Ultrasonic fingerprint identification method, chip, system, electronic equipment and storage medium

Abstract

The invention discloses an ultrasonic fingerprint identification method, a chip, a system, electronic equipment and a storage medium, and the method comprises the steps: controlling an ultrasonic piezoelectric transducer to work based on first configuration information, and obtaining one or more first fingerprint images; performing spatial frequency identification on the one or more first fingerprint images, and determining a first spatial frequency corresponding to the one or more first fingerprint images; when one or more first fingerprint images meet the adaptive condition, determining second configuration information based on the first spatial frequency and the first configuration information; and updating the first configuration information by adopting the second configuration information. According to the method, the first configuration information is dynamically adjusted based on the first spatial frequency corresponding to the first fingerprint image, so that the adjusted second configuration information can effectively guarantee the overall performance of the ultrasonic fingerprint system, the quality of the fingerprint image acquired subsequently is improved, the recognition effect is improved, and the universality of the system is improved.

Description

Technical Field

[0001] The present application relates to the field of ultrasonic fingerprint recognition technology, and in particular to an ultrasonic fingerprint recognition method, chip, system, electronic device and storage medium. Background Art

[0002] Ultrasonic fingerprint recognition technology uses ultrasound waves of a specific frequency to scan the finger. Due to the difference in acoustic impedance between the skin and air, the echo signal strength of the ultrasound waves varies. By detecting the echo signal strength at different locations, it is possible to distinguish the ridges and valleys of the same fingerprint, thus enabling fingerprint recognition. Compared with optical fingerprint recognition technology, ultrasonic fingerprint recognition offers advantages such as greater penetration, waterproofness, and higher security, making it suitable for a wide range of applications.

[0003] Ultrasonic fingerprint systems, currently based on ultrasonic fingerprint recognition technology, are already being used in mobile phones and other electronic devices to identify user fingerprints. Existing ultrasonic fingerprint systems typically operate with default configuration settings. However, due to the significant differences in fingerprint characteristics between users, these settings are incompatible with the system's configuration, impacting the quality of the captured fingerprint images and, consequently, the fingerprint recognition performance.

[0004] Application Contents

[0005] The embodiments of the present application provide an ultrasonic fingerprint recognition method, chip, system, electronic device, and storage medium to address the problem that the existing ultrasonic fingerprint recognition process is incompatible with the differences in fingerprint characteristics of different users, affecting the fingerprint image quality and fingerprint recognition effect.

[0006] An ultrasonic fingerprint recognition method, comprising:

[0007] controlling the ultrasonic piezoelectric transducer to operate based on the first configuration information to obtain one or more first fingerprint images;

[0008] performing spatial frequency recognition on the one or more first fingerprint images to determine a first spatial frequency corresponding to the one or more first fingerprint images;

[0009] When one or more of the first fingerprint images meet an adaptive condition, determining second configuration information based on the first spatial frequency and the first configuration information;

[0010] The first configuration information is updated using the second configuration information.

[0011] An ultrasonic fingerprint chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the ultrasonic fingerprint recognition method is implemented.

[0012] An ultrasonic fingerprint system comprises an ultrasonic piezoelectric transducer and the ultrasonic fingerprint chip, wherein the ultrasonic fingerprint chip is connected to the ultrasonic piezoelectric transducer.

[0013] An electronic device includes the ultrasonic fingerprint system.

[0014] A computer-readable storage medium stores a computer program, which implements the ultrasonic fingerprint recognition method when executed by a processor.

[0015] The above-mentioned ultrasonic fingerprint recognition method, chip, system, electronic device and storage medium control the ultrasonic piezoelectric transducer to operate based on the first configuration information, obtain the first fingerprint image and perform adaptive judgment. When the first fingerprint image meets the adaptive conditions, the first configuration information is dynamically adjusted based on the first spatial frequency corresponding to the first fingerprint image, so that the adjusted second configuration information can effectively guarantee the overall performance of the ultrasonic fingerprint system, thereby improving the quality of subsequently collected fingerprint images, thereby improving the recognition effect and improving the versatility of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments of the present application. 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 any creative work.

[0017] Figure 1 This is a flow chart of an ultrasonic fingerprint recognition method according to an embodiment of the present application;

[0018] Figure 2 is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0019] Figure 3 is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0020] Figure 4 is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0021] Figure 5 is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0022] Figure 6 is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0023] Figure 7is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0024] Figure 8 is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0025] Figure 9 is another flow chart of the ultrasonic fingerprint recognition method in one embodiment of the present application;

[0026] Figure 10 This is a schematic diagram of an ultrasonic fingerprint system in one embodiment of the present application;

[0027] Figure 11 This is the MTF curve corresponding to different user fingerprints;

[0028] Figure 12 It is the MTF curve corresponding to different frequencies;

[0029] Figure 13 It is a comparison chart of the signal-to-noise ratio corresponding to different spatial frequencies;

[0030] Figure 14 This is a comparison chart before and after configuration information adjustment. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0032] The ultrasonic fingerprint recognition method provided in the embodiment of the present application can be applied to an ultrasonic fingerprint system. The ultrasonic fingerprint system generally includes an ultrasonic piezoelectric transducer and an ultrasonic fingerprint chip. The ultrasonic fingerprint chip is connected to the ultrasonic piezoelectric transducer. The ultrasonic fingerprint chip can transmit an ultrasonic signal according to its corresponding configuration information (including frequency and echo delay), and receive the echo signal through the ultrasonic piezoelectric transducer, so as to determine the fingerprint image based on the echo signal, and then use the fingerprint image to perform fingerprint recognition. The echo delay here is the echo signal integration delay.

[0033] like Figure 10As shown, an ultrasonic fingerprint system generally includes an ultrasonic piezoelectric transducer and an ultrasonic fingerprint chip. The ultrasonic fingerprint chip can include a controller, a data processor, an ADC converter, and an algorithm processor. In this example, the controller is connected to the ultrasonic piezoelectric transducer, the data processor, the ADC converter, and the algorithm processor to control the operation of each module. The operation process is as follows: the controller controls the ultrasonic piezoelectric transducer to generate and receive ultrasonic signals; the ADC converter performs digital-to-analog conversion on the received ultrasonic signals and converts the converted signals into digital signals; the data processor completes data rearrangement and packaging, and sends the converted data to the algorithm processor for algorithm processing to complete fingerprint registration and recognition.

[0034] In one embodiment, if Figure 1 As shown, an ultrasonic fingerprint recognition method is provided, which is applied in Figure 10 Taking the ultrasonic fingerprint chip (hereinafter referred to as the chip) in the example, the following steps are included:

[0035] S101: Controlling an ultrasonic piezoelectric transducer to operate based on first configuration information to obtain one or more first fingerprint images;

[0036] S102: Perform spatial frequency recognition on one or more first fingerprint images to determine first spatial frequencies corresponding to the one or more first fingerprint images;

[0037] S103: When one or more first fingerprint images meet the adaptive condition, determine second configuration information based on the first spatial frequency and the first configuration information;

[0038] S104: Use the second configuration information to update the first configuration information.

[0039] The ultrasonic piezoelectric transducer is a device used to transmit ultrasonic signals and receive echo signals. Connected to the ultrasonic fingerprint chip, the transducer converts the applied voltage pulse excitation into mechanical vibrations based on the control signal output by the ultrasonic fingerprint chip, thereby emitting ultrasonic signals. When ultrasonic signals propagate through media such as air and fingers, they generate echo signals such as reflected and scattered waves, which can be used to determine the corresponding fingerprint image.

[0040] The first configuration information is the configuration information currently used to control the operation of the ultrasonic piezoelectric transducer. As an example, the first configuration information includes a first frequency and a first echo delay, where the first frequency is the frequency in the first configuration information and the first echo delay is the echo delay in the first configuration information.

[0041] The first fingerprint image is a fingerprint image collected after the ultrasonic piezoelectric transducer operates based on the first configuration information; the first fingerprint image can be understood as a fingerprint image collected before the configuration information is updated.

[0042] The adaptive condition is a pre-set condition for evaluating whether the configuration information needs to be adaptively updated. The adaptive condition may be a condition determined in advance based on a calibration experiment or other actual conditions to reflect that the configuration information is incompatible with the user's fingerprint feature.

[0043] As an example, in step S101, when a user's finger touches or approaches a mobile phone or other electronic device, the chip may control the ultrasonic piezoelectric transducer to operate based on first configuration information. Specifically, the chip may control the ultrasonic piezoelectric transducer to transmit ultrasonic signals and receive echo signals based on configuration items such as frequency and echo delay in the first configuration information, so as to determine the corresponding one or more first fingerprint images based on the echo signals. After receiving the one or more first fingerprint images, the chip automatically triggers an adaptive judgment process to perform adaptive judgment on the one or more first fingerprint images to evaluate whether the collected one or more first fingerprint images meet pre-set adaptive conditions, and then execute subsequent steps based on the comparison results.

[0044] The first spatial frequency refers to the spatial frequency identified based on one or more first fingerprint images. Spatial frequency refers to the number of periods of fingerprint ridges per unit length. A higher spatial frequency indicates denser fingerprint ridges, while a lower spatial frequency indicates sparser fingerprint ridges. Figure 11 The MTF (Modulation Transfer Function) curves corresponding to different fingerprint images are shown. The MTF curve contains multiple feature points. The horizontal coordinate cycle / mm of each feature point is the number of ridge and valley cycles within 1mm. The larger this value is, the higher the spatial frequency is. The vertical coordinate contrast of each feature point is the contrast, which is used to reflect the image quality.

[0045] As an example, in step S102, after receiving one or more first fingerprint images, the chip can directly invoke a pre-set spatial frequency processing algorithm to perform spatial frequency identification on the one or more first fingerprint images to determine the first spatial frequency corresponding to the one or more first fingerprint images. Alternatively, when the first fingerprint images meet the adaptive conditions, the chip can determine that the first configuration information is incompatible with the user's fingerprint features. To ensure subsequent effective identification of the user's fingerprint features, the chip can invoke a pre-set spatial frequency processing algorithm to perform spatial frequency identification on the one or more first fingerprint images to determine the first spatial frequency corresponding to the one or more first fingerprint images. The first spatial frequency can reflect the thickness of the fingerprint in the one or more collected first fingerprint images. Generally speaking, a lower first spatial frequency indicates a thicker fingerprint of the current user; conversely, a higher first spatial frequency indicates a finer fingerprint of the current user.

[0046] The second configuration information is configuration information determined after performing the adaptive operation, and is configuration information that needs to replace the first configuration information in order to control the operation of the ultrasonic piezoelectric transducer next time.

[0047] As an example, in step S103, when one or more first fingerprint images meet the adaptive conditions, the chip may determine that the first configuration information is incompatible with the user fingerprint features. In order to ensure the subsequent effective identification of the user fingerprint features, the first configuration information may be adjusted based on the first spatial frequency. Specifically, the first frequency and / or the first echo delay in the first configuration information may be adjusted to determine the second frequency and the second echo delay, and the second configuration information may be determined based on the second frequency and the second echo delay; the second frequency is the frequency in the second configuration information; the second echo delay is the echo delay of the second configuration information.

[0048] Figure 12 The MTF curves corresponding to different frequencies are shown. Specifically, for the same user fingerprint, the ultrasonic piezoelectric transducer is controlled to transmit ultrasonic signals based on different frequencies, and the fingerprint image corresponding to the same ultrasonic piezoelectric transducer (i.e., diffraction head) is collected. The fingerprint image is processed to determine its corresponding MTF curve. The MTF curve reflects the difference in the ultrasonic fingerprint system's ability to restore images of different spatial frequencies at different frequencies. Figure 12 As shown, the MTF curve contains multiple feature points. Each feature point corresponds to a ridge-valley cycle number (cycle / mm) and contrast. The larger the ridge-valley cycle number (cycle / mm), the higher the spatial frequency. Figure 12It can be seen that lower frequencies at low spatial frequencies have better contrast in the MTF curve, meaning lowering the frequency can better restore the image of a coarse fingerprint. Conversely, higher frequencies at high spatial frequencies have better contrast in the MTF curve, meaning higher frequencies can better restore the image of a fine fingerprint. Therefore, by adjusting the first frequency in the first configuration information, the ultrasonic fingerprint system can improve its image restoration capabilities at specific spatial frequencies, thereby adapting to the fingerprint characteristics of fingers with different spatial frequencies and achieving improved image quality.

[0049] Figure 13 The signal-to-noise ratio comparison diagram corresponding to different spatial frequencies is shown. The signal-to-noise ratio comparison diagram includes signal-to-noise ratio curves corresponding to multiple spatial frequencies. The signal-to-noise ratio curve includes multiple feature points. The horizontal axis of each feature point is the echo delay, and the vertical axis of each feature point is the signal-to-noise ratio. Figure 13 It can be seen that the echo delays corresponding to the peak signal-to-noise ratios for different spatial frequencies are different. That is, in regions with low spatial frequencies, the signal-to-noise ratio peak is reached at a relatively earlier echo delay, while in regions with high spatial frequencies, the signal-to-noise ratio peak is reached at a relatively later echo delay. Therefore, adjusting the echo delay according to the first spatial frequencies corresponding to one or more first fingerprint images will achieve a better signal-to-noise ratio and improve image quality. In summary, for the first spatial frequency, when the first spatial frequency is low, lowering the frequency in the configuration information and adjusting the echo delay in the configuration information forward can optimize the image quality of the fingerprint image; conversely, when the first spatial frequency is high, increasing the frequency in the configuration information and adjusting the echo delay in the configuration information backward can optimize the image quality of the fingerprint image.

[0050] As an example, in S104, after determining the second configuration information, the chip can use the second configuration information to update the first configuration information, so that the next time the ultrasonic piezoelectric transducer is controlled to operate based on the updated first configuration information, so as to achieve the configuration information for controlling the operation of the ultrasonic piezoelectric transducer according to the coarseness of the fingerprint corresponding to the first spatial frequency, so as to make it compatible with the differences in fingerprint characteristics of different users, help to ensure the quality of the collected fingerprint image and the fingerprint recognition effect, and improve the versatility of the system.

[0051] In this example, according to the first spatial frequency corresponding to the first fingerprint image, the corresponding configuration information is adjusted in a targeted manner, so that after the ultrasonic piezoelectric transducer works based on the second configuration information, it can collect a clearer fingerprint image with better image quality, which helps to improve its fingerprint recognition effect. Figure 14As shown, if the first spatial frequency identified by the first fingerprint image corresponding to User1 is low, it is necessary to lower the frequency and / or reduce the echo delay to determine its corresponding second configuration information; at this time, the second frequency is less than the first frequency, and the second echo delay is less than the first echo delay. Correspondingly, if the spatial frequency identified by the first fingerprint image corresponding to User3 is high, it is necessary to increase the frequency and / or increase the echo delay to determine its corresponding second configuration information; at this time, the second frequency is greater than the first frequency, and the second echo delay is greater than the first echo delay. Based on the first spatial frequency of the user's fingerprint, targeted adaptive configuration adjustments are made to obtain better fingerprint images.

[0052] In this example, the ultrasonic piezoelectric transducer is first controlled to operate based on the first configuration information, a first fingerprint image is obtained and an adaptive judgment is performed. When the first fingerprint image meets the adaptive conditions, the first configuration information is dynamically adjusted based on the first spatial frequency corresponding to the first fingerprint image, so that the adjusted second configuration information can effectively guarantee the overall performance of the ultrasonic fingerprint system, thereby improving the quality of subsequently collected fingerprint images, thereby improving the recognition effect and improving the versatility of the system.

[0053] In one embodiment, if Figure 2 As shown, after step S101, that is, after controlling the ultrasonic piezoelectric transducer to operate based on the first configuration information to obtain one or more first fingerprint images, the ultrasonic fingerprint recognition method further includes:

[0054] S201: Performing quality detection based on one or more first fingerprint images to determine first quality scores corresponding to the one or more first fingerprint images;

[0055] S202: If the first quality score is less than a preset score threshold, determine that one or more first fingerprint images meet the adaptive condition; the first quality score is the quality score of one first fingerprint image, or the arithmetic mean or weighted mean of the quality scores of multiple first fingerprint images.

[0056] The preset score threshold is a preset threshold used to evaluate whether the quality score of the fingerprint image meets a minimum standard.

[0057] In step S201, after acquiring a first fingerprint image, the chip may use a pre-set image quality detection algorithm to perform a quality detection on the first fingerprint image, determine a quality score corresponding to the first fingerprint image, and determine the quality score as the first quality score corresponding to the first fingerprint image. Alternatively, after acquiring multiple first fingerprint images, the chip may determine the acquisition time of the last first fingerprint image or the current time as the end time, acquire multiple first fingerprint images within a preset time period before the end time, and use a pre-set image quality detection algorithm to perform quality detection on the multiple first fingerprint images to determine a quality score corresponding to each first fingerprint image; then, the arithmetic mean or weighted mean of the quality scores of the multiple first fingerprint images is determined as the first quality score of the multiple first fingerprint images.

[0058] As an example, in step S202, after determining the first quality score corresponding to one or more first fingerprint images, the chip compares the first quality score with a preset score threshold; when the first quality score is less than the preset score threshold, it is determined that the overall image quality is poor, and there is a high probability that the first configuration information controlling the ultrasonic piezoelectric transducer does not match the spatial frequency of the user's fingerprint, and it is necessary to adaptively adjust the configuration information such as the frequency and / or echo delay of the ultrasonic piezoelectric transducer. Therefore, it is determined that the one or more first fingerprint images meet the adaptive condition; conversely, when the first quality score is not less than the preset score threshold, it is determined that the overall image quality is good, reflecting that the first configuration information controlling the ultrasonic piezoelectric transducer is relatively matched with the spatial frequency of the user's fingerprint, and there is no need to adaptively adjust the configuration information of the ultrasonic piezoelectric transducer. Therefore, it is determined that the first fingerprint image does not meet the adaptive condition.

[0059] In one embodiment, if Figure 3 As shown, after step S101, that is, after controlling the ultrasonic piezoelectric transducer to operate based on the first configuration information to obtain one or more first fingerprint images, the ultrasonic fingerprint recognition method further includes:

[0060] S301: Perform fingerprint recognition on a plurality of first fingerprint images, and determine a number of consecutive or cumulative times that the plurality of first fingerprint images cannot be successfully recognized;

[0061] S302: If the number of times that the multiple first fingerprint images fail to be successfully identified continuously or cumulatively is greater than a preset number threshold, it is determined that the one or more first fingerprint images meet the adaptive condition.

[0062] The preset number threshold is a preset threshold used to evaluate whether the number of times that the identification fails reaches a certain standard.

[0063] As an example, in step S301, after acquiring the first fingerprint image, the chip may perform fingerprint recognition on the first fingerprint image to determine the fingerprint recognition result corresponding to each first fingerprint image. The fingerprint recognition result includes two types: successful recognition and unsuccessful recognition. For example, the chip may call the registered fingerprint image in the fingerprint template library to perform fingerprint recognition on the first fingerprint image to determine the fingerprint recognition result corresponding to each first fingerprint image. After acquiring the fingerprint recognition result corresponding to the first fingerprint image, the chip needs to update the number of consecutive or cumulative unsuccessful recognitions. For example, if the fingerprint recognition result of the first fingerprint image acquired at the current moment is unsuccessful recognition, K=K+1 is used to update the number of consecutive or cumulative unsuccessful recognitions K; if the fingerprint recognition result of the first fingerprint image acquired at the current moment is successful recognition, K=0 is used to update the number of consecutive or cumulative unsuccessful recognitions.

[0064] As an example, in step S302, after the chip updates and determines the number of consecutive or cumulative unsuccessful identifications based on the most recently acquired first fingerprint image, it may compare the number of consecutive or cumulative unsuccessful identifications with a preset number threshold; when the number of consecutive or cumulative unsuccessful identifications is greater than the preset number threshold, it is determined that the number of consecutive or cumulative unsuccessful identifications is large, and it is highly likely that the first configuration information for controlling the ultrasonic piezoelectric transducer does not match the spatial frequency of the user's fingerprint, and it is necessary to adaptively adjust the frequency and / or echo delay and other configuration information of the ultrasonic piezoelectric transducer. Therefore, it is determined that the first fingerprint image meets the adaptive condition; conversely, when the number of consecutive or cumulative unsuccessful identifications is not greater than the preset number threshold, it is determined that the number of consecutive or cumulative unsuccessful identifications is small (i.e., the probability of successful identification is high), reflecting that the first configuration information for controlling the ultrasonic piezoelectric transducer is relatively matched with the spatial frequency of the user's fingerprint, and there is no need to adaptively adjust the configuration information of the ultrasonic piezoelectric transducer. Therefore, it is determined that the first fingerprint image does not meet the adaptive condition.

[0065] Furthermore, the adaptive condition can be evaluated based on the number of consecutive or cumulative unsuccessful identifications corresponding to the first fingerprint image and the first quality score. That is, when the number of consecutive or cumulative unsuccessful identifications of multiple first fingerprint images is greater than a preset number threshold and the first quality score is less than a preset score threshold, it is determined that the adaptive condition is met, so that the second configuration information can be subsequently determined based on the first spatial frequency and the first configuration information, so that the two processing flows process different data, which helps to improve the fault tolerance rate and further helps to improve the overall image quality and fingerprint recognition effect.

[0066] In one embodiment, after step S101, that is, after controlling the ultrasonic piezoelectric transducer to operate based on the first configuration information to obtain one or more first fingerprint images, the ultrasonic fingerprint recognition method further includes:

[0067] If the first spatial frequency is not within the spatial frequency threshold range, it is determined that the first fingerprint image meets the adaptive condition; the first spatial frequency is the spatial frequency of a first fingerprint image, or the arithmetic mean or weighted mean of the spatial frequencies of multiple first fingerprint images.

[0068] Among them, the spatial frequency threshold range is a pre-set spatial frequency range, and the spatial frequency threshold range is determined based on the lower limit spatial frequency threshold and the upper limit control frequency threshold. The lower limit spatial frequency threshold is a pre-set smaller spatial frequency threshold used to define whether the adaptive condition is met; the upper limit spatial frequency threshold is a pre-set larger spatial frequency threshold used to define whether the adaptive condition is met.

[0069] As an example, after determining the first spatial frequency corresponding to one or more first fingerprint images, the chip may compare the first spatial frequency with the spatial frequency threshold range; if the first spatial frequency is not within the spatial frequency threshold range, that is, the first spatial frequency is less than the lower spatial frequency threshold, or the first spatial frequency is greater than the upper spatial frequency threshold, then it is determined that the user fingerprint corresponding to the first fingerprint image is coarse or fine, and there may be a situation where the first configuration information is incompatible with the user's fingerprint characteristics, which will affect the quality of the collected fingerprint image and the fingerprint recognition effect. Therefore, it is determined that the first fingerprint image meets the adaptive condition. Conversely, if the first spatial frequency is within the spatial frequency threshold range, that is, the first spatial frequency is not less than the lower spatial frequency threshold, and the first spatial frequency is not greater than the upper spatial frequency threshold, it is determined that the user fingerprint of the first fingerprint image is of moderate thickness, so that the first configuration information is highly likely to match the user's fingerprint characteristics, and its fingerprint image quality and fingerprint recognition effect are good. Therefore, it is determined that the first fingerprint image does not meet the adaptive condition.

[0070] In this example, whether the adaptive condition is met can be evaluated based on the first spatial frequency corresponding to the first fingerprint image. When the adaptive condition is met, the second configuration information is further determined based on the first spatial frequency and the first configuration information, so that the two processing flows share the first spatial frequency as an intermediate parameter, which helps to reduce the amount of information processing and improve processing efficiency.

[0071] In one embodiment, if Figure 4 As shown, in step 102, spatial frequency recognition is performed on one or more first fingerprint images to determine a first spatial frequency corresponding to the first fingerprint image, including:

[0072] S401: Perform spatial frequency recognition on each first fingerprint image to determine the measured spatial frequency corresponding to each first fingerprint image;

[0073] S402: Determine a first spatial frequency corresponding to the first fingerprint image based on measured spatial frequencies corresponding to multiple first fingerprint images within a preset time period, where the first spatial frequency is an arithmetic mean or a weighted mean of the spatial frequencies of the multiple first fingerprint images.

[0074] As an example, in step S401, after acquiring a first fingerprint image, the chip may call a pre-set spatial frequency processing algorithm to perform recognition processing on the first fingerprint image and determine the MTF curve corresponding to the first fingerprint image. The MTF curve includes multiple feature points, each of which corresponds to a ridge-valley period and a contrast ratio. A larger ridge-valley period represents a higher spatial frequency, while a smaller ridge-valley period represents a lower spatial frequency. Therefore, the MTF curve can reflect the mapping relationship between different spatial frequencies and different contrast ratios. Then, based on the MTF curve corresponding to the first fingerprint image, the chip determines the measured spatial frequency corresponding to the first fingerprint image. This measured spatial frequency can be the spatial frequency corresponding to the contrast peak in the MTF curve, or it can be the spatial frequency determined by further analyzing and processing the MTF curve using other methods. It can be determined independently according to actual needs.

[0075] As an example, in step S402, after determining the measured spatial frequency corresponding to the first fingerprint image, the chip may determine the acquisition time of the first fingerprint image or the current time as the end time, obtain multiple first fingerprint images within a preset time period before the end time, and process the measured spatial frequencies corresponding to the multiple first fingerprint images to determine the first spatial frequency corresponding to the first fingerprint image. For example, the chip may average the measured spatial frequencies corresponding to the multiple first fingerprint images, or average the frequencies after removing outliers, to determine the arithmetic mean or weighted mean of the spatial frequencies of the multiple first fingerprint images as the first spatial frequency. This ensures that the ultimately determined first spatial frequency more accurately reflects the thickness of the fingerprint, avoiding the possibility that the acquired first spatial frequency may not accurately reflect the thickness of the fingerprint due to incidental events.

[0076] In one embodiment, if Figure 5 As shown, step S401, i.e., performing spatial frequency recognition on each first fingerprint image to determine the measured spatial frequency corresponding to each first fingerprint image, includes:

[0077] S501: Perform spatial frequency recognition on each first fingerprint image to determine an MTF curve corresponding to each first fingerprint image, where the MTF curve includes a plurality of feature points, each feature point corresponding to a ridge-valley period and a contrast ratio;

[0078] S502: Determine target contrasts corresponding to a plurality of first feature combinations based on an MTF curve corresponding to the first fingerprint image, where the first feature combination is a combination of K consecutive feature points, and the target contrast is determined based on the contrasts of all feature points in the first feature combination, where K ≥ 2.

[0079] S503: Determine the measured spatial frequency corresponding to each first fingerprint image based on all ridge and valley period numbers corresponding to the first feature combination with the largest target contrast.

[0080] As an example, in step S501, after obtaining the first fingerprint image, the chip can call a preset spatial frequency processing algorithm to identify and process the first fingerprint image, and determine the MTF curve corresponding to the first fingerprint image. The MTF curve includes multiple feature points, each feature point corresponds to a ridge and valley period number and a contrast. The larger the ridge and valley period number, the higher the spatial frequency. Conversely, the smaller the ridge and valley period number, the lower the spatial frequency.

[0081] As an example, in step S502, the chip can process the MTF curve graph corresponding to the first fingerprint image to determine the target contrast corresponding to multiple first feature combinations, where the first feature combination refers to a combination of K consecutive feature points in the MTF curve graph; the target contrast is the contrast after processing the contrast of all feature points in the first feature combination, which is used to reflect the overall performance of the first feature combination.

[0082] In one example, a sliding window can be used to process the MTF curve corresponding to the first fingerprint image. A first feature combination is formed based on K consecutive feature points within the sliding window. As the sliding window moves, multiple first feature combinations are formed. For example, as the sliding window moves, the combination formed by the 1st feature point to the kth feature point can be determined as the first first feature combination; the combination formed by the 2nd feature point to the k+1th feature point can be determined as the second first feature combination, and so on, to determine multiple first feature combinations.

[0083] In one example, after determining multiple first feature combinations, the chip can process the number of ridge and valley cycles corresponding to all feature points in the multiple first feature combinations, for example, by averaging, summing or performing other algorithms on the multiple ridge and valley cycle numbers to determine the target contrast corresponding to the first feature combination, so that the target contrast corresponding to the first feature combination can more effectively reflect the coarseness of the user's fingerprint feature than the contrast corresponding to a single feature point, so that it can avoid the situation where the contrast of a single feature point is large but the contrast of adjacent feature points is small, and the difference between the two is large, so that the contrast of a single feature point cannot effectively reflect the coarseness of the user's fingerprint feature.

[0084] As an example, in step S503, after determining the target contrasts corresponding to multiple first feature combinations, the chip can compare the target contrasts corresponding to the multiple first feature combinations, and determine the first feature combination corresponding to the maximum target contrast as the second feature combination; then process the number of ridge and valley periods corresponding to all feature points in the second feature combination, for example, the number of ridge and valley periods corresponding to all feature points can be processed as the mean or median to determine the measured spatial frequency corresponding to the first fingerprint image, so that the measured spatial frequency can more accurately reflect the coarseness of the user's fingerprint features.

[0085] In one embodiment, if Figure 6 As shown, step S103, i.e., determining the second configuration information based on the first spatial frequency and the first configuration information, includes:

[0086] S601: Determine multiple target configuration information based on the first spatial frequency and the first configuration information;

[0087] S602: Control the ultrasonic piezoelectric transducer to perform adaptive operation based on multiple target configuration information, and determine second configuration information from the multiple target configuration information.

[0088] The target configuration information is configuration information that is determined based on the first spatial frequency and the first configuration information and is not subjected to an adaptive operation.

[0089] As an example, in step S601, after determining the first spatial frequency corresponding to the first fingerprint image, the chip may adjust the first configuration information based on the first spatial frequency. Specifically, the chip may adjust the first frequency and / or the first echo delay in the first configuration information, and determine the adjusted configuration information as the target configuration information. For example, when the first spatial frequency is low, the frequency and / or the echo delay may be reduced to determine the target configuration information, so that when the ultrasonic piezoelectric transducer operates based on the target configuration information, a fingerprint image with higher image quality can be obtained. Conversely, when the first spatial frequency is high, the frequency and / or the echo delay may be increased to determine the target configuration information, so that when the ultrasonic piezoelectric transducer operates based on the target configuration information, a fingerprint image with higher image quality can be obtained. Conversely, when the first spatial frequency is high, the frequency and / or the echo delay may be increased to determine the target configuration information, so that when the ultrasonic piezoelectric transducer operates based on the target configuration information, a fingerprint image with higher image quality can be obtained.

[0090] As an example, in step S602, after determining multiple target configuration information, the chip cannot confirm which target configuration information better matches the user's fingerprint features. Therefore, it is necessary to control the ultrasonic piezoelectric transducer to perform adaptive operations based on the multiple target configuration information and determine the second configuration information from the multiple target configuration information. The second configuration information here can be understood as the configuration information that has been determined through the adaptive operation.

[0091] In this example, the chip can control the ultrasonic piezoelectric transducer to operate based on multiple target configuration information, that is, according to the frequency and echo delay in each target configuration information, control the ultrasonic piezoelectric transducer to emit ultrasonic signals, and receive echo signals such as reflected waves and scattered waves, and process the echo signals, including but not limited to processing operations such as beamforming and analog-to-digital conversion, to determine the feedback information of the ultrasonic piezoelectric transducer. Based on the feedback information, it is determined which target configuration information better matches the user's fingerprint characteristics, and the target configuration information that best matches the user's fingerprint characteristics is selected and determined as the second configuration information to ensure the ultrasonic fingerprint system's recognition effect on the user's fingerprint.

[0092] In one embodiment, step S601, i.e., determining a plurality of target configuration information based on the first spatial frequency and the first configuration information, includes:

[0093] Based on the first spatial frequency and the first configuration information, a plurality of adaptive configuration information is generated, and the plurality of adaptive configuration information is determined as a plurality of target configuration information.

[0094] As an example, when the chip stores only one configuration information (i.e., the first configuration information) in the memory, if the first fingerprint image meets the adaptive conditions and it is determined that the first configuration information needs to be adaptively adjusted, it is necessary to call the pre-set configuration information generation logic to process the two input parameters of the first spatial frequency and the first configuration information to generate multiple adaptive configuration information, and the multiple adaptive configuration information can be directly determined as the target configuration information. The adaptive configuration information here is the newly generated configuration information based on the first spatial frequency and the first configuration information. In this example, when the first spatial frequency is low, the frequency in the adaptive configuration information is less than the frequency in the first configuration information, and / or the echo delay in the adaptive configuration information is less than the echo delay in the first configuration information; conversely, when the first spatial frequency is high, the frequency in the adaptive configuration information is greater than the frequency in the first configuration information, and / or the echo delay in the adaptive configuration information is greater than the echo delay in the first configuration information.

[0095] In this example, the target configuration information is adaptive configuration information, which is dynamically generated based on the first spatial frequency and the first configuration information, so that it better matches the user fingerprint features corresponding to the first spatial frequency, so that when the ultrasonic piezoelectric transducer operates based on the adaptive configuration information, a fingerprint image with higher image quality can be obtained; moreover, since the adaptive configuration information is dynamically generated, it does not need to occupy more storage resources, which helps to save system storage resources.

[0096] In one embodiment, the first configuration information includes a first frequency and a first echo delay;

[0097] like Figure 7As shown, based on the first spatial frequency and the first configuration information, multiple adaptive configuration information are generated, including:

[0098] S701: Determine an adaptive coefficient based on a first spatial frequency and a preset spatial frequency;

[0099] S702: Determine N adaptive frequencies based on the first frequency and the adaptive coefficient;

[0100] S703: Determine M adaptive echo delays based on the first frequency and the adaptive coefficient;

[0101] S704: Determine a plurality of adaptive configuration information based on the N adaptive frequencies and the M adaptive echo delays.

[0102] The preset spatial frequency is a pre-set spatial frequency. In one example, the preset spatial frequency can be a spatial frequency recognition performed on the collected fingerprint image based on big data technology, and the average of multiple spatial frequencies is determined to reflect the basic situation of the spatial frequencies of most user fingerprints.

[0103] As an example, in step S701, the chip may calculate the corresponding adaptive coefficient based on the first spatial frequency and the preset spatial frequency corresponding to the first fingerprint image. The adaptive coefficient can be understood as a coefficient used to adaptively adjust the first configuration information. In this example, the chip may calculate the frequency difference between the first spatial frequency and the preset spatial frequency, and determine the quotient of the frequency difference and the preset spatial frequency as the adaptive coefficient, that is, ratio = (PITCH_avg – PITCH_base) / PITCH_base, where PITCH_avg is the first spatial frequency, PITCH_base is the preset spatial frequency, and ratio is the adaptive coefficient.

[0104] As an example, the chip may determine N adaptive frequencies based on the first frequency and the adaptive coefficient in the first configuration information. The adaptive frequency can be understood as the frequency in the adaptive configuration information. In this example, the chip may determine N frequency changes based on the adaptive coefficient and a preset frequency increment threshold; and then determine the N adaptive frequencies based on the first frequency and the N frequency changes.

[0105] For example, the first frequency is F_now, and the frequency increment threshold is K_F. N frequency changes can be determined based on K_F*ratio*i, where 0≤i≤N-1; then, the sum of the first frequency and any frequency change is determined as the corresponding adaptive frequency, and the N adaptive frequencies determined are as follows: T_1=T_now; T_2=T_now+K_T*ratio*1; ...; T_M=T_now+K_T*ratio*(M-1).

[0106] As an example, the chip may determine M adaptive echo delays based on the first echo delay and the adaptive coefficient in the first configuration information. The adaptive echo delay can be understood as the echo delay in the adaptive configuration information. In this example, the chip may determine M echo delay changes based on the adaptive coefficient and a preset echo delay increment threshold; and then determine M adaptive echo delays based on the first echo delay and the M echo delay changes.

[0107] For example, the first echo delay is T_now, and the echo delay increment threshold is K_T. M echo delay changes can be determined based on K_T*ratio*j, where 0≤j≤M-1; then, the sum of the first echo delay and any echo delay change is determined as the corresponding adaptive echo delay. The M adaptive echo delays determined are as follows: T_1=T_now, T_2=T_now+K_T*ratio*1, …, T_M=T_now+K_T*ratio*(M-1).

[0108] As a chip, the chip forms N*M adaptive configuration information based on N adaptive frequencies and M adaptive echo delays. The specific adaptive configuration information is as follows:

[0109] [F_1,T_1],[F_1,T_2]…[F_1,T_M]

[0110] [F_2,T_1],[F_2,T_2]…[F_2,T_M]

[0111] …

[0112] [F_N,T_1],[F_N,T_2]…[F_N,T_M]

[0113] In this example, based on the first spatial frequency and the first configuration information, N*M adaptive configuration information are dynamically generated to make it more closely match the user fingerprint features corresponding to the first spatial frequency, so that when the ultrasonic piezoelectric transducer operates based on the adaptive configuration information, a fingerprint image with higher image quality can be obtained.

[0114] In one embodiment, step S601, i.e., determining a plurality of target configuration information based on the first spatial frequency and the first configuration information, includes:

[0115] Based on the first spatial frequency and the preset spatial frequency, a configuration adjustment direction is determined, and a plurality of preset configuration information matching the configuration adjustment direction is determined as a plurality of target configuration information.

[0116] The preset spatial frequency is a pre-set spatial frequency. In one example, the preset spatial frequency can be a mean spatial frequency determined by pre-processing spatial frequency recognition of collected fingerprint images based on big data technology, which can reflect the basic spatial frequency of most user fingerprints. The preset configuration information is pre-set configuration information, which is generally stored in the memory corresponding to the ultrasonic fingerprint system and can be automatically called according to actual circumstances.

[0117] As an example, when the chip stores multiple preset configurations in memory, if a first fingerprint image meets the adaptive conditions and determines that the first configuration requires adaptive adjustment, it first dynamically determines the corresponding configuration adjustment direction based on the first spatial frequency corresponding to the first fingerprint image and the preset spatial frequency. This configuration adjustment direction reflects the direction in which the frequency and / or echo delay should be increased or decreased. The chip then reads the multiple preset configurations from memory and identifies the multiple preset configurations that match the configuration adjustment direction as the multiple target configurations.

[0118] In this example, the target configuration information can be pre-stored preset configuration information. After determining its corresponding configuration adjustment direction based on the first spatial frequency and the preset spatial frequency, some preset configuration information that matches the configuration adjustment direction is directly selected from multiple preset configuration information and determined as the target configuration information. This helps to ensure the efficiency of obtaining the target configuration information, thereby improving the efficiency of adaptive adjustment of the configuration information of the ultrasonic fingerprint system.

[0119] In one embodiment, the first configuration information includes a first frequency and a first echo delay;

[0120] Each preset configuration information includes a preset frequency and a preset echo delay;

[0121] Accordingly, based on the first spatial frequency and the preset spatial frequency, a configuration adjustment direction is determined, and multiple preset configuration information matching the configuration adjustment direction is determined as multiple target configuration information, including:

[0122] (1) If the first spatial frequency is less than the preset spatial frequency, determining that the configuration adjustment direction is a reduction direction, and determining the preset configuration information in which the preset frequency is less than the first frequency and / or the preset echo delay is less than the first echo delay as the target configuration information;

[0123] (2) If the first spatial frequency is greater than the preset spatial frequency, the configuration adjustment direction is determined to be an increasing direction, and the preset configuration information in which the preset frequency is greater than the first frequency and / or the preset echo delay is greater than the first echo delay is determined as the target configuration information.

[0124] As an example, the first configuration information includes a first frequency and a first echo delay; accordingly, the preset configuration information includes a preset frequency and a preset echo delay, where the preset frequency is the frequency in the preset configuration information; the preset echo delay is the echo delay in the preset configuration information, and the memory pre-stores A*B groups of preset configuration information as follows:

[0125] [(preset frequency 1, preset echo delay 1),…,(preset frequency 1, preset echo delay b)]

[0126] [(preset frequency 2, preset echo delay 1),…,(preset frequency 2, preset echo delay b)]

[0127] …

[0128] [(preset frequency a, preset echo delay 1),…,(preset frequency a, preset echo delay b)]

[0129] In this example, the chip compares the first spatial frequency corresponding to the first fingerprint image with a preset spatial frequency. When the first spatial frequency is less than the preset spatial frequency, it indicates that the spatial frequency corresponding to the user's fingerprint is low and the fingerprint is coarse. In this case, lowering the frequency can better restore the fingerprint image corresponding to the coarse fingerprint, and lowering the echo delay can better improve the image's signal-to-noise ratio peak. Therefore, the configuration adjustment direction can be determined to be a reduction direction. Next, the chip can compare the first frequency with multiple preset frequencies and the first echo delay with multiple preset echo delays, and determine the preset configuration information where the preset frequency is less than the first frequency and / or the preset echo delay is less than the first echo delay as the target configuration information. This can not only ensure the efficiency of obtaining the target configuration information, but also ensure the quality of the fingerprint image after the configuration information is adjusted, which helps to improve the fingerprint recognition effect.

[0130] Accordingly, the chip compares the first spatial frequency corresponding to the first fingerprint image with the preset spatial frequency. When the first spatial frequency is greater than the preset spatial frequency, it indicates that the spatial frequency corresponding to the user's fingerprint is higher and the fingerprint is finer. In this case, increasing the frequency can better restore the fingerprint image corresponding to the fine fingerprint, and increasing the echo delay can better improve the image's signal-to-noise ratio peak. Therefore, the configuration adjustment direction can be determined to be increasing. The chip can then compare the first frequency with multiple preset frequencies and the first echo delay with multiple preset echo delays, and determine the preset configuration information where the preset frequency is greater than the first frequency and / or the preset echo delay is greater than the first echo delay as the target configuration information. This can not only ensure the efficiency of obtaining the target configuration information, but also ensure the quality of the fingerprint image after the configuration information is adjusted, which helps to improve the fingerprint recognition effect.

[0131] In one embodiment, if Figure 8As shown, step S302, i.e., controlling the ultrasonic piezoelectric transducer to perform adaptive operation based on multiple target configuration information, and determining second configuration information from the multiple target configuration information, includes:

[0132] S801: Controlling the ultrasonic piezoelectric transducer to perform adaptive operation based on each target configuration information to obtain multiple second fingerprint images corresponding to each target configuration information;

[0133] S802: Perform image quality detection on each second fingerprint image to determine a second quality score corresponding to each second fingerprint image;

[0134] S803: Determine the target configuration information of the second fingerprint image corresponding to the second maximum quality score as the second configuration information.

[0135] As an example, in step S801, after determining multiple target configurations, the chip controls the ultrasonic piezoelectric transducer to operate based on each target configuration. Specifically, based on the frequency and echo delay in each preset configuration, the chip controls the ultrasonic piezoelectric transducer to transmit ultrasonic signals, receive echo signals such as reflected and scattered waves, and processes the echo signals to determine multiple second fingerprint images corresponding to each target configuration. The second fingerprint images are fingerprint images captured by the ultrasonic piezoelectric transducer after operating based on the target configuration.

[0136] As an example, in step S802, the chip performs image quality detection on each second fingerprint image to determine a second quality score corresponding to each second fingerprint image. The calculation process of the second quality score is the same as the calculation process of the first quality score corresponding to the first fingerprint image mentioned above. To avoid repetition, they are not described here one by one.

[0137] As an example, in step S803, after determining the second quality scores corresponding to multiple second fingerprint images, the chip compares the multiple second quality scores, determines the maximum second quality score, and determines the target configuration information corresponding to the second fingerprint image corresponding to the maximum second quality score as the second configuration information, so as to subsequently update the currently used first configuration information based on the second configuration information, so as to realize dynamic adjustment of the configuration information for controlling the operation of the ultrasonic piezoelectric transducer, so that it is compatible with the differences in fingerprint characteristics of different users, which helps to ensure the quality of the collected fingerprint images and the fingerprint recognition effect, and improve the versatility of the system.

[0138] In one embodiment, if Figure 9 As shown, after step S104, that is, after adopting the second configuration information to update the first configuration information, the ultrasonic fingerprint recognition method further includes:

[0139] S901: Perform spatial frequency recognition on one or more second fingerprint images to determine second spatial frequencies corresponding to the one or more second fingerprint images;

[0140] S902: updating the spatial frequency threshold range based on the second spatial frequency; the second spatial frequency is the spatial frequency of a second fingerprint image, or the arithmetic mean or weighted mean of the spatial frequencies of multiple second fingerprint images.

[0141] As an example, after the chip determines the target configuration information corresponding to the second fingerprint image corresponding to the maximum value of the second mass score as the second configuration information and uses the second configuration information to update the first configuration information in the memory, it is necessary to further perform spatial frequency identification on one or more second fingerprint images corresponding to the second configuration information (i.e., the second fingerprint image corresponding to the maximum value of the second mass score) to determine the second spatial frequency corresponding to the second fingerprint image. The calculation process of the second spatial frequency is the same as the calculation process of the above-mentioned first spatial frequency. To avoid repetition, they are not described here one by one.

[0142] As an example, after the chip detects the second spatial frequency corresponding to the second fingerprint image, it can compare the second spatial frequency with the spatial frequency threshold range used to evaluate whether the adaptive conditions are met. According to the comparison result, the spatial frequency threshold range is adaptively adjusted so that the first spatial frequency corresponding to the first fingerprint image collected next time can be compared with the updated spatial frequency threshold range to evaluate whether the adaptive conditions are met, so as to dynamically adjust its adaptive conditions to match the user's fingerprint characteristics to ensure the smooth progress of the adaptive process.

[0143] In one embodiment, the spatial frequency threshold range includes a lower spatial frequency threshold and an upper spatial frequency threshold;

[0144] Step S902, i.e., updating the spatial frequency threshold range based on the second spatial frequency, includes:

[0145] S9021: If the second spatial frequency is less than the lower spatial frequency threshold, use the second spatial frequency to update the lower spatial frequency threshold;

[0146] S9022: If the second spatial frequency is greater than the upper spatial frequency threshold, use the second spatial frequency to update the upper spatial frequency threshold.

[0147] As an example, after determining the second spatial frequency corresponding to the second fingerprint image, the chip can compare the second spatial frequency with the lower spatial frequency threshold and the upper spatial frequency threshold; if the second spatial frequency is less than the lower spatial frequency threshold, it is determined that the spatial frequency of the second fingerprint image collected based on the second configuration information is small, reflecting that the user fingerprint is coarse, and the lower spatial frequency threshold corresponding to the spatial frequency threshold range needs to be updated using the second spatial frequency; if the second spatial frequency is greater than the upper spatial frequency threshold, it is determined that the spatial frequency of the second fingerprint image collected based on the second configuration information is large, reflecting that the user fingerprint is fine, and the upper spatial frequency threshold corresponding to the spatial frequency threshold range needs to be updated using the second spatial frequency; if the second spatial frequency is between the lower spatial frequency threshold and the upper spatial frequency threshold, there is no need to adjust the spatial frequency threshold range.

[0148] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0149] In one embodiment, an ultrasonic fingerprint chip is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the ultrasonic fingerprint recognition method in the above embodiment is implemented, for example Figure 1 Steps S101-S104 in , or Figures 2 to 9 To avoid repetition, no further details are given here.

[0150] In one embodiment, an ultrasonic fingerprint system is provided, including an ultrasonic piezoelectric transducer and an ultrasonic fingerprint chip. The ultrasonic fingerprint chip is connected to the ultrasonic piezoelectric transducer. To avoid repetition, details are not given here.

[0151] In one embodiment, an electronic device is provided, including the ultrasonic fingerprint system described above. The electronic device may be a portable electronic device, such as a smartphone, tablet computer, laptop computer, personal digital assistant, etc. In other embodiments, the electronic device may also be a smart wearable device. The embodiments of the present disclosure do not limit the type of electronic device.

[0152] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the ultrasonic fingerprint recognition method in the above embodiment is implemented, for example Figure 1 Steps S101-S104 in , or Figures 2 to 9 To avoid repetition, no further details are given here.

[0153] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, which can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0154] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0155] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. An ultrasonic fingerprint recognition method, wherein: include: controlling the ultrasonic piezoelectric transducer to operate based on the first configuration information to obtain one or more first fingerprint images; performing spatial frequency recognition on the one or more first fingerprint images to determine a first spatial frequency corresponding to the one or more first fingerprint images; When one or more of the first fingerprint images meet an adaptive condition, determining second configuration information based on the first spatial frequency and the first configuration information; The first configuration information is updated using the second configuration information.

2. The ultrasonic fingerprint recognition method according to claim 1, wherein: After controlling the ultrasonic piezoelectric transducer to operate based on the first configuration information to obtain one or more first fingerprint images, the ultrasonic fingerprint recognition method further includes: performing quality detection based on the one or more first fingerprint images to determine a first quality score of the one or more first fingerprint images; If the first quality score is less than a preset score threshold, it is determined that one or more of the first fingerprint images meet the adaptive condition; the first quality score is the quality score of one of the first fingerprint images, or the arithmetic average or weighted average of the quality scores of multiple first fingerprint images.

3. The ultrasonic fingerprint recognition method according to claim 1, wherein: After controlling the ultrasonic piezoelectric transducer to operate based on the first configuration information to obtain one or more first fingerprint images, the ultrasonic fingerprint recognition method further includes: performing fingerprint recognition on the plurality of first fingerprint images, and determining a number of consecutive or cumulative failures of successful recognition of the plurality of first fingerprint images; If the number of times that the plurality of first fingerprint images fail to be successfully identified continuously or cumulatively is greater than a preset number threshold, it is determined that the one or more first fingerprint images meet the adaptive condition.

4. The ultrasonic fingerprint recognition method according to claim 1, wherein: After performing spatial frequency recognition on the one or more first fingerprint images and determining the first spatial frequencies corresponding to the one or more first fingerprint images, the ultrasonic fingerprint recognition method further includes: If the first spatial frequency is not within the spatial frequency threshold range, it is determined that the first fingerprint image meets the adaptive condition; the first spatial frequency is the spatial frequency of a first fingerprint image, or the arithmetic mean or weighted mean of the spatial frequencies of multiple first fingerprint images.

5. The ultrasonic fingerprint recognition method according to claim 1, wherein: The performing spatial frequency recognition on one or more first fingerprint images to determine a first spatial frequency corresponding to the first fingerprint image includes: performing spatial frequency recognition on each of the first fingerprint images to determine a measured spatial frequency corresponding to each of the first fingerprint images; Based on the measured spatial frequencies corresponding to the plurality of first fingerprint images within a preset time period, a first spatial frequency corresponding to the first fingerprint image is determined, where the first spatial frequency is an arithmetic mean or a weighted mean of the spatial frequencies of the plurality of first fingerprint images.

6. The ultrasonic fingerprint recognition method according to claim 5, wherein: The performing spatial frequency recognition on each of the first fingerprint images to determine the measured spatial frequency corresponding to each of the first fingerprint images includes: Performing spatial frequency recognition on each of the first fingerprint images to determine an MTF curve corresponding to each of the first fingerprint images, wherein the MTF curve includes a plurality of feature points, each of the feature points corresponding to a ridge-valley period and a contrast ratio; Determining, based on an MTF curve graph corresponding to the first fingerprint image, a target contrast corresponding to a plurality of first feature combinations, where the first feature combination is a combination of K consecutive feature points, and the target contrast is determined based on the contrast of all feature points in the first feature combination, where K is greater than or equal to 2; The measured spatial frequency corresponding to each of the first fingerprint images is determined based on all ridge and valley period numbers corresponding to the first feature combination with the largest target contrast.

7. The ultrasonic fingerprint recognition method according to claim 1, wherein: The determining, based on the first spatial frequency and the first configuration information, second configuration information includes: determining a plurality of target configuration information based on the first spatial frequency and the first configuration information; The ultrasonic piezoelectric transducer is controlled to perform an adaptive operation based on the plurality of target configuration information, and second configuration information is determined from the plurality of target configuration information.

8. The ultrasonic fingerprint recognition method according to claim 7, wherein: The determining, based on the first spatial frequency and the first configuration information, a plurality of target configuration information includes: Based on the first spatial frequency and the first configuration information, a plurality of adaptive configuration information is generated, and the plurality of adaptive configuration information is determined as a plurality of target configuration information.

9. The ultrasonic fingerprint recognition method according to claim 8, wherein: The first configuration information includes a first frequency and a first echo delay; The generating a plurality of adaptive configuration information based on the first spatial frequency and the first configuration information includes: determining an adaptive coefficient based on the first spatial frequency and a preset spatial frequency; Determining N adaptive frequencies based on the first frequency and the adaptive coefficient; determining M adaptive echo delays based on the first frequency and the adaptive coefficient; A plurality of adaptive configuration information is determined based on the N adaptive frequencies and the M adaptive echo delays.

10. The ultrasonic fingerprint recognition method according to claim 7, wherein: The determining, based on the first spatial frequency and the first configuration information, a plurality of target configuration information includes: Based on the first spatial frequency and the preset spatial frequency, a configuration adjustment direction is determined, and a plurality of preset configuration information matching the configuration adjustment direction is determined as a plurality of target configuration information.

11. The ultrasonic fingerprint recognition method according to claim 10, wherein: The first configuration information includes a first frequency and a first echo delay; Each of the preset configuration information includes a preset frequency and a preset echo delay; The determining of the configuration adjustment direction based on the first spatial frequency and the preset spatial frequency, and determining multiple preset configuration information matching the configuration adjustment direction as multiple target configuration information includes: If the first spatial frequency is less than the preset spatial frequency, determining that the configuration adjustment direction is a reduction direction, and determining the preset configuration information in which the preset frequency is less than the first frequency and / or the preset echo delay is less than the first echo delay as the target configuration information; If the first spatial frequency is greater than the preset spatial frequency, the configuration adjustment direction is determined to be an increasing direction, and the preset configuration information in which the preset frequency is greater than the first frequency, and / or the preset echo delay is greater than the first echo delay is determined as the target configuration information.

12. The ultrasonic fingerprint recognition method according to claim 7, wherein: The controlling the ultrasonic piezoelectric transducer to perform an adaptive operation based on the plurality of target configuration information, and determining the second configuration information from the plurality of target configuration information, comprises: controlling the ultrasonic piezoelectric transducer to perform an adaptive operation based on each target configuration information to obtain a plurality of second fingerprint images corresponding to each target configuration information; Performing image quality detection on each second fingerprint image to determine a second quality score corresponding to each second fingerprint image; The target configuration information of the second fingerprint image corresponding to the maximum value of the second quality score is determined as the second configuration information.

13. The ultrasonic fingerprint recognition method according to claim 12, wherein: After adopting the second configuration information to update the first configuration information, the ultrasonic fingerprint recognition method further includes: performing spatial frequency recognition on the one or more second fingerprint images to determine a second spatial frequency corresponding to the one or more second fingerprint images; The spatial frequency threshold range is updated based on the second spatial frequency; the second spatial frequency is the spatial frequency of one second fingerprint image, or the arithmetic mean or weighted mean of the spatial frequencies of multiple second fingerprint images.

14. The ultrasonic fingerprint recognition method according to claim 13, wherein: The spatial frequency threshold range includes a lower spatial frequency threshold and an upper spatial frequency threshold; The updating of the spatial frequency threshold range based on the second spatial frequency includes: If the second spatial frequency is less than the lower spatial frequency threshold, updating the lower spatial frequency threshold by using the second spatial frequency; If the second spatial frequency is greater than the upper spatial frequency threshold, the upper spatial frequency threshold is updated using the second spatial frequency.

15. An ultrasonic fingerprint chip comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the ultrasonic fingerprint recognition method according to any one of claims 1 to 14 is implemented.

16. An ultrasonic fingerprint system, wherein: It comprises an ultrasonic piezoelectric transducer and the ultrasonic fingerprint chip according to claim 15, wherein the ultrasonic fingerprint chip is connected to the ultrasonic piezoelectric transducer.

17. An electronic device, wherein: Including the ultrasonic fingerprint system as claimed in claim 16.

18. A computer-readable storage medium storing a computer program, wherein: When the computer program is executed by a processor, the ultrasonic fingerprint recognition method according to any one of claims 1 to 14 is implemented.

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