Biometric feature collection method, chip and computer readable storage medium

Abstract

The embodiment of the present invention relates to the field of biometric detection technology, and discloses a biometric acquisition method, chip, terminal and computer-readable storage medium. The above-mentioned biometric acquisition method includes: obtaining configuration parameters; wherein the configuration parameters include: a first exposure time, a first area and a target light sensitivity value, the first area being a local area in the light sensitivity area of ​​the biometric acquisition chip; exposing the first area according to the first exposure time, and obtaining the light sensitivity value of the first area; determining the second exposure time required to acquire the target light sensitivity value in the light sensitivity area according to the light sensitivity value of the first area and the first exposure time; acquiring a biometric image according to the second exposure time, so that the accuracy of the acquired biometric image can be improved, and the accuracy of subsequent biometric identification or registration can be increased.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of biometric detection technology, and in particular to a biometric collection method, a chip, and a computer-readable storage medium. Background Art

[0002] Biometrics has become an emerging interactive technology in the interactive unlocking solution of terminals, among which optical fingerprint recognition technology has become a very convenient and fast fingerprint recognition solution. Optical fingerprint recognition technology adopts a hidden fingerprint design under the screen, and the fingerprint icon area displayed on the screen can be directly pressed to unlock the device. More and more mobile phone projects of whole machine manufacturers support optical fingerprint recognition function, and screens produced by different manufacturers are also introduced. The screens produced by different manufacturers are quite different.

[0003] At present, during the calibration stage of the whole machine, a default exposure time is set for the biometric acquisition chip in the whole machine. When the whole machine is shipped out of the factory, the biometric image is acquired based on the default exposure time. Due to changes in the external environment, the adaptability of the biometric acquisition chip to changes in the external environment is easily reduced, affecting the accuracy of the acquired biometric image and reducing the accuracy of subsequent biometric identification or registration. Taking the under-screen fingerprint acquisition chip in the mobile phone as an example, the fluctuation of the fingerprint light spot can easily cause the under-screen fingerprint acquisition chip to have a poor adaptability to the fingerprint light spot, affecting the accuracy of the acquired fingerprint image and reducing the accuracy of subsequent fingerprint identification or registration. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a biometric collection method, a chip and a computer-readable storage medium, so as to improve the accuracy of the collected biometric images and increase the accuracy of subsequent biometric identification or registration.

[0005] To solve the above technical problems, an embodiment of the present invention provides a biometric acquisition method, which is applied to a biometric acquisition chip, including: obtaining configuration parameters; wherein the configuration parameters include: a first exposure time, a first area and a target sensitivity value, the first area being a local area in the photosensitive area of ​​the biometric acquisition chip; exposing the first area according to the first exposure time, and obtaining the sensitivity value of the first area; determining the second exposure time required to collect the target sensitivity value in the photosensitive area according to the sensitivity value of the first area and the first exposure time; and collecting a biometric image according to the second exposure time.

[0006] An embodiment of the present invention also provides a biometric feature collection chip, comprising: a processing unit and a storage unit connected to the processing unit, the storage unit storing instructions that can be executed by the processing unit, and the instructions are executed by the processing unit so that the processing unit can perform the above-mentioned biometric feature collection method.

[0007] An embodiment of the present invention further provides a terminal, comprising the above-mentioned biometric feature collection chip.

[0008] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program, wherein the computer program implements the above-mentioned biometric feature collection method when executed by a processor.

[0009] In the embodiment of the present invention, when collecting biometric image, firstly, according to the first exposure time in the configuration parameters, a local area (i.e., the first area) in the photosensitive area of ​​the biometric collection chip is partially exposed to obtain the photosensitive value of the first area. Considering that there is a preset relationship between the photosensitive value and the exposure time, the second exposure time required to collect the target photosensitive value in the photosensitive area can be reasonably and accurately determined according to the photosensitive value of the first area and the first exposure time. In other words, when collecting biometric images, it is not based on the default exposure time at the time of leaving the factory, but based on the second exposure time obtained in the current environment, so that the collected biometric images are more accurate. Even if the external environment changes, that is, the current environment is changed compared with the environment where the biometric collection chip is located when the default exposure time is determined, since the second exposure time is equivalent to being determined in the current environment, the second exposure time can adapt to the changes in the external environment, thereby making the adaptability of the biometric collection chip to the external environment better, reducing the impact of the changes in the external environment on the collection performance, and is conducive to improving the accuracy of subsequent biometric identification or registration. Furthermore, since the first area is a local area in the photosensitive area, the speed of local exposure is faster, which can speed up the acquisition of biometric images to a certain extent, thereby speeding up the subsequent biometric identification or registration. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0011] Figure 1 is a schematic diagram of the fingerprint spot mentioned in the embodiment of the present application;

[0012] Figure 2is a flow chart of a biometric feature collection method mentioned in an embodiment of the present application;

[0013] Figure 3 is a schematic diagram of the relationship between the first area and the photosensitive area mentioned in the embodiment of the present application;

[0014] Figure 4 is a schematic diagram of marking information of each pixel in the first area mentioned in an embodiment of the present application;

[0015] Figure 5 is a schematic diagram of a bad block area in the first area mentioned in an embodiment of the present application;

[0016] Figure 6 is a schematic diagram of the linear relationship between the photosensitivity and the exposure time mentioned in the embodiments of the present application;

[0017] Figure 7 is a flow chart of another biometric feature collection method mentioned in the embodiments of the present application;

[0018] Figure 8 is a flowchart of an implementation method of step 706 mentioned in the embodiment of the present application;

[0019] Fig. 9 is a schematic diagram of the distribution of the first area and the second area in the photosensitive area mentioned in the embodiment of the present application;

[0020] Fig.10 is a flowchart of an implementation method of step 802 mentioned in the embodiment of the present application;

[0021] Fig.11 is a schematic diagram of a horizontal stripe image mentioned in an embodiment of the present application;

[0022] Fig.12 It is a flowchart of an implementation method of collecting a biometric feature image according to a second exposure duration mentioned in an embodiment of the present application;

[0023] Fig.13 It is a flow chart of the biometric feature collection method applied to the under-screen fingerprint collection chip mentioned in the embodiment of the present application;

[0024] Fig.14 It is a schematic diagram of the structure of the biometric feature acquisition chip mentioned in the embodiments of this application. DETAILED DESCRIPTION

[0025] To make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented. The division of the following embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other without contradiction.

[0026] With the rapid development of the terminal industry, biometric acquisition technology has received more and more attention. The under-screen biometric acquisition technology is to set the biometric acquisition chip under the screen, and collect images of external objects through the biometric acquisition chip to realize subsequent biometric identification or biometric registration. Among them, biometric identification can include: fingerprint recognition, palm print recognition, iris recognition, face recognition, etc. At present, organic light-emitting diode (OLED) screens and liquid crystal display (LCD) screens are self-luminous display screens and non-self-luminous display screens that are widely used in mobile phones, tablets and other terminals. Among them, the OLED screen is a current-type organic light-emitting device, which can control each display unit (also called pixel) to emit light independently through the display driver module.

[0027] Take fingerprint collection as an example, that is, the biometric collection chip is a fingerprint collection chip. Terminals using OLED screens can realize under-screen optical fingerprint collection. The fingerprint collection chip is set under the OLED screen, so the fingerprint collection chip can also be called an under-screen fingerprint collection chip. The pixels in the OLED screen can be used as fingerprint excitation light sources for screen lighting. The pixels located in the fingerprint detection area (also known as the photosensitive area) of the OLED screen are driven to emit light, thereby displaying a fingerprint spot in the fingerprint detection area. The light emitted is used as the excitation light for fingerprint identification and irradiates the finger above the OLED screen. After scattering, reflection or transmission by the finger, a fingerprint detection light carrying the fingerprint information of the finger is formed. The fingerprint detection light returns to the OLED screen and is transmitted through the OLED screen to the fingerprint collection chip below. The fingerprint collection chip can receive the fingerprint detection light and convert the fingerprint detection light into a corresponding electrical signal, thereby realizing fingerprint image collection. The schematic diagram of the above fingerprint spot can be seen in Figure 1When the user needs to unlock the terminal 101 or perform other fingerprint verification, the user only needs to press the finger on the area where the fingerprint spot 102 is located to realize fingerprint collection, and then the fingerprint matching verification can be further performed based on the collected fingerprint image to complete fingerprint recognition.

[0028] In the related art, during the mass production stage of the whole machine, the terminal with an under-screen fingerprint collection chip will set the default exposure time at the factory based on the result of the whole machine calibration, and the default exposure time will be stored in the terminal. After the terminal leaves the factory, when the user uses the terminal for fingerprint registration or fingerprint recognition, the fingerprint image will be collected based on the default exposure time stored in the terminal.

[0029] The inventor of this application has found that if the fingerprint spot fluctuates during the user's use of the terminal, it is easy to cause a low accuracy rate of fingerprint recognition. Among them, the fluctuation of the fingerprint spot may include: fluctuation of the brightness of the fingerprint spot, fluctuation of the color temperature, etc. The situation where the fingerprint spot fluctuates may include: due to the abnormality of the fingerprint spot during the calibration stage of the whole machine, the default exposure time set at the factory is inaccurate; during the user's use, the terminal is in an environment such as switching wallpapers, screen aging, software updates, etc. The inventor found through research that the reason why the fingerprint spot fluctuates and the fingerprint recognition accuracy is low is that after the terminal leaves the factory and is used by the user, the under-screen fingerprint acquisition chip still collects fingerprint images based on the default exposure time set at the factory, and will not adjust the default exposure time during use, resulting in the poor adaptability of the under-screen fingerprint acquisition chip to the fingerprint spot, resulting in a low accuracy rate of fingerprint recognition.

[0030] In order to solve the problem that the above-mentioned biometric acquisition chip (such as the fingerprint acquisition chip under the screen) has poor adaptability to changes in the external environment (such as fingerprint spot fluctuations), which affects the accuracy of the collected biometric image (such as fingerprint image), the embodiment of the present application provides a biometric acquisition method, which is applied to the biometric acquisition chip, including: obtaining configuration parameters; wherein the configuration parameters include: a first exposure time, a first area and a target light sensitivity value, the first area is a local area in the light sensitivity area of ​​the biometric acquisition chip; exposing the first area according to the first exposure time, and obtaining the light sensitivity value of the first area; determining the second exposure time required to collect the target light sensitivity value in the light sensitivity area according to the light sensitivity value of the first area and the first exposure time; and collecting the biometric image according to the second exposure time. The application scenarios of this embodiment may include: scenarios where biometric image acquisition is required, such as biometric identification, biometric registration, etc. Biometric identification and biometric registration may be fingerprint identification, fingerprint registration, face recognition, face registration, etc. When the biometric acquisition chip determines that biometric image acquisition is required, the process of biometric acquisition in this embodiment may be triggered, that is, the configuration parameters are started.

[0031] In the embodiment of the present application, when the biometric feature acquisition chip is performing biometric feature image acquisition, it first performs local exposure on a local area (i.e., the first area) in the photosensitive area of ​​the biometric feature acquisition chip according to the first exposure time in the configuration parameters to obtain the photosensitive value of the first area. Considering that there is a preset relationship between the photosensitive value and the exposure time, the second exposure time required to acquire the target photosensitive value in the photosensitive area can be reasonably and accurately determined according to the photosensitive value of the first area and the first exposure time. In other words, when acquiring the biometric feature image, it is not based on the default exposure time at the time of leaving the factory, but based on the second exposure time obtained in the current environment to acquire the biometric feature image, so that the acquired biometric feature image is more accurate. Even if the external environment changes, that is, the current environment has changed compared to the environment in which the biometric feature acquisition chip is located when the default exposure time is determined, since the second exposure time is equivalent to being determined in the current environment, the second exposure time can adapt to the changes in the external environment, thereby making the adaptability of the biometric feature acquisition chip to the external environment better, reducing the impact of the changes in the external environment on the acquisition performance, and is conducive to improving the accuracy of subsequent biometric feature recognition or registration. Furthermore, since the first area is a local area in the photosensitive area, the speed of local exposure is faster, which can speed up the acquisition of biometric images to a certain extent, thereby speeding up the subsequent biometric identification or registration.

[0032] In one embodiment, the biometric feature acquisition chip is an under-screen fingerprint acquisition chip, and the biometric feature image collected by the under-screen fingerprint acquisition chip can be used for fingerprint recognition or fingerprint registration. For a terminal including an under-screen fingerprint acquisition chip, even if the fingerprint spot fluctuates on the terminal screen during the actual use of the terminal by the user, since the second exposure time is determined under the condition of fingerprint spot fluctuation, the second exposure time can adapt to the fingerprint spot fluctuation, thereby making the under-screen fingerprint acquisition chip more adaptable to the fingerprint spot, reducing the impact of fingerprint spot fluctuation on fingerprint recognition performance, and helping to improve fingerprint recognition accuracy. In a specific implementation, the biometric feature acquisition chip can also be an iris feature acquisition chip, a palm print feature acquisition chip, a face feature acquisition chip, etc.

[0033] In one embodiment, the flowchart of the biometric feature collection method can be referred to Figure 2 ,include:

[0034] Step 201: Obtain configuration parameters.

[0035] Step 202: Expose the first area according to a first exposure duration, and obtain a photosensitivity value of the first area.

[0036] Step 203: Determine a second exposure time required to collect a target light sensitivity value in the light sensitivity area according to the light sensitivity value of the first area and the first exposure time.

[0037] Step 204: Capture a biometric image according to the second exposure duration.

[0038] The configuration parameters in step 201 include: a first exposure time, a first area and a target light sensitivity value, wherein the first area is a local area in the light sensitive area of ​​the biometric feature acquisition chip. The configuration parameters can be pre-set by those skilled in the art according to actual needs.

[0039] In one embodiment, the acquisition of configuration parameters in step 201 includes: acquiring configuration parameters after detecting a preset trigger condition; wherein the preset trigger condition includes: the need to perform biometric registration and / or the need to perform biometric identification. That is, the biometric acquisition chip acquires configuration parameters after determining that biometric registration and / or biometric identification are required. The way in which the biometric acquisition chip determines that biometric registration is required may be: the biometric acquisition chip receives notification information that the user needs to perform biometric registration, and the notification information may be sent by a processor in the terminal, wherein the processor may be a central processing unit (CPU), a microprocessor, a coprocessor, etc. in the terminal. The terminal may be a mobile phone, a tablet computer, or other device. The way in which the biometric acquisition chip determines that biometric identification is required may be: the biometric acquisition chip determines that the terminal needs to be unlocked based on biometric identification, needs to make a payment based on biometric identification, etc. Optionally, the preset trigger condition may also include: the biometric acquisition chip detects that it is activated, and then the biometric acquisition chip acquires configuration parameters when it detects that it is activated.

[0040] In one embodiment, the acquisition of configuration parameters in step 201 includes: when a preset trigger condition is detected, acquiring the internally stored configuration parameters. After the configuration parameters are preset, they can be pre-stored in the biometric acquisition chip, for example, the preset configuration parameters can be written into the register of the biometric acquisition chip. In other words, the biometric acquisition chip can acquire the configuration parameters by itself, which is conducive to quickly acquiring the configuration parameters.

[0041] In one embodiment, the configuration parameters obtained in step 201 include: receiving the configuration parameters sent by the application software in the terminal. The configuration parameters are sent by the application software, and the biometric acquisition chip does not need to store these configuration parameters, which is conducive to saving costs and storage space. Moreover, it is convenient to modify the configuration parameters through the application software according to actual needs, and the convenience of modifying the configuration parameters is improved. Optionally, the configuration parameters sent by the application software (hereinafter also referred to as the software end) in the receiving terminal can be: when a preset trigger condition is detected, the configuration parameters sent by the receiving software end. For example, the software end can send the configuration parameters to the biometric acquisition chip after detecting the preset trigger condition, and the preset trigger condition has been described above. It will not be repeated here. In a specific implementation, the biometric acquisition chip can be in a dormant state when there is no need to collect data. When biometric collection is required, the biometric acquisition chip is awakened and the software end starts to send configuration parameters.

[0042] In one embodiment, after receiving the configuration parameters sent by the software end, the biometric acquisition chip can store the configuration parameters in a register. When the preset trigger condition is detected again in the future, the biometric acquisition chip can directly obtain the configuration parameters from the register in the biometric acquisition chip without the need to be sent by the software end each time, which is conducive to improving the convenience of obtaining the configuration parameters.

[0043] In one embodiment, the biometric feature acquisition chip is an under-screen fingerprint acquisition chip, and the need for biometric registration and / or biometric identification includes: detecting that the area where the fingerprint spot on the screen is located is pressed, and the preset duration is greater than or equal to the minimum duration required for the fingerprint spot to start to light up and stabilize. The acquisition of configuration parameters in step 201 includes: after detecting that the area where the fingerprint spot on the screen is located is pressed, the configuration parameters are acquired again at intervals of a preset duration. The minimum duration required for the fingerprint spot to start to light up and stabilize can be obtained by a person skilled in the art according to actual needs through testing, for example, it can be set to 40ms to 50ms, but this embodiment does not specifically limit this. When it is detected that the area where the fingerprint spot on the screen is located is pressed, it can be understood that the under-screen fingerprint acquisition chip determines that fingerprint identification or fingerprint registration is currently required. By obtaining the configuration parameters after a preset interval, it is helpful to ensure that the fingerprint acquisition chip under the screen obtains the configuration parameters after the fingerprint spot displayed on the screen is stable, and then calculates the subsequent second exposure time based on the configuration parameters, so that the second exposure time is obtained after the fingerprint spot is stable, which improves the accuracy of the obtained second exposure time, thereby improving the accuracy of the collected fingerprint image, so as to improve the accuracy of subsequent fingerprint recognition or fingerprint registration.

[0044] In one embodiment, after detecting that the area where the fingerprint spot is located is pressed, the fingerprint acquisition chip under the screen can send the information of the detection of being pressed to the software end. The software end starts timing when receiving the information of being pressed. After the timing reaches a preset time, the configuration parameters are sent to the fingerprint acquisition chip under the screen, so that the fingerprint acquisition chip under the screen can obtain the configuration parameters at intervals of a preset time after detecting that the area where the fingerprint spot on the screen is located is pressed. The configuration parameters are sent by the software end, and the fingerprint acquisition chip under the screen does not need to store these configuration parameters, which is conducive to saving costs and storage space. Moreover, after the preset time interval, the software end sends the configuration parameters to the fingerprint acquisition chip under the screen, so that the second exposure time is obtained after the fingerprint spot is stable, which improves the accuracy of the second exposure time, thereby improving the accuracy of the collected fingerprint image, so as to improve the accuracy of subsequent fingerprint recognition or fingerprint registration.

[0045] In one embodiment, the fingerprint acquisition chip under the screen can start timing when it detects that the area where the fingerprint spot is located is pressed. After the timing reaches a preset time, the configuration parameters pre-stored in the register are obtained from the register of the fingerprint acquisition chip under the screen, so that the fingerprint acquisition chip under the screen can obtain the configuration parameters at intervals of a preset time after detecting that the area where the fingerprint spot on the screen is located is pressed. The fingerprint acquisition chip under the screen can obtain the configuration parameters by itself without interacting with the software end, which is conducive to quickly obtaining the configuration parameters. Moreover, after the preset time interval, the fingerprint acquisition chip under the screen obtains the configuration parameters again, so that the second exposure time is obtained after the fingerprint spot is stable, which improves the accuracy of the second exposure time, thereby improving the accuracy of the collected fingerprint image, so as to improve the accuracy of subsequent fingerprint recognition or fingerprint registration.

[0046] In one embodiment, the first exposure duration (referred to as T1) can be determined based on the linearity of the biometric acquisition chip. The smaller the linearity, the smaller the first exposure duration. Linearity is an important indicator for describing a biometric acquisition chip. The smaller the linearity, the better the linearity, that is, the more accurate the linearity. The better the linearity, the shorter T1 can be set. The worse the linearity, the longer T1 can be set. The inventors have found through research that the linearity of the biometric acquisition chip will affect the accuracy of the light intensity estimated based on the collected photosensitivity value within the same exposure duration, and the accuracy of the estimated light intensity will further affect the accuracy of the collected biometric image. Therefore, in this embodiment, the first exposure duration is determined based on the linearity of the biometric acquisition chip, and the smaller the linearity, the smaller the first exposure duration is, which is conducive to improving the accuracy of the collected biometric image to a certain extent, thereby improving the accuracy of subsequent biometric identification or registration.

[0047] In one embodiment, the first exposure time can also be determined according to the linearity of the biometric acquisition chip and the standard time preset for completing fingerprint recognition. Among them, the standard time required to complete biometric recognition can also be called: Key Performance Indicator time (KPI time). KPI time can be set by those skilled in the art according to actual needs. For example, when the recognition speed requirement is high, the KPI time can be set shorter, and when the recognition speed requirement is low, the KPI time can be set longer. The setting of KPI time can meet the requirements of recognition speed in different recognition scenarios. The larger the KPI time, the longer T1 can be set, and the smaller the KPI time, the shorter T1 can be set. Finally, the size of T1 can be determined by comprehensively considering KPI time and linear characteristics, and T1 is greater than 0 milliseconds. The inventor found through research that the length of the first exposure time T1 will affect KPI time, and the larger T1 is, the greater the impact on recognition speed. Therefore, the first exposure time determined according to KPI time and the linearity of the biometric acquisition chip in this embodiment is conducive to balancing recognition speed and recognition accuracy, and can complete biometric recognition within the standard time while ensuring recognition accuracy to a certain extent.

[0048] In one embodiment, the first exposure time is greater than 0 milliseconds and less than or equal to 10 milliseconds. That is, the value range of the first exposure time T1 is between 0 and 10 milliseconds. A smaller value of T1 is conducive to shortening the time to complete biometric feature collection, thereby shortening the time for subsequent biometric feature identification or registration. In a specific implementation, within a certain range (such as between 0 and 10 milliseconds), the larger the value of T1, the more accurate the determined T2, and thus the more accurate the collected biometric feature image.

[0049] In one embodiment, the first exposure time T1 is determined according to the KPI time and the linearity of the biometric acquisition chip, and 0ms<T1≤10ms. That is, T1 is selected between 0ms and 10ms according to the KPI time and the linearity of the biometric acquisition chip, which is conducive to speeding up the acquisition speed as much as possible while ensuring that the accuracy of the acquisition is not affected.

[0050] In one embodiment, the biometric feature acquisition chip is arranged below the screen, and the area of ​​the first area is determined according to the structure of the screen, which is a soft screen or a hard screen. The area of ​​the first area determined based on the soft screen is greater than the area of ​​the first area determined based on the hard screen. In other words, the first area of ​​the soft screen is larger than that of the hard screen. Due to the collapse of the center of the soft screen, the area of ​​the first area taken is larger than that of the hard screen. The collapse of the center of the soft screen makes the photosensitivity value collected by the pixels located at the center of the soft screen smaller. Therefore, a larger first area is taken, so that the photosensitivity value collected by the pixels in the larger first area can be combined to obtain the photosensitivity value of the first area, which is conducive to adapting to the requirements of different screen types for the size of the first area and improving the accuracy of the photosensitivity value collected after local exposure.

[0051] In one embodiment, reference may be made to Figure 3 , the center of the first area 301 is the focusing center 303 of the photosensitive area 302. The focusing center 303 can be understood as the projection point of the center of the lens assembled with the biometric acquisition chip in the photosensitive area 302. It can be understood that during the assembly of the biometric acquisition chip and the lens, there may be assembly tolerances, so that the center of the lens and the center of the photosensitive area in the biometric acquisition chip are not completely coincident in the vertical direction. Therefore, the first area 301 is an area centered on the focusing center of the photosensitive area, and the photosensitive values ​​collected by each pixel in the first area centered on the focusing center are relatively concentrated and have small differences, which is conducive to improving the accuracy of the photosensitive values ​​obtained in the first area. However, in a specific implementation, the center of the first area can also be directly the center of the photosensitive area.

[0052] In one embodiment, the area of ​​the first area determined based on the soft screen is larger than the area of ​​the first area determined based on the hard screen, and the centers of the first areas in the soft screen and the hard screen are both the focusing centers of the photosensitive areas, which is beneficial for further improving the accuracy of the acquired photosensitivity value of the first area while adapting to the requirements of different screen types for the size of the first area.

[0053] In a specific implementation, it is considered that the larger the first area is, the more accurate the light intensity detection is. However, when the first area is larger to a certain extent, the accuracy of the light intensity detection will not increase any more. At the same time, the larger the first area is, the longer it takes to collect the biometric image. Therefore, the size of the first area can be determined by simulation. For example, the size of the first area can be gradually increased during the simulation process, and the accuracy of the light intensity detection and the time required to collect the biometric image after each increase in the first area are determined. According to the accuracy of the light intensity detection and the time required to collect the biometric image, a compromise value is taken for the first area, so that the determined first area can ensure that the time to collect the biometric image is not too long, and will not have too much impact on the accuracy of the light intensity detection.

[0054] In one embodiment, the number of pixels in the first area is an integer multiple of the number of pixels that need to be read out in a one-pixel mode, which is determined based on the image readout mode binning of the biometric acquisition chip. For example, the image readout mode binning of the biometric acquisition chip is 2*2, that is, the number of pixels that need to be read out in a one-pixel mode is 4, and the number of pixels in the first area is an integer multiple of 4. For example, the image readout mode binning of the biometric acquisition chip is 4*4, that is, the number of pixels that need to be read out in a one-pixel mode is 16, and the number of pixels in the first area is an integer multiple of 16. The selection of the first area takes into account the image readout mode binning of the biometric acquisition chip itself, facilitates the subsequent processing of pixels in the first area based on binning, is conducive to adapting to the image readout mode of the biometric acquisition chip itself, and improves the speed of image readout, that is, improves the speed of acquiring biometric images.

[0055] In one embodiment, the first area is a rectangular area, such as Figure 3 The first area can be represented by the coordinates (x0, y0) (x1, y1) of the two points A and B in the figure. It can be understood that a pixel array including a number of pixels is distributed in the photosensitive area 302, pixel A is in the x0th row and y0th column of the pixel array, and pixel B is in the x1th row and y1th column of the pixel array. If the configuration parameter of the first area is sent by the software end, the software end can directly send the coordinates of the boundary points of the first area, such as Figure 3 The coordinates of the two points A and B in the image can reduce the amount of data sent and increase the sending speed. If the configuration parameter of the first area is pre-stored in the biometric collection chip, the coordinates of the boundary points of the first area can be stored in the biometric collection chip, which can reduce the amount of stored data and save storage space.

[0056] In one embodiment, the first area can also be represented by the marking information of the pixels in the entire photosensitive area, for example: all pixels in the first area 301 are marked as "X", and the pixels in the photosensitive area 302 except the pixels in the first area 301 are marked as "Y", and the pixels in the entire photosensitive area can be represented as an array composed of "X" and "Y", and the area formed by "X" in the array is the first area 301. If the configuration parameter of the first area is sent by the software end, the software end can directly send the above-mentioned array composed of "X" and "Y", which is convenient for the biometric feature acquisition chip to clearly distinguish the first area in the photosensitive area directly according to the received array composed of "X" and "Y". If the configuration parameter of the first area is pre-stored in the biometric feature acquisition chip, the above-mentioned array composed of "X" and "Y" can be stored in the biometric feature acquisition chip, which is convenient for the biometric feature acquisition chip to clearly distinguish the first area in the photosensitive area directly according to the stored array composed of "X" and "Y".

[0057] In one embodiment, the biometric acquisition chip is arranged below the screen, and the target photosensitivity value is determined based on the gain value corresponding to the structure of the screen. The structure of the screen is a soft screen or a hard screen, and the gain value corresponding to the soft screen is greater than the gain value corresponding to the hard screen. The target photosensitivity value is recorded as Target, and the gain value is recorded as Gain. Gain can represent the amplification factor of the signal. Gain and Target have a preset corresponding relationship, and the corresponding relationship can be set by those skilled in the art according to actual needs. In a specific implementation, the gain value Gain of the screen can be stored in a register of the biometric acquisition chip. In this embodiment, considering that the transmittance of the soft screen is generally lower than that of the hard screen, therefore, setting the gain value corresponding to the soft screen to be greater than the gain value corresponding to the hard screen is conducive to ensuring that the soft screen and the hard screen can have the same target photosensitivity value, facilitating the processing of the biometric acquisition chip, so that the biometric acquisition chip can maintain a set of algorithms while being compatible with the soft screen and the hard screen, which is conducive to improving the compatibility and applicability of the biometric acquisition chip.

[0058] In step 202, the light sensitivity value of the first area can be understood as the light sensitivity value collected by the pixels located in the first area. Specifically, the light sensitivity value of the first area can be: obtaining the light sensitivity value collected by the pixels in the first area that meet the preset conditions. The preset conditions can be set according to actual needs. Several forms of preset conditions are described below:

[0059] Optionally, the preset condition may be any one of the following: one or more random pixels in the first area, pixels located at the center of the first area, and all pixels in the first area.

[0060] Optionally, the preset condition may be: pixels in the first area that are not bad pixels. The above bad pixels may include two categories: one is bad pixels formed due to process limitations; the other is pixels with a color filter (CF) set on the top (referred to as CF points). Both of these bad pixels can be tested out during the whole machine test phase before leaving the factory and stored in the whole machine, which may be a mobile phone, tablet computer or other terminal. Considering that pixels with CF may actually only receive red light, or only receive green light, or only receive blue light, compared to other pixels without CF, pixels with CF only receive light of a certain band, and pixels with CF have different photosensitivity compared to other surrounding pixels without CF, which may cause some interference in the final collected biometric image. Therefore, in this embodiment, pixels with CF are also regarded as pixels that are bad pixels.

[0061] In the case of the preset condition that the pixels in the first area are not bad pixels, the configuration parameters, in addition to the above-mentioned first exposure time, first area and target photosensitivity, also include: reference information for determining the first type of pixels in the first area that are bad pixels, then the acquisition of the photosensitivity value of the first area mentioned in step 202 may include: acquiring the photosensitivity values ​​collected by the second type of pixels in the first area except the first type of pixels according to the reference information. In other words, the biometric acquisition chip can acquire the photosensitivity values ​​collected by the pixels in the first area that are not bad pixels. The photosensitivity values ​​collected by bad pixels are significantly different from those collected by normal pixels. Acquiring the photosensitivity values ​​collected by the pixels in the first area that are not bad pixels is conducive to improving the accuracy of the acquired photosensitivity values ​​of the first area, thereby improving the accuracy of the second exposure time determined subsequently.

[0062] In one embodiment, the above-mentioned reference information includes: marking information of each pixel in the first area, and the marking information includes: first marking information for characterizing that the pixel belongs to a bad pixel and second marking information for characterizing that the pixel does not belong to a bad pixel. Then, the biometric feature acquisition chip can determine that the first-category pixels belonging to the bad pixel are pixels marked with the first marking information based on the reference information, and then obtain the light sensitivity values ​​collected by the second-category pixels that do not belong to the bad pixel in the first area. Among them, the first marking information and the second marking information can be set according to actual needs. For example, the first marking information is represented by "0", that is, the first-category pixels belonging to the bad pixel are marked as "0", and the second marking information is represented by "1", that is, the normal pixels that do not belong to the bad pixel (also called the second-category pixels) are marked as "1". The schematic diagram of the marking information of each pixel in the first area can be referred to. Figure 4If the configuration parameter of reference information is sent by the software end, the software end can directly send the marking information of each pixel in the first area, so that the biometric acquisition chip can directly distinguish whether each pixel is a bad pixel according to the marking information of each pixel. If the configuration parameter of reference information is first stored in the biometric acquisition chip, the biometric acquisition chip can store the following information: Figure 4 The array shown facilitates the biometric feature acquisition chip to clearly distinguish whether each pixel is a bad pixel directly based on the stored array.

[0063] In another embodiment, the above-mentioned reference information includes: coordinate information of the bad block area determined based on the first type of pixels belonging to the bad pixel, then the biometric feature acquisition chip can determine the first type of pixels belonging to the bad pixel in the first area as pixels in the bad block area according to the reference information. The bad block area can be the smallest rectangular area formed by the first type of pixels belonging to the bad pixel, so that the coordinate information of the bad block area can be directly represented by the coordinate information of the boundary points of the bad block area, and the data volume of the reference information is relatively small. For example, the schematic diagram of the bad block area in the first area can refer to Figure 5 , Figure 5 The area framed by the dotted line is the bad block area. Figure 5 It can be seen that since the bad block area appears as a regular rectangular area, pixels that are not bad pixels are allowed to exist in the bad block area, such as Figure 5 There are also two normal pixels marked as "1" in the bad block area. The biometric acquisition chip can regard all pixels in the bad block area as first-class pixels belonging to bad points. The existence of individual normal pixels in the bad block area will not have much impact on subsequent processing. Among them, if the reference information configuration parameter is sent by the software end, the software end can directly send the coordinate information of the bad block area, which can reduce the amount of data sent and increase the sending speed. If the reference information configuration parameter is pre-stored in the biometric acquisition chip, the biometric acquisition chip can store the coordinate information of the bad block area, which can reduce the amount of stored data and save storage space.

[0064] In one embodiment, step 202 may be: after the biometric feature acquisition chip detects the preset trigger condition, it exposes the first area according to the first exposure time after the preset time interval, and obtains the light sensitivity value of the first area. By exposing the area locally after the preset time interval, it is helpful to ensure that the biometric feature acquisition chip can be in a relatively stable state during the local exposure, so that the second exposure time is obtained in a relatively stable state, which improves the accuracy of obtaining the second exposure time, and thus can improve the accuracy of the collected biometric feature image.

[0065] For example, the biometric feature acquisition chip is an under-screen fingerprint acquisition chip. When the under-screen fingerprint acquisition chip detects that the area where the fingerprint spot on the screen is located is pressed, it can first obtain the configuration parameters. After detecting that the area where the fingerprint spot on the screen is located is pressed, the first area is exposed according to the first exposure time after a preset time interval, and the photosensitivity value of the first area is obtained. After the area where the fingerprint spot on the screen is located is pressed, the fingerprint spot begins to light up, and after the preset time interval, the fingerprint spot is stabilized by default, that is, after the fingerprint spot is stable, the first area is exposed. In a specific implementation, the under-screen fingerprint acquisition chip can also start to obtain configuration parameters after a preset time interval after detecting that the area where the fingerprint spot on the screen is located is pressed, and then execute the step of exposing the first area.

[0066] In step 203, considering that there is a preset relationship between the photosensitivity value and the exposure time, the second exposure time required to collect the target photosensitivity value in the photosensitive area can be determined in combination with the preset relationship. The preset relationship can be a linear relationship between the photosensitivity value and the exposure time. For example, Figure 6 The linear relationship between the photosensitivity value and the exposure time is combined with the linear relationship, the photosensitivity value Rawdata of the first area, the target photosensitivity value Target and the first exposure time T1 to calculate the second exposure time T2.

[0067] In one embodiment, if the light sensitivity value of the first area acquired in step 202 is: the light sensitivity value collected by a pixel that meets the preset condition, the biometric feature collection chip can directly use the light sensitivity value collected by the pixel that meets the preset condition as the light sensitivity value of the first area (recorded as Rawdata), and then, according to Rawdata, T1, Target, and Figure 6 The linear relationship shown is used to calculate T2.

[0068] In one embodiment, if the light sensitivity value of the first area acquired in step 202 is: the light sensitivity value collected by multiple pixels that meet the preset conditions, the biometric feature collection chip can sort the light sensitivity values ​​collected by the multiple pixels that meet the preset conditions from small to large, and select a light sensitivity value within the preset range as the light sensitivity value of the first area according to the arrangement order of the light sensitivity values. Then, according to the selected light sensitivity value, T1, Target, and Figure 6The linear relationship shown is used to calculate T2. The preset range does not include the photosensitivity values ​​arranged in the first N positions, nor does it include the photosensitivity values ​​arranged in the last N positions. N is an integer greater than 1. The specific value of N can be set by a person skilled in the art according to actual needs, and this embodiment does not specifically limit this. Considering that the photosensitivity values ​​arranged in the first N positions and the photosensitivity values ​​arranged in the last N positions may both be abnormal photosensitivity values, selecting a photosensitivity value within the preset range as the photosensitivity value of the first area can avoid the interference of the abnormal photosensitivity value on the photosensitivity value of the first area, which is conducive to improving the accuracy of the determined photosensitivity value of the first area, thereby improving the accuracy of the calculated T2.

[0069] In one embodiment, if the light sensitivity value of the first area acquired in step 202 is the light sensitivity value collected by multiple pixels that meet the preset conditions, the biometric feature collection chip can average the light sensitivity values ​​collected by the multiple pixels that meet the preset conditions to obtain the pixel average value of the first area, and use the pixel average value as the light sensitivity value of the first area. Then, according to the pixel average value, T1, Target, and Figure 6 The linear relationship shown is used to calculate T2. The average value of the light sensitivity values ​​collected by multiple pixels is used as the light sensitivity value of the first area, which reduces the interference caused by the inaccurate light sensitivity values ​​collected by individual pixels, making the determined light sensitivity value of the first area more accurate and reasonable, thereby improving the accuracy of the calculated T2.

[0070] In step 204, according to the second exposure time, collecting the biometric image can be understood as: the biometric collection chip exposes the photosensitive area of ​​the biometric collection chip with T2, and obtains the photosensitivity value of the photosensitive area, and obtains the biometric image based on the photosensitivity value.

[0071] The biometric acquisition method in this embodiment can be understood as adopting an automatic exposure control (AutoExposure Control, AEC) method, and the first exposure time is relatively short. Therefore, it can be understood that when it is determined that biometric identification or registration is required, the first area is automatically short-exposed according to the configuration parameters, and the photosensitivity value of the first area is obtained. Then, the second exposure time T2 is determined by linear fitting in combination with the linear relationship between the photosensitivity value and the exposure time, and the biometric acquisition chip is configured to expose the photosensitivity area with T2, thereby obtaining a biometric image. Since the second exposure time is equivalent to being determined by short-exposure of a local area in the current environment, the second exposure time can adapt to changes in the external environment, thereby making the biometric acquisition chip more adaptable to the external environment, reducing the impact of changes in the external environment on the acquisition performance, and is conducive to improving the accuracy of subsequent biometric identification or registration.

[0072] In one embodiment, the configuration parameters include, in addition to the first exposure time, the first area, the target photosensitivity value, and the reference information: a filter coefficient; after obtaining the photosensitivity values ​​collected by the second type of pixels other than the first type of pixels in the first area according to the reference information, it also includes: using the fill photosensitivity value as the photosensitivity value collected by the first type of pixels; wherein the fill photosensitivity value is the photosensitivity value collected by the second type of pixels around the first type of pixels; filtering the photosensitivity values ​​collected by the first type of pixels and the photosensitivity values ​​collected by the second type of pixels according to the filter coefficient to obtain the filtered photosensitivity values; determining the second exposure time required to collect the target photosensitivity value in the photosensitivity area according to the photosensitivity value of the first area and the first exposure time, including: determining the second exposure time required to collect the target photosensitivity value in the photosensitivity area according to the filtered photosensitivity value and the first exposure time. The flowchart of the biometric feature collection method in this embodiment can be referred to. Figure 7 ,include:

[0073] Step 701: Obtain configuration parameters.

[0074] Step 702: Determine the first type of pixels in the first area that are bad pixels according to the reference information.

[0075] Step 703: Expose the first area according to the first exposure time to obtain the light sensitivity values ​​collected by the second type of pixels except the first type of pixels in the first area.

[0076] Step 704: Use the filled light sensitivity value as the light sensitivity value collected by the first type of pixels; wherein the filled light sensitivity value is the light sensitivity value collected by the second type of pixels around the first type of pixels.

[0077] Step 705: Filter the light-sensitivity values ​​collected by the first type of pixels and the light-sensitivity values ​​collected by the second type of pixels according to the filter coefficients to obtain filtered light-sensitivity values.

[0078] Step 706: Determine a second exposure time required to collect a target light sensitivity value in the light sensitive area according to the filtered light sensitivity value and the first exposure time.

[0079] Step 707: Capture a biometric image according to the second exposure duration.

[0080] Among them, step 701 is similar to step 201, and the main difference is that the configuration parameters in step 701 include, in addition to the first exposure time, the first area, and the target photosensitivity value, reference information and filter coefficients for determining the first type of pixels in the first area that are bad pixels. The reference information has been described above and will not be repeated here. The filter coefficients can be set by those skilled in the art according to actual needs.

[0081] In one embodiment, the biometric feature acquisition chip is arranged below the screen, and the filter coefficient is determined according to the structure of the screen; wherein, the structure of the screen is a soft screen or a hard screen, and the filter coefficient determined based on the hard screen is greater than the filter coefficient determined based on the soft screen. The inventor has found through research that different screen structures have different degrees of influence on the light sensitivity value acquired by pixels, that is, there are differences in the upward burrs formed by the biometric feature image on different screen structures. Therefore, the filter coefficient determined according to the structure of the screen in this embodiment is more targeted and can filter the light sensitivity value more reasonably, thereby reducing the influence of different screen structures on the light sensitivity value acquired by pixels, so as to further improve the accuracy of the determined second exposure time.

[0082] Optionally, considering that different assembly tolerances of the biometric acquisition chip during assembly ultimately affect the photosensitive value of the pixel collection, there are also differences. Therefore, in this embodiment, the filter coefficient can also be determined according to the structure of the screen and the assembly tolerance of the biometric acquisition chip, and the photosensitive value can be filtered with a more reasonable filter coefficient, thereby minimizing the influence of different screen structures and assembly tolerances on the photosensitive value of the pixel collection, so as to further improve the accuracy of the determined second exposure time. Among them, the assembly tolerance is mainly reflected in the error of the object distance P and / or the error of the image distance Q of the lens after the biometric acquisition chip and the lens are assembled. The error of the object distance P can be understood as: the difference between the object distance P after assembly and the preset standard object distance, and the error of the image distance Q can be understood as: the difference between the image distance Q after assembly and the preset standard image distance. When the error of the object distance P and / or the error of the image distance Q are large, the burrs will also be aggravated at this time, and a larger filter coefficient is required to filter out the burrs. In other words, the larger the assembly tolerance, the larger the determined filter coefficient can be, so that the burrs can be filtered out. In a specific implementation, the filter coefficient can also be dynamically adjusted according to actual needs to achieve a better filtering level. The preset standard object distance and the preset standard image distance can be set according to actual needs, and this embodiment does not specifically limit this.

[0083] In step 702, if the reference information is: the marking information of each pixel in the first area, the marking information includes: the first marking information used to characterize that the pixel belongs to a bad pixel and the second marking information used to characterize that the pixel does not belong to a bad pixel, then the first type of pixels in the first area that belong to bad pixels determined by the biometric feature acquisition chip according to the reference information are: the pixels marked with the first marking information. If the reference information is the coordinate information of the bad block area determined based on the first type of pixels that belong to bad pixels, then the first type of pixels in the first area that belong to bad pixels determined by the biometric feature acquisition chip according to the reference information are: the pixels in the bad block area.

[0084] In step 703, the biometric feature acquisition chip exposes the first area according to the first exposure time to obtain the light sensitivity values ​​collected by the second type of pixels in the first area except the first type of pixels, that is, obtains the light sensitivity values ​​collected by the normal pixels in the first area.

[0085] In step 704, the biometric feature collection chip can use the light sensitivity values ​​collected by the second type of pixels around the first type of pixels to fill the first type of pixels, that is, use the light sensitivity values ​​collected by the normal pixels around the bad point to fill the bad point, and set the light sensitivity values ​​collected by the pixels belonging to the bad point to the light sensitivity values ​​collected by the normal pixels around the bad point. The normal pixels around the bad point can be the normal pixels closest to the bad point.

[0086] In step 705, the biometric feature acquisition chip filters the light sensitivity values ​​collected by the first type of pixels and the light sensitivity values ​​collected by the second type of pixels according to the filter coefficient to obtain filtered light sensitivity values. That is, the biometric feature acquisition chip filters the light sensitivity values ​​collected by all pixels in the first area to obtain filtered light sensitivity values. Among them, when filtering, the filtering methods that can be used are: median filtering, Gaussian low-pass filtering, etc. However, this embodiment does not specifically limit this, and other filtering methods can also be used in specific implementations.

[0087] In this embodiment, the light sensitivity value collected by the bad pixel, i.e., the first type of pixel, is replaced with the light sensitivity value collected by the normal pixel points around the bad pixel, which facilitates the subsequent overall filtering of the light sensitivity values ​​of all pixels in the first area directly according to the filter coefficient, avoiding the sudden change of the light sensitivity value caused by removing the bad pixel without filling and directly filtering. The light sensitivity value after filtering can better reflect the real perception of the pixel to the light signal from the outside world. The second exposure time determined by combining the light sensitivity value after filtering can better adapt to the changes in the external environment, thereby making the biometric acquisition chip more adaptable to the external environment, reducing the impact of changes in the external environment on the acquisition performance, and is conducive to improving the accuracy of subsequent biometric identification or registration. Among them, for under-screen fingerprint acquisition, the above-mentioned light signal from the outside world can be understood as the excitation light used for fingerprint acquisition irradiated on the finger above the screen, and after being scattered, reflected or transmitted by the finger, the fingerprint detection light carrying the fingerprint information of the finger is formed.

[0088] In step 706, determining the second exposure time required to collect the light-sensitive value in the light-sensitive area according to the filtered light-sensitive value and the first exposure time may include: averaging the light-sensitive values ​​of each pixel in the first area after filtering to obtain the pixel average value of the first area, and using the pixel average value as the light-sensitive value of the first area. Then, according to the pixel average value, T1, Target, and the like Figure 6 The linear relationship shown is used to calculate T2.

[0089] In one embodiment, the implementation of step 706 can refer to Figure 8 ,include:

[0090] Step 801: Obtain the photosensitivity value of the second area.

[0091] Step 802: Determine the second exposure time required to collect the target light sensitivity value in the light sensitivity area according to the filtered light sensitivity value, the light sensitivity value of the second area and the first exposure time.

[0092] The second area is the edge area of ​​the photosensitive area, and the edge area is an area for detecting the circuit noise of the biometric acquisition chip. The second area does not overlap with the first area. Circuit noise can be understood as the noise of the circuit in the biometric acquisition chip. The circuit in the biometric acquisition chip may include: gain circuit, analog-to-digital conversion circuit, etc. The distribution diagram of the first area and the second area in the photosensitive area can be referred to Fig. 9 , Fig. 9 The middle photosensitive area 302 includes: a second area 901 located at the edges of the photosensitive area 302 and a non-dark area 902 surrounded by the second area 901 , and the first area 301 is located in the non-dark area 902 .

[0093] The edge area of ​​the photosensitive area of ​​the biometric feature acquisition chip may be shielded by the shielding material, and it is not easy to sense external light. Among them, the shielding material can be metal, that is, the edge area of ​​the photosensitive area is covered by metal, and the area covered by metal can be called the second area, or it can be called the Dark area, the metal-covered area or the black-covered area. Since the pixels in the second area are covered by metal, they generally cannot receive external light, but when strong light is irradiated, the strong light will penetrate the metal covering the second area, so that the pixels in the second area may receive some external light when strong light is irradiated. The light-sensitivity value collected by the pixels in the second area can be understood as: the light-sensitivity value collected by the pixel when it is not sensitive to light in the current environment, referred to as the Dark value, so the Dark value can be used to represent the reference value that the pixel can collect in the absence of light, and the reference value can be used to characterize the size of the circuit noise. In the case of light, the light-sensitivity value collected by the pixel minus the Dark value can represent: the light-sensitivity value actually collected by the pixel after removing the reference, that is, the light-sensitivity value actually collected by the pixel after removing the circuit noise. The photosensitivity value after removing the reference can eliminate the influence of circuit noise and can more accurately reflect the light signal from the outside world sensed by the pixel.

[0094] In one embodiment, step 801 may be: obtaining the light sensitivity value collected by the pixels at the non-edge of the second area. The inventors have found through research that although the pixels in the second area are generally not easily sensitive to external light, they are still easily disturbed by strong light from the outside, especially the pixels in the edge area of ​​the second area are more likely to be disturbed by strong light. Therefore, in this embodiment, when obtaining the light sensitivity value of the second area, the light sensitivity value collected by the pixels at the non-edge of the second area is obtained, so that in the current environment, the determined Dark value can exclude the interference of strong light from the outside, and can more accurately reflect the light sensitivity value collected by the pixels when not sensitive to light, thereby improving the accuracy of the determined second exposure time.

[0095] In one embodiment, step 801 may be: obtaining the light sensitivity values ​​collected by the middle a column of pixels and / or the middle a row of pixels in the second region, where a is an integer greater than or equal to 1. For example, Fig. 9 , the second area 901 is distributed around the edges of the photosensitive area 302, and the second area 901 may include: sub-area 1 at the left edge of the photosensitive area 302, sub-area 2 at the right edge of the photosensitive area 302, sub-area 3 at the upper edge of the photosensitive area 302, and sub-area 4 at the lower edge of the photosensitive area 302. The middle a column of pixels and / or the middle a row of pixels of the second area may include any one of the following or a combination thereof: the middle a column of pixels of sub-area 1, the middle a column of pixels of sub-area 2, the middle a row of pixels of sub-area 3, and the middle a row of pixels of sub-area 4. For example, there are 13 columns of pixels in sub-area 1, and the middle a column of pixels of sub-area 1 may be the middle 8 columns of pixels of sub-area 1, wherein the 2 columns on the left edge and the 3 columns on the right edge of the original 13 columns of pixels may be removed, thereby leaving the middle 8 columns of pixels, and then the Dark value collected by the middle 8 columns of pixels of sub-area 1 is obtained. The middle a column of pixels and / or the middle a row of pixels in the second area are far from the edge of the second area itself and have more concentrated data. This can improve the accuracy of the Dark value, which is the benchmark value that the pixel can collect in the absence of light, while avoiding interference from strong light, thereby improving the accuracy of the determined second exposure time.

[0096] In step 802, the filtered sensitivity value may be: the filtered sensitivity value corresponding to each pixel in the first area. When determining the second exposure time required to collect the target sensitivity value in the photosensitive area based on the filtered sensitivity value, the sensitivity value of the second area, and the first exposure time, one of the filtered sensitivity values ​​corresponding to each pixel in the first area may be selected as Rawdata1, and one of the sensitivity values ​​collected by the pixels in the second area may be selected as Dark1, and then, T2 may be calculated based on Rawdata1, Dark1, T1, and Target. For example, T2 may be calculated using the following formula:

[0097]

[0098] Among them, the selection method of Rawdata1 can be: sorting the filtered sensitivity values ​​corresponding to each pixel in the first area from small to large, and selecting one as Rawdata1 within the preset range according to the arrangement order of each filtered sensitivity value. Among them, the preset range does not include the filtered sensitivity values ​​arranged in the first N positions, nor does it include the filtered sensitivity values ​​arranged in the last N positions. N is an integer greater than 1. The specific value of N can be set by those skilled in the art according to actual needs, and this embodiment does not specifically limit this. Dark1 can also be selected in a similar manner, and will not be repeated here to avoid repetition. Considering that the sensitivity values ​​arranged in the first N positions and the filtered sensitivity values ​​arranged in the last N positions may both belong to abnormal sensitivity values, selecting one as Rawdata1 within the preset range can avoid calculating T2 through abnormal sensitivity values, which is conducive to improving the accuracy of the determined T2. In this embodiment, when calculating T2, since the filtered sensitivity value Rawdata1 corresponding to a pixel in the first area and Dark1 collected by a pixel in the second area are selected, the data processing process is relatively simple, which is conducive to quickly obtaining T2, thereby improving the recognition speed.

[0099] In one embodiment, the implementation of step 802 can refer to Fig.10 ,include:

[0100] Step 1001: Determine the average light sensitivity value of the first area according to the filtered light sensitivity value.

[0101] Step 1002: Determine an average light sensitivity value of the second area according to the light sensitivity values ​​collected by the pixels in the second area.

[0102] Step 1003: Determine a second exposure time required to collect a target light sensitivity value in the light sensitive area according to the average light sensitivity value of the first area, the average light sensitivity value of the second area, and the first exposure time.

[0103] In step 1001, the biometric feature acquisition chip may average the filtered photosensitive values ​​corresponding to each pixel in the first region to obtain an average photosensitive value of the first region. Optionally, the biometric feature acquisition chip may also sort the filtered photosensitive values ​​corresponding to each pixel in the first region from small to large, and average the filtered photosensitive values ​​within a preset range to obtain an average photosensitive value of the first region. The preset range does not include the filtered photosensitive values ​​arranged in the first N positions, nor does it include the filtered photosensitive values ​​arranged in the last N positions, where N is an integer greater than 1.

[0104] In step 1002, the biometric feature collection chip may average the light sensitivity values ​​collected by the pixels in the second area to obtain an average light sensitivity value of the second area. The light sensitivity values ​​collected by the pixels in the second area may include: light sensitivity values ​​collected by pixels at non-edges of the second area. Alternatively, the light sensitivity values ​​collected by the pixels in the second area may include: light sensitivity values ​​collected by pixels in the middle a column and / or the middle a row of pixels in the second area.

[0105] In step 1003, the average light sensitivity value of the first area is recorded as Rawmean, and the average light sensitivity value of the second area is recorded as Darkmean. Then, the second exposure time T2 can be calculated by the following formula:

[0106]

[0107] In this embodiment, the average light sensitivity value of the first area can reflect the average level of the light sensitivity values ​​of each pixel after bad pixel filling and filtering, and the average light sensitivity value of the second area can reflect the average level of the light sensitivity values ​​collected by the pixels in the second area, which reduces the interference caused by the inaccurate light sensitivity values ​​collected by individual pixels, and is conducive to improving the accuracy of the calculated T2. At the same time, when calculating Darkmean, the light sensitivity values ​​collected by the pixels at the edge of the Dark area can be excluded, which is conducive to avoiding the interference of strong light from the outside, and can more accurately reflect the light sensitivity values ​​collected by the pixels when not sensitive to light, thereby further improving the accuracy of the determined second exposure time. Both Target and Rawmean use Darkmean for subtraction, which is conducive to excluding the influence of the structure of the screen itself on the light sensitivity values ​​collected by the pixels in the current environment, thereby further improving the adaptability of the calculated T2 to the current environment, making the adaptability of the biometric acquisition chip to the current environment better, reducing the influence of changes in the external environment on the acquisition performance, and is conducive to further improving the accuracy of subsequent biometric identification or registration.

[0108] In one embodiment, the configuration parameters mentioned in step 201 or step 701, in addition to the first exposure time, the first area and the target photosensitivity value, also include: an upper limit time corresponding to the photosensitivity area and / or a lower limit time corresponding to the photosensitivity area. The biometric image is collected according to the second exposure time mentioned in step 204 or step 707, including: when the configuration parameters also include the upper limit time, if the second exposure time is greater than the upper limit time, the biometric image is collected according to the upper limit time; when the configuration parameters also include the lower limit time, if the second exposure time is less than the lower limit time, the biometric image is collected according to the lower limit time.

[0109] Among them, the upper limit duration corresponding to the photosensitive area is recorded as T2_max, and the lower limit duration corresponding to the photosensitive area is recorded as T2_min. T2_min and T2_max can be set by those skilled in the art according to actual needs, aiming to avoid the exposure duration used in the final acquisition of the biometric image being too long or too short, so as to ensure that the final acquired biometric image can be relatively clear and convenient for identification or registration. The inventor found through research that the second exposure duration calculated in abnormal situations such as strong light environment, indoor environment, and normal lighting of the acquisition spot may be too short or too long. Therefore, by setting the upper limit duration and / or the lower limit duration, when the second exposure duration is greater than the upper limit duration, the biometric image is acquired according to the upper limit duration; when the second exposure duration is less than the lower limit duration, the biometric image is acquired according to the lower limit duration, which is conducive to avoiding the situation that the final acquired biometric image is inaccurate due to the second exposure duration calculated under abnormal circumstances being too short or too long, and ensuring that the final acquired biometric image can be relatively clear and convenient for identification or registration.

[0110] In one embodiment, the biometric feature collection chip is set in the terminal, and the configuration parameters also include an upper limit time length corresponding to the photosensitive area and a lower limit time length corresponding to the photosensitive area, and the upper limit time length and the lower limit time length satisfy the following relationship:

[0111] T2_max=T0+T0*a1

[0112] T2_min=T0-T0*a2

[0113] Among them, T0 is the default exposure time of the terminal when it leaves the factory, T2_max is the upper limit time, T2_min is the lower limit time, and a2 is greater than or equal to a1. Among them, a2 and a1 can be set according to actual needs, for example, the value ranges of a1 and a2 are as follows: 10%≤a1≤30%, 30%≤a2≤50%. The default exposure time of the terminal when it leaves the factory can be the default exposure time set based on the result of the whole machine calibration when the terminal is in the mass production stage of the whole machine. Through research, the inventor found that the probability and amplitude of the second exposure time fluctuating in the direction exceeding the default exposure time are small, and the probability and amplitude of the second exposure time fluctuating in the direction below the default exposure time are large. Therefore, a2 is greater than or equal to a1, which is conducive to adapting to the different fluctuations that may actually exist in the second exposure time.

[0114] For example, the default exposure time of the terminal is 50ms when it leaves the factory, so T2_max can be selected between 55ms (50+50*10%=60ms) and 65ms (50+50*30%=65ms). T2_min can be selected between 30ms (50-50*30%=35ms) and (50-50*50%=25ms). Assume that T2_max=65ms, T2_min=35ms, if T2 is greater than 65ms, 65ms is used as the exposure time to collect biometric images; if T2 is less than 35ms, 35ms is used as the exposure time to collect biometric images.

[0115] In one embodiment, the configuration parameters mentioned in step 201 or step 701 also include: a pulse width modulation (PWM) dimming cycle of the screen. The step 204 or step 707 mentioned in collecting the biometric image according to the second exposure time includes: if the second exposure time is not equal to an integer multiple of the PWM dimming cycle, adjusting the second exposure time to an integer multiple of the PWM dimming cycle, and collecting the biometric image according to the adjusted second exposure time.

[0116] For example, the second exposure duration can be adjusted to an integer multiple of the PWM dimming cycle by the following formula:

[0117] T2'=(uint8(T2 / T2_pwm))*T2_pwm

[0118] Wherein, T2' is the adjusted second exposure time, T2 is the second exposure time determined in step 203 or step 706, T2_pwm is the PWM dimming cycle of the screen, and uint8 represents a data type of unsigned integer.

[0119] In this embodiment, the inventors have found through research that for a screen with a high drop ratio, when the second exposure time is not equal to an integer multiple of the PWM dimming cycle, the collected biometric image may have horizontal stripes, such as Fig.11 The fingerprint image shown is a horizontal stripe image. Therefore, in this embodiment, the second exposure duration is adjusted to an integer of the PWM dimming cycle, and the biometric image is collected with the adjusted second exposure duration, which is conducive to avoiding the appearance of horizontal stripes in the biometric image collected by the biometric collection chip set under the screen of the high drop ratio type, thereby improving the accuracy of the collected biometric image.

[0120] Among them, the brightness drop of the screen of the high drop ratio type meets any of the following conditions: when dimming is performed using the PWM dimming method, the brightness of the screen drops to less than 10% of the normal brightness of the screen between two PWM dimming cycles; when dimming is performed using the DC dimming method, the brightness of the screen between frames drops to less than 10% of the normal brightness of the screen. Among them, the normal brightness of the screen can be set according to actual needs, and the normal brightness of different screens may be different, which is not specifically limited in this embodiment. In a specific implementation, if the screen of the terminal is a screen of the high drop ratio type, the PWM dimming cycle of the screen can be added to the configuration parameters.

[0121] In one embodiment, according to the second exposure time, the implementation method of collecting the biometric image can refer to Fig.12 ,include:

[0122] Step 1201: adjusting the parameter value of the first parameter, the parameter value of the second parameter, and the parameter value of the third parameter according to the second exposure duration to obtain the target parameter value of the first parameter, the target parameter value of the second parameter, and the target parameter value of the third parameter.

[0123] Step 1202: Collect a biometric image according to the target parameter value of the first parameter, the target parameter value of the second parameter, and the target parameter value of the third parameter.

[0124] The first parameter is the duration of the line blanking phase, recorded as H_Blank. In the scanning process of converting optical signals into electrical signals, the scan always starts from the upper left corner of the image and moves forward horizontally. When the scanning point reaches the right edge of the image, the scanning point quickly returns to the left and restarts the second line scan below the starting point of the first line. The return process between lines is called horizontal blanking, also known as line blanking.

[0125] The second parameter is the duration of the field blanking phase, recorded as V_Blank. A complete image scanning signal, consisting of a sequence of line signals separated by horizontal blanking intervals, is called a frame. After the scanning point scans a frame, it returns from the lower right corner of the image to the upper left corner of the image to start scanning a new frame. This time interval is called vertical blanking, also known as field blanking.

[0126] The third parameter is the delay time for each row of pixels to start exposure, recorded as V_Delay. The third parameter is how long each row of pixels is delayed to start exposure.

[0127] In step 1201, the biometric feature acquisition chip can determine the first scanning time required to scan a single row of pixels and the second scanning time required to scan a single pixel. Then, according to the first relationship, the parameter value of the first parameter is adjusted to obtain the target parameter value of the first parameter; according to the second relationship, the parameter value of the second parameter and the parameter value of the third parameter are adjusted to obtain the target parameter value of the second parameter and the target parameter value of the third parameter. Among them, the target parameter value of the first parameter conforms to the first relationship, which is the relationship between the second scanning time, the number of pixels in each row of the pixel array, the parameter value of the first parameter and the first scanning time. The target parameter value of the second parameter and the target parameter value of the third parameter conform to the second relationship, which is the relationship between the first scanning time, the total number of rows in the pixel array, the parameter value of the second parameter, the parameter value of the third parameter and the second exposure time.

[0128] The first scanning time required to scan a single row of pixels can be recorded as Row_time. The First Input First Output (FIFO) storage capacity and the Serial Peripheral Interface (SPI) speed of the biometric acquisition chip will affect the size of Row_time. The SPI speed may limit the minimum value of Row_time. A biometric acquisition chip has a corresponding Row_time, which can be obtained by testing the biometric acquisition chip in the parameter test of the mass production stage and stored in the biometric acquisition chip.

[0129] The second scanning time required to scan a single pixel can be recorded as 1 / pixel_clock, where pixel_clock is the clock period of the pixel. Pixel_clock can be obtained from the parameter test of the biometric acquisition chip in the mass production stage and stored in the biometric acquisition chip. For example, pixel_clock = 20MHz, 1 / pixel_clock = 50ns.

[0130] The number of pixels in each row of the pixel array is recorded as H_Valid, and the total number of rows in the pixel array is recorded as V_Valid. It can be understood that for a certain biometric feature acquisition chip, H_Valid and V_Valid in the biometric feature acquisition chip can be determined.

[0131] The first relation can be expressed as follows:

[0132] Row_time=(H_Blank+H_Valid)*(1 / pixel_clock)

[0133] The second relationship can be expressed as follows:

[0134]

[0135] It can be understood that in the above-mentioned first relationship and second relationship, H_Valid, V_Valid, 1 / pixel_clock, Row_time, and T2 are all determined values, and H_Blank, V_Blank, and V_Delay are three parameter values ​​to be adjusted.

[0136] In a specific implementation, H_Blank can be adjusted through the first relationship to eventually obtain a target parameter value of the first parameter that meets the first relationship, and finally the parameter value that can make the first relationship hold true is used as the adjusted target parameter value of the first parameter.

[0137] In a specific implementation, V_Blank and V_Delay can be adjusted through the second relationship, so that a target parameter value of the second parameter and a target parameter value of the third parameter that meet the second relationship are finally obtained, and finally the two parameter values ​​that can make the second relationship valid are used as the adjusted target parameter value of the second parameter and the target parameter value of the third parameter. Since there are two parameters V_Blank and V_Delay as variables in the second relationship, one variable can be fixed first and the other variable can be adjusted. When the adjustment of the other variable can no longer make the calculation result close to T2, the previously fixed variable can be adjusted. By adjusting the two variables with each other, two target parameter values ​​that can make the second relationship valid are finally adjusted.

[0138] In one embodiment, the configuration parameter further includes: a lower limit parameter value of the first parameter, and adjusting the parameter value of the first parameter according to the first relationship to obtain a target parameter value of the first parameter, including: in the process of adjusting the parameter value of the first parameter according to the first relationship, if the parameter value of the first parameter is adjusted to the lower limit parameter value and still cannot meet the first relationship, taking the lower limit parameter value as the target parameter value of the first parameter. Wherein, the lower limit parameter value of the first parameter can be recorded as H_Blank_min, and H_Blank_min can be determined based on the minimum value of Row_time. The smaller the minimum value of Row_time is, the smaller H_Blank_min is, and the larger the minimum value of Row_time is, the larger H_Blank_min is. That is, in this embodiment, in the process of adjusting H_Blank, if H_Blank is already equal to H_Blank_min, and the first relationship cannot be established, H_Blank_min can be directly used as the target parameter value of the first parameter after the final adjustment, that is, the minimum target parameter value of the first parameter is H_Blank_min. The parameter value of the first parameter directly affects the first scanning time Row_time consumed for scanning a single row of pixels, and Row_time will affect the normal output of the sensitivity value. Therefore, setting the lower limit parameter value of the first parameter is helpful to ensure that the normal output of the sensitivity value is not affected during adjustment.

[0139] In one embodiment, in the process of adjusting the parameter values ​​of H_Blank, V_Blank, and V_Delay, H_Blank can also be directly adjusted to H_Blank_min in the configuration parameters, and V_Delay is first fixed to 0, and V_Blank is adjusted until the adjustment of V_Blank fails to make the second relationship hold, and then V_Delay is adjusted. This adjustment is conducive to reducing the complexity of adjustment and speeding up the adjustment speed, thereby speeding up the speed of collecting biometric images, so as to speed up the subsequent biometric identification or registration.

[0140] After the target parameter value of the first parameter, the target parameter value of the second parameter and the target parameter value of the third parameter are obtained after adjustment, the target parameter values ​​of these three parameters can be set in the biometric acquisition chip so that the final exposure time presented by the biometric acquisition chip when acquiring the biometric image is T2.

[0141] In one embodiment, the biometric feature acquisition chip is an under-screen fingerprint acquisition chip. The flowchart of the biometric feature acquisition method applied to the under-screen fingerprint acquisition chip can be referred to Fig.13 ,include:

[0142] Step 1301: After the software waits for the fingerprint spot displayed on the screen to stabilize, it sends configuration parameters to the biometric feature collection chip.

[0143] Among them, the software end waits for the fingerprint spot displayed on the screen to stabilize, which can be understood as: after the software end determines that the fingerprint spot displayed on the screen is pressed, it waits for a preset time, and the preset time is greater than or equal to the minimum time required for the fingerprint spot to be lit and stabilized. After the software end waits for the preset time, it is assumed that the fingerprint spot is stable, and the software end sends configuration parameters to the biometric acquisition chip.

[0144] The configuration parameters include: first exposure time T1, first area, target light sensitivity value Target, reference information, filter coefficient, upper limit time T2_max corresponding to the light sensitive area, lower limit time T2_min corresponding to the light sensitive area, and lower limit parameter value H_Blank_min of the first parameter. If the screen is a high drop ratio screen, the configuration parameters also include the PWM dimming cycle of the screen.

[0145] Step 1302: Expose the first area according to the first exposure time to obtain the light sensitivity value collected by each pixel in the first area.

[0146] Step 1303: Remove the first-category pixels that are bad pixels in each pixel in the first area, use the filled photosensitivity value as the photosensitivity value collected by the first-category pixels, and filter the photosensitivity values ​​collected by the first-category pixels and the photosensitivity values ​​collected by the second-category pixels in the first area according to the filter coefficient to obtain filtered photosensitivity values.

[0147] The filling photosensitivity value is the first photosensitivity value collected by the second type of pixels located around the first type of pixels.

[0148] Step 1304: Determine the average light sensitivity value of the first area according to the filtered light sensitivity value.

[0149] Step 1305: Determine an average light sensitivity value of the second area based on light sensitivity values ​​collected from pixels at non-edge locations of the second area.

[0150] Step 1306: Determine a second exposure time T2 required to collect a target light sensitivity value in the light sensitive area according to the average light sensitivity value of the first area, the average light sensitivity value of the second area, and the first exposure time.

[0151] Step 1307: If T2>T2_max, then collect a biometric image based on T2_max.

[0152] Step 1308: If T2<T2_min, then collect a biometric image based on T2_min.

[0153] Step 1309: If T2_min≤T2≤T2_max, then collect a biometric image based on T2.

[0154] In step 1307, the fingerprint collection chip under the screen can adjust the three parameters H_Blank, V_Blank, and V_Delay according to T2_max. The second relationship used in the adjustment can be expressed as follows:

[0155]

[0156] In step 1308, the fingerprint collection chip under the screen can adjust the three parameters of H_Blank, V_Blank, and V_Delay according to T2_min. The second relationship used in the adjustment can be expressed as follows:

[0157]

[0158] Finally, the fingerprint collection chip under the screen can collect biometric images according to the three adjusted parameters. Among them, the minimum H_Blank can be adjusted to H_Blank_min.

[0159] The biometric feature collection method applied to the under-screen fingerprint collection chip in this embodiment can improve the adaptability of the under-screen fingerprint collection chip to the fingerprint light spot, reduce the impact of fingerprint light spot fluctuations on fingerprint collection performance, and help improve the accuracy of fingerprint recognition or registration.

[0160] The step division of the above methods is only for the purpose of clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0161] The embodiment of the present application also relates to a biometric feature collection chip, such as Fig.14 As shown, it includes a processing unit 1401 and a storage unit 1402 connected to the processing unit 1401, the storage unit 1402 stores instructions that can be executed by the processing unit 1401, and the instructions are executed by the processing unit 1401 so that the processing unit 1401 can execute the biometric collection method in any one of the above embodiments.

[0162] The embodiment of the present application also relates to a terminal, including: Fig.14 The biometric acquisition chip shown.

[0163] The embodiments of the present application also relate to a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the above method embodiments are implemented.

[0164] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0165] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for collecting biometric features, characterized in that: Applied to biometric acquisition chips, including: Acquire configuration parameters; wherein the configuration parameters include: a first exposure time, a first area, and a target light sensitivity value, wherein the first area is a local area in the light sensitive area of ​​the biometric feature acquisition chip; Exposing the first area according to the first exposure time, and obtaining a photosensitivity value of the first area; Determining, according to the photosensitivity value of the first area and the first exposure time, a second exposure time required to collect the target photosensitivity value in the photosensitivity area; collecting a biometric image according to the second exposure time; The first exposure time is determined according to the linearity of the biometric feature acquisition chip. The smaller the linearity is, the smaller the first exposure time is.

2. The biometric feature collection method according to claim 1, characterized in that: The biometric feature acquisition chip is set in the terminal, and the acquisition configuration parameters include: Receive configuration parameters sent by application software in the terminal.

3. The biometric feature collection method according to claim 1, characterized in that: The obtaining of configuration parameters includes: When a preset trigger condition is detected, configuration parameters are obtained; wherein the preset trigger condition includes: the need to perform biometric registration and / or the need to perform biometric identification.

4. The biometric feature collection method according to claim 3, characterized in that: Exposing the first area according to the first exposure duration and acquiring the light sensitivity value of the first area includes: When the preset trigger condition is detected, the first area is exposed according to the first exposure duration after an interval of a preset time, and the photosensitivity value of the first area is obtained.

5. The biometric feature collection method according to claim 4, characterized in that: The biometric collection chip is an under-screen fingerprint collection chip, and the need for biometric registration and / or biometric identification includes: detecting that the area where the fingerprint spot on the screen is located is pressed, and the preset time length is greater than or equal to the minimum time length required for the fingerprint spot to start to light up and for the fingerprint spot to stabilize.

6. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The configuration parameters further include: reference information for determining first-category pixels in the first area that are bad pixels, and obtaining the light sensitivity value of the first area includes: According to the reference information, light sensitivity values ​​collected by the second type of pixels in the first area except the first type of pixels are obtained.

7. The biometric feature collection method according to claim 6, characterized in that: The reference information includes: marking information of each pixel in the first area, the marking information includes: first marking information used to indicate that the pixel is a bad pixel and second marking information used to indicate that the pixel is not a bad pixel; or The reference information includes: coordinate information of a bad block area determined based on first-category pixels belonging to bad pixels.

8. The biometric feature collection method according to claim 6, characterized in that: The configuration parameters further include: a filter coefficient; after acquiring the light sensitivity values ​​collected by the second type of pixels other than the first type of pixels in the first area according to the reference information, further including: Using the filling light sensitivity value as the light sensitivity value collected by the first type of pixels; wherein the filling light sensitivity value is the light sensitivity value collected by the second type of pixels around the first type of pixels; Filtering the light-sensitivity values ​​collected by the first-type pixels and the light-sensitivity values ​​collected by the second-type pixels according to the filtering coefficient to obtain filtered light-sensitivity values; The determining, according to the light sensitivity value of the first area and the first exposure time, a second exposure time required to collect the target light sensitivity value in the light sensitivity area includes: A second exposure time required to collect the target light sensitivity value in the light sensitivity area is determined according to the filtered light sensitivity value and the first exposure time.

9. The biometric feature collection method according to claim 8, characterized in that: The determining, according to the filtered light sensitivity value and the first exposure time, a second exposure time required to collect the target light sensitivity value in the light sensitivity area includes: Acquire a photosensitivity value of a second area; wherein the second area is an edge area of ​​the photosensitivity area, the second area does not overlap with the first area, and the edge area is an area for detecting circuit noise of the biometric feature acquisition chip; A second exposure time required to collect the target sensitivity value in the photosensitive area is determined according to the filtered sensitivity value, the sensitivity value of the second area and the first exposure time.

10. The biometric feature collection method according to claim 9, characterized in that: The obtaining of the light sensitivity value of the second area includes: Acquire the light sensitivity values ​​collected by the pixels at the non-edge of the second area.

11. The biometric feature collection method according to claim 9, characterized in that: The obtaining of the light sensitivity value of the second area includes: Acquire the light sensitivity values ​​collected by the middle a columns of pixels and / or the middle a rows of pixels in the second area, where a is an integer greater than or equal to 1.

12. The biometric feature collection method according to any one of claims 9 to 11, characterized in that: The determining, according to the filtered light sensitivity value, the light sensitivity value of the second area, and the first exposure time, a second exposure time required to collect the target light sensitivity value in the light sensitivity area includes: Determining an average light sensitivity value of the first area according to the filtered light sensitivity value; Determining an average light sensitivity value of the second area according to light sensitivity values ​​collected by pixels in the second area; A second exposure time required to collect the target light sensitivity value in the light sensitivity area is determined according to the average light sensitivity value of the first area, the average light sensitivity value of the second area, and the first exposure time.

13. The method for collecting biometric characteristics according to claim 12, characterized in that: The determining, according to the average light sensitivity value of the first area, the average light sensitivity value of the second area, and the first exposure time, a second exposure time required to collect the target light sensitivity value in the light sensitivity area includes: The second exposure duration is calculated by the following formula: Among them, T2 is the second exposure time, T1 is the first exposure time, Target is the target sensitivity value, Rawmean is the average sensitivity value of the first area, and Darkmean is the average sensitivity value of the second area.

14. The biometric feature collection method according to claim 8, characterized in that: The biometric feature acquisition chip is arranged below the screen, and the filter coefficient is determined according to the structure of the screen; wherein, the structure of the screen is a soft screen or a hard screen, and the filter coefficient determined based on the hard screen is greater than the filter coefficient determined based on the soft screen.

15. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The configuration parameters also include: an upper limit time length corresponding to the photosensitive area and / or a lower limit time length corresponding to the photosensitive area, and collecting a biometric image according to the second exposure time length includes: In the case where the configuration parameters also include the upper limit time length, if the second exposure time length is greater than the upper limit time length, collecting a biometric feature image according to the upper limit time length; In the case where the configuration parameters also include the lower limit time length, if the second exposure time length is less than the lower limit time length, the biometric image is collected according to the lower limit time length.

16. The biometric feature collection method according to claim 15, characterized in that: The biometric feature collection chip is set in the terminal, and the configuration parameters also include an upper limit time length corresponding to the photosensitive area and a lower limit time length corresponding to the photosensitive area, and the upper limit time length and the lower limit time length satisfy the following relationship: T2_max=T0+T0*a1 T2_min=T0-T0*a2 Among them, T0 is the default exposure time of the terminal when it leaves the factory, T2_max is the upper limit time, T2_min is the lower limit time, and a2 is greater than or equal to a1.

17. The biometric feature collection method according to claim 16, characterized in that: The value ranges of a1 and a2 are as follows: 10%≤a1≤30%, 30%≤a2≤50%.

18. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The biometric feature acquisition chip is arranged below the screen, and the configuration parameters also include: a pulse width modulation (PWM) dimming cycle of the screen; The step of collecting a biometric image according to the second exposure duration includes: If the second exposure time is not equal to an integer multiple of the PWM dimming period, adjusting the second exposure time to an integer multiple of the PWM dimming period; The biometric image is collected according to the adjusted second exposure time.

19. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The first exposure duration is greater than 0 milliseconds and less than or equal to 10 milliseconds.

20. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The biometric feature acquisition chip is arranged below the screen, and the target photosensitivity value is determined based on a gain value corresponding to the structure of the screen. The structure of the screen is a soft screen or a hard screen, and the gain value corresponding to the soft screen is greater than the gain value corresponding to the hard screen.

21. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The biometric feature acquisition chip is arranged below the screen, and the area of ​​the first region is determined according to the structure of the screen. The structure of the screen is a soft screen or a hard screen, and the area of ​​the first region determined based on the soft screen is greater than the area of ​​the first region determined based on the hard screen.

22. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The center of the first area is the focusing center of the photosensitive area.

23. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The number of pixels in the first area is an integer multiple of the number of pixels that need to be read out in a one-pixel mode determined based on the image readout mode binning of the biometric feature acquisition chip.

24. The biometric feature collection method according to any one of claims 1 to 5, characterized in that: The biometric feature acquisition chip includes a pixel array having a plurality of pixels, and the step of acquiring a biometric feature image according to the second exposure time includes: According to the second exposure duration, adjusting the parameter value of the first parameter, the parameter value of the second parameter and the parameter value of the third parameter to obtain the target parameter value of the first parameter, the target parameter value of the second parameter and the target parameter value of the third parameter; wherein the first parameter is the duration of the row blanking stage, the second parameter is the duration of the field blanking stage, and the third parameter is the delay duration for starting exposure of each row of pixels; A biometric image is collected according to the target parameter value of the first parameter, the target parameter value of the second parameter, and the target parameter value of the third parameter.

25. The method for collecting biometric characteristics according to claim 24, characterized in that: The adjusting the parameter value of the first parameter, the parameter value of the second parameter, and the parameter value of the third parameter according to the second exposure time to obtain the target parameter value of the first parameter, the target parameter value of the second parameter, and the target parameter value of the third parameter includes: Determine a first scanning time required to scan a single row of pixels and a second scanning time required to scan a single pixel; According to the first relationship, the parameter value of the first parameter is adjusted to obtain a target parameter value of the first parameter; wherein the target parameter value of the first parameter conforms to the first relationship, and the first relationship is: Row_time=(H_Blank+H_Valid)*(1 / pixel_clock) Wherein, Row_time is the first scanning duration, 1 / pixel_clock is the second scanning duration, H_Blank is the parameter value of the first parameter, and H_Valid is the number of pixels in each row of the pixel array; According to the second relationship, the parameter value of the second parameter and the parameter value of the third parameter are adjusted to obtain the target parameter value of the second parameter and the target parameter value of the third parameter; wherein the target parameter value of the second parameter and the target parameter value of the third parameter conform to the second relationship, and the second relationship is: Wherein, T2 is the second exposure time, V_Blank is the parameter value of the second parameter, V_Valid is the total number of rows in the pixel array, and V_Delay is the parameter value of the third parameter.

26. The biometric feature collection method according to claim 25, characterized in that: The configuration parameter also includes: a lower limit parameter value of the first parameter, and adjusting the parameter value of the first parameter according to the first relationship to obtain a target parameter value of the first parameter includes: In the process of adjusting the parameter value of the first parameter according to the first relationship, if the parameter value of the first parameter still fails to meet the first relationship when adjusted to the lower limit parameter value, the lower limit parameter value is used as the target parameter value of the first parameter.

27. A biometric feature collection chip, characterized in that: It includes a processing unit and a storage unit connected to the processing unit, the storage unit stores instructions that can be executed by the processing unit, and the instructions are executed by the processing unit so that the processing unit can execute the biometric collection method as described in any one of claims 1 to 26.

28. A terminal, characterized in that: Comprising the biometric feature collection chip as described in claim 27.

29. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the biometric feature collection method according to any one of claims 1 to 26 is implemented.

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