WO2018141119A1

WO2018141119A1 - Fingerprint acquisition method, apparatus, and terminal

Info

Publication number: WO2018141119A1
Application number: PCT/CN2017/074815
Authority: WO
Inventors: 李丹洪
Original assignee: 华为技术有限公司
Priority date: 2017-02-03
Filing date: 2017-02-24
Publication date: 2018-08-09
Also published as: CN108701218B; CN108701218A

Abstract

A fingerprint acquisition method, an apparatus and a terminal, which are used for improving the quality of fingerprint images, thereby increasing the success rate of fingerprint recognition. Said method is applied to a terminal, wherein a fingerprint component is placed under cover glass of a display screen and a region on said cover glass corresponding to the fingerprint component is a fingerprint acquisition region, said method comprising: a terminal obtaining a user fingerprint image which is acquired by a fingerprint component, wherein the user fingerprint image comprises a non-fingerprint feature, said non-fingerprint feature comprising a defective point and/or a non-uniform image grayscale; the terminal calibrating the user fingerprint image according to non-fingerprint feature information of a pre-saved test fingerprint image, a test fingerprint image being a fingerprint image which is obtained by the terminal in advance in said fingerprint acquisition region by using a fingerprint test head having a flat surface.

Description

Method, device and terminal for fingerprint collection

The present application claims priority to Chinese Patent Application No. JP-A No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. in.

Technical field

The present application relates to the field of image processing, and in particular, to a method, an apparatus, and a terminal for fingerprint collection.

Background technique

Fingerprint recognition technology verifies identity by fingerprint comparison, which is the most widely used biometric recognition technology. In order to improve security, fingerprint recognition is more and more widely used in terminal devices such as mobile phones. Based on reliability, industrial design (ID) appearance, waterproof and dustproof, mobile phone suppliers tend to adopt full-screen display and place fingerprint devices under the cover glass of the display (such as The fingerprint sensor) scheme, such as the mobile phone example shown in FIG. 1, the cover glass 101 of the display screen is dug under the blind hole, and then the fingerprint device 102 is placed under the blind hole. When the fingerprint device 102 collects the fingerprint, the user's finger is not directly The fingerprint device 102 is contacted.

At present, the fingerprints collected by the above scheme generally have a problem of poor overall image quality. The fragility of the glass makes it necessary to make the glass have a certain thickness when using glass as the cover material, which leads to an increase in the distance between the fingerprint device and the user's finger, which leads to weakening of the signal, weakening of the signal and aliasing in space. It will cause obvious loss of the quality of the captured fingerprint image (for example, the partial pattern of the fingerprint image is not clear); in addition, the unevenness of the glass will result in uneven signal, partial black or white, and the sticker of the glass. Causes of dust or the like during the process may cause an increase in dead spots on the fingerprint image. For example, FIG. 2 shows an example of a fingerprint image that is more common at present, which includes a dead pixel 201, a non-uniform 202, and an invisible region 203.

It can be seen that all the above-mentioned situations may result in poor quality of the collected fingerprint image, increase the difficulty of fingerprint recognition, and have a negative impact on the user's fingerprint recognition rate experience, which may easily cause problems such as failure to enter and verification failure. Therefore, how to solve the above problems, improve the quality of fingerprint images, and thus increase the success rate of fingerprint recognition is urgently studied by the industry.

Summary of the invention

The present application provides a method, a device and a terminal for fingerprint collection, which are used to improve the quality of fingerprint images, thereby increasing the success rate of fingerprint recognition.

In a first aspect, the present application provides a fingerprint collection method, which is applied to a terminal of a fingerprint device placed under a cover glass of a display screen, and a region corresponding to the fingerprint device on the cover glass is a fingerprint collection area. The method includes:

The terminal acquires a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a dead pixel and/or an image gray scale unevenness;

The terminal calibrates the user fingerprint image according to the non-fingerprint type feature information of the test fingerprint image stored in advance;

The test fingerprint image is a fingerprint image acquired by the terminal in the fingerprint collection area by using a surface-finished fingerprint test head in advance.

It can be seen that, by the above manner, the terminal collects the fingerprint device placed under the cover glass of the display screen. After the user fingerprint image, the user fingerprint image can be calibrated according to the non-fingerprint feature information of the pre-stored test fingerprint image, thereby effectively reducing the defect caused by the cover glass and the processing technology on the quality of the user fingerprint image. The effect is to improve the quality of the user's fingerprint image and increase the success rate of fingerprint recognition.

In a possible implementation, the non-fingerprint feature includes a dead pixel; the terminal calibrates the user fingerprint image according to the non-fingerprint feature information of the pre-stored test fingerprint image, including:

The terminal removes a dead pixel of the fingerprint image of the user according to the dead point information of the test fingerprint image stored in advance.

In a possible implementation, the terminal removes the dead pixels of the user fingerprint image according to the dead point information of the test fingerprint image stored in advance, including:

Determining, by the terminal, a dead point of the test fingerprint image according to a gray value of each point in the test fingerprint image, and determining a pixel position and a gray value of a dead point of the test fingerprint image;

Determining, by the terminal, a point located in the pixel location in the user fingerprint image as a dead point of the user fingerprint image;

The terminal subtracts the gray value of the dead point of the user fingerprint image from the gray value of the dead point located at the same pixel position in the test fingerprint image to obtain a calibrated user fingerprint image.

In the above manner, the terminal will be able to remove the dead pixels caused by factors such as dust during the bonding process of the cover glass in the fingerprint image of the user, thereby improving the quality of the fingerprint image of the user.

In a possible implementation manner, the terminal determines, according to a gray value of each point in the test fingerprint image, a dead point of the test fingerprint image, including:

The terminal calculates, for each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the first reference point, where the first reference point is a right adjacent point of the point ;

If the difference between the gray value of the point and the gray value of the first reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image at the point is greater than Determining the point as a dead point of the test fingerprint image when the first reference point is different from the average gray value of the test fingerprint image, otherwise determining the first reference point as the test A bad point in the fingerprint image.

The terminal calculates, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the second reference point, where the second reference point is a lower adjacent point of the point ;

If the difference between the gray value of the point and the gray value of the second reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image at the point is greater than Determining the point as a dead point of the test fingerprint image when the second reference point is different from the average gray value of the test fingerprint image, otherwise determining the second reference point as the test A bad point in the fingerprint image.

In a possible implementation manner, the non-fingerprint type feature includes image gray scale unevenness;

The terminal calibrates the user fingerprint image according to the non-fingerprint type feature information of the test fingerprint image stored in advance, including:

The terminal calibrates the gray value of each point in the user fingerprint image according to the image gray unevenness information of the test fingerprint image stored in advance.

In a possible implementation, the terminal calibrates the gray value of each point in the user fingerprint image according to the image gray unevenness information of the test fingerprint image stored in advance, including:

Determining, by the terminal, a grayscale tilt of the test fingerprint image according to a gray value of each point in the test fingerprint image Oblique surface, and determining a tilt angle of the gray scale inclined surface and an intersection line of the gray scale inclined surface and a standard horizontal plane;

The terminal calibrates the gray value of the point to each point in the user fingerprint image according to the gray tilt angle and the distance from the projection point of the point on the standard horizontal plane to the intersection line .

Through the above manner, the terminal will be able to calibrate the image gray unevenness caused by factors such as unevenness of the cover glass or unevenness of the ink in the fingerprint image of the user, thereby improving the quality of the fingerprint image of the user.

In a second aspect, the present application provides a device for fingerprint collection, which is applied to a terminal for placing a fingerprint device under a cover glass of a display screen, and a region corresponding to the fingerprint device on the cover glass is a fingerprint collection area. , the device includes:

An acquiring module, configured to acquire a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a dead pixel and/or an image gray scale unevenness;

a calibration module, configured to calibrate the user fingerprint image according to non-fingerprint type feature information of the pre-stored test fingerprint image;

In a possible implementation manner, the non-fingerprint feature includes a dead point;

The calibration module is specifically configured to: remove a dead point of the fingerprint image of the user according to the dead point information of the pre-stored test fingerprint image.

In a possible implementation, the calibration module is specifically configured to:

Determining a dead point of the test fingerprint image according to a gray value of each point in the test fingerprint image, and determining a pixel position and a gray value of a dead point of the test fingerprint image;

Determining, in the user fingerprint image, a point located at the pixel position as a dead point of the user fingerprint image;

The gradation value of the dead point of the user fingerprint image is subtracted from the gradation value of the bad point located at the same pixel position in the test fingerprint image to obtain a calibrated user fingerprint image.

Calculating, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the first reference point, the first reference point being a right adjacent point of the point;

If the difference between the gray value of the point and the gray value of the first reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image is greater than the first Determining a point as a dead point of the test fingerprint image when a reference point is different from an average gray value of the test fingerprint image, otherwise determining the first reference point as the test fingerprint image A bad point.

Calculating, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the second reference point, wherein the second reference point is a lower adjacent point of the point;

If the difference between the gray value of the point and the gray value of the second reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image is greater than the first Determining the point as a dead point of the test fingerprint image when the difference between the second reference point and the average gray value of the test fingerprint image, otherwise determining the second reference point as the test fingerprint image A bad point.

The calibration module is specifically configured to: calibrate gray values of respective points in the user fingerprint image according to image gray unevenness information of the test fingerprint image stored in advance.

Determining, according to a gray value of each point in the test fingerprint image, a grayscale inclined surface of the test fingerprint image, and determining a tilt angle of the grayscale inclined surface and a intersection line between the grayscale inclined surface and a standard horizontal plane ;

For each point in the user fingerprint image, the gray value of the point is calibrated according to the grayscale tilt angle and the distance from the projected point of the point on the standard horizontal plane to the intersecting line.

The implementation of the device and the beneficial effects of any of the above second or second aspects of the present invention may be implemented in accordance with any of the above first aspect or the first aspect of the present invention. See, repetitions are not repeated here.

In a third aspect, the present application provides a terminal, including: a processor, a memory, a fingerprint device, and a display screen, wherein the display screen includes a cover glass, and the fingerprint device is placed under the cover glass. The area corresponding to the fingerprint device on the cover glass is a fingerprint collection area; wherein:

The fingerprint device is configured to collect a fingerprint image;

The memory is configured to store computer instructions;

The processor is configured to execute by calling a computer instruction stored in the memory:

Obtaining a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a dead pixel and/or an image gray scale unevenness;

Calibrating the user fingerprint image according to non-fingerprint type feature information of the test fingerprint image stored in advance;

The processor is specifically configured to: remove a dead point of the fingerprint image of the user according to the dead point information of the test fingerprint image stored in advance.

In a possible implementation manner, the processor is specifically configured to:

If the difference between the gray value of the point and the gray value of the second reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image is greater than the first The second reference point and the average gray of the test fingerprint image When the difference value is the difference, the point is determined as a bad point of the test fingerprint image, otherwise the second reference point is determined as a bad point of the test fingerprint image.

The processor is specifically configured to: calibrate a gray value of each point in the user fingerprint image according to image gray unevenness information of the test fingerprint image stored in advance.

The implementation of the terminal and the beneficial effects of any of the above third or third aspects of the present invention may be implemented in accordance with any of the above first aspect or the first aspect of the present invention. See, repetitions are not repeated here.

In a fourth aspect, the present application further provides a computer readable storage medium comprising instructions, when executed on a computer, causing a computer to perform the method according to any of the above first aspect or the first aspect of the present invention Implementation.

DRAWINGS

Figure 1 is a schematic diagram of current mobile phone fingerprint collection;

2 is a schematic diagram of a fingerprint image currently acquired;

FIG. 3 is a schematic block diagram showing a partial structure of a mobile phone 300 according to some embodiments of the present invention; FIG.

4 is a schematic flowchart of a method for collecting fingerprints according to some embodiments of the present invention;

5 is a schematic diagram of using a fingerprint test head to acquire a test fingerprint image according to some embodiments of the present invention;

6 is a schematic diagram of device connections in a terminal according to some embodiments of the present invention;

7 is a schematic diagram of a test fingerprint image obtained by a fingerprint test head according to some embodiments of the present invention;

FIG. 8 is a schematic flowchart of collecting information on a terminal of a factory production line according to some embodiments of the present invention; FIG.

FIG. 9 is a schematic flowchart of calibrating a user fingerprint image according to some embodiments of the present invention; FIG.

10 is a schematic flowchart of a terminal calibrating a user fingerprint image and authenticating a user according to some embodiments of the present invention;

11(a) is a schematic diagram of a pixel point and a pixel point connected to the right side of the pixel point in some embodiments of the present invention;

11(b) is a schematic diagram of a pixel point and a pixel point connected to the pixel point in some embodiments of the present invention;

12(a) is a schematic diagram showing the gray scale unevenness of a test fingerprint image in some embodiments of the present invention;

12(b) is a schematic cross-sectional view showing a gray scale unevenness of a test fingerprint image according to some embodiments of the present invention;

FIG. 13(a) is a schematic diagram of a user fingerprint image before calibration in some embodiments of the present invention; FIG.

FIG. 13(b) is a schematic diagram of a user fingerprint image after calibration according to some embodiments of the present invention; FIG.

FIG. 14 is a schematic structural diagram of an apparatus for collecting fingerprints according to some embodiments of the present invention; FIG.

FIG. 15 is a schematic structural diagram of a terminal according to some embodiments of the present invention.

detailed description

Embodiments of the present invention will be described below with reference to the accompanying drawings.

An industrial design solution for placing a fingerprint device under the cover glass of the display screen as shown in FIG. 1 provides a method, a device and a terminal for fingerprint collection, which are used to solve the fingerprint device collection under the design scheme. Fingerprint The image is affected by factors such as the thickness of the cover glass and the overall processing technology, and the problem of better quality cannot be exhibited.

The user fingerprint image collected by the fingerprint device should reflect the user's fingerprint feature (or can be understood as the biological feature of the user's fingerprint), such as the ridge and valley of the user's fingerprint, so as to achieve the purpose of identifying and authenticating the user. For the terminal where the fingerprint device is placed under the cover glass of the display screen, the fingerprint device is inevitably affected by the thickness of the cover glass and the processing technology when the fingerprint image is collected, which causes some fingerprint images to appear. Non-fingerprint features, such as the presence of dead spots on the image due to dust during the glass bonding process, such as uneven image grayness due to unevenness of the glass or unevenness of the fit.

In the fingerprint collection scheme provided by the embodiment of the present invention, a test fingerprint image is pre-stored on the terminal, and the fingerprint test image is in advance using a surface-finished fingerprint test head in the fingerprint collection area of the terminal (ie, The fingerprint image obtained by the area corresponding to the fingerprint device on the cover glass of the terminal display screen can be seen, the fingerprint test image will include the dead pixels and the image gray scale caused by the cover glass and the processing technology. Non-fingerprint type feature information such as unevenness; further, after acquiring the user fingerprint image collected by the fingerprint device placed under the cover glass, the terminal includes non-fingerprint by using non-fingerprint type feature information according to the pre-stored test fingerprint image The calibration of the user's fingerprint image of the class feature can effectively reduce the adverse effects on the fingerprint image quality of the user due to factors such as the cover glass and the processing technology, improve the quality of the user's fingerprint image, and increase the success rate of fingerprint recognition.

Specifically, in some embodiments of the present invention, the terminal may remove the dead pixels of the fingerprint image of the user according to the dead point information of the test fingerprint image stored in advance; the terminal may also not according to the image grayscale of the test fingerprint image stored in advance. Uniform information, calibrating the gray value of each point in the user fingerprint image.

The present application describes various embodiments in connection with a fingerprint device. A fingerprint device may refer to a device for acquiring a fingerprint image, such as a fingerprint sensor.

For example, the fingerprint sensor can be formed by an array of capacitive sensing elements, each capacitive sensing element of the array can record a voltage that varies with capacitively coupled capacitance, and the fingers can be capacitively coupled to each of the fingerprint sensors The capacitive sensing element enables the fingerprint sensor to sense the capacitance between each capacitive sensing element and the finger plane to determine the signal recorded at each capacitive sensing element to obtain a fingerprint image of the user. The resolution of the fingerprint device varies with the density of the sensing element, the distance between the fingerprint device and the finger, and the thickness of the dielectric covering the fingerprint device. An increase in the thickness of the dielectric will attenuate the signal between the finger and the fingerprint device.

For example, taking the ridge and valley of the user's fingerprint as an example, the ridge of the fingerprint is closer to the fingerprint sensor, and the capacitance of the capacitive sensing element at the corresponding pixel position is higher, thereby generating a higher signal, the valley of the fingerprint and the fingerprint sensor. Farther away, the capacitive sensing element at the corresponding pixel location produces a lower capacitance, thus producing a lower signal that reflects the user's fingerprint information by the difference in signal. The user fingerprint image may specifically include a set of grayscale values to provide fingerprint feature information about the user's finger. These fingerprint features can be stored as fingerprints of registered users in the database for later use, or can be compared to fingerprint image information of registered users stored in the database to identify and authenticate users.

It should be noted that the fingerprint device may be capacitively coupled, or may be coupled to the user's finger in other ways (such as electromagnetically); in addition, the fingerprint device may also perform optical sensing, infrared sensing, or Other sensed elements work in combination or in combination, which is not limited in this application.

The present application describes various embodiments in connection with a terminal having features of a fingerprint device placed under a cover glass of a display screen.

For example, the terminal described in the present application may include a mobile phone, a tablet computer, a personal digital assistant (PDA), a point of sales (POS), a car computer, a desktop computer, a notebook, and the like.

Taking a terminal as a mobile phone as an example, FIG. 3 shows a schematic block diagram of a partial structure of a mobile phone 300 according to some embodiments of the present invention. Referring to FIG. 3, the mobile phone 300 includes: a radio frequency (RF) circuit 310, a memory 320, and a location Processor 330, sensor 340, display screen 350, other input devices 360, input/output (I/O) subsystem 370, audio circuitry 380, and power supply 390. These components can communicate over one or more communication buses or signal lines.

It should be understood that the structure of the mobile phone shown in FIG. 3 does not constitute a limitation on the mobile phone, and may include more or less components than those illustrated, or combine some components, or split some components, or different. Assembly of parts. The components in the handset structure shown in FIG. 3 may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.

The RF circuit 310 can be used for receiving and transmitting signals during the transmission or reception of information or during a call. In particular, after receiving the downlink information of the base station, the processor 330 processes the data. In addition, the uplink data is designed to be sent to the base station. Generally, RF circuits include, but are not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like. In addition, RF circuitry 310 can also communicate with the network and other devices via wireless communication. The wireless communication may use any communication standard or protocol, including but not limited to global mobile communication systems, general packet radio services, code division multiple access, wideband code division multiple access, Long Term Evolution (LTE), email , short message service, etc.

The memory 320 can be used to store software programs and modules, and the processor 330 executes various functional applications and data processing of the mobile phone 300 by running software programs and modules stored in the memory 320. The memory 320 may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application required for at least one function, and the like; the storage data area may store data created according to the use of the mobile phone 300, and the like. Moreover, memory 320 can include high speed random access memory, and can also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid state storage device.

The processor 330 is the control center of the handset 300, which connects various portions of the entire handset using various interfaces and lines, by running or executing software programs and/or modules stored in the memory 320, and recalling data stored in the memory 320, The various functions and processing data of the mobile phone 300 are performed to perform overall monitoring of the mobile phone. Optionally, the processor 330 may include one or more processing units; optionally, the processor 330 may integrate an application processor (AP) and a modem processor, where the application processor mainly processes the operating system. The user interface, application, etc., the modem processor primarily handles wireless communications. It can be understood that the above modem processor may not be integrated into the processor 330.

The handset 300 can also include at least one sensor 340, such as the fingerprint device described above herein, to obtain a fingerprint image of the user. Other sensors such as a light sensor, a motion sensor, a pressure sensor, a gyroscope, a barometer, a hygrometer, a thermometer, an infrared sensor, and the like that can be configured in the mobile phone 100 are not described herein.

The display screen 350 can be used to display visual output to the user, including displaying information input by the user, information provided to the user, and various menus of the mobile phone 300, and also providing an input interface and an output interface between the device and the user, accepting the user. Input. The display screen 350 can include a display panel 351 and a touch panel 352. The display panel 351 can be configured in the form of a liquid crystal display, an organic light emitting diode, or the like. The touch panel 352, also referred to as a touch sensitive screen, can collect contact or non-contact operations on or near the user (such as a user using a finger, a stylus, or the like on the touch panel 352 or on the touch panel. The operation near 352), and the corresponding connection device is driven according to a preset program.

It should be noted that although not shown in FIG. 3, the display screen 350 of the mobile phone 300 is covered with a cover glass, the face of the cover glass in contact with the user's finger is not perforated, and the face facing the fingerprint device is partially thinned. (blind hole), the fingerprint device described above in the present application can be placed under the cover glass as one of the sensors 340 (such as the example shown in FIG. 1), and the cover glass corresponds to the fingerprint device The area can be used as a fingerprint collection area to collect user fingerprints.

An ink layer is placed between the top surface of the fingerprint device and the bottom surface of the cover glass, such as a cover glass. The ink layer is printed on the bottom surface such that the cover glass is opaque such that the fingerprint device is invisible to the user.

Other input devices 360 may include physical buttons (press buttons, rocker buttons, etc.), dials, slide switches, joysticks, click wheels, light mice, for receiving input numeric or character information, and for generating users with mobile phone 300 Set and key signal input related to function control.

The I/O subsystem 370 is used to control external devices for input and output, and may include other input device controllers 371, sensor controllers 372, and display controllers 373. One or more other input device controllers 371 can receive signals from other input devices 360 and/or send signals to other input devices 360. Display controller 373 can receive signals from display screen 350 and/or send signals to display screen 350. Sensor controller 372 can receive signals from one or more sensors 340 and/or send signals to one or more sensors 340.

The mobile phone 300 further includes an audio circuit 380, a speaker 381, a microphone 382 to provide an audio interface between the user and the mobile phone 300, a power source 390 (such as a battery) for powering the various components, and the power source can be logically passed through the power management system and the processor 330. Connected to manage charging, discharging, and power consumption functions through the power management system; camera, Bluetooth module, etc., will not be described here.

In addition, in the description of the present application, the term "and/or" means and includes any or all possible combinations of one or more associated listed items; the terms "first", "second", etc., only It is used to distinguish the purpose of the description, and is not to be construed as indicating or implying a relative importance, nor as an indication or implied order.

For the terminal having the process feature of placing the fingerprint device under the cover glass of the display screen, the embodiment of the invention provides a fingerprint collection scheme to improve the quality of the fingerprint image. FIG. 4 is a schematic flowchart diagram of a method for fingerprint collection provided by some embodiments of the present invention, which may be implemented by hardware, software programming, or a combination of hardware and software, and may be specifically placed under the cover glass of the display screen. On the terminal of the fingerprint device. For example, the mobile phone 300 shown in FIG. 3 can be used. The area corresponding to the fingerprint device on the cover glass of the display screen 350 is a fingerprint collection area. The fingerprint device collects the fingerprint, and the processor 330 reads the instruction in the memory 320. The flow shown in Figure 4 is performed.

As shown in FIG. 4, the process includes the following steps:

Step 401: The terminal acquires a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a bad point and/or an image gray scale unevenness;

Step 402: The terminal calibrates the user fingerprint image according to the non-fingerprint type feature information of the test fingerprint image stored in advance.

In some embodiments of the present invention, the fingerprint device placed under the cover glass senses that the user's finger covers the fingerprint collection area corresponding to the fingerprint device on the cover glass, and the user fingerprint image can be acquired; the fingerprint test image Due to factors such as cover glass and processing technology, non-fingerprint features such as dead pixels and uneven image gradation may be included; the terminal performs the fingerprint image of the user by using non-fingerprint feature information of the test fingerprint image stored in advance. Calibration will effectively reduce the adverse effects of the above factors on the quality of the user's fingerprint image, improve the quality of the user's fingerprint image, and increase the success rate of fingerprint lock recognition.

The test fingerprint image used by the terminal to calibrate the user fingerprint image may be a fingerprint image obtained by the terminal in advance in the fingerprint collection area by using a surface-finished fingerprint test head.

It should be noted that, based on the consideration of simplifying the processing in practical applications, the present application mainly describes a fingerprint test head having a flat surface, and the fingerprint test head may also have a regular texture, and those skilled in the art have grasped the solution provided by the present application. After that, it should be easy to think of a similar solution.

In addition, in order to enable the fingerprint device to sense the fingerprint test head to obtain a test fingerprint image, the fingerprint test head should also be electrically conductive similar to a human finger.

In some embodiments of the present invention, the fingerprint test head may also be configured with pressure (to simulate a real finger overlay operation) and cover operating parameters such as duration; in addition, the effective area of the fingerprint test head (with cover glass) The area of contact) can be configured to be equal to or larger than the fingerprint collection area on the cover glass corresponding to the fingerprint device.

In some embodiments of the present invention, the process of the terminal acquiring the test fingerprint image may occur before the terminal leaves the factory. For example, a test environment for acquiring a test fingerprint image may be configured at the end of the terminal device production line (for example, when the device has been assembled and entered the factory verification phase).

Specifically, in some embodiments of the present invention, the configurable terminal stores the test fingerprint image in a non-erasable storage area in the terminal after acquiring the test fingerprint image, or, in some embodiments of the present invention, The configurable terminal extracts the non-fingerprint feature information of the obtained test fingerprint image, and stores the extracted non-fingerprint feature information into a non-erasable storage area of the terminal, for example, to an area that cannot be deleted after being restored to the factory. By saving the above information to the non-erasable storage area in the terminal, the terminal can use the above information to calibrate the user fingerprint image collected by the fingerprint device during subsequent use.

For example, Figure 5 illustrates a schematic diagram of the use of a fingerprint test head to obtain a test fingerprint image in some embodiments of the invention.

As shown in FIG. 5, a fingerprint device 502 is disposed under the cover glass of the display screen of the terminal 501, and the fingerprint test head 500 having a flat surface covers the fingerprint collection area corresponding to the fingerprint device 502 on the cover glass of the display screen of the terminal 501. In turn, the fingerprint device 502 senses the fingerprint test head 500 to acquire a test fingerprint image.

Figure 6 shows a schematic diagram of device connections within a terminal in some embodiments of the invention.

As shown in FIG. 6, the AP 503 in the terminal 501 can obtain the test fingerprint image collected by the fingerprint device 502 through the bus; specifically, the AP 503 can provide a Trusted execution environment (TEE) 504 for The test fingerprint image collected by the fingerprint device 502 is processed, for example, by using a preset algorithm to extract non-fingerprint feature information of the test fingerprint image.

Figure 7 shows a schematic diagram of a test fingerprint image obtained by a fingerprint test head in some embodiments of the invention.

As shown in FIG. 7 , the test fingerprint image example includes non-fingerprint features such as a dead pixel 701 due to the thickness of the cover glass and process factors, and an image gray unevenness 702;

Further, the terminal 501 can extract the non-fingerprint feature information included therein according to the test fingerprint image, and save the extracted information in an area that cannot be deleted after being restored from the factory, so as to be used for calibration of the user fingerprint image during use by the subsequent terminal, and ending. Testing process.

In some embodiments of the present invention, each terminal to be shipped may be configured to be tested in a test environment similar to that shown in FIG. 5 in the production process of the terminal to obtain a non-fingerprint in the test fingerprint image. Feature information; an algorithm for extracting non-fingerprint feature information may be configured on the terminal, so that after the fingerprint device obtains the test fingerprint image through the fingerprint test head, the non-fingerprint feature information in the test fingerprint image is tested by a preset algorithm. After the extraction, save to the entire machine to restore the factory settings can not be erased.

For example, Figure 8 illustrates a flow diagram of the collection of information at a factory production line terminal in some embodiments of the present invention.

As shown in FIG. 8, after the test link is started on the factory production line, the terminal waits for the fingerprint test head to be pressed down (801), and after the fingerprint test head is pressed, the fingerprint device collects the test fingerprint image (802), and the terminal generates the test fingerprint image based on the test. The non-fingerprint feature information of the fingerprint image is tested (803), and the non-fingerprint feature information of the obtained test fingerprint image is further saved in the restored factory undeleteable area (804), and the process ends.

It can be seen that, by using the foregoing embodiment of the present invention, the non-fingerprint feature information of the test fingerprint image can be pre-stored on the terminal, and further, after the terminal acquires the user fingerprint image through step 401, the method described in step 402 can be performed. The user fingerprint image is calibrated according to the non-fingerprint type feature information of the pre-stored test fingerprint image.

For example, based on the device connection example in the terminal in some embodiments of the present invention shown in FIG. 6, FIG. 9 is a flow chart showing the calibration of the user fingerprint image in some embodiments of the present invention.

As shown in FIG. 9, after the fingerprint device 502 transmits the test fingerprint image to the AP 503 through the bus, the AP 503 performs processing to obtain non-fingerprint type feature information of the test fingerprint image, and stores the information in the database; the fingerprint device 502 passes The bus can transmit the user fingerprint image to the AP 503, and the AP 503 can read the non-fingerprint feature information of the test fingerprint image stored in the database to calibrate the user fingerprint image to obtain the calibrated user fingerprint image.

The calibrated user fingerprint image can be further used for specific processes such as user identification, user authentication, etc., to improve the accuracy of user identification and user authentication. For example, FIG. 10 is a flow chart showing the process of calibrating a user's fingerprint image and authenticating a user in some embodiments of the present invention.

As shown in FIG. 10, after the terminal is used and the authentication of the user fingerprint image is started, the terminal waits for the user's finger to press (1001), and the fingerprint device collects the user fingerprint image (1002) after the user presses the finger, and the terminal further based on the advance The non-fingerprint feature information of the stored test fingerprint image is used to calibrate the collected user fingerprint image (1003), and then the user authentication may be performed based on the calibrated fingerprint image (1004), for example, the calibrated fingerprint image may be transmitted to The user authentication algorithm authenticates the user to improve the authentication accuracy.

Specifically, in some embodiments of the present invention, in the case where the fingerprint image collected by the fingerprint device is caused by a factor such as dust during the cover glass bonding process, the terminal may have a non-fingerprint feature such as a dead pixel, and the terminal may perform the test according to the pre-stored. The bad point information of the fingerprint image removes the dead pixels of the user fingerprint image, thereby achieving the purpose of calibrating the user's fingerprint image.

In some embodiments of the present invention, the bad point information of the test fingerprint image may be determined by the terminal determining the bad point of the test fingerprint image according to the gray value of each point in the test fingerprint image, and the determined test fingerprint image is bad. The pixel position and gray value of the point;

Further, the terminal may determine a point in the user fingerprint image located at a pixel position indicated by the dead point information of the test fingerprint image as a dead point of the user fingerprint image; and subtract the gray value of the dead point of the user fingerprint image from the test. The gradation value of the bad point located at the same pixel position indicated in the dead point information of the fingerprint image is obtained as the calibrated user fingerprint image.

Specifically, in some embodiments of the present invention, the terminal may determine the dead pixels of the test fingerprint image by, but not limited to, the gray value of each point in the test fingerprint image:

The terminal calculates a difference between the gray value of the point and the gray value of the first reference point for each point in the test fingerprint image, where the first reference point is specifically the right adjacent point of the point;

If the difference between the gray value of the point and the gray value of the first reference point is greater than a preset threshold, the difference between the terminal and the average gray value of the test fingerprint image at the point is greater than the first reference point and the test fingerprint. When the difference of the average gray value of the image is, the point is determined as a bad point of the test fingerprint image, otherwise the first reference point is determined as a bad point of the test fingerprint image.

The terminal calculates a difference between the gray value of the point and the gray value of the second reference point for each point in the test fingerprint image, where the second reference point is the next adjacent point of the point;

If the difference between the gray value of the point and the gray value of the second reference point is greater than a preset threshold, the difference between the terminal and the average gray value of the test fingerprint image at the point is greater than the second reference point and the test fingerprint. When the difference of the average gray value of the image is, the point is determined as a bad point of the test fingerprint image, otherwise the second reference point is determined as a bad test image image. point.

In some embodiments of the invention, the above two methods can also be used in combination to quickly determine the dead pixels of the test fingerprint image.

For example, FIG. 11(a) shows a schematic diagram of a terminal using a pixel point and a pixel point connected to the right of the pixel point to determine a dead point in some embodiments of the present invention; FIG. 11(b) shows some embodiments of the present invention. The terminal uses a pixel and a pixel point connected to the pixel to determine a bad point.

Specifically, each point (i, j) is compared with a point (i, j+1) on the right side of the point and a point (i+1, j) below the point (the gray value is sequentially expressed as I). _(i,j) , I _(i,j+1) , I _(i+1,j) ), if the gray value difference exceeds the threshold fgrav, it will deviate from the average gray value of the whole image (I _Mean ) That point is marked as a dead pixel, marking the isolated dead pixels of the entire image;

The above process can be described by the following formula:

in case

And further confirm |I _(i,j) -I _mean |>|I _{(i, j+1)} -I _mean |, the point (i, j) is confirmed as a dead point; otherwise, it is confirmed |I _{(i, j)} -I _mean |<|I _(i,j+1) -I _mean |, the point (i, j+1) is confirmed as a dead point;

in case

And further confirm |I _(i,j) -I _mean |>|I _(i+1,j) -I _mean |, the point (i, j) is confirmed as a dead point; otherwise, it is confirmed |I _{(i, j)} -I _mean |<|I _(i+1,j) -I _mean |, the point (i+1,j) is confirmed as a dead point.

Specifically, in some embodiments of the present invention, in the case of non-fingerprint features such as unevenness of the image of the fingerprint image collected by the fingerprint device caused by unevenness of the cover glass or unevenness of the ink, etc., the terminal The gray value of each point in the user fingerprint image can be calibrated according to the image gray unevenness information of the test fingerprint image stored in advance.

Specifically, in some embodiments of the present invention, the image grayscale unevenness information of the test fingerprint image may be determined by the terminal according to the grayscale value of each point in the test fingerprint image, after determining the grayscale tilted surface of the test fingerprint image, a tilt angle of the gray scale inclined surface and a line intersecting the gray scale inclined surface with a standard horizontal plane;

Further, the terminal can calibrate the gray value of each point in the user fingerprint image according to the image gray unevenness information of the test fingerprint image stored in advance:

The terminal calibrates the gray value of the point in the user fingerprint image according to the gray tilt angle and the distance from the projection point of the point on the standard horizontal plane to the intersection line.

For example, taking the fingerprint device as the above-mentioned capacitive fingerprint sensor as an example, FIG. 12(a) is a schematic diagram showing the gray scale unevenness of the test fingerprint image collected by the fingerprint device in some embodiments of the present invention; FIG. 12(b) is FIG. A) Schematic diagram of the cut surface.

As shown in Figures 12(a) and 12(b), the z-axis represents the amount of signal sensed by the sensing element of the fingerprint device, x, y represents the position of the sensing element, and the origin is the point at which the signal amount is lowest;

It can be seen that due to the non-uniformity in the manufacturing process of the glass or ink, the capacitance reference values of the fingerprint device sensing different positions on the original array may be different, resulting in the test fingerprint image collected by the fingerprint device being at different pixel positions under the same trigger. The acquired gray value has a deviation, so that the gray scale of the fingerprint image generates a certain gray scale tilt, as shown in FIG. 12( a ), the gray scale tilt surface, according to which the gray scale tilt can be determined The angle of inclination of the face and the intersection of the gray slope and the standard horizontal plane.

Specifically, in some embodiments of the present invention, the terminal determines the intersection line between the determined gray scale inclined surface and the standard horizontal plane after determining the gray scale inclined surface of the test fingerprint image according to the gray value of each point in the test fingerprint image. Can be expressed as phase Intersection function: row*x+col*y=0;

Furthermore, for each point in the test fingerprint image, the terminal can pass the formula

Determine the distance from the projection point of the point projected to the standard horizontal plane to the above intersection line. Assuming z is used to represent the distance from the point to the horizontal plane on each inclined surface, then it can be seen that z=tan(θ)*d, ie

Thus, the tilt angle corresponding to each point in the test fingerprint image can be determined from z and d.

In some embodiments of the present invention, for each point in the user fingerprint image, the terminal determines the tilt angle (θ) corresponding to the point and the distance from the point to the intersection line (row*x+col*y=0). Then, the gray value of the point can be calibrated (for example, multiplication using the tan value of the tilt angle, etc.).

Further, in some embodiments of the present invention, after the terminal calibrates the user fingerprint image according to the non-fingerprint feature information of the test fingerprint image, the terminal may further process the user fingerprint image to change the original grayscale image into one. A clear binary dot plot to achieve accurate fingerprint extraction. Processing may include steps such as image segmentation, enhancement, filtering, binarization, and refinement, which will not be described in detail herein.

For example, based on the test fingerprint image acquired by the terminal in some embodiments of the present invention shown in FIG. 7, FIG. 13(a) is a schematic diagram showing the user fingerprint image acquired by the same terminal in some embodiments of the present invention. It can be seen that the user fingerprint image shown in FIG. 13(a) includes non-fingerprint features such as dead pixels and gray scale unevenness.

FIG. 13(b) is a schematic diagram showing a calibrated user fingerprint image obtained by the terminal after calibrating the user fingerprint image according to the non-fingerprint type feature information of the test fingerprint image stored in advance in some embodiments of the present invention.

It can be seen that there is no dead pixel in the calibrated user fingerprint image shown in Fig. 13(b), and the grayscale unevenness is adjusted, the image quality is enhanced, and the fingerprint characteristics of the user fingerprint, such as valley and The ridge is very obvious.

In summary, it can be seen that for the terminal for placing the fingerprint device under the cover glass of the display screen, the fingerprint collection scheme provided by the above embodiment of the present invention can be based on the non-fingerprint type of the pre-stored test fingerprint image. The feature information calibrates the user fingerprint image; and specifically, the terminal can use a surface-finished fingerprint test head to acquire the test fingerprint image. For example, the fingerprint test head of the plane can be used in the factory production line to make the terminal pre-acquire the test fingerprint image, and extract and store the non-fingerprint feature information of the test fingerprint image, and use the pre-stored when the user fingerprint image is acquired in the subsequent use of the terminal. The non-fingerprint feature information of the fingerprint image is tested to calibrate the user fingerprint image, so as to effectively reduce the adverse effects caused by the cover glass and the processing technology on the quality of the user's fingerprint image, thereby improving the quality of the user's fingerprint image and increasing the fingerprint. Identify the effect of success rate.

Based on the same inventive concept, the present application further provides a device for fingerprint collection, wherein the function module in the device can be implemented by hardware, software or a combination of hardware and software, and the device can be applied under the cover glass of the display screen. The terminal of the fingerprint device. For example, it can be applied to the mobile phone 300 shown in FIG.

FIG. 14 is a block diagram showing the structure of an apparatus for fingerprint collection provided in some embodiments of the present invention.

As shown in Figure 14, the device includes:

The obtaining module 1401 is configured to acquire a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a dead pixel and/or an image gray scale unevenness;

The calibration module 1402 is configured to calibrate the user fingerprint image according to the non-fingerprint type feature information of the pre-stored test fingerprint image;

The test fingerprint image is a fingerprint image obtained by the terminal in the fingerprint collection area of the terminal by using a flat-faced fingerprint test head in advance, where the fingerprint collection area is an area corresponding to the fingerprint device on the cover glass.

In some embodiments of the present invention, the non-fingerprint feature includes a dead pixel; the calibration module 1402 is specifically configured to: The dead point of the user fingerprint image is removed according to the dead point information of the test fingerprint image stored in advance.

In some embodiments of the present invention, the calibration module 1402 is specifically configured to:

In some embodiments of the present invention, the non-fingerprint type features include image gray scale inhomogeneity; the calibration module 1402 is configured to: calibrate the image according to image gray scale unevenness information of the test fingerprint image stored in advance The gray value of each point in the user's fingerprint image.

Specifically, the device for fingerprint collection provided by the foregoing embodiments of the present invention is similar to the principle for solving the problem by the method embodiment provided by the foregoing embodiments of the present invention. Therefore, the specific implementation of the device for fingerprint collection provided by the foregoing embodiments of the present invention is specifically implemented. The beneficial effects can be mutually understood with reference to the implementation and beneficial effects of the method provided by the foregoing embodiments of the present invention, and the repeated description is not repeated.

The division of the modules in the embodiment of the present application is schematic, and is only a logical function division. In actual implementation, there may be another division manner. In addition, each functional module in each embodiment of the present application may be integrated into one processing. In the device, it can also be physically existed alone, or two or more modules can be integrated into one module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules.

Based on the same inventive concept, the present application also provides a terminal. FIG. 15 is a schematic structural diagram of a terminal provided by some embodiments of the present invention.

As shown in FIG. 15, the terminal 1500 can include a processor 1501, a memory 1502, and a fingerprint device 1503. And the display screen not shown in FIG. 15 , wherein the display screen comprises a cover glass, the fingerprint device 1503 is placed under the cover glass, and the area corresponding to the fingerprint device 1503 on the cover glass is a fingerprint collection area;

The fingerprint device 1503 is configured to collect a fingerprint image, and the memory 1502 is configured to store a computer instruction.

The processor 1501 is configured to perform the method for fingerprint collection provided by the foregoing embodiments of the present invention by calling computer instructions stored in the memory 1502.

Specifically, the cover glass of the display screen of the terminal 1500 can be a complete plane on the user-facing side and a blind hole on the side facing the fingerprint device 1503 for placing the fingerprint device 1503; or The cover glass of the display screen of the terminal 1500 can also be a complete plane on the side facing the user side and the side facing the fingerprint device 1503, and the fingerprint device 1503 is placed under the cover glass.

Specifically, the processor 1501 may be a central processing module, or a digital processing module or the like. The memory 1502 may be a non-volatile memory such as a hard disk or a solid state hard disk or the like, or may be a volatile memory such as a random access memory. A memory is any other medium that can be used to carry or store desired program code in the form of an instruction or data structure and can be accessed by a computer, but is not limited thereto.

The foregoing embodiments of the present invention are similar to the principles of the method embodiments provided by the foregoing embodiments of the present invention. Therefore, the specific implementation and beneficial effects of the terminal provided by the foregoing embodiments of the present invention may be compared with the foregoing implementation of the present invention. The implementation of the method provided by the example and the beneficial effects are mutually related, and the present application will not be repeated here.

The specific connection medium between the processor 1501, the memory 1502, and the fingerprint device 1503 is not limited in the embodiment of the present application. The embodiment of the present application is exemplified in FIG. 15 by a bus connection between the processor 1501, the memory 1502, and the fingerprint device 1503. FIG. 15 is represented by a hollow double arrow line, but does not mean that there is only one bus or one type. The bus, the connection between other components, is only for illustrative purposes and is not limited. The bus can be divided into an address bus, a data bus, a control bus, and the like.

The embodiment of the present invention further provides a readable storage medium for storing software instructions required to execute the above-mentioned processor, which includes a program for executing the above-mentioned processor.

Those skilled in the art will appreciate that embodiments of the present application can be provided as a method, system, or computer program product. Thus, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment in combination of software and hardware. Moreover, the application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) including computer usable program code.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the present application. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing, such as a computer or other The instructions executed on the programmable device provide steps for implementing the functions specified in one or more blocks of the flowchart or in a flow or block of the flowchart.

It will be apparent to those skilled in the art that various modifications and changes can be made in the present application without departing from the scope of the application. Thus, it is intended that the present invention cover the modifications and variations of the present invention.

Claims

A fingerprint collection method is applied to a terminal for placing a fingerprint device under a cover glass of a display screen, and an area corresponding to the fingerprint device on the cover glass is a fingerprint collection area, wherein the method includes:

The terminal acquires a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a dead pixel and/or an image gray scale unevenness;

The terminal calibrates the user fingerprint image according to the non-fingerprint type feature information of the test fingerprint image stored in advance;

The test fingerprint image is a fingerprint image acquired by the terminal in the fingerprint collection area by using a surface-finished fingerprint test head in advance.
The method of claim 1, wherein the non-fingerprint feature includes a dead pixel; and the terminal calibrates the user fingerprint image according to the non-fingerprint feature information of the pre-stored test fingerprint image, including:

The terminal removes a dead pixel of the fingerprint image of the user according to the dead point information of the test fingerprint image stored in advance.
The method according to claim 2, wherein the terminal removes the dead pixels of the fingerprint image of the user according to the dead point information of the test fingerprint image stored in advance, including:

Determining, by the terminal, a dead point of the test fingerprint image according to a gray value of each point in the test fingerprint image, and determining a pixel position and a gray value of a dead point of the test fingerprint image;

Determining, by the terminal, a point located in the pixel location in the user fingerprint image as a dead point of the user fingerprint image;

The terminal subtracts the gray value of the dead point of the user fingerprint image from the gray value of the dead point located at the same pixel position in the test fingerprint image to obtain a calibrated user fingerprint image.
The method according to claim 3, wherein the terminal determines a dead point of the test fingerprint image according to a gray value of each point in the test fingerprint image, including:

The terminal calculates, for each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the first reference point, where the first reference point is a right adjacent point of the point ;

If the difference between the gray value of the point and the gray value of the first reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image at the point is greater than Determining the point as a dead point of the test fingerprint image when the first reference point is different from the average gray value of the test fingerprint image, otherwise determining the first reference point as the test A bad point in the fingerprint image.
The method according to claim 3 or 4, wherein the terminal determines a dead point of the test fingerprint image according to a gray value of each point in the test fingerprint image, including:

The terminal calculates, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the second reference point, where the second reference point is a lower adjacent point of the point ;

If the difference between the gray value of the point and the gray value of the second reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image at the point is greater than Determining the point as a dead point of the test fingerprint image when the second reference point is different from the average gray value of the test fingerprint image, otherwise determining the second reference point as the test A bad point in the fingerprint image.
The method according to any one of claims 1 to 5, wherein the non-fingerprint type features include image gray scale unevenness;

The terminal calibrates the user fingerprint image according to the non-fingerprint type feature information of the test fingerprint image stored in advance, including:

The terminal calibrates the gray value of each point in the user fingerprint image according to the image gray unevenness information of the test fingerprint image stored in advance.
The method according to claim 6, wherein the terminal calibrates the gray value of each point in the user fingerprint image according to image gray unevenness information of the test fingerprint image stored in advance, including:

Determining, according to a gray value of each point in the test fingerprint image, a grayscale inclined surface of the test fingerprint image, and determining a tilt angle of the grayscale inclined surface and the grayscale inclined surface and a standard horizontal plane Intersection line;

The terminal calibrates the gray value of the point to each point in the user fingerprint image according to the gray tilt angle and the distance from the projection point of the point on the standard horizontal plane to the intersection line .
A device for fingerprint collection is applied to a terminal for placing a fingerprint device under a cover glass of a display screen, and an area corresponding to the fingerprint device on the cover glass is a fingerprint collection area, wherein the device comprises:

An acquiring module, configured to acquire a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a dead pixel and/or an image gray scale unevenness;

a calibration module, configured to calibrate the user fingerprint image according to non-fingerprint type feature information of the pre-stored test fingerprint image;

The test fingerprint image is a fingerprint image acquired by the terminal in the fingerprint collection area by using a surface-finished fingerprint test head in advance.
The device according to claim 8, wherein said non-fingerprint type features include dead pixels;

The calibration module is specifically configured to:

The dead point of the user fingerprint image is removed according to the dead point information of the test fingerprint image stored in advance.
The device according to claim 9, wherein the calibration module is specifically configured to:

Determining a dead point of the test fingerprint image according to a gray value of each point in the test fingerprint image, and determining a pixel position and a gray value of a dead point of the test fingerprint image;

Determining, in the user fingerprint image, a point located at the pixel position as a dead point of the user fingerprint image;

The gradation value of the dead point of the user fingerprint image is subtracted from the gradation value of the bad point located at the same pixel position in the test fingerprint image to obtain a calibrated user fingerprint image.
The device according to claim 10, wherein the calibration module is specifically configured to:

Calculating, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the first reference point, the first reference point being a right adjacent point of the point;

If the difference between the gray value of the point and the gray value of the first reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image is greater than the first Determining a point as a dead point of the test fingerprint image when a reference point is different from an average gray value of the test fingerprint image, otherwise determining the first reference point as the test fingerprint image A bad point.
The device according to claim 10 or 11, wherein the calibration module is specifically configured to:

Calculating, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the second reference point, wherein the second reference point is a lower adjacent point of the point;

If the difference between the gray value of the point and the gray value of the second reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image is greater than the first Determining the point as a dead point of the test fingerprint image when the difference between the second reference point and the average gray value of the test fingerprint image, otherwise determining the second reference point A dead pixel for the test fingerprint image.
The apparatus according to any one of claims 8 to 12, wherein the non-fingerprint type feature includes image gray scale unevenness; and the calibration module is specifically configured to:

The gray value of each point in the user fingerprint image is calibrated according to the image gradation unevenness information of the test fingerprint image stored in advance.
The device according to claim 13, wherein the calibration module is specifically configured to:

Determining, according to a gray value of each point in the test fingerprint image, a grayscale inclined surface of the test fingerprint image, and determining a tilt angle of the grayscale inclined surface and a intersection line between the grayscale inclined surface and a standard horizontal plane ;

For each point in the user fingerprint image, the gray value of the point is calibrated according to the grayscale tilt angle and the distance from the projected point of the point on the standard horizontal plane to the intersecting line.
A terminal, comprising: a processor, a memory, a fingerprint device, and a display screen, wherein the display screen comprises a cover glass, the fingerprint device is placed under the cover glass, the cover The area corresponding to the fingerprint device on the panel glass is a fingerprint collection area; wherein:

The fingerprint device is configured to collect a fingerprint image;

The memory is configured to store computer instructions;

The processor is configured to execute by calling a computer instruction stored in the memory:

Obtaining a user fingerprint image collected by the fingerprint device, where the user fingerprint image includes a non-fingerprint feature, and the non-fingerprint feature includes a dead pixel and/or an image gray scale unevenness;

Calibrating the user fingerprint image according to non-fingerprint type feature information of the test fingerprint image stored in advance;

The test fingerprint image is a fingerprint image acquired by the terminal in the fingerprint collection area by using a surface-finished fingerprint test head in advance.
The terminal according to claim 15, wherein the non-fingerprint type feature includes a dead point;

The processor is specifically configured to:

The dead point of the user fingerprint image is removed according to the dead point information of the test fingerprint image stored in advance.
The terminal according to claim 16, wherein the processor is specifically configured to:

Determining a dead point of the test fingerprint image according to a gray value of each point in the test fingerprint image, and determining a pixel position and a gray value of a dead point of the test fingerprint image;

Determining, in the user fingerprint image, a point located at the pixel position as a dead point of the user fingerprint image;

The gradation value of the dead point of the user fingerprint image is subtracted from the gradation value of the bad point located at the same pixel position in the test fingerprint image to obtain a calibrated user fingerprint image.
The terminal according to claim 17, wherein the processor is specifically configured to:

Calculating, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the first reference point, the first reference point being a right adjacent point of the point;

If the difference between the gray value of the point and the gray value of the first reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image is greater than the first Determining a point as a dead point of the test fingerprint image when a reference point is different from an average gray value of the test fingerprint image, otherwise determining the first reference point as the test fingerprint image A bad point.
The terminal according to claim 17 or 18, wherein the processor is specifically configured to:

Calculating, between each point in the test fingerprint image, a difference between a gray value of the point and a gray value of the second reference point, wherein the second reference point is a lower adjacent point of the point;

If the difference between the gray value of the point and the gray value of the second reference point is greater than a preset threshold, the difference between the point and the average gray value of the test fingerprint image is greater than the first Determining the point as a dead point of the test fingerprint image when the difference between the second reference point and the average gray value of the test fingerprint image, otherwise determining the second reference point as the test fingerprint image A bad point.
The terminal according to any one of claims 15 to 19, wherein the non-fingerprint type feature includes image gray scale unevenness;

The processor is specifically configured to:

The gray value of each point in the user fingerprint image is calibrated according to the image gradation unevenness information of the test fingerprint image stored in advance.
The terminal according to claim 20, wherein the processor is specifically configured to:

Determining, according to a gray value of each point in the test fingerprint image, a grayscale inclined surface of the test fingerprint image, and determining a tilt angle of the grayscale inclined surface and a intersection line between the grayscale inclined surface and a standard horizontal plane ;

For each point in the user fingerprint image, the gray value of the point is calibrated according to the grayscale tilt angle and the distance from the projected point of the point on the standard horizontal plane to the intersecting line.
A computer readable storage medium, comprising instructions that, when run on a computer, cause the computer to perform the method of any one of claims 1 to 7.