Ultrasonic fingerprint identification method, ultrasonic fingerprint device and electronic equipment

Abstract

The invention provides an ultrasonic fingerprint identification method, an ultrasonic fingerprint device and electronic equipment. The influence of temperature on ultrasonic fingerprint identification can be reduced. The method is executed by an ultrasonic fingerprint device, the ultrasonic fingerprint device is arranged below a screen of the electronic equipment to achieve under-screen ultrasonic fingerprint recognition, and the method comprises the steps that the corresponding relation between multiple temperatures and multiple parameter sets is obtained, each parameter group comprises at least one of the following parameters: the frequency of an ultrasonic signal transmitted to a finger, the collection times of an ultrasonic fingerprint signal returned by the finger, and the delay of a collection window of the ultrasonic fingerprint signal relative to the transmission time of the ultrasonic signal; determining a target parameter group in the plurality of parameter groups according to the first temperature and the corresponding relationship; and performing fingerprint identification at the first temperature according to parameters in the target parameter group.

Description

[0001] This application is a divisional application of the invention application with the application date of September 16, 2022, application number 202211130195.2, and name “Ultrasonic fingerprint identification method, ultrasonic fingerprint device and electronic device”. Technical Field

[0002] The embodiments of the present application relate to the field of ultrasonic fingerprints, and more specifically, to an ultrasonic fingerprint recognition method, an ultrasonic fingerprint device, and an electronic device. Background Art

[0003] Ultrasonic fingerprint recognition technology is gradually becoming a mainstream fingerprint unlocking solution due to its advantages such as fast unlocking speed, high accuracy, simple entry and wide application range. During the ultrasonic fingerprint recognition process, the ultrasonic fingerprint device emits an ultrasonic signal, which passes through the bonding layer and the screen and other media to reach the screen surface. After being reflected by the finger on the screen surface, it passes through the screen and other layers again and returns to the ultrasonic fingerprint device. Since the fingerprint valley and fingerprint ridge of the finger have different reflectivity to the ultrasonic signal, the echo signal collected by the ultrasonic fingerprint device carries the fingerprint information. In addition, the ultrasonic fingerprint device also needs to collect the background signal returned when there is no finger pressing the screen surface. By subtracting the echo signal carrying the fingerprint information from the background signal that does not carry the fingerprint information, a clear fingerprint image can be obtained.

[0004] Since the background signal cannot be collected in real time and is usually stored in advance, there may be differences in the collection environment between the echo signal collected during the current fingerprint recognition and the stored background signal, such as different ambient temperatures. The temperature affects the time and signal strength of the signal return, and temperature changes may cause changes in the clarity of the fingerprint image. Therefore, how to reduce the impact of temperature on ultrasonic fingerprint recognition has become a problem that needs to be solved. Summary of the invention

[0005] The embodiments of the present application provide an ultrasonic fingerprint recognition method, an ultrasonic fingerprint device, and an electronic device, which can reduce the influence of temperature on ultrasonic fingerprint recognition.

[0006] In a first aspect, a method for ultrasonic fingerprint recognition is provided, the method being performed by an ultrasonic fingerprint device, the ultrasonic fingerprint device being arranged below a screen of an electronic device to implement under-screen ultrasonic fingerprint recognition, the method comprising: obtaining a correspondence between multiple temperatures and multiple parameter groups, wherein each parameter group includes at least one of the following parameters: the frequency of an ultrasonic signal emitted to a finger above the screen, the number of times an ultrasonic fingerprint signal carrying fingerprint information returned by the finger is collected, and a delay between the collection time of the ultrasonic fingerprint signal and the emission time of the ultrasonic signal; when the finger presses the screen, determining a target parameter group from the multiple parameter groups according to the current first temperature and the correspondence; and performing fingerprint recognition according to the parameters in the target parameter group.

[0007] In the embodiment of the present application, by configuring different parameter groups for different temperatures and determining the parameter group that matches the ambient temperature during fingerprint recognition, the influence of temperature on ultrasonic fingerprint recognition can be effectively reduced and the performance of fingerprint recognition can be improved.

[0008] In one implementation, determining a target parameter group from among the multiple parameter groups based on the first temperature and the corresponding relationship includes: determining a second temperature from among the multiple temperatures that is closest to the first temperature; and determining, based on the second temperature and the corresponding relationship, a parameter group from among the multiple parameter groups that corresponds to the second temperature as the target parameter group, wherein the parameter group corresponding to the second temperature is a parameter group that maximizes the difference between an ultrasonic fingerprint signal collected at the second temperature and an ultrasonic background signal, wherein the ultrasonic background signal is a signal that does not carry the fingerprint information and is collected when no finger is pressing the screen.

[0009] In one implementation, performing fingerprint recognition at the first temperature according to the parameters in the target parameter group includes: adjusting the delay in the target parameter group according to a compensation coefficient to obtain a target delay for fingerprint recognition at the first temperature; and performing fingerprint recognition at the first temperature according to the target delay.

[0010] For example, the target delay is equal to the sum of the product of the temperature difference obtained by subtracting the second temperature from the first temperature and the compensation coefficient and the delay in the target parameter group.

[0011] By setting the compensation coefficient, the sampling delay matching the first temperature at the current fingerprint recognition can be accurately calculated, thereby further improving the clarity of the fingerprint image and reducing the influence of temperature on ultrasonic fingerprint recognition.

[0012] In an implementation manner, performing fingerprint recognition at the first temperature according to the parameters in the target parameter group includes: performing fingerprint recognition at the first temperature according to the frequency and / or the number of acquisitions in the target parameter group.

[0013] In a second aspect, an ultrasonic fingerprint device is provided, which is arranged under the screen of an electronic device to realize under-screen ultrasonic fingerprint recognition, and the ultrasonic fingerprint device includes: a processing module, used to: obtain the correspondence between multiple temperatures and multiple parameter groups, wherein each parameter group includes at least one of the following parameters: the frequency of the ultrasonic signal emitted to the finger above the screen, the number of collection times of the ultrasonic fingerprint signal carrying fingerprint information returned by the finger, and the delay of the collection time of the ultrasonic fingerprint signal relative to the emission time of the ultrasonic signal; when the finger presses the screen, determine the target parameter group from the multiple parameter groups according to the current first temperature and the correspondence; a detection module, used to perform fingerprint recognition according to the parameters in the target parameter group.

[0014] In one implementation, the processing module is specifically used to: determine a second temperature that is closest to the first temperature among the multiple temperatures; and determine, based on the second temperature and the corresponding relationship, a parameter group among the multiple parameter groups that corresponds to the second temperature as the target parameter group, wherein the target parameter group is a parameter group that maximizes the signal strength collected at the second temperature.

[0015] In one implementation, the processing module is further used to adjust the delay in the target parameter group according to a compensation coefficient to obtain a target delay for fingerprint recognition at the first temperature; and the detection module is specifically used to perform fingerprint recognition at the first temperature according to the target delay.

[0016] In one implementation, the target delay is equal to the sum of a product of a temperature difference obtained by subtracting the second temperature from the first temperature and the compensation coefficient and the delay in the target parameter group.

[0017] In one implementation, the detection module is specifically configured to perform fingerprint recognition at the first temperature according to the frequency and / or the number of acquisition times in the target parameter group.

[0018] In a third aspect, an electronic device is provided, comprising: a screen; and the ultrasonic fingerprint device described in the second aspect or any possible implementation of the second aspect, wherein the ultrasonic fingerprint device is arranged below the screen to implement under-screen ultrasonic fingerprint recognition. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic diagram of the principle of ultrasonic fingerprint recognition.

[0020] Figure 2 This is an architecture diagram of an ultrasonic fingerprint system to which the present application can be applied.

[0021] Figure 3 It is a schematic flow chart of the method of ultrasonic fingerprint recognition according to an embodiment of the present application.

[0022] Figure 4 It is the law of change of signal intensity collected at different temperatures over time.

[0023] Figure 5 yes Figure 3 A schematic diagram of a possible specific process of the ultrasonic fingerprint recognition method is shown.

[0024] Figure 6 It is a schematic diagram of the law of how the signal mean value of the fingerprint image of the embodiment of the present application changes with temperature.

[0025] Figure 7 is a schematic block diagram of an ultrasonic fingerprint device according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0027] The ultrasonic fingerprint device acquires the fingerprint image of the finger by emitting ultrasonic signals to the finger and receiving the echo signals returned by the finger. Since ultrasonic signals can penetrate the epidermis of the skin and are less affected by the details of the fingerprint surface, the ultrasonic fingerprint device has a better recognition rate in scenes such as stains and wet hands, and also has stronger anti-counterfeiting characteristics.

[0028] Figure 1 This is a schematic diagram of the principle of ultrasonic fingerprint recognition. Figure 1 As shown, the ultrasonic signal P(A0) emitted by the ultrasonic fingerprint device 300 passes through the screen 200 and reaches its upper surface. Due to the difference in acoustic impedance between the skin and the screen 200, and between the air and the screen 200, the ultrasonic signal P(A0) will be reflected to form an echo signal P(A1). The finger 100 includes a fingerprint ridge 110 and a fingerprint valley 120. When the finger 100 presses the screen 200, the fingerprint ridge 110 and the screen 200 are in contact, and there is an air gap between the fingerprint valley 120 and the screen 200. Therefore, there is a difference in the signal strength returned from the fingerprint ridge 110 and the signal strength returned from the fingerprint valley 120. This difference can be used to obtain the fingerprint image of the finger 100, thereby realizing ultrasonic fingerprint recognition.

[0029] In addition, the ultrasonic fingerprint device 300 also needs to collect the signal returned when no finger is pressing the screen 200. Here, the signal collected by the ultrasonic fingerprint device 300 when no finger is pressing the screen 200 is called the ultrasonic background signal, and the signal collected by the ultrasonic fingerprint device 300 when the finger 100 presses the screen 200 is called the ultrasonic fingerprint signal. By subtracting the ultrasonic fingerprint signal carrying fingerprint information from the ultrasonic background signal not carrying fingerprint information, a clear fingerprint image can be obtained.

[0030] Since the ultrasonic background signal cannot be collected in real time and is usually stored in advance, there may be differences in the collection environment between the ultrasonic fingerprint signal collected during the current fingerprint recognition and the stored ultrasonic background signal, such as different ambient temperatures. The temperature affects the signal return time and signal strength, so temperature changes may cause changes in the clarity of the fingerprint image.

[0031] The present application aims to provide an ultrasonic fingerprint recognition solution, which optimizes the effect of ultrasonic fingerprint recognition by configuring multiple sets of fingerprint recognition parameters to adapt to different operating temperatures.

[0032] Figure 2 4 is an architecture diagram of an ultrasonic fingerprint system 400 to which the present application can be applied. The ultrasonic fingerprint system 400 includes a controller 410, an ultrasonic sensor 420, a data processor 430, an analog digital converter (ADC) 440, and an algorithm processor 450. The ultrasonic sensor 420 is, for example, a piezoelectric sensor. The ultrasonic sensor 420, the data processor 430, the ADC 440, and the algorithm processor 450 are all controlled by the controller 410. The controller 410 controls the ultrasonic sensor 420 to transmit and receive ultrasonic signals. The signals received by the ultrasonic sensor 420 are converted into digital signals by the ADC 440. The data processor 430 rearranges and packages the digital signals, and sends the processed data to the algorithm processor 450 to complete the registration and identification of the fingerprint.

[0033] Figure 3 FIG. 1 is a schematic flow chart showing the method of ultrasonic fingerprint recognition according to an embodiment of the present application. Figure 3 As shown, the method 500 may be performed by an ultrasonic fingerprint device 300, which is disposed below the screen 200 of the electronic device to implement under-screen ultrasonic fingerprint recognition. Figure 3 As shown, method 500 includes some or all of the following steps.

[0034] In step 510, the corresponding relationship between a plurality of temperatures and a plurality of parameter groups is obtained.

[0035] Each parameter group includes at least one of the following parameters: the frequency of the ultrasonic signal emitted to the finger 100 above the screen 200, the number of times the ultrasonic fingerprint signal carrying its fingerprint information returned by the finger 100 is collected, and the delay between the collection time of the ultrasonic fingerprint signal and the emission time of the ultrasonic signal.

[0036] The number of acquisitions is the number of sampling windows of the ultrasonic fingerprint signal. Since each signal acquisition is to integrate the signal within the sampling window, the sampling window can also be called the integration window, and the number of acquisitions can also be called the integration number. One acquisition corresponds to a Tx coding and Rx receiving process. The signal strength can be increased by increasing the number of acquisitions to avoid the signal strength being too low to effectively perform fingerprint recognition; or the signal strength can be reduced by reducing the number of acquisitions to prevent signal saturation.

[0037] The delay is the delay of the sampling window relative to the emission time of the ultrasonic signal, that is, the time from the emission to the reception of the ultrasonic signal, also known as the flight time (flytime).

[0038] In step 520 , when the finger 100 presses the screen 200 , a target parameter group is determined from the plurality of parameter groups according to the current first temperature and the corresponding relationship.

[0039] In step 530, fingerprint recognition is performed according to the parameters in the target parameter group.

[0040] By configuring different parameter groups for different temperatures and determining the parameter group that matches the ambient temperature during fingerprint recognition, the influence of temperature on ultrasonic fingerprint recognition can be effectively reduced and the performance of fingerprint recognition can be improved.

[0041] For example, configuring the number of acquisitions to match different temperature configurations can reduce the impact of temperature changes on signal strength. Since the strength of signals of different frequencies at different temperatures is different, the frequency can also be adjusted synchronously for different temperatures to prevent signal saturation or signals that are too small.

[0042] For example, configuring sampling delays that match different temperature configurations can ensure that the sampling window is aligned with the signal peak position, thereby obtaining a better signal-to-noise ratio and reducing the impact of temperature changes on signal return time.

[0043] The temperature at which fingerprint recognition is currently performed is the first temperature, and the parameter group corresponding to the first temperature among the multiple temperatures is used as the target parameter group, and fingerprint recognition is performed at the first temperature based on the parameters in the target parameter group.

[0044] If the multiple temperatures do not include the first temperature at which the current fingerprint recognition is performed, then in step 520, a second temperature closest to the first temperature can be determined from the multiple temperatures, and based on the second temperature and the corresponding relationship, the parameter group corresponding to the second temperature from the multiple parameter groups can be determined as the target parameter group.

[0045] In this correspondence, the parameter values ​​in any two parameter groups in the multiple parameter groups may be partially different or completely different. The parameters in the parameter group corresponding to each temperature are the parameter group that maximizes the difference between the ultrasonic fingerprint signal collected at the temperature and the ultrasonic background signal, which is a signal that does not carry fingerprint information and is collected when there is no finger 100 pressing the screen 200. For example, the parameter group corresponding to the second temperature is the parameter group that maximizes the difference between the ultrasonic fingerprint signal collected at the second temperature and the ultrasonic background signal. The difference between the ultrasonic fingerprint signal and the ultrasonic background signal can be regarded as the signal mean of the fingerprint image, which reflects the difference between the fingerprint ridge 110 and the fingerprint valley 120.

[0046] When establishing the above correspondence, first, multiple temperatures are selected, for example, the ambient temperature range of the ultrasonic fingerprint device that may be used is -20°C to 60°C, and the temperature change amount STEP is set to 5°C or 10°C. Secondly, when the temperature T = -20°C, all available frequencies (F1, F2, ..., F m ), all available acquisition times (N1, N2, ..., N n ) and all available sampling delays (t1, t2, ..., t p ), here we assume that there are m frequencies, n acquisition times, and p sampling delays, then there are m×n×p possible parameter combinations.

[0047] The silicone test head can be used to simulate the fingerprint shape. Select the frequency F1 and the number of acquisitions N1, and traverse the delay t1 to t p , collect p groups of signals returned by the test head; select frequency F1 and acquisition times N2, traverse delay (t1, t2, ..., t p ), collect p groups of signals returned by the test head; ...; select frequency F1 and number of acquisitions N n , traversal delay (t1, t2, ..., t p ) to collect the p groups of signals returned by the test head.

[0048] Select frequency F2 and number of acquisitions N1, and traverse delays (t1, t2, ..., t p ), collect p groups of signals returned by the test head; select frequency F2 and acquisition times N2, traverse delay (t1, t2, ..., t p), collect p groups of signals returned by the test head; ...; select frequency F2 and number of acquisitions N n , traversal delay (t1, t2, ..., t p ) to collect the p groups of signals returned by the test head.

[0049] In sequence, until the frequency F1 is traversed to the frequency F m , and obtain m×n×p groups of ultrasonic fingerprint signals.

[0050] From the m×n×p groups of ultrasonic fingerprint signals, a group of ultrasonic fingerprint signals with the largest difference from the ultrasonic background signal is selected, and the frequency, number of acquisitions and delay used when acquiring this group of ultrasonic fingerprint signals are used as the parameter group corresponding to the temperature T=-20°C.

[0051] Similarly, when STEP=5°C, the corresponding parameter groups of T=-15°C, T=-10°C, ..., T=60°C can be obtained, thereby establishing a correspondence between multiple temperatures and multiple parameter groups. The correspondence is saved and loaded when the ultrasonic fingerprint device 300 is started.

[0052] The corresponding relationship can be expressed in various ways such as tables and functions. For example, a mapping table as shown in Table 1 can be established, in which each temperature corresponds to a parameter group. Each parameter group includes the frequency of the ultrasonic signal, the number of acquisitions of the ultrasonic fingerprint signal, the delay and the compensation coefficient. Table 1 is only an example. In actual applications, each parameter group may also include only one or two parameters, such as only the number of acquisitions and the delay.

[0053] Table 1

[0054]

[0055] According to the temperature at the time of current fingerprint recognition and the corresponding relationship shown in Table 1, the target parameter group for fingerprint recognition can be determined. For example, when the current first temperature is T1, fingerprint recognition is performed according to the transmission frequency F1, the number of acquisitions N1 and the delay t1. Specifically, the ultrasonic fingerprint device 300 transmits an ultrasonic signal with a frequency of F1 to the finger 100, and collects the ultrasonic fingerprint signal returned by the finger 100 after a delay of t1 at the transmission time, and the number of acquisitions is N1; when the first temperature is T2, fingerprint recognition is performed according to the frequency F1, the number of acquisitions N2 and the delay t2; when the first temperature is T3, fingerprint recognition is performed according to the frequency F1, the number of acquisitions N3 and the delay t3.

[0056] If the current first temperature does not belong to one of the multiple temperatures included in the corresponding relationship, fingerprint identification can be performed based on the parameter group corresponding to the second temperature closest to the first temperature among the multiple temperatures, that is, the parameter group corresponding to the second temperature is used as the target parameter group for fingerprint identification.

[0057] For example, in step 530 , fingerprint recognition may be performed based on the frequencies in the target parameter group.

[0058] For another example, in step 530, fingerprint recognition may be performed according to the number of acquisitions in the target parameter group.

[0059] For another example, in step 530, fingerprint recognition can be performed based on the sampling delay in the target parameter group; alternatively, the sampling delay in the target parameter group can be adjusted based on the compensation coefficient to obtain a target delay for fingerprint recognition at the first temperature, and fingerprint recognition can be performed based on the target delay.

[0060] like Figure 4 From the variation law of the signal strength collected at different temperatures over time, it can be seen that at different temperatures, the signal strength collected based on different delays is different. According to the variation law of the signal strength at each temperature, the delay corresponding to each temperature and the corresponding compensation coefficient can be obtained. When the multiple temperatures in the corresponding relationship do not include the current first temperature, the compensation coefficient can be used to fit the delay corresponding to the first temperature. The compensation coefficient can be stored in the ultrasonic fingerprint device 300 independently of the corresponding relationship, or it can be used as a part of the corresponding relationship, as shown in Table 1, for example, where the compensation coefficients corresponding to different temperatures can be different or the same. Table 1 takes the compensation coefficients corresponding to different temperatures as an example.

[0061] The second temperature among the multiple temperatures in the corresponding relationship is the temperature closest to the first temperature, and the target delay corresponding to the first temperature is determined according to the compensation coefficient and the delay corresponding to the second temperature for fingerprint recognition. Usually, there is a linear relationship between delay and temperature, so the temperature difference between the first temperature and the second temperature can be multiplied by the compensation coefficient, and then added to the delay corresponding to the second temperature to obtain the target delay corresponding to the first temperature, that is, the target delay corresponding to the first temperature = the delay corresponding to the second temperature + (first temperature - second temperature) × compensation coefficient.

[0062] By setting the compensation coefficient, the sampling delay matching any temperature can be accurately calculated, thereby further improving the clarity of the fingerprint image and reducing the influence of temperature on ultrasonic fingerprint recognition.

[0063] Figure 5 yes Figure 3 A possible specific process of the ultrasonic fingerprint recognition method 500 is shown. Figure 5 As shown, in step 501, the current temperature, that is, the first temperature, is acquired through a temperature sensor.

[0064] In step 502, the second temperature closest to the first temperature is searched in a mapping table using the first temperature as an index. The mapping table includes a correspondence between a plurality of temperatures and a plurality of parameter groups.

[0065] If the first temperature is one of the multiple temperatures in the mapping table, the second temperature is the first temperature; if the first temperature is not one of the multiple temperatures, the second temperature is the temperature closest to the first temperature. In the following, the first temperature and the second temperature are different as an example.

[0066] In step 503, the number of acquisitions corresponding to the second temperature is obtained.

[0067] In step 504, a frequency corresponding to the second temperature is obtained.

[0068] In step 505, a delay corresponding to the second temperature and a corresponding compensation coefficient are obtained.

[0069] In step 506, the first temperature and the second temperature are combined and the compensation coefficient is used to perform fitting calculation to obtain the target delay.

[0070] In step 507, parameter configuration is performed according to the number of acquisitions obtained in step 503, the frequency obtained in step 504, and the target delay obtained in step 506, and fingerprint recognition is performed.

[0071] After adopting the fingerprint recognition solution of the present application, the change rules of the signal mean of the fingerprint image at different temperatures in the actual test are as follows: Figure 6 As shown, from Figure 6 It can be seen that the ultrasonic fingerprint recognition solution based on the present application can quickly obtain the optimal parameter configuration according to the temperature at which the current fingerprint recognition is performed, so that the signal mean of the fingerprint image collected at different temperatures is maintained within a relatively high intensity range, which provides a good foundation for subsequent fingerprint image processing and recognition, and effectively improves the performance of ultrasonic fingerprint recognition.

[0072] The present application also provides an ultrasonic fingerprint device 300, such as Figure 7 As shown, the ultrasonic fingerprint device 300 is disposed below the screen 200 of the electronic device to implement under-screen ultrasonic fingerprint recognition. The ultrasonic fingerprint device 300 includes a processing module 310 and a detection module 320. The detection module 320 may include, for example, Figure 2 The ultrasonic sensor 420 shown in FIG. 4 , the processing module 310 may include, for example, Figure 2 The controller 410, ADC 440, data processor 430, etc. are shown. The processing module 310 may also include Figure 2 The algorithm processor 450 shown, or the algorithm processor 450 is a processor of an electronic device such as a CPU.

[0073] Among them, the processing module 310 is used to: obtain the correspondence between multiple temperatures and multiple parameter groups, wherein each parameter group includes at least one of the following parameters: the frequency of the ultrasonic signal emitted to the finger 100 above the screen 200, the number of collection times of the ultrasonic fingerprint signal carrying fingerprint information returned by the finger 100, and the delay between the collection time of the ultrasonic fingerprint signal and the emission time of the ultrasonic signal; when the finger 100 presses the screen 200, determine the target parameter group from the multiple parameter groups according to the current first temperature and the correspondence.

[0074] The detection module 320 is used to perform fingerprint recognition according to the parameters in the target parameter group.

[0075] In one implementation, the processing module 310 is specifically used to: determine a second temperature that is closest to the first temperature among multiple temperatures; and determine, based on the second temperature and the corresponding relationship, a parameter group corresponding to the second temperature among multiple parameter groups as a target parameter group, wherein the target parameter group is a parameter group that maximizes the signal strength collected at the second temperature.

[0076] In one implementation, the processing module 310 is further used to adjust the delay in the target parameter group according to the compensation coefficient to obtain a target delay for fingerprint recognition at the first temperature; the detection module 320 is specifically used to perform fingerprint recognition at the first temperature according to the target delay.

[0077] For example, the target delay is equal to the product of the temperature difference between the first temperature and the second temperature and the compensation coefficient, and the sum of the delays in the target parameter group.

[0078] In one implementation, the detection module 320 is specifically configured to perform fingerprint recognition at a first temperature according to the frequency and / or the number of acquisitions in the target parameter group.

[0079] It should be understood that the specific details of the ultrasonic fingerprint device 300 can refer to the above description of the ultrasonic fingerprint recognition method 500, and for the sake of brevity, they are not repeated here.

[0080] The present application also provides an electronic device 600, which includes a screen 200 and the above-mentioned ultrasonic fingerprint device 300. The ultrasonic fingerprint device 300 is arranged below the screen 200, so as to realize under-screen ultrasonic fingerprint recognition.

[0081] As an example but not limitation, the electronic device in the embodiment of the present application can be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a laptop computer, a desktop computer, a gaming device, an in-vehicle electronic device or a wearable smart device, as well as other electronic devices such as an electronic database, a car, and an automated teller machine (ATM). The wearable smart device includes a device with full functions and large size that can realize full or partial functions without relying on a smart phone, such as a smart watch or smart glasses, and includes a device that only focuses on a certain type of application function and needs to be used in conjunction with other devices such as a smart phone, such as various types of smart bracelets and smart jewelry for vital sign monitoring.

[0082] It should be noted that, under the premise of no conflict, the various embodiments described in this application and / or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application.

[0083] The systems, devices and methods disclosed in the embodiments of the present application may be implemented in other ways. For example, some features of the method embodiments described above may be ignored or not performed. The device embodiments described above are merely schematic, and the division of units is merely a logical function division. There may be other division methods in actual implementation, and multiple units or components may be combined or integrated into another system. In addition, the coupling between the units or the coupling between the components may be direct coupling or indirect coupling, and the coupling may include electrical, mechanical or other forms of connection.

[0084] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described devices and equipment and the technical effects produced can refer to the corresponding processes and technical effects in the aforementioned method embodiments, and will not be repeated here.

[0085] It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art to better understand the embodiments of the present application, rather than to limit the scope of the embodiments of the present application. Those skilled in the art can make various improvements and modifications based on the above embodiments, and these improvements or modifications all fall within the scope of protection of the present application.

[0086] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for ultrasonic fingerprint recognition, characterized in that: The method is performed by an ultrasonic fingerprint device, which is arranged below a screen of an electronic device to implement under-screen ultrasonic fingerprint recognition. The method includes: Acquire a correspondence between a plurality of temperatures and a plurality of parameter groups, wherein each parameter group includes the following parameters: a frequency of an ultrasonic signal emitted to a finger above the screen, a number of times an ultrasonic fingerprint signal carrying fingerprint information returned by the finger after the ultrasonic signal is emitted to the finger above the screen, a delay between the ultrasonic fingerprint signal acquisition time and the ultrasonic signal emission time, and a compensation coefficient; Wherein, the number of acquisition times is the number of sampling windows of the ultrasonic fingerprint signal, the delay is the delay of the sampling window relative to the emission time of the ultrasonic signal, and the delay is configured so that the ultrasonic fingerprint signal collected within the sampling window at each temperature includes the peak part of the ultrasonic signal, and the compensation coefficient corresponding to each temperature is the same, so that the difference between the ultrasonic fingerprint signal collected at each temperature and the pre-stored ultrasonic background signal is maximized, and the ultrasonic background signal is a signal that does not carry fingerprint information and is collected without a finger pressing the screen; When the finger presses the screen, determining a target parameter group from the multiple parameter groups according to a correspondence between the current first temperature and the multiple parameter groups; Fingerprint recognition is performed at the first temperature according to the parameters in the target parameter group.

2. The method according to claim 1, characterized in that The performing fingerprint recognition at the first temperature according to the parameters in the target parameter group includes: adjusting the delay in the target parameter group according to a compensation coefficient corresponding to the first temperature to obtain a target delay for fingerprint recognition at the first temperature; Fingerprint recognition is performed at the first temperature according to the target delay.

3. The method according to claim 1 or 2, characterized in that: The step of determining a target parameter group from the plurality of parameter groups according to the current first temperature and the corresponding relationship includes: determining a second temperature closest to the first temperature among the plurality of temperatures; According to the second temperature and the corresponding relationship, the parameter group corresponding to the second temperature among the multiple parameter groups is determined as the target parameter group, wherein the parameter group corresponding to the second temperature is the parameter group that maximizes the difference between the ultrasonic fingerprint signal collected at the second temperature and the ultrasonic background signal.

4. The method according to claim 3, characterized in that The target delay is equal to the sum of the product of the temperature difference obtained by subtracting the second temperature from the first temperature and the compensation coefficient and the delay in the target parameter group.

5. The method according to claim 1 or 2, characterized in that: The performing fingerprint recognition at the first temperature according to the parameters in the target parameter group includes: Fingerprint recognition is performed at the first temperature according to the frequency, the delay and the number of acquisitions in the target parameter group.

6. An ultrasonic fingerprint device, characterized in that: The ultrasonic fingerprint device is arranged under the screen of the electronic device to realize under-screen ultrasonic fingerprint recognition, and the ultrasonic fingerprint device includes: Processing modules for: Acquire a correspondence between a plurality of temperatures and a plurality of parameter groups, wherein each parameter group includes the following parameters: a frequency of an ultrasonic signal transmitted to a finger above the screen, a number of times an ultrasonic fingerprint signal carrying fingerprint information returned by the finger after the ultrasonic signal is transmitted to the finger above the screen, and a delay between a collection time of the ultrasonic fingerprint signal and a transmission time of the ultrasonic signal, and a compensation coefficient; Wherein, the number of acquisition times is the number of sampling windows of the ultrasonic fingerprint signal, the delay is the delay of the sampling window relative to the emission time of the ultrasonic signal, and the delay is configured so that the ultrasonic fingerprint signal collected within the sampling window at each temperature includes the peak part of the ultrasonic signal, and the compensation coefficient corresponding to each temperature is the same, so that the difference between the ultrasonic fingerprint signal collected at each temperature and the pre-stored ultrasonic background signal is maximized, and the ultrasonic background signal is a signal that does not carry fingerprint information and is collected without a finger pressing the screen; When the finger presses the screen, determining a target parameter group from the multiple parameter groups according to a correspondence between the current first temperature and the multiple parameter groups; A detection module is used to perform fingerprint recognition at the first temperature according to the parameters in the target parameter group.

7. The ultrasonic fingerprint device according to claim 6, characterized in that: The processing module is further used to adjust the delay in the target parameter group according to a compensation coefficient corresponding to the first temperature to obtain a target delay for fingerprint recognition at the first temperature; The detection module is specifically configured to perform fingerprint recognition at the first temperature according to the target delay.

8. The ultrasonic fingerprint device according to claim 6 or 7, characterized in that: The processing module is specifically used for: determining a second temperature closest to the first temperature among the plurality of temperatures; According to the second temperature and the corresponding relationship, the parameter group corresponding to the second temperature among the multiple parameter groups is determined as the target parameter group, wherein the parameter group corresponding to the second temperature is the parameter group that maximizes the difference between the ultrasonic fingerprint signal collected at the second temperature and the ultrasonic background signal.

9. The ultrasonic fingerprint device according to claim 8, characterized in that: The target delay is equal to the sum of the product of the temperature difference obtained by subtracting the second temperature from the first temperature and the compensation coefficient and the delay in the target parameter group.

10. The ultrasonic fingerprint device according to claim 6 or 7, characterized in that: The detection module is specifically used for: Fingerprint recognition is performed at the first temperature according to the frequency, the delay and the number of acquisitions in the target parameter group.

11. An electronic device, characterized in that: include: Screen; as well as, According to any one of claims 6 to 10, the ultrasonic fingerprint device is arranged below the screen to realize under-screen ultrasonic fingerprint recognition.

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