Fingerprint recognition device resolution testing method, device, system and storage medium

Abstract

A method for testing the resolution of a fingerprint recognition device, a device for testing the resolution of a fingerprint recognition device, a system for testing the resolution of a fingerprint recognition device, and a storage medium. The method for testing the resolution of a fingerprint recognition device comprises: obtaining multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested; obtaining the first direction resolution and the second direction resolution of the multiple test images; respectively obtaining the first direction resolution and the second direction resolution of the fingerprint recognition device to be tested based on the first direction resolution and the second direction resolution of the multiple test images, wherein the first direction intersects with the second direction. The method for testing the resolution of a fingerprint recognition device can avoid the influence of subjective factors such as damage and contamination of the test finger on the test result, thereby ensuring the accuracy and reliability of the test result.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to a method for testing the resolution of a fingerprint recognition device, a device for testing the resolution of a fingerprint recognition device, a system for testing the resolution of a fingerprint recognition device, and a storage medium. Background Art

[0002] With the development of pattern recognition technology, biometrics has become a hot spot in identity authentication technology with its irrefutable advantages of security, convenience and ease of operation. Human biological characteristics include fingerprints, voiceprints, faces, irises and palm prints. Compared with other biometric identification technologies, fingerprint recognition technology has attracted much attention due to its uniqueness and stability, as well as its advantages of high recognition efficiency, convenient collection and low cost, and has become one of the most widely used identification technologies in biometrics. Summary of the invention

[0003] At least one embodiment of the present disclosure provides a method for testing the resolution of a fingerprint recognition device, comprising: obtaining multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested; obtaining a first directional resolution and a second directional resolution of the multiple test images; and respectively obtaining a first directional resolution and a second directional resolution of the fingerprint recognition device to be tested based on the first directional resolution and the second directional resolution of the multiple test images, wherein the first direction intersects with the second direction.

[0004] For example, in the fingerprint recognition device resolution testing method provided in an embodiment of the present disclosure, the multiple standard test cards are independent of each other and constitute a test card group, or the multiple standard test cards are respectively located in multiple different areas of the same test mother card.

[0005] For example, in a method for testing the resolution of a fingerprint recognition device provided in an embodiment of the present disclosure, obtaining multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested includes: moving multiple standard test cards of the test mother card so that the multiple standard test cards in the multiple different areas are respectively located within the recognition areas of the fingerprint recognition device to collect the multiple test images.

[0006] For example, in a method for testing the resolution of a fingerprint recognition device provided in an embodiment of the present disclosure, the first directional resolution and the second directional resolution are respectively the horizontal resolution and the vertical resolution, and the first directional resolution and the second directional resolution of the fingerprint recognition device to be tested are respectively obtained based on the first directional resolution and the second directional resolution of the multiple test images, expressed as:

[0007]

[0008]

[0009] Wherein, Rx represents the first direction resolution of the fingerprint recognition device to be tested, Ry represents the second direction resolution of the fingerprint recognition device to be tested, and Rx n Indicates the first direction resolution of the test image of the nth standard test card in the test card set or the test mother card, Ry n It represents the second directional resolution of the test image of the nth standard test card in the test card set or the test mother card, N is the number of standard test cards included in the test card set or the test mother card, and 1≤n≤N.

[0010] For example, in the fingerprint recognition device resolution test method provided in an embodiment of the present disclosure, the first direction resolution of the test image of the nth standard test card in the test card set or the test mother card is expressed as:

[0011] Rx n =2.54*Px n / L

[0012] Among them, Px n / L represents the number of pixels of the nth standard test card in the first direction.

[0013] For example, in the fingerprint recognition device resolution test method provided in an embodiment of the present disclosure, the second direction resolution of the test image of the nth standard test card in the test card set or the test mother card is expressed as:

[0014] R n =2.54*Qy n / L

[0015] Among them, Qy n / L represents the number of pixels of the nth standard test card in the second direction.

[0016] For example, in a method for testing the resolution of a fingerprint recognition device provided in an embodiment of the present disclosure, when N=4, the test card includes a first standard test card, a second standard test card, a third standard test card and a fourth standard test card; the first standard test card and the third standard test card include stripes arranged in parallel along a first arrangement direction, the second standard test card and the fourth standard test card include stripes arranged in parallel along a second arrangement direction, and the first arrangement direction and the second arrangement direction intersect.

[0017] For example, in the method for testing the resolution of a fingerprint recognition device provided in an embodiment of the present disclosure, the stripe spacings of the first standard test card and the second standard test card are equal, the stripe spacings of the third standard test card and the fourth standard test card are equal, and the stripe spacings of the first standard test card and the second standard test card are greater than the stripe spacings of the third standard test card and the fourth standard test card.

[0018] For example, a method for testing the resolution of a fingerprint recognition device provided in an embodiment of the present disclosure further includes: performing image preprocessing operations on the multiple test images to obtain multiple processed images; and performing image comparison operations on the multiple processed images to output fingerprint recognition results.

[0019] For example, in the method for testing the resolution of a fingerprint recognition device provided in an embodiment of the present disclosure, the image preprocessing operation includes: performing an image segmentation operation, an image enhancement operation, an image binarization operation or an image thinning operation on the image to obtain the processed image.

[0020] For example, in a method for testing the resolution of a fingerprint recognition device provided in an embodiment of the present disclosure, the image comparison operation includes: extracting feature values ​​of the multiple processed images; when the similarity between the feature value and the template feature value in the fingerprint library is greater than or equal to a preset threshold, the fingerprint matches; when the similarity between the feature value and the template feature value in the fingerprint library is less than the preset threshold, the fingerprint does not match.

[0021] At least one embodiment of the present disclosure further provides a fingerprint recognition device resolution test device, comprising: an image acquisition unit, configured to acquire multiple test images of multiple standard test cards collected by a fingerprint recognition device to be tested; an image resolution acquisition unit, configured to acquire a first directional resolution and a second directional resolution of the multiple test images; a device resolution acquisition unit, configured to respectively acquire a first directional resolution and a second directional resolution of the fingerprint recognition device to be tested based on the first directional resolution and the second directional resolution of the multiple test images, wherein the first direction and the second direction intersect.

[0022] At least one embodiment of the present disclosure further provides a fingerprint recognition device resolution testing device, comprising: a processor; a memory; and one or more computer program modules, wherein the one or more computer program modules are stored in the memory and are configured to be executed by the processor, and the one or more computer program modules include instructions for executing a fingerprint recognition device resolution testing method provided in any embodiment of the present disclosure.

[0023] At least one embodiment of the present disclosure further provides a fingerprint recognition device resolution test system, comprising the fingerprint recognition device resolution test device provided by any embodiment of the present disclosure and a plurality of standard test cards.

[0024] At least one embodiment of the present disclosure further provides a storage medium for storing non-transitory computer-readable instructions. When the non-transitory computer-readable instructions are executed by a computer, instructions of a method for testing the resolution of a fingerprint recognition device provided in any embodiment of the present disclosure can be executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure.

[0026] Figure 1 A flowchart of an example of a method for testing the resolution of a fingerprint recognition device provided by an embodiment of the present disclosure;

[0027] Figure 2 A schematic diagram of a standard test card provided by an embodiment of the present disclosure;

[0028] Figure 3A A flowchart of another example of a method for testing the resolution of a fingerprint recognition device provided by an embodiment of the present disclosure;

[0029] Figure 3B A schematic diagram of a fingerprint recognition system provided by an embodiment of the present disclosure;

[0030] Figure 4 A flowchart of an image preprocessing operation provided by an embodiment of the present disclosure;

[0031] Figure 5 A flowchart of an image comparison operation provided by an embodiment of the present disclosure;

[0032] Figure 6 A schematic block diagram of a fingerprint recognition device resolution test device provided by an embodiment of the present disclosure;

[0033] Figure 7 A schematic block diagram of another fingerprint recognition device resolution test device provided by an embodiment of the present disclosure; and

[0034] Figure 8 A schematic diagram of a fingerprint recognition device resolution test system provided in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0036] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0037] The image acquisition part of the fingerprint recognition device is the front-end device of fingerprint recognition. The quality of the image it acquires will directly affect the difficulty of the back-end software algorithm and the fingerprint recognition rate. Therefore, in some occasions (such as production plants or quality inspection agencies, etc.), it is necessary to verify that the fingerprint recognition device meets the requirements of specific resolution. For example, the minimum resolution required by the fingerprint recognition system based on minutiae is 500dpi (dpi means the number of pixels per inch), while the minimum resolution required by the fingerprint recognition system based on sweat pores is 1000dpi. When testing the device resolution of the fingerprint recognition device, it is usually obtained by directly acquiring images from the finger to obtain a digital grayscale image with fingerprint texture information. On the one hand, this method requires a lot of manpower, material resources and time, and the testing cost is high; on the other hand, due to subjective factors such as possible contamination, damage or deformation of the finger, the fingerprint recognition device may not be able to acquire a clear fingerprint image, so that the device resolution of the fingerprint recognition device cannot be objectively evaluated.

[0038] At least one embodiment of the present disclosure provides a method for testing the resolution of a fingerprint recognition device, comprising: obtaining multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested; obtaining the first directional resolution and the second directional resolution of the multiple test images; and obtaining the first directional resolution and the second directional resolution of the fingerprint recognition device to be tested based on the first directional resolution and the second directional resolution of the multiple test images, respectively, where the first direction intersects the second direction.

[0039] At least one embodiment of the present disclosure further provides a fingerprint recognition device resolution testing apparatus, a fingerprint recognition device resolution testing system, and a storage medium corresponding to the above-mentioned fingerprint recognition device resolution testing method.

[0040] At least one embodiment of the present disclosure provides a method for testing the resolution of a fingerprint recognition device. On the one hand, the method can avoid the influence of subjective factors such as contamination or damage of the test finger on the test result, thereby objectively evaluating the device resolution of the fingerprint recognition device. On the other hand, the test method has high accuracy and reliability and requires low testing costs.

[0041] The embodiments of the present disclosure are described in detail below in conjunction with the accompanying drawings. It should be noted that the same reference numerals in different drawings will be used to refer to the same elements described.

[0042] Figure 1 A flowchart of an example of a method for testing the resolution of a fingerprint recognition device provided by an embodiment of the present disclosure. The fingerprint recognition device can collect fingerprint images and perform feature matching on the fingerprint images, and can be, for example, a fingerprint sensor, a fingerprint recognition module, and a fingerprint recognition machine. For example, the method for testing the resolution of the fingerprint recognition device can be implemented in software, loaded and executed by a processor in the fingerprint recognition device, or implemented in hardware, etc., to solve the problems of high testing cost and low accuracy generated during the test of the resolution of the fingerprint recognition device.

[0043] Below, reference Figure 1 The method for testing the resolution of the fingerprint recognition device provided by the embodiment of the present disclosure is described. Figure 1 As shown, the method for testing the resolution of the fingerprint recognition device includes steps S110 to S130, and the first direction resolution is the horizontal resolution and the second direction resolution is the vertical resolution. Thus, the device resolution of the fingerprint recognition device includes the horizontal resolution and the vertical resolution. However, the first direction and the second direction are not limited to being perpendicular to each other, and may also have other appropriate angles, such as 45°, 60°, 75°, etc.

[0044] Step S110: Acquire multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested.

[0045] For example, the standard test card is placed above the fingerprint recognition device to be tested, and multiple standard test cards of the test mother card are moved so that multiple standard test cards in multiple different areas (for example, the first standard test card 1, the second standard test card 2, the third standard test card 3 and the fourth standard test card 4) are respectively located in the recognition area of ​​the fingerprint recognition device to collect multiple test images. For example, the test image is the image information of the standard test card collected by the fingerprint recognition device. For example, the material of the multiple standard test cards can be silicone or plastic and other materials that can simulate and replace fingers to perform resolution testing of the fingerprint recognition device. For example, the fingerprint recognition device can obtain the test image through optical recognition technology, semiconductor recognition technology (such as capacitive recognition technology) or ultrasonic recognition technology.

[0046] For example, the multiple standard test cards are independent of each other and constitute a test card group, or the multiple standard test cards are located in multiple different areas of the same test mother card. Figure 2 In the example shown, the test mother card includes a first standard test card 1, a second standard test card 2, a third standard test card 3 and a fourth standard test card 4 and a first area 1, a second area 2, a third area 3 and a fourth area 4, and the four standard test cards are respectively located in the four different areas.

[0047] For example, in Figure 2 In the figure, the first standard test card 1 and the third standard test card 3 include stripes arranged in parallel along a first arrangement direction, and the second standard test card 2 and the fourth standard test card 4 include stripes arranged in parallel along a second arrangement direction. Here, the first arrangement direction and the second arrangement direction are vertically arranged. For example, the first arrangement direction in the figure is horizontal, and the second arrangement direction is vertical, or vice versa. The embodiments of the present disclosure are not limited to this. For example, Figure 2 As shown, the stripes are black and white grids evenly arranged on the surface of each standard test card.

[0048] It should be noted that the stripes included in the four standard test cards can also be arranged in parallel along four different arrangement directions, for example, the angles at which the second standard test card 2, the third standard test card 3 and the fourth standard test card 4 intersect with the stripes in the first standard test card 1 are 45°, 90° and 135° respectively. It should be noted that the arrangement directions and angles at which the multiple standard test cards intersect can also be any combination of other angles, as long as they meet the extension direction of the fingerprint of the finger, and the embodiments of the present disclosure are not limited to this. For example, in another example, the test card set or the test mother card can also include 8 standard test cards, and the stripe directions of the 8 standard test cards can also be arranged in parallel along eight different arrangement directions, and the embodiments of the present disclosure are not limited to this.

[0049] For example, the stripes may be vertical stripes or S-shaped stripes, and their specific shapes may be set according to the shape of the fingerprint of the finger, which is not limited in the embodiments of the present disclosure.

[0050] For example, Figure 2 As shown, the stripe spacing of the first standard test card 1 and the second standard test card 2 is equal, for example, the stripe spacing is recorded as a; the stripe spacing of the third standard test card 3 and the fourth standard test card 4 is equal, for example, the stripe spacing is recorded as b. For example, the stripe spacing of the first standard test card 1 and the second standard test card 2 is greater than the stripe spacing of the third standard test card 3 and the fourth standard test card 4, that is, a>b. It should be noted that it can also be set to b>a, and the specific setting method depends on the specific situation, and the embodiments of the present disclosure are not limited to this. For example, the values ​​of a and b are similar to the spacing of finger fingerprints, for example, 0.04 centimeters (cm) ≤ a ≤ 0.15 cm, 0.04 cm ≤ b ≤ 0.15 cm. It should be noted that the values ​​of a and b can be determined according to the specific situation, and the embodiments of the present disclosure are not limited to this. For example, each of the multiple standard test cards includes 49, 74 stripes, etc., and the embodiments of the present disclosure are not limited to this.

[0051] For example, each standard test card can be set to be a square with a length and a width of L. It should be noted that it is not limited to this, and can also be set to other shapes such as a circle or an ellipse. For example, in the embodiment of the present disclosure, L is equal to 5 centimeters (cm). It should be noted that the length and width L of the standard test card can be determined according to the specific situation, and the embodiment of the present disclosure does not limit this.

[0052] By using this standard test card to simulate and replace fingers for testing, the influence of subjective factors such as finger contamination, damage or deformation on the test results can be avoided, so that the device resolution of the fingerprint recognition device can be objectively evaluated. At the same time, it also reduces the testing cost and improves the accuracy and reliability of the device resolution test method.

[0053] For example, multiple test images can be acquired by an image acquisition unit, or by a central processing unit (CPU) or other processing units with data processing capability and / or instruction execution capability. The processing unit can be a general-purpose processor or a dedicated processor, and can be a processor based on X86 or ARM architecture.

[0054] Step S120: Acquire the horizontal resolution and vertical resolution of multiple test images.

[0055] For example, the multiple test images can be obtained through step S110. For example, before obtaining the horizontal resolution and vertical resolution of the multiple test images, the collected test images can be processed accordingly by using Gaussian filtering, binarization, erosion dilation, etc.

[0056] For example, the horizontal resolution of the test image of the nth standard test card in the test card set or test mother card is expressed as:

[0057] Rx n =2.54*Px n / L

[0058] Among them, Px n / L represents the number of pixels in the horizontal direction of the nth standard test card.

[0059] For example, the vertical resolution of the test image of the nth standard test card in the test card set or test mother card is expressed as:

[0060] R n =2.54*Qy n / L

[0061] Among them, Qy n / L represents the number of pixels in the vertical direction of the nth standard test card.

[0062] For example, the horizontal resolution and vertical resolution of the plurality of test images may be acquired by an image resolution acquisition unit, or may be implemented by a central processing unit (CPU) or other processing units having data processing capability and / or instruction execution capability.

[0063] Step S130: acquiring the horizontal resolution and the vertical resolution of the fingerprint recognition device to be tested based on the horizontal resolution and the vertical resolution of the plurality of test images respectively.

[0064] For example, the horizontal resolution and vertical resolution of the fingerprint recognition device to be tested obtained based on the horizontal resolution and vertical resolution of the multiple test images obtained in step S120 are respectively expressed as:

[0065]

[0066]

[0067] Among them, Rx represents the horizontal resolution of the fingerprint recognition device to be tested, Ry represents the vertical resolution of the fingerprint recognition device to be tested, and Rx n Indicates the horizontal resolution of the test image of the nth standard test card in the test card group or test mother card, Ry n Indicates the vertical resolution of the test image of the nth standard test card in the test card set or test mother card, N is the number of standard test cards included in the test card set or test mother card, 1≤n≤N. Figure 2 In the example shown, N is equal to 4.

[0068] For example, the horizontal resolution and vertical resolution of the fingerprint recognition device to be tested may be acquired by a device resolution acquisition unit, or may be implemented by a central processing unit (CPU) or other processing units with data processing capability and / or instruction execution capability.

[0069] Figure 3A This is a flowchart of another example of a method for testing the resolution of a fingerprint recognition device provided by an embodiment of the present disclosure. Figure 3A As shown, the test method for the resolution of the fingerprint recognition device also includes steps S140 to S150, which are the fingerprint recognition method of the fingerprint recognition device, that is, the process of performing fingerprint matching on the test image (e.g., fingerprint image) obtained by the fingerprint recognition device. Steps S140 to S150 of the fingerprint recognition method and their respective exemplary implementations are introduced below.

[0070] Step S140: performing image preprocessing operations on the multiple test images to obtain multiple processed images.

[0071] Step S150: performing an image comparison operation on the plurality of processed images to output a fingerprint recognition result.

[0072] For example, in the above method, the fingerprint image (i.e., the test image) can be collected by the fingerprint recognition device to be tested in steps S110 to S130, and the fingerprint image can be fingerprinted by steps S140 to S150. For example, the fingerprint recognition device to be tested includes a fingerprint collection device. For example, the fingerprint collection device includes an optical sensor, an ultrasonic sensor, or a semiconductor sensor. For example, the fingerprint collection device can collect fingerprint images using a conventional fingerprint image collection method in the art, which will not be described in detail here.

[0073] Figure 3B FIG. 1 is a schematic diagram of a fingerprint recognition system provided by an embodiment of the present disclosure. Figure 3B As shown, the fingerprint recognition system includes a training module 10 and an identification module 20. For example, the training module 10 is implemented in a server and can be used to enter fingerprints to form a fingerprint library, or to train and upgrade fingerprint classification and matching programs (such as neural network and other pattern recognition programs) based on an existing fingerprint library; the identification module 20 is installed in a fingerprint recognition terminal and is connected and communicated with a database or server, for example, through a wireless or wired network. However, the embodiments of the present disclosure are not limited to this. Figure 3B As shown, the training module 10 is configured to obtain a fingerprint library containing a large number of fingerprint features, so that the fingerprint image collected by the fingerprint recognition device is compared with the fingerprint features in the fingerprint library in the identification module 20 to determine whether the fingerprints match, thereby outputting the fingerprint recognition result.

[0074] like Figure 3B As shown, the training module 10 includes an image acquisition unit 11, an image preprocessing unit 12, a fingerprint image feature extraction unit 13 and a fingerprint library 14, which can be implemented in hardware, software, firmware and the like.

[0075] For example, the image acquisition unit 11 can acquire the fingerprint image through the fingerprint acquisition device in the above-mentioned fingerprint recognition device. The image preprocessing unit 12 and the fingerprint image feature extraction unit 13 can be implemented by corresponding computer programs. The fingerprint library 14 can be implemented using various appropriate types of data, such as a relational or non-relational database.

[0076] For example, the image preprocessing unit 12 can implement the image preprocessing operation in step S140. For example, in the process of collecting fingerprint images, due to the influence of various reasons such as surface skin characteristics, collection conditions and characteristic differences of image collection sensors, the collected fingerprint image is an image containing noise interference to varying degrees. For example, the ridges of the fingerprint may be disconnected, bridged or blurred, etc. This noisy fingerprint ridge structure seriously affects the recognition performance of the fingerprint recognition device.

[0077] The image preprocessing operation uses signal processing technology to remove various noise interferences in the image, turn it into a clear fingerprint image, and restore the fingerprint ridge structure in order to reliably extract the correct fingerprint features.

[0078] Figure 4 This is a flowchart of an image preprocessing operation provided by an embodiment of the present disclosure. That is,

[0079] Figure 4 for Figure 3AFlowchart of an example of step S140 shown in FIG. Figure 4 As shown, the image preprocessing operation includes steps S141 to S144.

[0080] Step S141: Image segmentation operation.

[0081] For example, the image segmentation operation can separate the foreground area containing fingerprints from the background area without fingerprints, so that the preprocessing process only processes the foreground area, which can not only greatly reduce the preprocessing time, but also reduce the interference of background pseudo-features on subsequent processing, thereby improving the performance of the entire fingerprint recognition system. The image segmentation operation can be implemented, for example, by an adaptive local threshold image segmentation method, a variance method based on image grayscale characteristics, or a directional map method using image directional information for segmentation.

[0082] Step S142: Image enhancement operation.

[0083] For example, the image quality of the fingerprint image directly extracted by an image acquisition sensor such as a scanner may not meet the requirements of image analysis. Therefore, an image enhancement operation can be used to improve the fingerprint image features to improve the analyzability of the fingerprint image. For example, the image enhancement operation can be implemented by median filtering, sharpening filtering or contrast enhancement, and its specific implementation method can adopt conventional methods in the field, which will not be repeated here. The image enhancement operation can enhance the edges and lines of the fingerprint image, making the image clearer and easier to process.

[0084] Step S143: Image binarization operation.

[0085] For example, the image binarization operation can convert the grayscale image of the collected fingerprint image into a binary image consisting of only 0 and 1, thereby further reducing the amount of data processing. The specific operation method can adopt conventional methods in the field and will not be repeated here.

[0086] Step S144: Image refinement operation.

[0087] For example, the image thinning operation can remove some unnecessary points (e.g., pseudo feature points, etc.) from the original fingerprint image by peeling off the collected fingerprint image layer by layer, but still keep the original shape until a processed image including the skeleton of the fingerprint image is obtained. For example, in order to further reduce the amount of information, only the fingerprint ridges can be thinned, so that the image features are more obvious. For example, the image thinning operation can also adopt conventional methods in the art, which will not be repeated here.

[0088] For example, the fingerprint image feature extraction unit 13 is configured to extract feature values ​​of the fingerprint image (i.e., the processed image) after the image thinning operation for fingerprint matching. For example, the feature value may include directional features, line features, etc. of the feature points of the fingerprint image. For example, the feature points of the fingerprint image include the mutation positions of the fingerprint ridges, such as endpoints, bifurcation points, ring points, isolated points, and short lines. For example, the endpoints, bifurcation points, or composite features (trifurcations or intersections) of the ridges may be selected as feature points for fingerprint recognition. For example, a 3×3 template may be used to examine the values ​​of each pixel and its 8 neighborhoods to determine whether the pixel is a feature point and its type and position.

[0089] For example, the feature values ​​of the extracted feature points are stored in registers of a controller (such as an FPGA) for implementing the fingerprint recognition method of the embodiment of the present disclosure and further stored to form a fingerprint library 14. When needed, the controller can read from the fingerprint library 14 to call it when performing feature matching.

[0090] like Figure 3B As shown, the identification module 20 includes an image acquisition unit 21, an image preprocessing unit 22, a fingerprint image feature extraction unit 23, a fingerprint classification and matching unit 24, and an output unit 25. For example, the image acquisition unit 21, the image preprocessing unit 22, the fingerprint image feature extraction unit 23 included in the identification module 20 and the image acquisition unit 11, the image preprocessing unit 12, the fingerprint image feature extraction unit 13 included in the training module 10 have similar working principles, and can be implemented in software, hardware, firmware, etc., respectively, which will not be repeated here.

[0091] The fingerprint classification and matching unit 24 can compare the collected fingerprint feature values ​​with the template feature values ​​stored in the fingerprint database to realize fingerprint verification / identification. For example, the fingerprint classification, as the initial stage of fingerprint matching, can distribute the input fingerprint image to each fingerprint sub-library, so that the input fingerprint image can only be matched with the fingerprint image in the sub-library, thereby reducing the search time in the fingerprint matching process and reducing the complexity of calculation. For example, a classification method based on a neural network, a classification method based on singular points, or a classification method based on ridge geometry can be used to realize fingerprint classification.

[0092] For example, the fingerprint classification and matching unit 24 may implement the image comparison operation in step S150. Figure 5 This is a flow chart of an image comparison operation provided by an embodiment of the present disclosure. That is, Figure 5 for Figure 3A Flowchart of an example of step S150 shown in FIG. Figure 5As shown, the image comparison operation includes steps S151 to S154, and fingerprint matching can be performed on the fingerprint image.

[0093] Step S151: extracting feature values ​​of multiple processed images.

[0094] For example, the extraction of feature values ​​can be implemented in the fingerprint image feature extraction unit 23 / 13, which will not be described in detail here.

[0095] Step S152: determine whether the number of matches between the feature value and the template feature value in the fingerprint library is greater than or equal to a preset threshold; if yes, execute step S153 to output a fingerprint match; if not, execute step S154 to output a fingerprint mismatch.

[0096] For example, the feature value of the processed image can be obtained by the image feature extraction unit 23, and the template feature value in the fingerprint library can be obtained by the above-mentioned training module 10. For example, the fingerprint library can refer to the fingerprint sub-library corresponding to the current processed image after fingerprint classification. For example, when the number of matches between the feature value and the template feature value in the fingerprint library is greater than or equal to a preset threshold, the fingerprint matches; when the number of matches between the feature value and the template feature value in the fingerprint library is less than the preset threshold, the fingerprint does not match. For example, the preset threshold can be set to 12, etc. It should be noted that the size of the preset threshold depends on the specific situation, and the embodiments of the present disclosure are not limited to this.

[0097] For example, for the feature value of any feature point of the template image in the fingerprint library, if there is a corresponding feature point within the range of the corresponding radius R in the image to be identified, and the feature value of the feature point is similar to the template feature value in the fingerprint library, for example, greater than 85%, then the feature value of the feature point is considered to be matched successfully, and the number of logarithms of successfully matched feature points in the image to be identified is counted. If the number of logarithms of successfully matched feature points is greater than or equal to a preset threshold, then the two fingerprints are considered to be matched successfully; otherwise, the fingerprint matching is unsuccessful. For example, the specific implementation method of the fingerprint matching can also adopt conventional methods in the field, which will not be introduced in detail here.

[0098] For example, the preset threshold may be stored in a register of a controller (eg, FPGA) for implementing the fingerprint recognition method of the embodiment of the present disclosure or in a predetermined location in a fingerprint library, and the controller may read it from the register or fingerprint library when needed.

[0099] The output unit 25 can output the result of fingerprint recognition. For example, as an independent fingerprint recognition system, the data recognized by the system can be directly displayed through a display device (such as a liquid crystal display device LCD), or the user can be informed of the detection result through a voice output device (speaker).

[0100] It should be noted that in various embodiments of the present disclosure, the process of the method for testing the resolution of the fingerprint recognition device may include more or fewer operations, and these operations may be performed sequentially or in parallel. Although the process of the method for testing the resolution of the fingerprint recognition device described above includes multiple operations that appear in a specific order, it should be clearly understood that the order of multiple operations is not limited. The method for testing the resolution of the fingerprint recognition device described above can be executed once or multiple times according to predetermined conditions. It should be noted that the following embodiments are the same and will not be repeated.

[0101] The method for testing the resolution of a fingerprint recognition device provided in the embodiment of the present disclosure can, on the one hand, avoid the influence of subjective factors such as damage or contamination of the test finger on the test result, thereby objectively evaluating the device resolution of the fingerprint recognition device; on the other hand, the method can improve the accuracy and reliability of the test result, and the required testing cost is relatively low.

[0102] Figure 6 The present invention provides a schematic block diagram of a fingerprint recognition device resolution test device according to an embodiment of the present invention. The fingerprint recognition device resolution test device 100 comprises an image acquisition unit 110 , an image resolution acquisition unit 120 and a device resolution acquisition unit 130 .

[0103] The image acquisition unit 110 is configured to acquire multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested. For example, the image acquisition unit 110 can implement step S110, which can be implemented by hardware, software, firmware, such as by FPGA devices, circuits or computer programs.

[0104] The image resolution acquisition unit 120 is configured to acquire the horizontal resolution and vertical resolution of the plurality of test images. For example, the image resolution acquisition unit 120 may implement step S120, which may be implemented by hardware, software, or firmware, such as by an FPGA device, circuit, or computer program.

[0105] The device resolution acquisition unit 130 is configured to respectively acquire the horizontal resolution and vertical resolution of the fingerprint recognition device to be tested based on the horizontal resolution and vertical resolution of the plurality of test images. For example, the device resolution acquisition unit 130 can implement step S130, which can be implemented by hardware, software, or firmware, such as by an FPGA device, circuit, or computer program.

[0106] It should be noted that in the embodiments of the present disclosure, more or fewer units / modules may be included, and the connection relationship between the units / modules is not limited and can be determined according to actual needs. The specific configuration of each unit / module is not limited and can be composed of analog devices according to the unit / module principle, or can be composed of digital chips, or in other applicable ways.

[0107] Figure 7 This is a schematic block diagram of another fingerprint recognition device resolution test device provided by an embodiment of the present disclosure. Figure 7 As shown, the fingerprint recognition device resolution testing apparatus 200 includes a processor 210 , a memory 220 , and one or more computer program modules 221 .

[0108] For example, the processor 210 is connected to the memory 220 via a bus system 230. For example, one or more computer program modules 221 may be stored in the memory 220. For example, one or more computer program modules 221 may include instructions for executing the method for testing the resolution of a fingerprint recognition device provided in any embodiment of the present disclosure. For example, the instructions in one or more computer program modules 221 may be executed by the processor 210. For example, the bus system 230 may be a commonly used serial or parallel communication bus, etc., and the embodiments of the present disclosure are not limited thereto.

[0109] For example, the processor 210 may be a central processing unit (CPU) or other forms of processing units with data processing capabilities and / or instruction execution capabilities, may be a general-purpose processor or a dedicated processor, and may control other components in the fingerprint recognition device resolution test device 200 to perform desired functions. The memory 220 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, a random access memory (RAM) and / or a cache memory (cache), etc. The non-volatile memory may include, for example, a read-only memory (ROM), a hard disk, a flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 210 may run the program instructions to implement the functions (implemented by the processor 210) in the embodiment of the present disclosure and / or other desired functions, such as the fingerprint recognition device resolution test method, etc. Various applications and various data may also be stored in the computer-readable storage medium, such as a fingerprint library and various data used and / or generated by the application.

[0110] It should be noted that, for the sake of clarity and brevity, the disclosed embodiment does not provide all the components of the fingerprint recognition device resolution test device 200. To achieve the necessary functions of the fingerprint recognition device resolution test device 200, those skilled in the art may provide and set other components not shown according to specific needs, and the disclosed embodiment does not limit this.

[0111] The technical effects of the fingerprint recognition device resolution test device 100 and the fingerprint recognition device resolution test device 200 in different embodiments may refer to the technical effects of the fingerprint recognition device resolution test method provided in the embodiments of the present disclosure, which will not be repeated here.

[0112] At least one embodiment of the present disclosure further provides a fingerprint recognition device resolution test system, comprising the fingerprint recognition device resolution test device provided by any embodiment of the present disclosure and a plurality of standard test cards. Figure 8 This is a schematic diagram of a fingerprint recognition device resolution test system provided by an embodiment of the present disclosure. Figure 8 As shown, the fingerprint recognition device resolution test system 1 includes a fingerprint recognition device resolution test device 300. For example, the fingerprint recognition device resolution test device 300 can be Figure 6 The fingerprint recognition device resolution test device 100 shown in Figure 7 The fingerprint recognition device resolution testing device 200 shown in FIG.

[0113] For example, the fingerprint recognition device resolution test system 1 further includes a plurality of standard test cards 400 and a fingerprint recognition device 500. For example, the standard test cards 400 and the fingerprint recognition device 500 can refer to the relevant description in the fingerprint recognition device resolution test method provided in the embodiment of the present disclosure, and will not be repeated here.

[0114] It should be noted that, for the sake of clarity and brevity, not all components of the fingerprint recognition device resolution test system 1 are shown. To achieve the necessary functions of the fingerprint recognition device resolution test system 1, those skilled in the art may provide and set other components not shown according to specific needs, and the embodiments of the present disclosure are not limited to this.

[0115] The technical effects of the fingerprint recognition device resolution testing system 1 may refer to the technical effects of the fingerprint recognition device resolution testing method provided in the embodiments of the present disclosure, which will not be described in detail here.

[0116] An embodiment of the present disclosure further provides a storage medium. For example, the storage medium is used to non-temporarily store computer-readable instructions, and when the non-temporary computer-readable instructions are executed by a computer (including a processor), the method for testing the resolution of a fingerprint recognition device provided in any embodiment of the present disclosure can be executed.

[0117] For example, the storage medium may be any combination of one or more computer-readable storage media, such as one computer-readable storage medium containing a computer-readable program code for obtaining image resolution, and another computer-readable storage medium containing a computer-readable program code for obtaining device resolution. For example, when the program code is read by a computer, the computer may execute the program code stored in the computer storage medium, and execute, for example, the method for testing the resolution of a fingerprint recognition device provided in any embodiment of the present disclosure.

[0118] For example, the storage medium may include a memory card of a smart phone, a storage component of a tablet computer, a hard disk of a personal computer, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disk read-only memory (CD-ROM), a flash memory, or any combination of the above storage media, or other applicable storage media. The following points need to be explained:

[0119] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.

[0120] (2) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0121] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the protection scope of the present invention. The protection scope of the present invention is determined by the appended claims.

Claims

1. A method for testing the resolution of a fingerprint recognition device, comprising: Acquire multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested; Acquire a first directional resolution and a second directional resolution of the plurality of test images; Acquire a first direction resolution and a second direction resolution of the fingerprint recognition device to be tested respectively based on the first direction resolution and the second direction resolution of the plurality of test images, wherein the first direction intersects with the second direction; Wherein, the plurality of standard test cards are independent of each other and constitute a test card group, or the plurality of standard test cards are respectively located in a plurality of different areas of the same test mother card; The first directional resolution and the second directional resolution are respectively the horizontal resolution and the vertical resolution, and the first directional resolution and the second directional resolution of the fingerprint recognition device to be tested are obtained based on the first directional resolution and the second directional resolution of the multiple test images as follows: Wherein, Rx represents the first direction resolution of the fingerprint recognition device to be tested, Ry represents the second direction resolution of the fingerprint recognition device to be tested, and Rx n Indicates the first direction resolution of the test image of the nth standard test card in the test card set or the test mother card, Ry n represents the second direction resolution of the test image of the nth standard test card in the test card set or the test mother card, N is the number of standard test cards included in the test card set or the test mother card, 1≤n≤N; The first direction resolution of the test image of the nth standard test card in the test card set or the test mother card is expressed as: Rx n =2.54*Px n / L Among them, Px n / L represents the number of pixels of the nth standard test card in the first direction; The second direction resolution of the test image of the nth standard test card in the test card set or the test mother card is expressed as: Ry n =2.54*Qy n / L Among them, Qy n / L represents the number of pixels of the nth standard test card in the second direction.

2. The method for testing the resolution of a fingerprint recognition device according to claim 1, wherein: Acquiring multiple test images of multiple standard test cards collected by the fingerprint recognition device to be tested includes: The multiple standard test cards of the test mother card are moved so that the multiple standard test cards in the multiple different areas are respectively located in the recognition area of ​​the fingerprint recognition device to collect the multiple test images.

3. The method for testing the resolution of a fingerprint recognition device according to claim 1, wherein: In the case of N=4, the test cards include a first standard test card, a second standard test card, a third standard test card and a fourth standard test card; The first standard test card and the third standard test card include stripes arranged in parallel along a first arrangement direction, the second standard test card and the fourth standard test card include stripes arranged in parallel along a second arrangement direction, and the first arrangement direction and the second arrangement direction intersect.

4. The method for testing the resolution of a fingerprint recognition device according to claim 3, wherein: The stripe spacings of the first standard test card and the second standard test card are equal, the stripe spacings of the third standard test card and the fourth standard test card are equal, and The stripe spacing between the first standard test card and the second standard test card is greater than the stripe spacing between the third standard test card and the fourth standard test card.

5. The method for testing the resolution of a fingerprint recognition device according to any one of claims 1 to 4, further comprising: Performing image preprocessing operations on the multiple test images to obtain multiple processed images; An image comparison operation is performed on the multiple processed images to output a fingerprint recognition result.

6. The method for testing the resolution of a fingerprint recognition device according to claim 5, wherein: The image preprocessing operation includes: An image segmentation operation, an image enhancement operation, an image binarization operation or an image thinning operation is performed on the image to obtain the processed image.

7. The method for testing the resolution of a fingerprint recognition device according to claim 5, wherein: The image comparison operation includes: extracting feature values ​​of the plurality of processed images; When the number of matches between the feature value and the template feature value in the fingerprint library is greater than or equal to a preset threshold, the fingerprint matches; When the number of matches between the feature value and the template feature value in the fingerprint library is less than the preset threshold, the fingerprint does not match.

8. A fingerprint recognition device resolution test device, comprising: An image acquisition unit, configured to acquire a plurality of test images of a plurality of standard test cards collected by the fingerprint recognition device to be tested; An image resolution acquisition unit, configured to acquire a first directional resolution and a second directional resolution of the plurality of test images; a device resolution acquisition unit, configured to respectively acquire a first direction resolution and a second direction resolution of the fingerprint recognition device to be tested based on the first direction resolution and the second direction resolution of the plurality of test images, wherein the first direction and the second direction intersect; Wherein, the plurality of standard test cards are independent of each other and constitute a test card group, or the plurality of standard test cards are respectively located in a plurality of different areas of the same test mother card; The first directional resolution and the second directional resolution are respectively the horizontal resolution and the vertical resolution, and the first directional resolution and the second directional resolution of the fingerprint recognition device to be tested are obtained based on the first directional resolution and the second directional resolution of the multiple test images as follows: Wherein, Rx represents the first direction resolution of the fingerprint recognition device to be tested, Ry represents the second direction resolution of the fingerprint recognition device to be tested, and Rx n Indicates the first direction resolution of the test image of the nth standard test card in the test card set or the test mother card, Ry n represents the second direction resolution of the test image of the nth standard test card in the test card set or the test mother card, N is the number of standard test cards included in the test card set or the test mother card, 1≤n≤N; The first direction resolution of the test image of the nth standard test card in the test card set or the test mother card is expressed as: Rx n =2.54*Px n / L Among them, Px n / L represents the number of pixels of the nth standard test card in the first direction; The second direction resolution of the test image of the nth standard test card in the test card set or the test mother card is expressed as: Ry n =2.54*Qy n / L Among them, Qy n / L represents the number of pixels of the nth standard test card in the second direction.

9. A fingerprint recognition device resolution test device, comprising: processor; Memory; One or more computer program modules, the one or more computer program modules are stored in the memory and are configured to be executed by the processor, the one or more computer program modules include instructions for executing the test method for the resolution of the fingerprint recognition device according to any one of claims 1-7.

10. A fingerprint recognition device resolution test system, comprising the fingerprint recognition device resolution test device according to claim 8 or 9 and a plurality of standard test cards.

11. A storage medium for storing non-transitory computer-readable instructions, which, when executed by a computer, can execute the instructions of the method for testing the resolution of a fingerprint recognition device according to any one of claims 1 to 7.

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