Information processing device, information processing method, and recording medium

Abstract

This information processing device comprises: an acquisition means for acquiring feature point information and ridge direction information, the feature point information including a first curvature indicating a degree of curvature of a first ridge adjacent to a feature point of a fingerprint and a second curvature indicating a degree of curvature of a second ridge which is different from the first ridge and is adjacent to the feature point, the ridge direction information indicating a ridge direction of a predetermined peripheral region of the feature point; and a storage means which, on the basis of the feature point information and the ridge direction information, generates and stores representative ridge information indicating a representative ridge direction of the predetermined peripheral region of the feature point for each combination of the first curvature and the second curvature.

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] It is known that ridge direction is used in fingerprint matching. For example, Patent Document 1 discloses that, during matching, ridge direction data and curvature data between registered data and matching data are compared.

[0003] Japanese Patent Application Publication No. 07-110860

[0004] This disclosure aims to improve upon the related art discussed above.

[0005] One aspect of the information processing device disclosed herein comprises an acquisition means for acquiring minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia of a fingerprint and a second curvature indicating the degree of curvature of a second ridge different from the first ridge and adjacent to the minutia, as well as ridge direction information indicating the ridge direction of a predetermined peripheral region of the minutia; and a storage means for generating and storing representative ridge information indicating the representative ridge direction of a predetermined peripheral region of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information.

[0006] One aspect of the information processing method disclosed herein is an information processing method executed by a computer, which acquires minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia of a fingerprint and a second curvature indicating the degree of curvature of a second ridge different from the first ridge and adjacent to the minutia, as well as ridge direction information indicating the ridge direction of a predetermined peripheral region of the minutia, and generates and saves representative ridge information indicating a representative ridge direction of a predetermined peripheral region of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information.

[0007] One aspect of the recording medium of this disclosure has recorded thereon a computer program that causes a computer to execute an information processing method that acquires minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia that a fingerprint has, and a second curvature indicating the degree of curvature of a second ridge that is different from the first ridge and adjacent to the minutia, as well as ridge direction information indicating the ridge directions of predetermined peripheral regions of the minutia, and generates and saves representative ridge information indicating the representative ridge directions of predetermined peripheral regions of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information.

[0008] 1A is a block diagram showing the configuration of an information processing device according to the present disclosure, and FIG. 1B is a flowchart showing the flow of information processing operations in the information processing device according to the present disclosure. FIG. 1A is a block diagram showing the configuration of an information processing device according to the present disclosure, and FIG. 1B is a flowchart showing the flow of information processing operations in the information processing device according to the present disclosure. FIG. 1B is a block diagram showing the configuration of an information processing device according to the present disclosure. FIG. 1C is a flowchart showing the flow of information processing operations in the information processing device according to the present disclosure. FIG. 1C is a block diagram showing the configuration of an information processing device according to the present disclosure. FIG. 1D is a flowchart showing the flow of information processing operations in the information processing device according to the present disclosure.

[0009] Hereinafter, an information processing device, an information processing method, and a recording medium according to an embodiment will be described with reference to the drawings. [1: First Embodiment]

[0010] A first embodiment of an information processing device, an information processing method, and a recording medium will be described below. Hereinafter, the first embodiment of the information processing device, the information processing method, and the recording medium will be described using an information processing device 1 according to this disclosure. [1-1: Configuration of Information Processing Device 1]

[0011] The configuration of an information processing device 1 according to this disclosure will be described with reference to Fig. 1(a) , which is a block diagram showing the configuration of the information processing device 1 according to this disclosure.

[0012] 1A, the information processing device 1 includes a calculation device 11, a storage device 12, and a communication device 13. The calculation device 11, the storage device 12, and the communication device 13 may be connected via a data bus 16.

[0013] The arithmetic device 11 includes at least one processor (i.e., one processor or multiple processors) as hardware. The processor may include, for example, a processor conforming to a von Neumann computer architecture. The processor conforming to the von Neumann computer architecture may include at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The processor may include, for example, a processor conforming to a non-von Neumann computer architecture. The processor conforming to the non-von Neumann computer architecture may include at least one of an FPGA (Field Programmable Gate Array) and an ASIC (Application Specific Circuit).

[0014] The arithmetic device 11 reads a computer program 121 including at least one of computer program code and computer program instructions. For example, the arithmetic device 11 may read the computer program 121 stored in the storage device 12. For example, the arithmetic device 11 may read the computer program 121 stored in a computer-readable, non-transitory recording medium using a recording medium reading device (not shown) included in the information processing device 1. The computer program 121 read from the recording medium may be stored in the storage device 12. The arithmetic device 11 may acquire (i.e., download or read) the computer program 121 from a device (not shown) located outside the information processing device 1 via the communication device 13 (or another communication device). The downloaded computer program 121 may be stored in the storage device 12.

[0015] The arithmetic device 11 executes the loaded computer program 121. As a result, logical functional blocks for executing processing to be performed by the information processing device 1 (e.g., information processing described below) are realized within the arithmetic device 11. In other words, the arithmetic device 11, together with the storage device 12, etc. in which the computer program 121 is recorded (in other words, together with the storage device 12 and the computer program 121 recorded in the storage device 12, etc.), can function as a controller or computer for realizing the logical functional blocks for executing processing to be performed by the information processing device 1. In other words, the at least one processor included in the arithmetic device 11, the memory (recording medium) included in the storage device 12, etc., and the computer program 121 are configured to cause the information processing device 1 to perform processing to be performed by the information processing device 1 (e.g., information processing described below). The arithmetic device 11 may output information to another computer, cloud server, or other device (not shown) provided outside the information processing device 1 via the communication device 13 (or other communication device).

[0016] The recording medium for recording the computer program 121 executed by the arithmetic device 11 may be at least one of a CD-ROM, CD-R, CD-RW, flexible disk, MO, DVD-ROM, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, and Blu-ray (registered trademark) optical disk, magnetic medium such as magnetic tape, magneto-optical disk, semiconductor memory such as USB memory, and any other medium capable of storing a program. The recording medium may include a device capable of recording the computer program 121 (for example, a general-purpose device or a dedicated device in which the computer program 121 is implemented in a state in which it can be executed in at least one of the forms of software and firmware). Furthermore, each process or function included in the computer program 121 may be realized by a logical processing block realized within the arithmetic device 11 when the arithmetic device 11 (i.e., processor) executes the computer program 121, or may be realized by hardware such as a predetermined gate array (FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit)) included in the arithmetic device 11, or may be realized in a form that mixes logical processing blocks and partial hardware modules that realize some elements of the hardware.

[0017] Fig. 1(a) shows an example of logical functional blocks implemented in a computing device 11 for executing information processing. As shown in Fig. 1, an acquisition unit 111 and a storage unit 112 are implemented in the computing device 11. The processes performed by the acquisition unit 111 and the storage unit 112 will be described with reference to Fig. 1(b).

[0018] The storage device 12 includes at least one memory capable of storing desired data. In other words, the storage device 12 includes at least one memory containing desired data. For example, the storage device 12 may store a computer program 121 executed by the arithmetic device 11. In this case, the storage device 12 (memory) may be used as the above-mentioned recording medium for recording the computer program 121 executed by the arithmetic device 11. The storage device 12 may temporarily store data used by the arithmetic device 11 when the arithmetic device 11 is executing the computer program 121. The storage device 12 may also store data to be stored long-term by the information processing device 1. The storage device 12 may include at least one of a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device. In other words, the storage device 12 may include a non-temporary recording medium.

[0019] The communication device 13 can communicate with devices external to the information processing device 1 or 2 via a communication network (not shown). The communication device 13 may be a communication interface based on standards such as Ethernet (registered trademark), Wi-Fi (registered trademark), Bluetooth (registered trademark), or USB (Universal Serial Bus). [1-2: Information Processing Method Executed by the Information Processing Device 1]

[0020] 1B, an information processing method executed by the information processing device 1 will be described. FIG. 1B is a flowchart showing an example of the flow of the information processing method executed by the information processing device 1.

[0021] 1B, the acquiring unit 111 acquires minutia information and ridge direction information (step S11). The minutia information includes information about minutiae of a fingerprint. Minutiae include at least one of end points where a ridge is cut and branch points where a ridge is branched.

[0022] The minutia information includes a first curvature indicating the degree of curvature of a first ridge line adjacent to the minutia point, and a second curvature indicating the degree of curvature of a second ridge line adjacent to the minutia point. The curvature is information obtained by quantifying the degree of curvature of a ridge line adjacent to the minutia point. The second ridge line is a ridge line different from the first ridge line. The first ridge line and the second ridge line may be core lines obtained by thinning ridge lines.

[0023] FIG. 2 illustrates an overview of minutia information. In other words, FIG. 2 illustrates the concept of curvature in this embodiment. As illustrated in FIG. 2, curvature represents the degree of curvature of two ridges RL and RR adjacent to both sides of a minutia with respect to the direction of the minutia. The direction of the arrow pointing out from the minutia indicates the direction of the minutia. The ridge RL illustrated in FIG. 2 may be an example of a first ridge. Furthermore, the ridge RR illustrated in FIG. 2 may be an example of a second ridge.

[0024] The curvature may be represented by, for example, 15 integers from "-7" to "7". For example, a curvature that is largely curved to the left may be represented by "-7". Furthermore, a curvature that is largely curved to the right may be represented by "7". In this case, the curvature VL of the ridge RL and the curvature VR of the ridge RR illustrated in FIG. 2( a) may both be represented by "1". Furthermore, the curvature VL of the ridge RL and the curvature VR of the ridge RR illustrated in FIG. 2( b) may both be represented by "-3". Furthermore, the curvature VL of the ridge RL illustrated in FIG. 2( c) may be represented by "-4", and the curvature VR of the ridge RR may be represented by "4". Note that the 15 integers from "-7" to "7" are merely one example of how to represent curvature, and are merely an example used to make this disclosure easier to understand.

[0025] The ridge direction information indicates the ridge direction of a predetermined peripheral region of the feature point. The predetermined peripheral region includes a region where at least a portion of the first ridge and the second ridge are present. The predetermined peripheral region may be a region wider than the region where the first ridge and the second ridge are present. The predetermined peripheral region may be a region that can be associated with the first curvature and the second curvature. The predetermined peripheral region may be a region that can be affected by the first curvature and the second curvature.

[0026] The storage unit 112 generates representative ridge information indicating the representative ridge direction of a predetermined peripheral region of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information (step S12). The storage unit 112 stores the representative ridge information (step S13). The storage unit 112 may store the representative ridge information in the storage device 12. The storage unit 112 may create a database of representative ridge information (sometimes referred to as a "representative ridge information database") in the storage device 12. [1-3: Technical Effects of Information Processing Device 1]

[0027] Curvature information is set for minutiae of a fingerprint. The information processing device 1 according to this disclosure uses this curvature information to determine a representative ridge direction around a minutiae for each curvature. This allows the information processing device 1 to provide a mechanism (for example, the representative ridge information database described above) that can present a representative ridge direction around a minutiae from the curvature of the minutiae. [2: Second Embodiment]

[0028] A second embodiment of an information processing device, an information processing method, and a recording medium will be described below. Hereinafter, the second embodiment of an information processing device, an information processing method, and a recording medium will be described using an information processing device 2 according to this disclosure. [2-1: Configuration of Information Processing Device 2]

[0029] The configuration of the information processing device 2 according to this disclosure will be described with reference to Fig. 3(a) , which is a block diagram showing the configuration of the information processing device 2 according to this disclosure.

[0030] 3A, the information processing device 2 may further include an input device 14 and an output device 15 in addition to the calculation device 11, the storage device 12, and the communication device 13. However, the information processing device 2 does not necessarily have to include at least one of the input device 14 and the output device 15. The calculation device 11, the storage device 12, the communication device 13, the input device 14, and the output device 15 may be connected via a data bus 16.

[0031] 3A, in addition to the acquisition unit 211 and the storage unit 112, a restoration unit 213 is further realized in the calculation device 11 in the second embodiment. Furthermore, a representative ridge information database DB may be realized in the storage device 12 in the second embodiment. Note that the representative ridge information database DB may be realized in a storage device outside the information processing device 2.

[0032] The input device 14 is a device that accepts information input to the information processing device 2 from outside the information processing device 2. For example, the input device 14 may include an operation device (e.g., at least one of a keyboard, a mouse, and a touch panel) that can be operated by an operator of the information processing device 2. For example, the input device 14 may include a reading device that can read information recorded as data on a recording medium that can be externally attached to the information processing device 2.

[0033] The output device 15 is a device that outputs information to the outside of the information processing device 2. For example, the output device 15 may output information as an image. That is, the output device 15 may include a display device (a so-called display) that can display an image showing the information to be output. For example, the output device 15 may output information as sound. That is, the output device 15 may include an audio device (a so-called speaker) that can output sound. For example, the output device 15 may output information on paper. That is, the output device 15 may include a printing device (a so-called printer) that can print desired information on paper.

[0034] The information processing device 2 is configured as a device for creating a database, similar to the information processing device 1. Furthermore, the information processing device 2 is configured as a device for restoring the ridge direction of a fingerprint. The information processing device 2 restores the ridge direction of a fingerprint using the representative ridge information database described above. [2-2: Information Processing Method Executed by Information Processing Device 2]

[0035] 3B, a description will be given of the operation of restoring the fingerprint ridge direction in the information processing device 2. FIG. 3B is a flowchart showing the flow of the operation of restoring the fingerprint ridge direction in the information processing device 2.

[0036] 3B, the acquiring unit 211 acquires fingerprint information indicating a fingerprint having minutiae (step S21). In this embodiment, the fingerprint information includes minutiae information. The fingerprint information may or may not include ridge direction information. The fingerprint information may exist for each fingerprint image.

[0037] The restoration unit 213 adds representative ridge information corresponding to the first curvature and the second curvature of the minutiae to the fingerprint information based on the positions and directions of the minutiae (step S22). The restoration unit 213 generates a restored ridge direction by restoring the ridge direction of the ridge direction unit based on the representative ridge direction in the ridge direction unit included in the fingerprint (step S23). [2-3: Technical Effects of the Information Processing Device 2]

[0038] Fingerprint matching often uses the similarity of minutiae arrangement. However, it is known that accuracy can be improved by using the ridge direction in areas where no minutiae exist. The ridge direction can be calculated from the core line and defined as the ridge direction. However, for example, core lines do not exist in old data from the past. When a core line does not exist, the ridge direction cannot be defined, and it cannot be used for fingerprint matching. Core lines are information that has been correctly corrected by forensic scientists. Therefore, when a core line is automatically extracted from the original fingerprint image, it often deviates from the correct core line.

[0039] The information processing device 2 according to this disclosure can generate a reconstructed ridge direction using a mechanism capable of presenting a representative ridge direction around a minutia (for example, the representative ridge information database described above). By using this reconstructed ridge direction, the accuracy of fingerprint matching can be improved. [3: Third Embodiment]

[0040] A third embodiment of an information processing device, an information processing method, and a recording medium will be described below. Hereinafter, the third embodiment of an information processing device, an information processing method, and a recording medium will be described using an information processing device 3 according to this disclosure. [3-1: Information processing method executed by information processing device 3] [a: Database creation operation]

[0041] The information processing device 3 is configured as a device for creating a database, similar to the information processing device 1. Below, differences from the first embodiment will be described in detail, and descriptions of other overlapping parts will be omitted as appropriate.

[0042] 5A, the creation of a database in the information processing device 3 will be described. FIG. 5A is a flowchart showing the flow of the database creation operation in the information processing device 3.

[0043] As shown in FIG. 5( a), the acquiring unit 311 acquires minutiae information and ridge direction information (step S31). The ridge direction information in the third embodiment includes information indicating the ridge element direction of each of a plurality of ridge elements included in a predetermined peripheral region of a minutiae of a fingerprint, with the direction of the minutiae as the reference. FIG. 6( a) illustrates an outline of the ridge direction information. FIG. 6( a) shows an example of a peripheral region A of a minutiae M and a plurality of ridge elements E included in the peripheral region A. FIG. 6( a) illustrates a case in which the peripheral region A includes 288 (=17×17−1) ridge elements E. Although only one ridge element E is labeled in FIG. 6( a), all of the circular regions surrounded by dotted lines in FIG. 6( a) are ridge elements E. The alphanumeric characters (0 to 9, a to f) labeled within each region of the ridge elements E illustrated in FIG. 6( a) indicate an example of the ridge element direction with the direction of the minutiae M as the reference. In other words, the ridge element E is an element that represents a ridge element direction based on the direction of the minutia point M. Note that the number of ridge elements and the types of ridge element directions described above are merely examples, and are merely examples used to make this disclosure easier to understand.

[0044] The storage unit 312 generates representative ridge information for each combination of the first curvature and the second curvature (step S32). The representative ridge information in the third embodiment includes information indicating the representative ridge element direction of each of the multiple ridge elements. The storage unit 312 determines the representative ridge element direction for each of the multiple ridge elements for each combination of the first curvature and the second curvature based on the multiple ridge element directions. For example, as described above, when the curvature is expressed by 15 integers from -7 to 7, there are 225 combinations of the first curvature and the second curvature. Also, for example, as described above, the surrounding region may include 288 ridge elements. In this case, the storage unit 312 determines the representative ridge element direction for each of the 288 ridge elements for each of the 225 combinations.

[0045] Fig. 6(b) illustrates ridge direction information for multiple minutiae having the same first curvature and second curvature. The storage unit 312 determines a representative ridge element direction for each ridge element based on multiple ridge element directions. Fig. 6(c) illustrates representative ridge information generated by arranging the determined representative ridge element directions. When the ridge direction information is information about 288 (=17×17−1) ridge elements E as illustrated in Fig. 6(a), the representative ridge information may also be information about 288 (=17×17−1) ridge elements E.

[0046] The storage unit 312 may, for example, average a plurality of ridge element directions to obtain a representative ridge element direction. Alternatively, the storage unit 312 may, for example, determine the median of a plurality of ridge element directions as the representative ridge element direction.

[0047] The storage unit 312 stores the representative ridge information (step S23). The storage unit 312 may create a representative ridge information database DB in the storage device 12.

[0048] Although Fig. 6 illustrates a square peripheral region, the shape of the peripheral region is not limited to a square. For example, a circle may be used as another example of the shape of the peripheral region. [b: Ridge Direction Restoration Operation]

[0049] The information processing device 3 is configured as a device for restoring the ridge directions of a fingerprint. The information processing device 3 restores the ridge directions of a fingerprint using the representative ridge information database DB described above.

[0050] 5B, a description will be given of the operation of restoring the fingerprint ridge direction in the information processing device 3. FIG. 5B is a flowchart showing the flow of the operation of restoring the fingerprint ridge direction in the information processing device 3.

[0051] 5B, the acquisition unit 311 acquires fingerprint information indicating a fingerprint having minutiae (step S36). The restoration unit 313 adds representative ridge information corresponding to the first and second curvatures of the minutiae to the fingerprint information based on the positions and directions of the minutiae (step S37).

[0052] Fig. 7(a) illustrates minutiae in a fingerprint. Fig. 7(b) illustrates a case where representative ridge information corresponding to the first curvature and second curvature of the minutiae is added to fingerprint information. As illustrated in Fig. 7(b), the restoration unit 313 corrects the corresponding representative ridge information according to the direction of the minutiae of the fingerprint, and adds the corrected representative ridge information to the fingerprint information. Note that in Fig. 7, for the sake of explanation, the minutiae of interest are denoted by the symbols M1 and M2.

[0053] The restoration unit 313 generates a restored ridge direction by restoring the ridge direction of the ridge direction unit based on the representative ridge element direction of the ridge element in the ridge direction unit included in the fingerprint (step S38). Fig. 8 illustrates an example of a ridge direction unit included in a fingerprint. Each of the areas surrounded by a dashed line in Fig. 8 is a ridge direction unit. Note that in Fig. 8, the ridge direction unit of interest is denoted by the symbol U for the sake of explanation. Fig. 9 illustrates an example of the relationship between the ridge direction unit U and representative ridge element information.

[0054] The restoration unit 313 may generate a restored ridge direction by increasing the weight of the value of the representative ridge element direction as the ridge element in the ridge direction unit is closer to the corresponding minutiae. Fig. 9(b) is an enlarged view of the periphery of the ridge direction unit U illustrated in Fig. 9(a). As illustrated in Fig. 9(b), the distance d1 between the ridge element included in the representative ridge information corresponding to minutiae M1 and minutiae M1 is closer than the distance d2 between the ridge element included in the representative ridge information corresponding to minutiae M2 and minutiae M2. In this case, the magnitude of the weight of the value of the representative ridge element direction of the ridge element included in the representative ridge information corresponding to minutiae M1 may be greater than the magnitude of the weight of the value of the representative ridge element direction of the ridge element included in the representative ridge information corresponding to minutiae M2.

[0055] 8 and 9 illustrate square ridge direction units, but the shape of the ridge direction units is not limited to a square. For example, the shape of the ridge direction unit may be rectangular. For example, the shape of the ridge direction unit may be circular. The size of the ridge direction unit may be determined according to the requirements for restoring the ridge direction. For example, the size of the ridge direction unit may be determined to be equal to the size of the ridge element. The ridge direction units may have different shapes and sizes depending on their positions in the fingerprint. Different ridge direction units may have overlapping regions. Different ridge direction units may not necessarily be in contact with each other.

[0056] It should be noted that errors in the reconstructed ridge direction near the axis center (near minutiae) may be resolved by increasing the amount of sample data when constructing the database. Alternatively, they may be resolved by creating a separate database from axis (core) information and fingerprint pattern information. The axis information includes position information of the fingerprint center (center of whorl, center of convex shape, etc.) entered by the operator. Also, ridges often have a large degree of curvature near the axis. For this reason, the axis information defines the axis direction (details omitted) in addition to the position information. If minutiae are scattered around the vicinity of the axis, the ridge direction can be found from the curvature of the minutiae, but if there are no minutiae near the axis, it is difficult to correctly reconstruct the ridge direction. Therefore, a separate ridge direction database may be created from the axis positions and directions, and used in the same way as the curvature. [3-2: Technical Effects of Information Processing Device 3]

[0057] The information processing device 3 according to this disclosure can generate a reconstructed ridge direction using a mechanism capable of presenting a representative ridge direction around a minutia point (for example, the representative ridge information database described above). By using this reconstructed ridge direction, the accuracy of fingerprint matching can be improved. In particular, the information processing device 3 can accurately reconstruct a ridge direction by weighting according to the distance between a ridge element in a ridge direction unit and a minutia point corresponding to the ridge element. [4: Fourth Embodiment]

[0058] Fourth Embodiment of Information Processing Apparatus, Information Processing Method, and Recording Medium Will Be Described Hereinafter, a fourth embodiment of an information processing apparatus, an information processing method, and a recording medium will be described using an information processing apparatus 4 according to this disclosure.

[0059] As shown in Fig. 10, in addition to the acquisition unit 311, the storage unit 312, and the restoration unit 313, a determination unit 414, a generation unit 415, an assignment unit 416, and a registration unit 417 are further implemented within the calculation device 11 in the fourth embodiment. Furthermore, in addition to the representative ridge information database DB, an old fingerprint information database O and a new fingerprint information database N may be implemented within the storage device 12 in the fourth embodiment. Note that the old fingerprint information database O and the new fingerprint information database N may be implemented in a storage device outside the information processing device 4. Below, differences from the first to third embodiments will be described in detail, and descriptions of other overlapping parts will be omitted as appropriate. [4-1: Information Processing Method Executed by Information Processing Device 4]

[0060] The information processing operation in the information processing device 4 will be described with reference to Fig. 11. Fig. 11 is a flowchart showing the flow of the information processing operation in the information processing device 4.

[0061] 11 , the acquiring unit 311 acquires fingerprint information (step S41). The acquiring unit 311 may acquire fingerprint information from an old fingerprint information database O. In this embodiment, the old fingerprint information database O is a database in which fingerprint information is registered, and the fingerprint information registered in the old fingerprint information database O may or may not have ridge direction information.

[0062] The restoration unit 313 determines whether the fingerprint information acquired in step S41 includes ridge direction information corresponding to minutiae (step S42). If the fingerprint information includes ridge direction information (step S42: Yes), the registration unit 417 registers the fingerprint information including the ridge direction information in a new fingerprint information database N (step S46). In this embodiment, the new fingerprint information database N is a database in which fingerprint information is registered, and the fingerprint information registered in the new fingerprint information database N includes ridge direction information.

[0063] If the fingerprint information does not include ridge direction information (step S42: No), the restoration unit 313 generates a restored ridge direction (step S43). The generation unit 415 associates the fingerprint information not including ridge direction information with information indicating the restored ridge direction, and generates restored fingerprint information (step S44).

[0064] The assigning unit 416 assigns predetermined flag information to the reconstructed fingerprint information (step S45). When assigning predetermined flag information to the reconstructed fingerprint information, the assigning unit 416 does not need to assign predetermined flag information to fingerprint information including ridge direction information. Alternatively, the assigning unit 416 may assign first flag information to fingerprint information including ridge direction information, and assign second flag information to the reconstructed fingerprint information.

[0065] The assigning unit 416 may also assign predetermined flag information to fingerprint information registered in the old fingerprint information database that corresponds to the restored fingerprint information to be registered in the new fingerprint information database. In other words, predetermined flag information may be assigned to fingerprint information registered in the old fingerprint information database that does not include ridge direction information.

[0066] Alternatively, the assigning unit 416 may assign predetermined flag information to fingerprint information including ridge direction information, but may not assign predetermined flag information to the reconstructed fingerprint information. In other words, the assigning unit 416 may assign predetermined flag information to at least one of fingerprint information including ridge direction information and the reconstructed fingerprint information, thereby making it possible to distinguish whether or not the information indicating the ridge direction included in the fingerprint information registered in the new fingerprint information database N has been reconstructed.

[0067] The registration unit 417 registers the reconstructed fingerprint information in the new fingerprint information database N (step S46). The registration unit 417 may register the reconstructed fingerprint information in the new fingerprint information database N so as to correspond to the fingerprint information registered in the old fingerprint information database O that corresponds to the reconstructed fingerprint information. When the registration unit 417 designates fingerprint information registered in one of the new fingerprint information database N and the old fingerprint information database O, the registration unit 417 may add information that enables immediate designation of the corresponding fingerprint information registered in the other of the new fingerprint information database N and the old fingerprint information database O. For example, the registration unit 417 may add information indicating that the fingerprint information registered in the old fingerprint information database O and the reconstructed fingerprint information to be registered in the corresponding new fingerprint information database N correspond to each other.

[0068] The registration unit 417 determines whether there is fingerprint information that has not been acquired from the old fingerprint information database O (step S47), and if there is fingerprint information that has not been acquired (step S47: Yes), the process returns to step S41, and if there is no fingerprint information that has not been acquired (step S47: No), the information processing operation in the fourth embodiment ends. [4-2: Technical Effects of the Information Processing Device 4]

[0069] The information processing device 4 according to this disclosure can construct a new fingerprint information database N in which all fingerprint information includes ridge direction information. The information processing device 4 can construct the new fingerprint information database N so that it can determine whether the ridge direction information included in the registered fingerprint information has been restored. [5: Fifth Embodiment]

[0070] A fifth embodiment of an information processing device, an information processing method, and a recording medium will be described. Hereinafter, a fifth embodiment of an information processing device, an information processing method, and a recording medium will be described using an information processing device 5 according to this disclosure.

[0071] As shown in FIG. 12 , in addition to the acquisition unit 311, the storage unit 312, the restoration unit 313, the determination unit 414, the generation unit 415, the assignment unit 416, and the registration unit 417, a presentation unit 518 and a matching unit 519 are further implemented within the calculation device 11 in the fifth embodiment. The presentation unit 518 may include an acquisition unit 5181 and a determination unit 5182. The matching unit 519 may include a first matching unit 5191 and a second matching unit 5192. Below, differences from the first to fourth embodiments will be described in detail, and descriptions of other overlapping portions will be omitted as appropriate. [5-1: Information Processing Method Executed by Information Processing Device 5]

[0072] The information processing operation in the information processing device 5 will be described with reference to Fig. 13. Fig. 13 is a flowchart showing the flow of the information processing operation in the information processing device 5.

[0073] 13, when a request to perform a fingerprint matching operation is received (step S50: Yes), the acquisition unit 5181 acquires characteristic information indicating the characteristics of the fingerprint matching operation to be performed (step S51). The characteristic of the fingerprint matching operation to be performed may be the importance of the fingerprint matching operation to be performed.

[0074] The determination unit 5182 determines fingerprint information to be used in the fingerprint matching operation to be performed according to the characteristics acquired in step S51 (step S52). The determination unit 5182 determines at least one of fingerprint information that does not include ridge direction information and reconstructed fingerprint information as the fingerprint information to be used in the fingerprint matching operation to be performed.

[0075] If the fingerprint matching operation to be performed is relatively important, the determining unit 5182 may determine both the fingerprint information not including ridge direction information and the reconstructed fingerprint information as the fingerprint information to be used in the fingerprint matching operation to be performed. The presenting unit 518 presents at least one of the fingerprint information not including ridge direction information and the reconstructed fingerprint information as the fingerprint information to be used in the fingerprint matching operation to be performed (step S53).

[0076] The matching unit 519 acquires fingerprint information registered in the new fingerprint information database N (step S54). The matching unit 519 determines whether the fingerprint information acquired in step S54 is reconstructed fingerprint information (step S55).

[0077] If the fingerprint information is reconstructed fingerprint information (step S45: Yes), the first matching unit 5191 performs first matching (step S56). The first matching may be fingerprint matching using both minutiae and ridge directions.

[0078] The matching unit 519 determines whether or not it is necessary to perform the second matching (step S57). That is, the matching unit 519 determines whether or not the determination unit 5182 has determined that both the fingerprint information not including ridge direction information and the reconstructed fingerprint information are to be used in the fingerprint matching operation to be performed.

[0079] If the second matching needs to be performed (step S57: Yes), the matching unit 519 acquires the corresponding fingerprint information registered in the old fingerprint information database O (step S58). The second matching unit 5192 performs the second matching (step S59). The second matching may be fingerprint matching using minutiae.

[0080] If the fingerprint information is not reconstructed fingerprint information (step S55: No), the first matching unit 5191 performs only the first matching (step S60).

[0081] The matching unit 519 determines whether or not to end the matching operation (step S61). For example, the matching unit 519 may determine to end the matching operation when the matching of the fingerprint information to be matched is successful. Alternatively, the matching unit 519 may determine to end the matching operation when the matching with all fingerprint images registered in the new fingerprint information database N is completed. If the matching operation is not to be ended (step S61: No), the process returns to step S54 and further matching operations are performed. [5-2: Technical Effects of the Information Processing Device 5]

[0082] The information processing device 5 according to this disclosure can perform fingerprint matching using both minutiae and ridge directions. When the registered fingerprint image is restored fingerprint information, the information processing device 5 can perform fingerprint matching using both the fingerprint image registered in the new fingerprint information database N and the fingerprint image registered in the old fingerprint information database O, depending on the characteristics of the fingerprint matching operation to be performed.

[0083] In particular, in the case of important cases, it is possible to prevent oversight of inquiries by targeting fingerprint information without ridge direction information registered in the old fingerprint information database O in addition to fingerprint information including ridge direction information registered in the new fingerprint information database N as the target of inquiry. As will be described later, the accuracy of fingerprint matching using reconstructed fingerprint information is statistically higher than the accuracy of fingerprint matching using fingerprint information without ridge direction information. However, when focusing on individual fingerprint information, the matching score may decrease, so in important cases, fingerprint images registered in the old fingerprint information database O are also targeted for comparison. [6: Implementation Results]

[0084] Latent fingerprint information was compared with fingerprint information including ridge direction information, fingerprint information not including ridge direction information, and reconstructed fingerprint information in which ridge directions were reconstructed. Registered fingerprint information 257 was compared with latent fingerprint information 257. As a result, the matching rate with fingerprint information including ridge direction information was 66.5%, the matching rate with fingerprint information not including ridge direction information was 64.6%, and the matching rate with reconstructed fingerprint information was 66.5%.

[0085] Furthermore, the higher the frequency of unpaired scores, the higher the total number of scores. When fingerprint information including ridge direction information was used, the total number of scores was 12,690, when fingerprint information not including ridge direction information was used, the total number of scores was 13,387, and when reconstructed fingerprint information was used, the total number of scores was 12,712.

[0086] In this way, restoring the ridge direction allows for better matching than when ridge direction information is not included. Furthermore, using the restored fingerprint information allows for matching equivalent to when fingerprint information including ridge direction information is used.

[0087] [7: Supplementary Note] The above-described embodiment can be further described as in the following supplementary note, but is not limited to the following: [Supplementary Note 1] An information processing device comprising: an acquisition means for acquiring minutia information including a first curvature indicating the degree of curvature of a first ridge line adjacent to a minutia point of a fingerprint and a second curvature indicating the degree of curvature of a second ridge line different from the first ridge and adjacent to the minutia point, and ridge direction information indicating the ridge directions of predetermined peripheral regions of the minutia point; and a storage means for generating and storing representative ridge information indicating the representative ridge directions of predetermined peripheral regions of the minutia point for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information. [Supplementary Note 2] The information processing device according to Supplementary Note 1, comprising: the acquisition means acquires fingerprint information indicating a fingerprint having minutiae, adds the representative ridge information corresponding to a combination of the first curvature and the second curvature of the minutiae to the fingerprint information using the minutiae as a reference, and generates a restored ridge direction by restoring the ridge direction of the ridge direction unit based on the representative ridge direction within the ridge direction unit included in the fingerprint. [Supplementary Note 3] The information processing device according to Supplementary Note 1, wherein the ridge direction information includes information indicating a ridge element direction of each of a plurality of ridge elements included in a predetermined peripheral area of ​​the minutiae, with the direction of the minutiae as a reference, and the storage means determines a representative ridge element direction for each of the plurality of ridge elements based on the ridge element direction for each combination of the first curvature and the second curvature, and generates representative ridge information including information indicating the representative ridge element direction of each of the plurality of ridge elements for each combination of the first curvature and the second curvature. [Supplementary Note 4] The information processing device according to Supplementary Note 3, further comprising: the acquiring means acquires fingerprint information indicating a fingerprint having minutiae; adding the representative ridge information corresponding to a combination of the first curvature and the second curvature of the minutiae to the fingerprint information based on the minutiae; and a restoring means for generating a restored ridge direction by restoring the ridge direction of the ridge direction unit based on the representative ridge element direction of the ridge element in the ridge direction unit included in the fingerprint.[Supplementary Note 5] The information processing device according to Supplementary Note 4, wherein the restoration means generates the restored ridge direction by increasing a weight of the value of the representative ridge element direction of the ridge element the closer the ridge element in the ridge direction unit is to the minutiae corresponding to the ridge element. [Supplementary Note 6] The information processing device according to Supplementary Note 2 or 4, wherein the restoration means corrects the corresponding representative ridge information according to the direction of the minutiae of the fingerprint. [Supplementary Note 7] The information processing device according to Supplementary Note 2 or 4, comprising: a determination means for determining whether the fingerprint information includes the ridge direction information corresponding to the minutiae, and when it is determined that the ridge direction information is not included, the restoration means generates the restored ridge direction. [Supplementary Note 8] The information processing device according to Supplementary Note 7, comprising: a generation means for generating restored fingerprint information by associating fingerprint information not including the ridge direction information with information indicating the restored ridge direction. [Supplementary Note 9] The information processing device according to Supplementary Note 8, comprising: an assignment means for assigning predetermined flag information to at least one of fingerprint information including the ridge direction information and the restored fingerprint information. [Supplementary Note 10] The information processing device according to Supplementary Note 8, comprising a presentation means for acquiring characteristic information indicating characteristics of a fingerprint matching operation to be performed, and presenting at least one of fingerprint information not including ridge direction information and the reconstructed fingerprint information as fingerprint information to be used in the fingerprint matching operation to be performed according to the characteristics. [Supplementary Note 11] The information processing device according to Supplementary Note 10, wherein the characteristic of the fingerprint matching operation to be performed is the importance of the fingerprint matching operation to be performed. [Supplementary Note 12] The information processing device according to Supplementary Note 11, wherein the presentation means presents both fingerprint information not including the ridge direction information and the reconstructed fingerprint information as fingerprint information to be used in the fingerprint matching operation to be performed when the importance of the fingerprint matching operation to be performed is relatively high. [Supplementary Note 13] The information processing device according to Supplementary Note 3, wherein the storage means calculates the representative ridge element direction by averaging the multiple ridge element directions. [Supplementary Note 14] The information processing device according to Supplementary Note 9, wherein the assigning means assigns the predetermined flag information to fingerprint information including the ridge direction information, and does not assign the predetermined flag information to the reconstructed fingerprint information.[Supplementary Note 15] The information processing device according to Supplementary Note 9, wherein the assigning means does not assign the predetermined flag information to fingerprint information including the ridge direction information, but assigns the predetermined flag information to the reconstructed fingerprint information. [Supplementary Note 16] The information processing device according to Supplementary Note 9, wherein the assigning means assigns first flag information to fingerprint information including the ridge direction information, and assigns second flag information to the reconstructed fingerprint information. [Supplementary Note 17] The information processing device according to Supplementary Note 8, wherein the acquiring means acquires the fingerprint information registered in first fingerprint information storage means, and comprises registration means for registering the reconstructed fingerprint information in second fingerprint information storage means so as to correspond to the fingerprint information stored in the first fingerprint information storage means that corresponds to the reconstructed fingerprint information. [Supplementary Note 18] The information processing device according to Supplementary Note 10, comprising matching means for performing matching using fingerprint information presented by the presenting means. [Supplementary Note 19] An information processing method executed by a computer, comprising: acquiring minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia of a fingerprint and a second curvature indicating the degree of curvature of a second ridge different from the first ridge and adjacent to the minutia, and ridge direction information indicating the ridge direction of a predetermined peripheral region of the minutia; and generating and saving representative ridge information indicating the representative ridge direction of a predetermined peripheral region of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information. [Supplementary Note 20] A recording medium having recorded thereon a computer program for causing a computer to execute an information processing method, which comprises acquiring minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia of a fingerprint and a second curvature indicating the degree of curvature of a second ridge different from the first ridge and adjacent to the minutia, as well as ridge direction information indicating the ridge directions of predetermined peripheral regions of the minutia, and generating and saving representative ridge information indicating the representative ridge directions of predetermined peripheral regions of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information.

[0088] 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.

[0089] 1, 2, 3, 4, 5 Information processing device 111, 211, 311 Acquisition unit 112, 312 Storage unit 213, 313 Restoration unit 414 Determination unit 415 Generation unit 416 Assignment unit 417 Registration unit 518 Presentation unit 5181 Acquisition unit 5182 Decision unit 519 Matching unit 5191 First matching unit 5192 Second matching unit DB Representative ridge information database O Old fingerprint information database N New fingerprint information database

Claims

1. An information processing device comprising: an acquisition means for acquiring minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia of a fingerprint and a second curvature indicating the degree of curvature of a second ridge different from the first ridge adjacent to the minutia, as well as ridge direction information indicating the ridge direction of a predetermined peripheral area of the minutia; and a storage means for generating and storing representative ridge information indicating the representative ridge direction of a predetermined peripheral area of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information.

2. The information processing device according to claim 1, further comprising: a restoration means for restoring a ridge direction obtained by restoring the ridge direction of a ridge direction unit included in the fingerprint based on the representative ridge direction within the ridge direction unit included in the fingerprint, the restoration means for restoring the ridge direction of the ridge direction unit based on the representative ridge direction within the ridge direction unit included in the fingerprint, and the information processing device further comprising: a restoration means for restoring the ridge direction of the ridge direction unit based on the representative ridge direction within the ridge direction unit included in the fingerprint, the information processing device ...

3. The information processing device according to claim 1, wherein the ridge direction information includes information indicating the ridge element direction of each of a plurality of ridge elements included in a predetermined peripheral area of the feature point, with the direction of the feature point as a reference; and the storage means determines a representative ridge element direction for each of the plurality of ridge elements for each combination of the first curvature and the second curvature based on the ridge element direction; and generates representative ridge information including information indicating the representative ridge element direction of each of the plurality of ridge elements for each combination of the first curvature and the second curvature.

4. The information processing device according to claim 3, further comprising: a restoration means for restoring a ridge direction of a ridge direction unit included in the fingerprint, said restoration means for restoring the ridge direction of the ridge direction unit based on the representative ridge element direction of the ridge element within the ridge direction unit included in the fingerprint, said restoration means for acquiring fingerprint information indicating a fingerprint having minutiae; adding the representative ridge information corresponding to the combination of the first curvature and the second curvature of the minutiae to the fingerprint information, said representative ridge element direction of the ridge element within the ridge direction unit included in the fingerprint, said restoration means for restoring the ridge direction of the ridge direction unit based on the representative ridge element direction of the ridge element within the ridge direction unit included in the fingerprint, 5. The information processing device according to claim 4, wherein the restoration means generates the restored ridge direction by increasing the weight of the value of the representative ridge element direction of the ridge element the closer the ridge element in the ridge direction unit is to the feature point corresponding to the ridge element.

6. The information processing device according to claim 2 or 4, wherein the restoration means corrects the corresponding representative ridge information in accordance with the direction of minutiae of the fingerprint.

7. An information processing device according to claim 2 or 4, further comprising a determination means for determining whether the fingerprint information includes the ridge direction information corresponding to the minutiae, and if it is determined that the fingerprint information does not include the ridge direction information, the restoration means generates the restored ridge direction.

8. An information processing apparatus according to claim 7, further comprising: a generating means for generating reconstructed fingerprint information by associating fingerprint information not including said ridge direction information with information indicating said reconstructed ridge direction.

9. An information processing apparatus according to claim 8, further comprising: an assigning means for assigning predetermined flag information to at least one of the fingerprint information including the ridge direction information and the reconstructed fingerprint information.

10. An information processing device as described in claim 8, further comprising a presentation means for acquiring characteristic information indicating the characteristics of a fingerprint matching operation to be performed, and presenting, according to said characteristics, at least one of fingerprint information not including said ridge direction information and said reconstructed fingerprint information as fingerprint information to be used in said fingerprint matching operation to be performed.

11. The information processing device according to claim 10, wherein the characteristic of the fingerprint matching operation to be performed is the importance of the fingerprint matching operation to be performed.

12. The information processing device according to claim 11, wherein the presentation means presents both the fingerprint information not including the ridge direction information and the reconstructed fingerprint information as fingerprint information to be used in the fingerprint matching operation to be performed when the importance of the fingerprint matching operation to be performed is relatively high.

13. The information processing device according to claim 3, wherein said storage means determines said representative ridge element direction by averaging said plurality of ridge element directions.

14. The information processing device according to claim 9, wherein said assigning means assigns said predetermined flag information to fingerprint information including said ridge direction information, and does not assign said predetermined flag information to said reconstructed fingerprint information.

15. The information processing device according to claim 9, wherein said assigning means does not assign said predetermined flag information to fingerprint information including said ridge direction information, but assigns said predetermined flag information to said reconstructed fingerprint information.

16. The information processing device according to claim 9, wherein said assigning means assigns first flag information to fingerprint information including said ridge direction information, and assigns second flag information to said reconstructed fingerprint information.

17. An information processing device as described in claim 8, wherein the acquisition means acquires the fingerprint information registered in a first fingerprint information storage means, and includes a registration means for registering the reconstructed fingerprint information in a second fingerprint information storage means so as to correspond to the fingerprint information stored in the first fingerprint information storage means that corresponds to the reconstructed fingerprint information.

18. The information processing device according to claim 10, further comprising: a matching means for performing matching using the fingerprint information presented by said presentation means.

19. An information processing method executed by a computer, comprising: acquiring minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia of a fingerprint, and a second curvature indicating the degree of curvature of a second ridge different from the first ridge and adjacent to the minutia, as well as ridge direction information indicating the ridge direction of a predetermined peripheral region of the minutia; and generating and saving representative ridge information indicating the representative ridge direction of a predetermined peripheral region of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information.

20. A recording medium having recorded thereon a computer program that causes a computer to execute an information processing method that acquires minutia information including a first curvature indicating the degree of curvature of a first ridge adjacent to a minutia in a fingerprint, and a second curvature indicating the degree of curvature of a second ridge different from the first ridge and adjacent to the minutia, as well as ridge direction information indicating the ridge direction of a predetermined peripheral region of the minutia, and generates and saves representative ridge information indicating the representative ridge direction of a predetermined peripheral region of the minutia for each combination of the first curvature and the second curvature based on the minutia information and the ridge direction information.

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