position on the fingerprint image.

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