Under-screen fingerprint collection method, device, terminal and storage medium

Abstract

The embodiments of the present application disclose an under-screen fingerprint collection method, device, terminal and storage medium, which belongs to the field of under-screen fingerprint. The method includes: controlling the image sensor of the under-screen fingerprint module to perform the nth exposure to obtain the nth fingerprint image, the nth fingerprint image is the fingerprint image collected after n exposures; in response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement, controlling the image sensor to perform the n+1th exposure to obtain the n+1th fingerprint image; in response to the nth signal amount of the nth fingerprint image meeting the signal amount requirement, determining the nth fingerprint image as the target fingerprint image. The dynamic exposure time is used to obtain the fingerprint image, so as to avoid the problem of reduced fingerprint image collection quality due to changes in light spot brightness, external environment, screen transmittance and protective film transmittance when setting a fixed exposure time, which helps to improve the collection quality of the fingerprint image and improve the accuracy of fingerprint recognition using the fingerprint image.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of under-screen fingerprint collection, and in particular to an under-screen fingerprint collection method, device, terminal and storage medium. Background Art

[0002] Under-screen fingerprint collection is a technology that sets the fingerprint module under the screen. When the finger touches the screen, the light source emits light to illuminate the finger, and the image sensor of the fingerprint module receives the reflected light to realize fingerprint image collection.

[0003] In related technologies, before leaving the factory, terminals that use under-screen fingerprint collection technology need to set the exposure time of the image sensor in the fingerprint module based on factors such as the brightness of the light spot formed by the light source and the screen transmittance. When fingerprint images are subsequently collected, the image sensor collects fingerprint images based on the exposure time. Summary of the invention

[0004] The embodiments of the present application provide a method, device, terminal and storage medium for collecting fingerprints under the screen. The technical solution is as follows:

[0005] On the one hand, an embodiment of the present application provides an under-screen fingerprint collection method, the method is used for a terminal provided with an under-screen fingerprint module, the method comprising:

[0006] Controlling the image sensor of the under-screen fingerprint module to perform an nth exposure to obtain an nth fingerprint image, where the nth fingerprint image is a fingerprint image collected after n exposures, and n is a positive integer;

[0007] In response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement, controlling the image sensor to perform an n+1th exposure to obtain an n+1th fingerprint image;

[0008] In response to the nth signal amount of the nth fingerprint image satisfying the signal amount requirement, the nth fingerprint image is determined as a target fingerprint image.

[0009] On the other hand, an embodiment of the present application provides an under-screen fingerprint collection device, the device comprising:

[0010] A control module, used to control the image sensor of the under-screen fingerprint module to perform an n-th exposure to obtain an n-th fingerprint image, wherein the n-th fingerprint image is a fingerprint image collected after n exposures, and n is a positive integer;

[0011] The control module is further configured to control the image sensor to perform an (n+1)th exposure to obtain an (n+1)th fingerprint image in response to the nth signal amount of the (n)th fingerprint image not satisfying the signal amount requirement;

[0012] The first determining module is configured to determine the nth fingerprint image as a target fingerprint image in response to the nth signal quantity of the nth fingerprint image satisfying a signal quantity requirement.

[0013] On the other hand, an embodiment of the present application provides a terminal, which includes a processor, a memory and an under-screen fingerprint module, wherein the memory stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement the under-screen fingerprint collection method as described in the above aspects.

[0014] On the other hand, an embodiment of the present application provides a computer-readable storage medium, in which at least one program code is stored, and the program code is loaded and executed by a processor to implement the under-screen fingerprint collection method as described in the above aspects.

[0015] On the other hand, an embodiment of the present application provides a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. The processor of the terminal reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the terminal executes the under-screen fingerprint collection method provided in various optional implementations of the above aspects.

[0016] The technical solution provided in the embodiments of the present application can bring the following beneficial effects:

[0017] In an embodiment of the present application, the terminal controls the image sensor of the fingerprint module under the screen to perform continuous exposure, and determines whether the fingerprint image meets the information amount requirement based on the amount of information of the fingerprint image collected after each exposure, and if the information amount requirement is not met, continues to control the image sensor for exposure until the exposure is met. The terminal uses dynamic exposure time to obtain the fingerprint image, and there is no need to set a fixed exposure time at the factory. It can also avoid the problem of reduced fingerprint image acquisition quality due to changes in light spot brightness, external environment, screen transmittance and protective film transmittance when a fixed exposure time is set, which helps to improve the acquisition quality of the fingerprint image, and thereby improve the accuracy of subsequent fingerprint recognition using the fingerprint image. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A structural block diagram of a terminal provided by an exemplary embodiment of the present application is shown;

[0020] Figure 2 is a schematic diagram showing the principle of an under-screen fingerprint collection process according to an exemplary embodiment;

[0021] Figure 3 It is a flow chart of an under-screen fingerprint collection method provided by an exemplary embodiment of the present application;

[0022] Figure 4 is a flow chart of an under-screen fingerprint collection method provided by another exemplary embodiment of the present application;

[0023] Figure 5 is a schematic diagram of an implementation of an under-screen fingerprint collection process shown in an exemplary embodiment of the present application;

[0024] Figure 6 is a flow chart of an under-screen fingerprint collection method provided by another exemplary embodiment of the present application;

[0025] Figure 7 is a flow chart of an under-screen fingerprint collection method provided by another exemplary embodiment of the present application;

[0026] Figure 8 is a schematic diagram of an implementation of an under-screen fingerprint collection process shown in another exemplary embodiment of the present application;

[0027] Fig. 9 A structural block diagram of an under-screen fingerprint collection device provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0029] Please refer to Figure 1 , which shows a block diagram of a terminal provided by an exemplary embodiment of the present application. The terminal 1000 may be a smart phone, a tablet computer, a wearable device, etc. The terminal 1000 in the present application may include one or more of the following components: a processor 1010, a memory 1020, and an under-screen fingerprint module 1030.

[0030] The processor 1010 may include one or more processing cores. The processor 1010 uses various interfaces and lines to connect the various parts of the entire terminal 1000, and executes various functions and processes data of the terminal 1000 by running or executing instructions, programs, code sets or instruction sets stored in the memory 1020, and calling data stored in the memory 1020. Optionally, the processor 1010 can be implemented in at least one hardware form of digital signal processing (DSP), field programmable gate array (FPGA), and programmable logic array (PLA). The processor 1010 can integrate one or more combinations of a central processing unit (CPU), a graphics processing unit (GPU), a neural network processor (NPU), and a modem. Among them, the CPU mainly processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; the NPU is used to implement artificial intelligence (AI) functions; and the modem is used to process wireless communications. It is understandable that the above-mentioned modem may not be integrated into the processor 1010, but may be implemented by a separate chip.

[0031] The memory 1020 may include a random access memory (RAM) or a read-only memory (ROM). Optionally, the memory 1020 includes a non-transitory computer-readable storage medium. The memory 1020 may be used to store instructions, programs, codes, code sets, or instruction sets. The memory 1020 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the following various method embodiments, etc.; the data storage area may store data created according to the use of the terminal 1000 (such as audio and video data, fingerprint data, application data), etc.

[0032] The under-screen fingerprint module 1030 is a component set under the display screen for collecting fingerprint images when the finger touches the display screen. Among them, the terminal 1000 can be provided with a single under-screen fingerprint module 1030, and the under-screen fingerprint module 1030 is set below the fixed display screen area (usually set below the lower middle display screen, which is convenient for users to enter fingerprints when holding the terminal 1000 with one hand), and users can only realize fingerprint collection and recognition by touching the fixed display screen area; or, the terminal 1000 can be provided with multiple under-screen fingerprint modules 1030, and multiple under-screen fingerprint modules 1030 are distributed below different display screen areas, and users can realize fingerprint collection and recognition by touching any display screen area.

[0033] The key component of the screen fingerprint module 1030 for realizing fingerprint image acquisition is the image sensor, which can be a complementary metal oxide semiconductor (CMOS). When fingerprint image acquisition is performed, fingerprint image acquisition is achieved by controlling the exposure of the image sensor.

[0034] In the embodiment of the present application, the terminal 1000 is also provided with a display screen, which can be a liquid crystal display (LCD) display screen or an organic light-emitting diode (OLED) display screen. When an LCD display screen is used, the terminal 1000 uses an external light source as an excitation light source for fingerprint image acquisition (i.e., a light source that provides light to illuminate the finger), and when an OLED display screen is used, the self-luminous unit in the display screen area corresponding to the screen fingerprint module 1030 is used as an excitation light source for fingerprint image acquisition. In some embodiments, the display screen also has a touch function, so that when a touch signal is detected, the excitation light source is controlled to emit light, and the fingerprint module 1030 under the screen is controlled to perform fingerprint image acquisition.

[0035] In addition, those skilled in the art will appreciate that the structure of the terminal 1000 shown in the above figures does not constitute a limitation on the terminal, and the terminal may include more or fewer components than shown, or combine certain components, or arrange the components differently. For example, the terminal 1000 also includes components such as sensors, speakers, power supplies, and wireless communication components, which will not be described in detail here.

[0036] Take the terminal equipped with OLED display as an example. Figure 2As shown, an OLED substrate 22 is disposed below the touch panel 21 of the terminal, a light-emitting diode 23 is disposed on the OLED substrate 22, and an under-screen fingerprint module 24 is disposed below the OLED substrate 22, and the under-screen fingerprint module 24 includes an image sensor 25. When the user's finger 26 touches the touch panel 21, the light emitted by the light-emitting diode 23 passes through the touch panel 21 to illuminate the finger 26, and is reflected on the surface of the finger 26. The reflected light passes through the gap between the light-emitting diodes 23 and is received by the image sensor 25 in an exposed state, thereby realizing fingerprint image acquisition.

[0037] It can be seen that in the under-screen fingerprint collection technology based on the reflection principle, the collection quality of the fingerprint image is closely related to factors such as screen transmittance and light source brightness. Due to differences between different terminals, in order to improve the collection quality of fingerprint images, in related technologies, terminals need to undergo under-screen fingerprint calibration before leaving the factory, thereby fixing the exposure time of the image sensor so that the image sensor can be controlled for image collection based on the exposure time. Among them, when performing under-screen fingerprint calibration, it is necessary to calculate the exposure time of the image processor based on parameters such as light source brightness and screen transmittance.

[0038] However, in actual usage scenarios, the brightness of the light source will decrease as the terminal is used for longer, and the user may put a protective film on the screen surface. If the fixed exposure time is still used, the fingerprint image quality may be reduced due to insufficient exposure time, thereby reducing the fingerprint recognition accuracy.

[0039] However, in the under-screen fingerprint collection method provided in the embodiment of the present application, the terminal does not control the image sensor of the under-screen fingerprint module based on a fixed exposure time, but adopts a continuous exposure method to control the image sensor to perform multiple exposures in succession, and performs a signal amount detection on the fingerprint image collected after each exposure. When the signal amount does not meet the requirements, the image sensor continues to be controlled to be exposed until the signal amount meets the requirements. Compared with fingerprint image acquisition based on a fixed exposure time, the dynamic exposure scheme provided in the embodiment of the present application is adopted. On the one hand, since the terminal can adaptively extend or shorten the exposure time of the image sensor according to the signal amount of the fingerprint image actually collected, so that the fingerprint images collected in different scenarios have sufficient signal amount, there is no need to set a fixed exposure time to ensure that the collected fingerprint image has sufficient signal amount, thereby eliminating the under-screen fingerprint calibration process before the terminal leaves the factory, and realizing the under-screen fingerprint calibration-free before the terminal leaves the factory; on the other hand, it can avoid the problem of reduced fingerprint image acquisition quality due to changes in light source brightness, external environment, screen transmittance and protective film transmittance, and avoid underexposure or overexposure problems when using a fixed exposure time for exposure in certain usage scenarios, ensuring that high-quality fingerprint images can be collected in different usage scenarios, thereby improving the accuracy of subsequent fingerprint recognition using fingerprint images.

[0040] Please refer to Figure 3 , which shows a flow chart of an under-screen fingerprint collection method provided by an exemplary embodiment of the present application. In this embodiment, the method is used for Figure 1 Taking the terminal shown in FIG. 1 as an example, the method includes:

[0041] Step 301, control the image sensor of the fingerprint module under the screen to perform the nth exposure to obtain the nth fingerprint image, the nth fingerprint image is the fingerprint image collected after n exposures, and n is a positive integer.

[0042] In one possible implementation, in response to a fingerprint collection instruction, the terminal controls the image sensor of the fingerprint module under the screen to expose, wherein the fingerprint collection instruction can be triggered when the display screen receives a touch operation, and the touch operation includes a fingerprint unlocking operation, a fingerprint payment operation, or a fingerprint entry operation, etc. This embodiment is not limited to this.

[0043] In the embodiment of the present application, the terminal does not control the image sensor to perform a single long exposure, but controls the image sensor to perform multiple short exposures in succession. For example, in the related art, the terminal controls the image sensor to perform a single exposure with an exposure time of 40ms, while in the embodiment of the present application, when the terminal controls the image sensor to perform multiple exposures in succession, each exposure time is 5ms.

[0044] Accordingly, during the fingerprint image acquisition process, the terminal does not acquire a single fingerprint image, but acquires a fingerprint image after each exposure. Regarding the method of obtaining the nth fingerprint image after the nth exposure, in a possible implementation, the image sensor acquires a fingerprint image each time it is exposed, and the nth fingerprint image is obtained by superimposing the fingerprint images acquired after the current round (i.e., the nth round) and the exposures before the current round (i.e., the 1st to the n-1th times).

[0045] It should be noted that the nth fingerprint image is the original fingerprint image collected by the image sensor, that is, unprocessed data (raw data).

[0046] Step 302: In response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement, the image sensor is controlled to perform an (n+1)th exposure to obtain an (n+1)th fingerprint image.

[0047] After obtaining the nth fingerprint image, the terminal obtains the nth signal quantity of the nth fingerprint image and detects whether the nth signal quantity meets the signal quantity requirement. The signal quantity requirement is preset in the terminal and is used to represent the signal quantity required to be achieved when the collected fingerprint image meets the requirement (recognition requirement or entry requirement).

[0048] In a possible implementation, the signal quantity requirements in different terminals are uniformly set, and there is no need to calibrate and set the terminals one by one before leaving the factory.

[0049] Regarding the specific method of obtaining the nth amount of information, in one possible implementation, the under-screen fingerprint module determines the nth signal amount of the nth fingerprint image based on the grayscale value (used to characterize the degree of brightness, also known as grayscale or color scale) of each pixel in the nth fingerprint image, and outputs the nth signal amount to the terminal.

[0050] When the exposure time of the image sensor is insufficient, the nth signal amount does not meet the signal amount requirement. In order to further improve the signal amount of the fingerprint image, the terminal controls the image sensor to perform the next exposure, thereby obtaining the n+1th fingerprint image. Correspondingly, the signal amount of the n+1th fingerprint image is the n+1th signal amount.

[0051] The process of controlling the image sensor to perform the (n+1)th exposure is similar to the process of performing the (n)th exposure, and will not be described in detail in this embodiment.

[0052] Since the n+1th fingerprint image is the fingerprint image collected after n+1 exposures, that is, it is generated based on the nth fingerprint image, the signal amount of the n+1th fingerprint image is greater than the signal of the nth fingerprint image, that is, as the number of exposures increases, the signal amount of the fingerprint image continues to increase.

[0053] Step 303: In response to the nth signal quantity of the nth fingerprint image satisfying the signal quantity requirement, the nth fingerprint image is determined as a target fingerprint image.

[0054] When the exposure time of the image sensor is sufficient, the nth signal quantity meets the signal quantity requirement. In order to avoid overexposure of the fingerprint image caused by continued exposure, the terminal controls the image sensor to stop exposure and determines the nth fingerprint image as the target fingerprint image.

[0055] In one possible implementation, when under-screen fingerprint collection is triggered in a fingerprint entry scenario, the terminal uses the target fingerprint image as a fingerprint template and stores it; when under-screen fingerprint collection is triggered in a fingerprint recognition scenario, the terminal matches the target fingerprint image with the fingerprint template to obtain a fingerprint recognition result, and then executes subsequent processes based on the fingerprint recognition result, such as fingerprint payment, fingerprint unlocking, etc.

[0056] By adopting the solution provided in the embodiment of the present application, the terminal no longer controls the image sensor to collect fingerprint images based on the exposure time, but controls the image sensor to collect fingerprint images based on the signal amount, thereby adaptively adjusting the exposure time of the image sensor in different situations, thereby ensuring the collection quality of the fingerprint image.

[0057] It should be noted that, because the exposure time of the image sensor is different in different situations, the terminal needs to control the light source based on the total exposure time of the image sensor. For example, during continuous exposure and image acquisition, the terminal controls the light-emitting diodes in the display area corresponding to the fingerprint module under the screen in the OLED display to be lit, and after the exposure and image acquisition is completed, the light-emitting diodes in the display area are turned off.

[0058] In a possible application scenario, for a terminal equipped with an OLED display and an under-screen fingerprint module, in the initial use, the screen brightness is high and no protective film is affixed. At this time, after the terminal controls the image sensor to perform 4 exposures, the signal amount of the collected fingerprint image meets the signal amount requirement, and the fingerprint image collection time is 4 exposure times.

[0059] When the user sticks a protective film on the terminal screen, the overall transmittance of the screen is reduced. Therefore, the terminal controls the image sensor to perform 5 exposures before the signal amount of the collected fingerprint image can meet the signal amount requirement. The collection time of the fingerprint image is 5 exposure times.

[0060] As the terminal usage time increases, the screen brightness decreases. Therefore, the terminal controls the image sensor to perform 6 exposures before the signal amount of the collected fingerprint image meets the signal amount requirement. The collection time of the fingerprint image is 6 exposure times.

[0061] To sum up, in the embodiment of the present application, the terminal controls the image sensor of the under-screen fingerprint module to perform continuous exposure, and determines whether the fingerprint image meets the information amount requirement based on the amount of information of the fingerprint image collected after each exposure, and if the information amount requirement is not met, continues to control the image sensor for exposure until the exposure is met. The terminal uses dynamic exposure time to obtain the fingerprint image, and there is no need to set a fixed exposure time at the factory. It can also avoid the problem of reduced fingerprint image acquisition quality due to changes in light spot brightness, external environment, screen transmittance and protective film transmittance when a fixed exposure time is set, which helps to improve the acquisition quality of the fingerprint image, and thereby improve the accuracy of subsequent fingerprint recognition using the fingerprint image.

[0062] Regarding the specific method of determining whether the semaphore requirement is met, in one possible implementation, a target semaphore corresponding to the fingerprint image is preset in the terminal. Accordingly, after obtaining the nth fingerprint image, the terminal determines whether the nth semaphore meets the semaphore requirement based on the nth semaphore and the target semaphore.

[0063] In some embodiments, the target signal quantity can be set in different forms. For example, the target signal quantity can be a single value or a value range composed of two values. Correspondingly, for target signal quantities in different settings, the terminal determines whether the signal quantity meets the signal quantity requirements in different ways. The following embodiments will be used to illustrate these differences.

[0064] Please refer to Figure 4 , which shows a flow chart of an under-screen fingerprint collection method provided by another exemplary embodiment of the present application. In this embodiment, the method is used for Figure 1 Taking the terminal shown in FIG. 1 as an example, the method includes:

[0065] Step 401, control the image sensor of the fingerprint module under the screen to perform the nth exposure to obtain the nth fingerprint image, the nth fingerprint image is the fingerprint image collected after n exposures, and n is a positive integer.

[0066] The implementation of this step may refer to the above step 301, and this embodiment will not be described in detail here.

[0067] Step 402: determine the absolute value of the difference between the nth signal amount and the first target signal amount.

[0068] The terminal is preset with a first target signal amount, which is obtained by analyzing the signal amounts corresponding to a large number of standard fingerprint images, wherein the standard fingerprint image is a fingerprint image whose recognition accuracy meets the accuracy requirement (for example, above 95%). For example, the first target signal amount is set to 1800.

[0069] Optionally, the first target signal quantities set in different terminals are the same.

[0070] In a possible implementation, when the signal amount of the actual fingerprint image is slightly less than or slightly greater than the first target signal amount, the fingerprint image is considered to meet the signal amount requirement. Therefore, in this embodiment, after the terminal obtains the nth signal amount of the nth fingerprint image, it calculates the absolute value of the signal amount difference between the nth signal amount and the first target signal amount, and detects whether the absolute value of the signal amount difference is greater than the difference threshold. If the signal amount difference is greater than or equal to the difference threshold, the terminal executes steps 403 to 404, and if the absolute value of the signal amount difference is less than the difference threshold, the terminal executes steps 405 to 406.

[0071] In an illustrative example, W is the first target signal, B n is the nth semaphore, and the absolute value of the semaphore difference is |WB n |, when |WB n |≥100, the terminal executes steps 403 to 404. When |WB n|<100, the terminal executes steps 405 to 406.

[0072] Step 403: In response to the absolute value of the semaphore difference being greater than or equal to the difference threshold, it is determined that the nth semaphore does not meet the semaphore requirement.

[0073] When the fingerprint image is collected by continuous multiple exposure, since the total exposure time of the image sensor in the initial stage of continuous exposure is short, the signal amount of the fingerprint image is small and less than the first target signal amount. Correspondingly, the absolute value of the signal amount difference between the signal amount of the fingerprint image and the first target signal amount is greater than the difference threshold, and the terminal determines that the signal amount requirement is not met.

[0074] Step 404: in response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement, controlling the image sensor to perform an (n+1)th exposure to obtain an (n+1)th fingerprint image.

[0075] The implementation of this step may refer to the above step 302, and this embodiment will not be described in detail here.

[0076] Indicative, such as Figure 5 As shown, the terminal controls the image sensor in the fingerprint module under the screen to perform the first exposure, and obtains the first signal amount of the first fingerprint image as 900. When the first target signal value is 1800, since the absolute value of the difference between the signal amounts of the two is 900>100 (difference threshold), the terminal determines that the signal amount requirement is not met and performs a second exposure.

[0077] Since the second signal amount of the second fingerprint image obtained after the second exposure is 1100, and the absolute value of the signal amount difference with the first target signal value is 700>100, the terminal determines that the signal amount requirement is still not met and performs a third exposure.

[0078] Since the third signal amount of the third fingerprint image obtained after the third exposure is 1350, and the absolute value of the signal amount difference with the first target signal value is 450>100, the terminal determines that the signal amount requirement is still not met and performs the fourth exposure.

[0079] Step 405: In response to the absolute value of the semaphore difference being less than the difference threshold, determining that the nth semaphore meets the semaphore requirement.

[0080] As the number of continuous exposures increases, the total exposure time of the image sensor gradually increases, and the signal amount of the fingerprint image also gradually increases. Correspondingly, the absolute value of the signal amount difference between the signal amount of the fingerprint image and the first target signal amount gradually decreases (the signal amount of the fingerprint image gradually approaches the first target signal amount or even slightly exceeds the first target signal amount). When the absolute value of the signal amount difference is less than the difference threshold, the terminal determines that the signal amount requirement is met.

[0081] Step 406: In response to the nth signal quantity of the nth fingerprint image satisfying the signal quantity requirement, the nth fingerprint image is determined as a target fingerprint image.

[0082] The implementation of this step may refer to the above step 303, and this embodiment will not be described in detail here.

[0083] Indicative, such as Figure 5 As shown, since the fourth signal amount of the fourth fingerprint image obtained after the fourth exposure is 1760, and the absolute value of the signal amount difference with the first target signal value is 40<100, the terminal determines that the signal amount requirement is met, thereby controlling the image sensor to stop exposure, and determines the fourth fingerprint image as the target fingerprint image.

[0084] In another possible implementation, the terminal is provided with a second target signal amount and a third target signal amount, and the second target signal amount and the third target signal amount constitute a target signal amount interval. The terminal determines whether the signal amount requirement is met by detecting whether the signal amount of the fingerprint image belongs to the target signal amount area interval.

[0085] Optionally, in response to the nth semaphore not belonging to the target semaphore interval, the terminal determines that the nth semaphore does not meet the semaphore requirement; in response to the nth semaphore belonging to the target semaphore interval, the terminal determines that the nth semaphore meets the semaphore requirement.

[0086] In some embodiments, the second target signal amount is less than the third target signal amount, and the terminal compares the magnitude relationship between the nth signal amount and the second target signal amount, and compares the magnitude relationship between the nth signal amount and the third target signal amount. If the nth signal amount is greater than or equal to the second target signal amount, and the nth signal amount is less than or equal to the third target signal amount, it is determined that the signal amount requirement is met. If the nth signal amount is less than the second target signal amount, or the nth signal amount is greater than the third target signal amount, it is determined that the signal amount requirement is not met.

[0087] In an illustrative example, the second target semaphore is 1700, and the third target semaphore is 2000. Figure 5 As shown, since the signal amount of the fingerprint image collected by the first to third exposures is outside [1700,2000], the terminal determines that the signal amount requirement is not met; and the signal amount of the fingerprint image collected by the fourth exposure is within [1700,2000], the terminal determines that the signal amount requirement is met.

[0088] By adopting the solution provided in the above embodiment, the terminal only needs to pre-set a unified target signal amount before leaving the factory. There is no need to calculate and set the exposure time one by one according to parameters such as the screen transmittance and light source brightness of the terminal, thereby eliminating the calibration process and realizing fingerprint image acquisition without calibration.

[0089] Regarding the exposure duration of each exposure during the under-screen fingerprint collection process, in a possible implementation, the terminal uses a uniform exposure duration each time it controls the image sensor to expose.

[0090] Optionally, the terminal controls the image sensor to perform an nth exposure based on the first exposure duration to obtain an nth fingerprint image, wherein the exposure duration of each exposure of the image sensor is the first exposure duration.

[0091] The first exposure time can be preset in the terminal together with the target signal amount. When the fingerprint image is collected, the terminal reads the first exposure time and the target signal amount.

[0092] Indicative, such as Figure 5 As shown, the first exposure time is 5ms. When the signal amount of the fingerprint image does not meet the signal amount requirement, the terminal controls the image sensor to expose for 5ms and obtains the newly collected fingerprint image. Of course, the first exposure time can also use other values, which are not limited in this embodiment.

[0093] In actual application scenarios, the acquisition quality of the fingerprint image under the screen may also be affected by external environmental factors. For example, in a strong light environment, ambient light may be collected by the image sensor through the screen, and collecting too much ambient light will cause the fingerprint image to be overexposed. In order to further improve the acquisition quality of the fingerprint image, in a possible implementation, the terminal can adjust the first exposure time based on external environmental factors.

[0094] Please refer to Figure 6 , which shows a flow chart of an under-screen fingerprint collection method provided by another exemplary embodiment of the present application. In this embodiment, the method is used for Figure 1 Taking the terminal shown in FIG. 1 as an example, the method includes:

[0095] Step 601, in response to a fingerprint collection instruction, obtain the ambient light brightness.

[0096] The ambient light brightness is collected by an ambient light sensor provided in the terminal. Optionally, when a touch operation is received on the fingerprint recognition area under the display screen, the terminal obtains the ambient light brightness collected by the ambient light sensor, and the touch operation includes a fingerprint unlocking operation, a fingerprint payment operation, or a fingerprint entry operation, etc.

[0097] Step 602: determining a first exposure time based on the ambient light brightness, wherein the first exposure time is negatively correlated with the ambient light brightness.

[0098] In a possible implementation, the terminal is preset with a correspondence between ambient light brightness and exposure duration, which may be a correspondence table or a functional relationship, which is not limited in this embodiment. Accordingly, the terminal determines the first exposure duration corresponding to the ambient light brightness based on the correspondence.

[0099] Since the longer the exposure time, the higher the probability that the image sensor will collect ambient light, and the higher the ambient light brightness, the greater the impact on the collection of the fingerprint image, the terminal controls the first exposure time of the image sensor each time and is negatively correlated with the ambient light brightness, that is, the higher the ambient light brightness, the shorter the first exposure time, and conversely, the weaker the ambient light brightness, the longer the first exposure time.

[0100] In an illustrative example, if the current ambient light brightness is 5000 lx, the terminal determines that the first exposure time is 5 ms; if the current ambient light brightness is 10000 lx, the terminal determines that the first exposure time is 3 ms.

[0101] Step 603: Based on the first exposure duration, control the image sensor to perform an nth exposure to obtain an nth fingerprint image, wherein the exposure duration of each exposure of the image sensor is the first exposure duration.

[0102] Further, after the first exposure duration is determined based on the ambient light brightness, the terminal uses the first exposure duration each time it controls the image sensor to expose.

[0103] Step 604: In response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement, the image sensor is controlled to perform an (n+1)th exposure to obtain an (n+1)th fingerprint image.

[0104] Step 605: In response to the nth signal quantity of the nth fingerprint image satisfying the signal quantity requirement, the nth fingerprint image is determined as a target fingerprint image.

[0105] In this embodiment, the terminal determines the exposure time based on the ambient light brightness, and controls the image sensor to perform multiple continuous exposures with the exposure time. On the one hand, it simplifies the implementation process of the dynamic exposure scheme, and on the other hand, it reduces the probability of overexposure of the collected fingerprint image due to excessive ambient light, thereby improving the collection quality and collection success rate of fingerprint images in strong light environments.

[0106] When the image sensor is controlled to perform continuous exposure based on the first exposure duration, since the first exposure duration is usually set to a shorter duration, the signal amount of the fingerprint image in the early stage of continuous exposure is usually small and cannot meet the signal amount requirement. Accordingly, it is not meaningful to perform signal amount requirement detection in the early stage of continuous exposure. Therefore, in order to avoid meaningless signal amount requirement detection, in another possible implementation, the terminal can control the image sensor to use the exposure duration corresponding to the current exposure round (that is, the exposure duration of each exposure is not the same) according to the current exposure round, so that the exposure duration in the early stage of continuous exposure is longer than the exposure duration in the later stage of continuous exposure, thereby reducing the frequency of signal amount detection in the early stage of continuous exposure.

[0107] Please refer to Figure 7 , which shows a flow chart of an under-screen fingerprint collection method provided by another exemplary embodiment of the present application. In this embodiment, the method is used for Figure 1 Taking the terminal shown in FIG. 1 as an example, the method includes:

[0108] Step 701, based on the current exposure round, determine a second exposure duration, where the second exposure duration is negatively correlated with the current exposure round.

[0109] In a possible implementation, a correspondence between exposure rounds and exposure durations is preset in the terminal, and the correspondence may be a correspondence table or a functional relationship, which is not limited in this embodiment. Accordingly, the terminal determines the second exposure duration corresponding to the current exposure round based on the correspondence.

[0110] In order to reduce the frequency of signal detection in the early stage of continuous exposure, the second exposure duration is negatively correlated with the current exposure round, that is, the exposure duration of each exposure in the early stage of continuous exposure is greater than the exposure duration of each exposure in the late stage of continuous exposure.

[0111] Optionally, if the current exposure round is the first time, the terminal determines the second exposure duration as a first value; if the current exposure round is the mth time, the terminal determines the second exposure duration as a second value, wherein the first value is greater than the second value, and m is an integer greater than or equal to 2.

[0112] Indicative, such as Figure 8 As shown, if the current exposure round is the first, the terminal determines that the second exposure duration is 15ms, and when the second exposure starts, the terminal determines that the second exposure duration is 5ms. It can be seen that, by adopting the solution provided in this embodiment, in the first 15ms of fingerprint image acquisition, the terminal only needs to perform one exposure and signal detection, while the uniform exposure duration continuous exposure solution (such as Figure 5 ), in the first 15ms of fingerprint image acquisition, the terminal needs to perform three exposures and signal detection.

[0113] Of course, in addition to using a longer exposure time in the first round and using a uniform and shorter second exposure time starting from the second round, in other possible ways, the terminal can use different exposure times in each round, such as 15ms, 10ms, 8ms, 5ms, etc., which is not limited in this embodiment.

[0114] and Figure 6 Similar to the illustrated embodiment, in order to reduce the impact of external environmental factors on the quality of fingerprint image acquisition and improve the acquisition quality of fingerprint images, in a possible implementation manner, in response to a fingerprint acquisition instruction, the terminal obtains the ambient light brightness. Further, when determining the second exposure time based on the current exposure round, the terminal determines the second exposure time based on the ambient light brightness and the current exposure round, wherein the second exposure time is negatively correlated with the ambient light brightness, that is, under the same exposure round, the higher the ambient light brightness, the shorter the second exposure time used, and the lower the ambient light brightness, the longer the second exposure time used.

[0115] In an illustrative example, if the current ambient light brightness is 5000lx, during the first exposure, the terminal determines that the exposure time used is 20ms, and starting from the second exposure, the terminal determines that the exposure time used is 5ms; if the current ambient light brightness is 10000lx, during the first exposure, the terminal determines that the exposure time used is 15ms, and starting from the second exposure, the terminal determines that the exposure time used is 4ms.

[0116] Step 702: Based on the second exposure time, control the image sensor to perform an nth exposure to obtain an nth fingerprint image.

[0117] Correspondingly, the terminal controls the image sensor to perform the nth exposure based on the determined second exposure duration to obtain the nth fingerprint image.

[0118] Step 703: In response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement, the image sensor is controlled to perform an (n+1)th exposure to obtain an (n+1)th fingerprint image.

[0119] It should be noted that before controlling the image sensor to perform the n+1th exposure, the terminal needs to determine the second exposure duration based on the current exposure round (i.e., the n+1th exposure) so as to perform the n+1th exposure and image acquisition based on the determined second exposure duration.

[0120] Step 704: In response to the nth signal quantity of the nth fingerprint image satisfying the signal quantity requirement, the nth fingerprint image is determined as a target fingerprint image.

[0121] In this embodiment, the terminal dynamically determines the exposure time of the image sensor during this exposure based on the current exposure round, thereby reducing the exposure and signal detection frequency in the early stage of continuous exposure, avoiding the waste of processing resources caused by meaningless signal detection in the early stage, and reducing the power consumption of fingerprint collection under the screen while ensuring the quality of fingerprint image collection. In addition, in this embodiment, the terminal determines the exposure time in combination with the ambient light brightness, reducing the probability of overexposure of the collected fingerprint image due to excessive ambient light, and further improving the collection quality and collection success rate of fingerprint images in strong light environments.

[0122] In addition to dynamically determining the exposure duration based on the current exposure round, in other possible implementations, the terminal may also dynamically determine the exposure duration used in the current exposure round based on the signal amount of the fingerprint image obtained by the previous exposure. Optionally, the terminal determines the third exposure duration based on the n-1th signal amount of the n-1th fingerprint image, wherein the third exposure duration is negatively correlated with the n-1th signal amount.

[0123] Since the signal amount of the fingerprint image gradually increases and gradually approaches the target signal amount with the increase of the number of exposure times, in some embodiments, the terminal determines the third exposure time based on the signal amount difference between the n-1th signal amount and the target signal amount, wherein the third exposure time is positively correlated with the signal amount difference, that is, the smaller the signal amount difference is (that is, the closer the n-1th signal amount is to the target signal amount), the shorter the third exposure time is, thereby improving the acquisition speed of the target fingerprint image; conversely, the larger the signal amount difference is, the longer the third exposure time is, thereby reducing the number of continuous exposures and the signal amount detection frequency.

[0124] Further, the terminal controls the image sensor to perform an nth exposure based on the third exposure duration to obtain an nth fingerprint image.

[0125] Optionally, the correspondence between the third exposure duration and the signal quantity difference may be preset in the terminal.

[0126] In an illustrative example, during the first exposure, the terminal controls the image sensor to expose for 5ms, and obtains a first signal amount of 900 for the first fingerprint image; during the second exposure, the terminal determines the exposure time of the second exposure to be 15ms (corresponding to the signal amount difference of 900) based on the first signal amount 900 and the target signal amount 1800, thereby controlling the image sensor to expose for 10ms, and obtains a second signal amount of 1400 for the second fingerprint image; during the third exposure, the terminal determines the exposure time of the third exposure to be 5ms (corresponding to the signal amount difference of 400) based on the second signal amount 1400 and the target signal amount 1800, thereby controlling the image sensor to expose for 5ms, and obtains a third signal amount of 1850 for the third fingerprint image, and then determines the third fingerprint image as the target fingerprint image.

[0127] It should be noted that when dynamically determining the exposure time used in the current exposure round based on the signal amount of the fingerprint image obtained in the last exposure, the terminal can also fine-tune the determined exposure time based on the ambient light brightness. For example, when the ambient light intensity is too high, the determined exposure time is reduced. This embodiment will not be repeated here.

[0128] In actual application scenarios, if the transmittance of the protective film used is poor, or the screen brightness attenuation is too serious, the acquisition of the target fingerprint image takes too long, affecting the user experience. In order to determine whether there is an abnormality in the time spent on acquiring the target fingerprint image, after the target fingerprint image is acquired using the solutions provided in the above embodiments, the terminal determines the total exposure time of n exposures and detects whether the total exposure time is greater than the time threshold (for example, 40ms). If it is greater than the time threshold, it is determined that there is an abnormality in the fingerprint image acquisition, and a prompt message is displayed.

[0129] Optionally, when a uniform exposure duration is used for each exposure, the total exposure duration = n × single exposure duration; when the exposure duration used for each exposure is dynamically determined based on the signal amount of the fingerprint image obtained in the exposure round or the last image acquisition, the total exposure duration is the cumulative result of the exposure duration used for each exposure.

[0130] Optionally, the terminal determines the cause of the abnormality based on the usage time and the protective film information (such as the type or model of the protective film), and displays the cause of the abnormality as prompt information so that the user can troubleshoot the abnormality based on the prompt information.

[0131] The following is an embodiment of the device of the present application, which can be used to execute the embodiment of the method of the present application. For details not disclosed in the embodiment of the device of the present application, please refer to the embodiment of the method of the present application.

[0132] Please refer to Fig. 9 , which shows a structural block diagram of an under-screen fingerprint collection device provided by an embodiment of the present application. The device may include:

[0133] The control module 910 is used to control the image sensor of the under-screen fingerprint module to perform an n-th exposure to obtain an n-th fingerprint image, where the n-th fingerprint image is a fingerprint image collected after n exposures, and n is a positive integer;

[0134] The control module 910 is further configured to control the image sensor to perform an (n+1)th exposure to obtain an (n+1)th fingerprint image in response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement;

[0135] The first determination module 920 is configured to determine the nth fingerprint image as a target fingerprint image in response to the nth signal amount of the nth fingerprint image satisfying a signal amount requirement.

[0136] Optionally, the device comprises:

[0137] The second determination module is used to determine whether the nth semaphore meets the semaphore requirement based on the nth semaphore and a target semaphore, and the target semaphore is preset in the terminal.

[0138] Optionally, the target signal quantity is a first target signal quantity;

[0139] The second determining module is used to:

[0140] Determine an absolute value of a signal quantity difference between the nth signal quantity and the first target signal quantity;

[0141] In response to an absolute value of the semaphore difference being less than a difference threshold, determining that the nth semaphore meets the semaphore requirement;

[0142] In response to the absolute value of the semaphore difference being greater than or equal to the difference threshold, it is determined that the nth semaphore does not meet the semaphore requirement.

[0143] Optionally, the target signal quantity includes a second target signal quantity and a third target signal quantity, and the second target signal quantity and the third target signal quantity constitute a target signal quantity interval;

[0144] The second determining module is used to:

[0145] In response to the nth semaphore belonging to the target semaphore interval, determining that the nth semaphore meets the semaphore requirement;

[0146] In response to the nth semaphore not belonging to the target semaphore interval, it is determined that the nth semaphore does not meet the semaphore requirement.

[0147] Optionally, the control module 910 is used to:

[0148] Based on the first exposure duration, the image sensor is controlled to perform an n-th exposure to obtain the n-th fingerprint image, wherein the exposure duration of each exposure of the image sensor is the first exposure duration.

[0149] Optionally, the device further comprises:

[0150] A brightness acquisition module, used to acquire the ambient light brightness in response to a fingerprint collection instruction;

[0151] The third determination module is used to determine the first exposure time based on the ambient light brightness, and the first exposure time is negatively correlated with the ambient light brightness.

[0152] Optionally, the control module 910 is used to:

[0153] Determining a second exposure duration based on a current exposure round, where the second exposure duration is negatively correlated with the current exposure round;

[0154] Based on the second exposure time, the image sensor is controlled to perform an nth exposure to obtain the nth fingerprint image.

[0155] Optionally, the device further comprises:

[0156] A brightness acquisition module, used to acquire the ambient light brightness in response to a fingerprint collection instruction;

[0157] The control module 910 is specifically used for:

[0158] Based on the ambient light brightness and the current exposure round, a second exposure duration is determined, and the second exposure duration is negatively correlated with the ambient light brightness.

[0159] Optionally, the control module 910 is used to:

[0160] Determining a third exposure time based on the n-1th signal amount of the n-1th fingerprint image, wherein the third exposure time is negatively correlated with the n-1th signal amount;

[0161] Based on the third exposure time, the image sensor is controlled to perform an nth exposure to obtain the nth fingerprint image.

[0162] Optionally, the device further comprises:

[0163] A fourth determination module is used to determine the total exposure duration of n exposures;

[0164] The prompt module is used to display a prompt message in response to the total exposure time being greater than a time threshold, wherein the prompt message is used to indicate that an abnormality exists in fingerprint collection.

[0165] To sum up, in the embodiment of the present application, the terminal controls the image sensor of the under-screen fingerprint module to perform continuous exposure, and determines whether the fingerprint image meets the information amount requirement based on the amount of information of the fingerprint image collected after each exposure, and if the information amount requirement is not met, continues to control the image sensor for exposure until the exposure is met. The terminal uses dynamic exposure time to obtain the fingerprint image, and there is no need to set a fixed exposure time at the factory. It can also avoid the problem of reduced fingerprint image acquisition quality due to changes in light spot brightness, external environment, screen transmittance and protective film transmittance when a fixed exposure time is set, which helps to improve the acquisition quality of the fingerprint image, and thereby improve the accuracy of subsequent fingerprint recognition using the fingerprint image.

[0166] An embodiment of the present application also provides a computer-readable storage medium, which stores at least one program code, and the program code is loaded and executed by a processor to implement the under-screen fingerprint collection method described in the above embodiments.

[0167] According to one aspect of the present application, a computer program product or a computer program is provided, the computer program product or the computer program including computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of a terminal reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the terminal executes the under-screen fingerprint collection method provided in various optional implementations of the above aspects.

[0168] It should be understood that the "multiple" mentioned in this article refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. In addition, the step numbers described in this article only illustrate a possible execution sequence between the steps. In some other embodiments, the above steps may not be executed in the order of the numbers, such as two steps with different numbers are executed at the same time, or two steps with different numbers are executed in the opposite order to the diagram. The embodiments of the present application are not limited to this.

[0169] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for collecting fingerprints under the screen, characterized in that: The method is used for a terminal provided with an under-screen fingerprint module, and the method comprises: In a continuous multiple-round exposure mode, based on a current exposure round, determining a second exposure duration, wherein the second exposure duration is negatively correlated with the current exposure round; Based on the second exposure time, control the image sensor of the under-screen fingerprint module to perform an n-th exposure to obtain an n-th fingerprint image, where the n-th fingerprint image is a fingerprint image collected after n exposures, where n is a positive integer; In response to the nth signal amount of the nth fingerprint image not meeting the signal amount requirement, controlling the image sensor to perform an n+1th exposure to obtain an n+1th fingerprint image; In response to the nth signal amount of the nth fingerprint image satisfying the signal amount requirement, the nth fingerprint image is determined as a target fingerprint image, and the target fingerprint image is used to be stored as a fingerprint template or to be matched with a fingerprint template.

2. The method according to claim 1, characterized in that After controlling the image sensor of the under-screen fingerprint module to perform an nth exposure and obtaining an nth fingerprint image, the method includes: Based on the nth semaphore and a target semaphore, it is determined whether the nth semaphore meets the semaphore requirement, and the target semaphore is preset in the terminal.

3. The method according to claim 2, characterized in that The target signal quantity is a first target signal quantity; The determining, based on the nth semaphore and the target semaphore, whether the nth semaphore meets the semaphore requirement includes: Determine an absolute value of a signal quantity difference between the nth signal quantity and the first target signal quantity; In response to an absolute value of the semaphore difference being less than a difference threshold, determining that the nth semaphore meets the semaphore requirement; In response to the absolute value of the semaphore difference being greater than or equal to the difference threshold, it is determined that the nth semaphore does not meet the semaphore requirement.

4. The method according to claim 2, characterized in that: The target signal quantity includes a second target signal quantity and a third target signal quantity, and the second target signal quantity and the third target signal quantity constitute a target signal quantity interval; The determining, based on the nth semaphore and the target semaphore, whether the nth semaphore meets the semaphore requirement includes: In response to the nth semaphore belonging to the target semaphore interval, determining that the nth semaphore meets the semaphore requirement; In response to the nth semaphore not belonging to the target semaphore interval, it is determined that the nth semaphore does not meet the semaphore requirement.

5. The method according to claim 1, characterized in that The method further comprises: In response to the fingerprint collection instruction, obtaining the ambient light brightness; The determining the second exposure duration based on the current exposure round includes: Based on the ambient light brightness and the current exposure round, the second exposure duration is determined, and the second exposure duration is negatively correlated with the ambient light brightness.

6. The method according to any one of claims 1 to 4, characterized in that: After determining the nth fingerprint image as the target fingerprint image, the method further includes: Determine the total exposure duration of n exposures; In response to the total exposure time being greater than the time threshold, a prompt message is displayed, where the prompt message is used to indicate that an abnormality exists in fingerprint collection.

7. An under-screen fingerprint collection device, characterized in that: The device comprises: A control module, configured to determine, in a continuous multiple-round exposure mode, based on a current exposure round, a second exposure duration, wherein the second exposure duration is negatively correlated with the current exposure round; Based on the second exposure time, control the image sensor of the under-screen fingerprint module to perform an n-th exposure to obtain an n-th fingerprint image, where the n-th fingerprint image is a fingerprint image collected after n exposures, where n is a positive integer; The control module is further configured to control the image sensor to perform an (n+1)th exposure to obtain an (n+1)th fingerprint image in response to the nth signal amount of the (n)th fingerprint image not satisfying the signal amount requirement; The first determination module is used to determine the nth fingerprint image as a target fingerprint image in response to the nth signal quantity of the nth fingerprint image meeting the signal quantity requirement, wherein the target fingerprint image is used to be stored as a fingerprint template or to be matched with a fingerprint template.

8. A terminal, characterized in that: The terminal includes a processor, a memory and an under-screen fingerprint module, the memory stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement the under-screen fingerprint collection method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: At least one program code is stored in the computer-readable storage medium, and the program code is loaded and executed by the processor to implement the under-screen fingerprint collection method as described in any one of claims 1 to 6.

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