Fingerprint acquisition method and flexible circuit board for fingerprint acquisition

Abstract

The embodiment of the invention provides a fingerprint collection method and a flexible circuit board for fingerprint collection, and the method comprises the steps: providing a fingerprint collection unit with a capacitive fingerprint module, and enabling the fingerprint collection unit to collect fingerprints and generate a fingerprint image; preprocessing the fingerprint image; carrying out binaryzation on the preprocessed fingerprint image to carry out black and white processing on the preprocessed fingerprint image; the fingerprint image after binarization is refined; extracting feature points from the refined fingerprint image; the fingerprint image is compared with a fingerprint database according to the feature points, the comparison result is output, the fingerprints can be accurately collected and compared, in the process, two different voltages are formed in the contact process of the ridge and the groove, the fingerprint image is formed, and therefore the fingerprint image can be accurately collected and compared. And therefore, the influence of temperature, humidity and brightness of illumination on fingerprint acquisition can be avoided.

Description

Technical Field

[0001] The present application belongs to the technical field of fingerprint collection, and in particular to a fingerprint collection method and a flexible circuit board used for fingerprint collection. Background Art

[0002] In the prior art, mobile phone fingerprint recognition generally uses an optical fingerprint module. The optical fingerprint module uses the principle of light refraction and reflection to collect fingerprints. Specifically, the emitted light is refracted on the concave and convex patterns on the fingerprint surface. According to the different refraction angles and the brightness of the light, image information of different brightness levels can be collected to complete the fingerprint collection.

[0003] The above optical fingerprint module has high requirements on temperature and humidity during the process of collecting fingerprints. In the case of weak or strong light, fingerprints cannot be collected accurately. In addition, the optical fingerprint module needs to occupy a large space.

[0004] To address the above problems, no effective solution has been proposed yet.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0006] The purpose of this application is to provide a fingerprint collection method and a flexible circuit board for fingerprint collection to solve the above problems.

[0007] This application provides a fingerprint collection method, including:

[0008] A fingerprint collection unit having a capacitive fingerprint module is provided for collecting fingerprints and generating fingerprint images;

[0009] Preprocessing the fingerprint image;

[0010] Binarizing the preprocessed fingerprint image to perform black-and-white processing on the preprocessed fingerprint image;

[0011] Refining the binary fingerprint image;

[0012] Extracting feature points from the refined fingerprint image;

[0013] The fingerprint image is compared with a fingerprint library according to the feature points, and the comparison result is output.

[0014] Preferably, the step of "preprocessing the fingerprint image" includes performing extreme value filtering on the fingerprint image, performing a first smoothing process on the fingerprint image after extreme value filtering, sharpening the fingerprint image after the first smoothing process, and performing a second smoothing process on the sharpened fingerprint image.

[0015] Preferably, in the first smoothing step, the mean square value of the grayscale difference between the pixels of the entire image and its period is selected as a threshold for processing.

[0016] Preferably, in the step of the second smoothing process, a threshold is set, and weighted smoothing is performed on the elements to obtain smoothed grayscale values.

[0017] Preferably, in the step of thinning the binarized fingerprint image, data of the binarized fingerprint image is registered.

[0018] Preferably, in the step of comparing the fingerprint image with the fingerprint database, the fingerprint image is matched with the fingerprints in the fingerprint database in terms of ridges.

[0019] Preferably, the fingerprint acquisition unit is provided with an acquisition side, the acquisition side contacts the fingerprint, and a capacitor array is installed near a side wall of the acquisition unit opposite to the acquisition side.

[0020] A flexible circuit board for fingerprint collection, wherein a capacitive fingerprint module is arranged in the flexible circuit board for forming a fingerprint image.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention collects fingerprints by setting a capacitive fingerprint module, thereby effectively forming an accurate fingerprint image. The capacitive fingerprint module is set in the fingerprint collection unit, thereby accurately collecting and comparing fingerprints. In the above process, two voltages of different sizes are formed in the process of contact between ridges and grooves to form a fingerprint image, thereby avoiding the influence of temperature, humidity and light brightness on fingerprint collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of this application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 This is an overall flow chart of a fingerprint collection method and a flexible circuit board used for fingerprint collection provided in the embodiments of this application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be described clearly and completely below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0026] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "upper", "middle", "lower", "inner", "outer", "front", "back", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. The terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following describes an implementation method of the present invention based on its overall structure.

[0027] Reference Figure 1 As shown, the embodiment of the present application provides a fingerprint collection method, including:

[0028] A fingerprint collection unit having a capacitive fingerprint module is provided for collecting fingerprints and generating fingerprint images;

[0029] Preprocess the fingerprint image;

[0030] Binarization is performed on the preprocessed fingerprint image to perform black and white processing on the preprocessed fingerprint image;

[0031] Refine the binary fingerprint image;

[0032] Extract feature points from the refined fingerprint image;

[0033] The fingerprint image is compared with the fingerprint library according to the feature points, and the comparison result is output.

[0034] According to the above process, those skilled in the art can set a fingerprint collection unit in the process of setting the collection of fingerprints. The fingerprint collection unit is specifically provided with a capacitive fingerprint module. The capacitive fingerprint module can be used to collect fingerprints and generate fingerprint images.

[0035] Specifically, during the process of collecting fingerprints, the surface of the finger contacts the fingerprint collection unit. The contact process may include pressing or scratching. Preferably, the fingerprint collection unit is provided with a collection side, the collection side contacts the fingerprint, and a capacitor array is installed near the side wall of the collection unit opposite to the collection side.

[0036] That is, the skilled person can set the fingerprint collection unit to include at least one collection side. The side of the finger on which the fingerprint needs to be collected can be pressed or scratched with the collection side. The fingerprint of the finger has protruding ridges and grooves away from the collection side. Furthermore, the capacitor array installed near the side wall opposite to the collection side of the collection unit can form two voltages of different magnitudes during the contact between the ridges and the grooves.

[0037] It can be understood that in the capacitor array, an electric field is formed by the silicon wafer and the conductive subcutaneous electrolyte. Two voltages of different magnitudes are formed during the contact between the ridges and the grooves, thereby forming a pressure difference. A unique fingerprint image can be formed based on the pressure difference, thereby accurately measuring the fingerprint.

[0038] After the fingerprint image is formed, the fingerprint image can be preprocessed to obtain a clear fingerprint image. Specifically, in the preprocessing process, the preprocessed fingerprint image is further binarized, and then the preprocessed fingerprint image can be further processed in black and white.

[0039] The fingerprint image is binarized to improve the processing efficiency of the fingerprint image. The binarization process can obtain a binary image, which refers to an image with only black (gray value 0) and white (gray value 1) in the entire image, and no grayscale changes are shown on them.

[0040] In digital image processing, binary images play a very important role. This is because in practical image processing systems, high processing speed and low cost are required, and the processing of light and dark images with large amounts of information is too expensive. Moreover, the binary image can be analyzed and described using concepts in geometry, which is much more convenient than grayscale images. Therefore, binary image processing has become an independent and important branch of image processing and has been widely used.

[0041] For fingerprint recognition, all information must be included in the binary description of ridges and valleys. Therefore, it is necessary to determine whether each point on the image belongs to the object area or the background area based on the original grayscale image, thereby generating a corresponding binary image. It can not only greatly reduce the storage volume, but also make the subsequent discrimination process less disturbed, greatly simplifying the subsequent processing method.

[0042] Those skilled in the art can continue to refine the binary fingerprint image to obtain a clear fingerprint image. In the field of binary image processing, refinement is a very important processing link. For example, if the interference fringe image is not refined into a line, there is no way to accurately obtain data and calculate it because the fringe is thick and wide and the edges are diffuse.

[0043] On the other hand, if a connected component can be devalued with a linear structure, the thinning problem of the image has become a hot topic in image processing. There are many people who have the outline of the ridgeline of the fingerprint and the related endpoints and intersections. However, the ridgeline after binarization has a certain width. This characteristic of its characterization is of great significance both in image recognition and data compression. Therefore, the binary width will add a lot of trouble to the subsequent recognition. Therefore, the width of the fingerprint ridgeline should be gradually peeled off first, so that the ridgeline becomes a thin line with a width of only one pixel, which will be very beneficial to the next step of analysis. The fingerprint image after thinning is processed according to the general processing rules of the fingerprint, and the invalid ridgeline bridges and connection gaps are removed.

[0044] The refined fingerprint image continues to extract feature points. Based on the extracted feature points, the fingerprint image is then compared with the fingerprint library, and the comparison results are output. If the feature points of the fingerprint image are the same as the fingerprint feature points stored in the fingerprint library, the match can be completed.

[0045] In summary, those skilled in the art can accurately collect and compare fingerprints by setting a capacitive fingerprint module in the fingerprint collection unit. In the above process, two voltages of different magnitudes are formed by the contact between the ridges and the grooves to form a fingerprint image, thereby avoiding the influence of temperature, humidity and light intensity on fingerprint collection.

[0046] Furthermore, the capacitive fingerprint module is arranged on the fingerprint acquisition unit, thereby effectively reducing the volume of the fingerprint acquisition unit and effectively optimizing the overall space occupation.

[0047] Preferably, the step of "preprocessing the fingerprint image" includes performing extreme value filtering on the fingerprint image, performing a first smoothing process on the fingerprint image after extreme value filtering, sharpening the fingerprint image after the first smoothing process, and performing a second smoothing process on the sharpened fingerprint image.

[0048] Preferably, in the first smoothing step, the mean square value of the grayscale difference between the pixels of the entire image and its period is selected as the threshold for processing. After the first smoothing, the fingerprint image can be made clearer.

[0049] More preferably, in the second smoothing step, a threshold is set and weighted smoothing is performed on the elements to obtain smoothed gray values, thereby making the lines in the fingerprint image appear clearer.

[0050] Preferably, in the step of thinning the binary fingerprint image, the data of the binary fingerprint image is registered. In the above thinning process, the ridge lines of the binary fingerprint image can be processed. After processing, the data of the fingerprint image can be registered, and then the processed fingerprint image can be further compared.

[0051] Preferably, in the step of comparing the fingerprint image with the fingerprint library, the fingerprint image and the fingerprints in the fingerprint library are matched by lines. That is, the fingerprint image can be compared and matched with the fingerprints in the fingerprint library based on the line comparison to complete the fingerprint recognition.

[0052] The present application also provides a flexible circuit board for fingerprint collection, in which a capacitive fingerprint module is provided for forming a fingerprint image. Through the capacitive fingerprint module and the method steps in the above embodiment, the collection and comparison and matching of fingerprints can be stably completed.

[0053] Although different specific embodiments are mentioned in the content of this application, this application is not limited to the situations described in the industry standards or embodiments, etc. Some industry standards or slightly modified implementation plans based on the implementation of the custom methods or embodiments can also achieve the same, equivalent or similar, or predictable implementation effects after deformation of the above embodiments. The embodiments of data acquisition, processing, output, judgment methods, etc. after these modifications or deformations can still fall within the scope of the optional implementation plans of this application.

[0054] Although the present application has been described through embodiments, those skilled in the art will appreciate that there are many modifications and changes to the present application without departing from the spirit of the present application. It is intended that the attached embodiments include these modifications and changes without departing from the present application.

Claims

1. A fingerprint collection method, characterized in that: The following steps are involved: A fingerprint collection unit having a capacitive fingerprint module is provided for collecting fingerprints and generating fingerprint images; Preprocessing the fingerprint image; Binarizing the preprocessed fingerprint image to perform black-and-white processing on the preprocessed fingerprint image; Refining the binary fingerprint image; Extracting feature points from the refined fingerprint image; The fingerprint image is compared with a fingerprint library according to the feature points, and the comparison result is output.

2. The fingerprint collection method according to claim 1, characterized in that: The step of "preprocessing the fingerprint image" includes performing extreme value filtering on the fingerprint image, performing a first smoothing process on the fingerprint image after extreme value filtering, sharpening the fingerprint image after the first smoothing process, and performing a second smoothing process on the sharpened fingerprint image.

3. The fingerprint collection method according to claim 2, characterized in that: In the first smoothing step, the mean square value of the grayscale difference between the pixels of the entire image and its period is selected as a threshold for processing.

4. The fingerprint collection method according to claim 2, characterized in that: In the second smoothing step, a threshold is set, and weighted smoothing is performed on the elements to obtain smoothed grayscale values.

5. The fingerprint collection method according to claim 1, characterized in that: In the step of thinning the binarized fingerprint image, data of the binarized fingerprint image is registered.

6. The fingerprint collection method according to claim 1, characterized in that: In the step of comparing the fingerprint image with the fingerprint database, the fingerprint image and the fingerprints in the fingerprint database are matched in terms of ridges.

7. The fingerprint collection method according to claim 1, characterized in that: The fingerprint collection unit is provided with a collection side, the collection side contacts the fingerprint, and a capacitor array is installed near a side wall of the collection unit opposite to the collection side.

8. A flexible circuit board for fingerprint collection, characterized in that: The capacitive fingerprint module as claimed in claims 1 to 7 is arranged in the flexible circuit board for forming a fingerprint image.

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