An ultrasonic sensor array adaptive control method and device

Abstract

Embodiments of the present application provide an ultrasonic sensor array adaptive control method, the ultrasonic sensor array is arranged below a screen protection film, the method comprises: obtaining pressing data of the ultrasonic sensor array under finger pressing and non-pressing data when the finger is lifted; judging whether the screen protection film state changes according to the data processing of the pressing data and the non-pressing data; and adaptively adjusting the configuration of the ultrasonic sensor array according to the change. Embodiments of the present application can quickly determine whether the screen protection film is installed, removed or replaced, and then adaptively adjust the configuration of the ultrasonic sensor array.

Description

Technical Field

[0001] This application relates to an ultrasonic sensor array, and more particularly to an adaptive control method and apparatus for an ultrasonic sensor array. Background Technology

[0002] Ultrasonic fingerprint recognition systems acquire fingerprint images through an array of ultrasonic sensors. Unlike optical imaging, the piezoelectric transducers inside the ultrasonic sensors generate ultra-high frequency sound waves that can penetrate the epidermis, forming a fingerprint by measuring the energy of the reflected waves.

[0003] The image is easily captured and is less affected by the details of the fingerprint surface, allowing for recognition even when the hands are dirty or wet. Compared to existing capacitive and optical fingerprint recognition technologies, it offers advantages in both security (anti-counterfeiting) and accuracy.

[0004] The ultrasonic sensor array receives sound wave signals from finger reflections on the device screen. If the device screen is covered with a screen protector, it may seriously affect the intensity of sound wave reflection, causing an overall phase shift in the sound wave signal. This results in unclear fingerprint image details, reduced resolution, and a lower fingerprint recognition rate. 5. Summary of the Invention

[0005] This application provides an adaptive control method and apparatus for an ultrasonic sensor array, which can quickly determine whether the state of the screen protector has changed, i.e., whether it is installed, removed, or replaced, and readjust the configuration of the ultrasonic sensor array to reduce the impact of screen protector changes on fingerprint images and fingerprint recognition.

[0006] A first aspect of this application provides an adaptive control method for an ultrasonic sensor array, wherein the ultrasonic sensor array is disposed under a screen protector, comprising: acquiring pressure data of the ultrasonic sensor array under finger pressure.

[0007] The system collects non-press data when the finger is lifted; it processes the press and non-press data to determine whether the screen protector state has changed; and it adaptively adjusts the configuration of the ultrasonic sensor array based on the changes.

[0008] In some possible implementations, the acquisition of pressure data from the ultrasonic sensor array under finger pressure and

[0009] The non-pressing data when the finger is lifted also includes: acquiring the Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press, where N is a positive integer; acquiring the ultrasonic sensor array...

[0010] The array includes the N-1th fingerprint signal under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th finger press; the step of determining whether the screen protector state has changed by processing the data based on the press data and non-press data further includes: determining whether the screen protector state has changed by processing the data based on the Nth fingerprint signal and the N-1th reference signal.

[0011] In some possible implementations, the step of determining whether the screen protector state has changed by processing data based on the Nth fingerprint signal and the (N-1)th reference signal further includes: determining whether the fingerprint is successfully matched based on the Nth fingerprint signal and the (N-1)th reference signal; if the match is successful, calculating the fingerprint contrast based on the Nth fingerprint signal and the (N-1)th reference signal; if the ratio of the fingerprint contrast of the Nth fingerprint signal to the (N-1)th reference signal is less than a first threshold, determining that the screen protector state has changed.

[0012] In some possible implementations, acquiring the pressure data of the ultrasonic sensor array under finger pressure and the non-pressure data when the finger is lifted further includes: acquiring the Nth fingerprint signal of the ultrasonic sensor array under the Nth finger pressure and the Nth reference signal when the finger is lifted after the Nth finger pressure, where N is a positive integer; acquiring the N-1th fingerprint signal of the ultrasonic sensor array under the (N-1)th finger pressure and the N-1th reference signal when the finger is lifted after the (N-1)th finger pressure; and determining whether the screen protector state has changed by performing data processing based on the pressure data and the non-pressure data further includes: determining whether the screen protector state has changed by performing data processing based on the Nth reference signal and the (N-1)th reference signal.

[0013] In some possible implementations, the step of determining whether the screen protector state has changed by processing data based on the Nth reference signal and the (N-1)th reference signal further includes: calculating the spatial region inconsistency between the Nth reference signal and the (N-1)th reference signal; if the ratio of the spatial region inconsistency of the Nth reference signal to the spatial region inconsistency of the (N-1)th reference signal is less than a second threshold; determining that the screen protector state has changed.

[0014] In some possible implementations, the method further includes: if the ratio of the spatial region inconsistency of the Nth reference signal to the spatial region inconsistency of the (N-1)th reference signal is not less than a second threshold; calculating the spatial region inconsistency based on the difference between the Nth reference signal and the (N-1)th reference signal; if the spatial region inconsistency of the difference is greater than a third threshold; determining that the screen protector state has changed.

[0015] In some possible implementations, when N is 1, the ultrasonic sensor array acquires the first fingerprint signal under the first finger press and the first reference signal when the finger is lifted after the first press; acquires the initial reference signal of the ultrasonic sensor array before the first finger press and lift operation; and performs data processing based on the first fingerprint signal, the first reference signal and the initial reference signal to determine whether the screen protector state has changed.

[0016] In some possible implementations, the change includes installing, removing, or replacing the screen protector.

[0017] In some possible implementations, the step of adaptively adjusting the configuration of the ultrasonic sensor array based on the replacement or removal further includes: triggering a recalibration process after determining that the screen protector has changed; detecting a finger press-and-release operation; acquiring the fingerprint signal at time M and the reference signal at time M, where M is a positive integer, for multiple time interval windows; calculating the screen echo delay after the screen protector state changes based on the film thickness and film sound velocity; determining whether the fingerprint is successfully matched based on the fingerprint signal at time M and the reference signal at time M-1; if the match is successful, calculating the fingerprint contrast for the multiple time interval windows; and selecting the time interval window with the largest fingerprint contrast to update the configuration of the screen echo delay.

[0018] In some possible implementations, the step of calculating the screen echo delay after the screen protector is replaced or removed based on the film thickness and film sound velocity further includes: the screen echo delay after the screen protector is replaced or removed is equal to the screen echo delay before the screen protector is replaced or removed plus or minus the echo time for different film thicknesses.

[0019] In some possible implementations, the following steps are taken: First, a reference signal at time M corresponding to the time interval window with the maximum fingerprint contrast is obtained. Then, the saturation of the screen echo signal is determined based on the reference signal at time M. Next, the number of integrations of the fingerprint signal is adjusted based on the saturation of the screen echo signal. Finally, the number of integrations is updated within the time interval window with the maximum fingerprint contrast. The ultrasonic sensor array is then controlled to adaptively adjust based on the screen echo delay and the number of integrations.

[0020] A second aspect of this application provides an adaptive control device for an ultrasonic sensor array, wherein the ultrasonic sensor array is disposed below a screen protector, and includes: a first data acquisition module for acquiring pressure data of the ultrasonic sensor array under finger pressure and non-pressure data when the finger is lifted; a data processing module for performing data processing based on the pressure data and non-pressure data to determine whether the state of the screen protector has changed; and a correction module for adaptively adjusting the configuration of the ultrasonic sensor array based on the change.

[0021] In some possible implementations, the first data acquisition module is further configured to: acquire the Nth fingerprint signal of the ultrasonic sensor array under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth press, where N is a positive integer; acquire the N-1th fingerprint signal of the ultrasonic sensor array under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th press.

[0022] In some possible implementations, the system further includes: a fingerprint matching judgment module, used to determine whether a fingerprint is successfully matched based on the Nth fingerprint signal and the (N-1)th reference signal; a contrast calculation module, used to calculate the fingerprint contrast based on the Nth fingerprint signal and the (N-1)th reference signal if the fingerprint matching judgment module determines that the fingerprint is successfully matched; and a film state judgment module, used to determine that the screen protector state has changed if the ratio of the fingerprint contrast of the Nth fingerprint signal to the (N-1)th reference signal is less than a first threshold.

[0023] Among some possible implementations are: a trigger module for triggering a recalibration process after a change in the screen protector; a detection module for detecting finger press-and-release operations; a second data acquisition module for acquiring the fingerprint signal at time M and the reference signal at time M, where M is a positive integer, across multiple time interval windows; a calibration parameter calculation module for calculating the screen echo delay after the screen protector state changes based on the film thickness and film sound velocity; a fingerprint matching judgment module for determining whether a fingerprint match is successful based on the fingerprint signal at time M and the reference signal at time M-1; a contrast calculation module for calculating the fingerprint contrast across the multiple time interval windows if a match is successful; and a calibration module for selecting the time interval window with the highest fingerprint contrast to update the screen echo delay configuration.

[0024] In some possible implementations, the system further includes: a second data acquisition module, which is also used to acquire the reference signal at time M corresponding to the time interval window with the maximum fingerprint contrast; a correction parameter calculation module, which is also used to determine the saturation of the screen echo signal based on the reference signal at time M; and adjust the integration count of the fingerprint signal based on the saturation of the screen echo signal; a correction module, which is used to update the configuration of the integration count during the time interval window with the maximum fingerprint contrast; and to control the ultrasonic sensor array to adaptively adjust according to the screen echo delay and the integration count.

[0025] This application embodiment collects data on the pressure of the ultrasonic sensor array under finger pressure and the non-pressure data when the finger is lifted before and after the screen protector state changes. Based on the pressure data and non-pressure data, it performs data processing to determine whether the screen protector has been installed, removed, or replaced, and determines whether the ultrasonic piezoelectric sensor array configuration needs to be recalibrated. This can reduce the impact of screen protector state changes on fingerprint images and fingerprint recognition. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments conforming to this application and, together with the specification, serve to explain the technical solutions of this application. Some specific embodiments of this application will be described in detail below with reference to the accompanying drawings in an exemplary and non-limiting manner. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale.

[0027] Figure 1 The flowchart of the adaptive control method for an ultrasonic sensor array provided in the embodiments of this application;

[0028] Figure 2 The flowchart of the adaptive control method for an ultrasonic sensor array provided in another embodiment of this application;

[0029] Figure 3 The step flow of an adaptive control method for an ultrasonic sensor array provided in another embodiment of this application;

[0030] Figure 4 A schematic diagram comparing the fingerprint contrast of five types of films provided in the embodiments of this application;

[0031] Figure 5 The flowchart of the adaptive control method for an ultrasonic sensor array provided in another embodiment of this application;

[0032] Figure 6 The flowchart of the adaptive control method for an ultrasonic sensor array provided in another embodiment of this application;

[0033] Figure 7 A comparative schematic diagram showing the spatial inconsistency of three types of membranes provided in the embodiments of this application;

[0034] Figure 8 The flowchart of the adaptive control method for an ultrasonic sensor array provided in another embodiment of this application;

[0035] Figure 9 A schematic diagram comparing the spatial inconsistencies of the differences between the three types of membranes provided in the embodiments of this application;

[0036] Figure 10 A schematic diagram of the overall process for determining changes in the state of a screen protector provided in an embodiment of this application;

[0037] Figure 11 This is a schematic diagram of the recalibration process of the ultrasonic array provided in an embodiment of this application;

[0038] Figure 12 This is a schematic diagram of the recalibration process for an ultrasonic array provided in another embodiment of this application;

[0039] Figure 13 This is a schematic diagram of an adaptive control device for an ultrasonic sensor array according to an embodiment of this application. Detailed Implementation

[0040] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings. Various details are set forth in this application because these details relate to certain embodiments. However, this application may also be implemented in a manner different from that described herein. Modifications to the discussed embodiments can be made by those skilled in the art without departing from this application. Therefore, this application is not limited to the specific embodiments disclosed herein.

[0041] The adaptive control method for ultrasonic sensor arrays provided in this application is applicable to adaptively calibrating the ultrasonic sensor array during fingerprint image recognition in an ultrasonic fingerprint recognition system. This reduces the impact of screen protector installation, removal, or replacement, improves fingerprint image quality, increases fingerprint recognition success rate, and ultimately enhances user experience. To facilitate understanding of the technical solution provided in this application, a brief description of the ultrasonic fingerprint recognition system is provided below.

[0042] Ultrasonic fingerprint recognition systems use a transmitter to generate ultrasonic waves and transmit them to the object being detected through a transmission medium. The ultrasonic transmitter can be operatively coupled to an ultrasonic sensor array configured to detect a portion of the ultrasonic waves reflected from the object. At each material interface encountered by the ultrasonic pulse, a portion of the ultrasonic pulse can be reflected. The ultrasonic fingerprint recognition system acquires a fingerprint image through the ultrasonic sensor array. Because the ultrasonic sensor array is located beneath the screen and screen protector, the acoustic signal received by the array originates from the finger reflection wave from the device screen. Changes in the state of the screen protector, such as installation, removal, or replacement, can severely affect the intensity of the reflected acoustic waves, causing an overall phase shift in the acoustic signal. This results in unclear fingerprint image details, reduced resolution, and a lower fingerprint recognition rate.

[0043] Current methods for detecting screen protector installation, removal, or replacement rely solely on comparing changes in the image structure of an ultrasonic fingerprint recognition system when it is not pressed. However, in real-world applications, changes in ambient temperature can alter the image structure, potentially leading to misjudgments if only data from the unpressed state is used. Furthermore, screen protectors can range from thicker materials like tempered glass (PET and GH_0.3mm) to thinner materials like hydrogel films (hydrogel films and AR2.3%). Different types of screen protectors will result in different judgment criteria, and relying solely on changes in the image structure when unpressed may also lead to misjudgments.

[0044] This application provides an adaptive control method for an ultrasonic sensor array. It compares and processes non-pressing and pressing data of a user's finger before and after installing or removing a screen protector to determine whether the protector is installed, removed, or replaced. Then, if a change in the screen protector's state is determined, the ultrasonic sensor array configuration parameters are recalibrated to mitigate the impact of the change and ensure fingerprint recognition accuracy.

[0045] See Figure 1 , Figure 1 The present application illustrates a step flow of an adaptive control method for an ultrasonic sensor array according to an embodiment of the present application, including:

[0046] S20. Acquire the pressure data of the ultrasonic sensor array when the finger is pressed and the non-pressing data when the finger is lifted;

[0047] S30. Based on the pressed data and non-pressed data, perform data processing to determine whether the state of the screen protector has changed;

[0048] S40. Adaptively adjust the configuration of the ultrasonic sensor array according to the changes.

[0049] Furthermore, the change in the state of the screen protector includes one of installation, removal, or replacement. Specifically, installation may include the initial installation of the screen protector, removal may include removing the screen protector after it has cracked, and replacement may include replacing the old screen protector with a new one.

[0050] Specifically, during fingerprint recognition, the ultrasonic sensor array acquires real-time data on pressure when the finger is pressed and non-pressure data when the finger is lifted. Based on the current pressure and non-pressure data (e.g., after the screen protector is installed, removed, or replaced) and the previous pressure and non-pressure data (e.g., before the screen protector is installed, removed, or replaced), the system processes the data to determine whether the screen protector has undergone a change in status, such as installation, removal, or replacement. This makes the determination more accurate. Furthermore, based on the determination of status changes, the system quickly and adaptively adjusts the configuration parameters of the ultrasonic sensor array during the finger pressing recognition process to reduce the impact of screen protector changes, improve image quality, and ensure fingerprint recognition rate.

[0051] In a specific implementation of an embodiment of this application, see [link to relevant documentation]. Figure 2 The steps further include:

[0052] S201. Obtain the Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press, where N is a positive integer;

[0053] S202, acquire the N-1th fingerprint signal under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th finger press;

[0054] S301. Based on the Nth fingerprint signal and the (N-1)th reference signal, perform data processing to determine whether the state of the screen protector has changed;

[0055] S40. Adaptively adjust the configuration of the ultrasonic sensor array according to the changes.

[0056] Specifically, during the use of electronic devices, fingerprint unlocking is performed through N finger press operations, where N represents the number of finger press operations and is a positive integer. This application determines the state change of the screen protector by comparing and analyzing the pressing data and non-pressing data collected during two consecutive finger press operations for fingerprint unlocking. In other words, it compares the data collected during the Nth and N-1th finger press operations to determine whether the state of the screen protector has changed during this period. Specifically, when the user presses the finger for the Nth time, the fingerprint signal at the current moment is obtained, and when the user lifts the finger, the reference signal at the current moment is obtained. The data processing based on the fingerprint signal at the current moment and the reference signal at the previous moment (i.e., the N-1th time) determines whether the screen protector has changed. The above determination process is more accurate.

[0057] Further, when N is 1, the system acquires the first fingerprint signal under the first finger press and the first reference signal when the finger is released after the first press; it also acquires the initial reference signal of the ultrasonic sensor array before the first finger press and release operation; and it performs data processing based on the first fingerprint signal, the first reference signal, and the initial reference signal to determine whether the screen protector state has changed. It is worth noting that before the user performs the first fingerprint recognition operation, i.e., during user registration, it is necessary to retain the reference data (initial reference data) when the screen is not pressed. The initial reference data is then compared with the first fingerprint signal and the first reference signal collected during the first finger press to determine whether the screen protector is being installed for the first time.

[0058] In practice, the fingerprint signal from the finger press can be subtracted from the reference signal, and then diffraction can be further eliminated to obtain a fingerprint image with resolution. If the state of the screen protector changes, the fingerprint image will show obvious screen structured image, resulting in severe segmentation. This allows for the determination of whether the screen protector is installed, removed, or replaced. Finally, the configuration of the ultrasonic sensor array is adaptively adjusted based on the determination result.

[0059] In another specific implementation of the embodiments of this application, see [link to relevant documentation]. Figure 3 Step S301 further includes:

[0060] S3011. Determine whether the fingerprint is successfully matched based on the Nth fingerprint signal and the (N-1)th reference signal;

[0061] S3012. If the match is successful, calculate the fingerprint contrast based on the Nth fingerprint signal and the (N-1)th reference signal.

[0062] S3013. If the ratio of the fingerprint contrast of the Nth fingerprint signal to the (N-1)th reference signal is less than the first threshold, it is determined that the state of the screen protector has changed.

[0063] In practical applications, accurately judging changes in the state of the screen protector is the key to adaptive control of ultrasonic sensor array calibration.

[0064] Specifically, since some types of screen protectors can attenuate signals, this embodiment of the application can determine whether a screen protector is applied by calculating the fingerprint contrast of the pressed data. The fingerprint contrast is calculated based on the Nth fingerprint signal and the (N-1)th reference signal; the higher the fingerprint contrast, the clearer the image. Figure 4A schematic diagram comparing fingerprint contrast for five types of films is shown. The fingerprint contrast (contrast) without a film is significantly greater than that with PET and GH_0.3mm films. This demonstrates that the fingerprint contrast (contrast_N) of the Nth fingerprint signal and the fingerprint contrast (contrast_N-1) of the (N-1)th fingerprint signal can be calculated and compared to determine if the screen protector status has changed. Specifically, if the ratio of the fingerprint contrast of the Nth fingerprint signal to that of the (N-1)th fingerprint signal is less than a first threshold, it is determined that the screen protector status has changed. More specifically, the first threshold can be set to 0.7 (contrast_N < contrast_N-1 * 0.7). The first threshold can also be set to other values ​​according to actual needs, and this is not intended to limit this application.

[0065] In another specific implementation of the embodiments of this application, see [link to relevant documentation]. Figure 5 The steps further include:

[0066] S201. Obtain the Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press, where N is a positive integer;

[0067] S202, acquire the N-1th fingerprint signal under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th finger press;

[0068] S302. Based on the Nth reference signal and the (N-1)th reference signal, perform data processing to determine whether the state of the screen protector has changed;

[0069] S40. Adaptively adjust the configuration of the ultrasonic sensor array according to the changes.

[0070] Specifically, changes to the screen protector can also be determined by comparing the inconsistency of spatial areas across the entire screen using non-press data. That is, data processing is performed based on the Nth reference signal and the (N-1)th reference signal to determine whether the screen protector has been replaced or removed. See [link to relevant documentation]. Figure 6 Step S302 further includes:

[0071] S3021. Calculate the spatial region inconsistency between the Nth reference signal and the (N-1)th reference signal;

[0072] S3022. If the ratio of the spatial region inconsistency of the Nth reference signal to the spatial region inconsistency of the (N-1)th reference signal is less than the second threshold;

[0073] S3023, Determines that the status of the screen protector has changed.

[0074] Since the position of the integration window changes before and after the state of the screen protector changes, resulting in signal attenuation and significant changes in the inconsistency of the spatial area of ​​the entire screen, the embodiments of this application can be used to determine whether to replace, install or remove the screen protector.

[0075] Specifically, calculating spatial region inconsistency is equivalent to calculating the mean square error of the entire screen; calculating the spatial region inconsistency (Snoise_N) of the Nth reference signal is equivalent to calculating the mean square error of the Nth reference signal; and calculating the spatial region inconsistency (Snoise_N-1) of the (N-1)th reference signal is equivalent to calculating the mean square error of the (N-1)th reference signal. Generally speaking, the mean square error value without a screen protector is much larger than the mean square error value with a screen protector. (Reference) Figure 7 , Figure 7 This diagram illustrates a comparison of the spatial regional inconsistencies of three types of membranes. Figure 7 It is evident that the spatial inconsistency noise without a screen protector is significantly greater than that under the three types of films: privacy hydrogel film, hydrogel film, and AR film. Therefore, the installation, replacement, or removal of the screen protector can be determined by calculating the spatial inconsistency noise_N of the Nth reference signal and the spatial inconsistency noise_N-1 of the (N-1)th reference signal, and comparing their magnitudes. Specifically, if the ratio of the spatial inconsistency of the Nth reference signal to that of the (N-1)th reference signal is less than a second threshold, it can be determined that the screen protector has been installed, replaced, or removed. More specifically, the second threshold can be set to 0.75 (Snoise_N < Snoise_N-1 * 0.75), and can also be set to other values ​​according to actual needs, which are not intended to limit this application.

[0076] In another specific implementation of the embodiments of this application, see [link to relevant documentation]. Figure 8 Step S302 further includes:

[0077] S3024. If the ratio of the spatial region inconsistency of the Nth reference signal to the spatial region inconsistency of the (N-1)th reference signal is not less than the second threshold;

[0078] S3025. Calculate the spatial region inconsistency based on the difference between the Nth reference signal and the (N-1)th reference signal;

[0079] S3026. If the spatial inconsistency of the difference is greater than the third threshold, it is determined that the state of the screen protector has changed.

[0080] In practice, the spatial region inconsistency SubSnoise can also be calculated based on the difference between the Nth reference signal and the (N-1)th reference signal. That is, after subtracting the Nth reference signal and the (N-1)th reference signal, the spatial region inconsistency SubSnoise is calculated based on the difference. More specifically, the above subtraction process can also include phase filtering, temperature compensation, and image filtering. Figure 9 A comparative schematic diagram of the spatial inconsistency of the differences between three types of films is shown. The SubSnoise without a film is significantly smaller than that of the privacy hydrogel film, hydrogel film, and AR film. This demonstrates that the spatial inconsistency can be calculated based on the difference between the Nth and (N-1)th reference signals. The replacement or removal of the screen protector is determined by comparing the SubSnoise of the spatial inconsistency with that of the film without a film. Specifically, if the spatial inconsistency of the difference exceeds a third threshold, it is determined that the screen protector has been replaced or removed. This third threshold can be set according to actual needs and is not intended to limit this application.

[0081] like Figure 10 The diagram shows the overall process for determining changes in the state of the screen protector. This process allows for more accurate determination of changes in the state of the screen protector, thereby enabling timely adaptive adjustment of the configuration of the ultrasonic sensor array.

[0082] Once a change in the screen protector's status is detected—that is, after installation, removal, or replacement—a recalibration process will be automatically triggered. This requires recalibrating the relevant configuration parameters of the ultrasonic array. (Refer to...) Figure 11 , Figure 11 A schematic diagram of the recalibration process for the ultrasonic array is shown.

[0083] Specifically, in another specific implementation of the embodiments of this application, step S40 further includes:

[0084] S401. Triggering recalibration process after determining that the screen protector has changed;

[0085] S402, Detect finger pressing and lifting operation;

[0086] S403. Collect the fingerprint signal and the reference signal at time M of multiple time interval windows, where M is a positive integer;

[0087] S404. Calculate the screen echo delay after the screen protective film state changes based on the film thickness and film sound velocity.

[0088] S405. Determine whether the fingerprint is successfully matched based on the fingerprint signal at time M and the reference signal at time M-1.

[0089] S406. If the match is successful, calculate the fingerprint contrast of the multiple time interval windows;

[0090] S407. Select the time interval window with the highest fingerprint contrast and update the screen echo delay configuration.

[0091] Because the position of the integration window changes after the screen protector's state changes, receiving the echo signal using the same configuration as before the screen protector's state change will result in signal attenuation, requiring screen echo delay correction. Specifically, the screen echo delay New_delay after the screen protector is installed, replaced, or removed is equal to the screen echo delay Old_delay before the screen protector was replaced or removed, plus or minus the echo time for different film thicknesses, i.e., New_delay = Old_delay ± n * Step, where Step represents the echo time required for a sound wave of a certain speed to pass through a screen protector of a unit film thickness. Optionally, Step can be 50ns; n can represent the film thickness, i.e., the screen protector thickness can be n * unit film thickness. Optionally, depending on the type of film, n representing the thickness can be n = 1, 2, 4, or 8. The specific parameter values ​​here are not intended to limit this application.

[0092] More specifically, after the screen protector is installed, removed, or replaced, a recalibration process is triggered, and the finger press-and-release operation is detected. During the next fingerprint recognition process when the finger is pressed and released, the fingerprint signal at time M and the reference signal at time M are collected in multiple time interval windows. Here, M is a positive integer. Since too many time interval windows cannot be collected indefinitely in practical applications, M can optionally be 4 time interval windows, that is, the integral window position data of 4 time intervals are collected. M can also be selected according to actual needs and is not intended to limit this application.

[0093] Further, the fingerprint is determined to be successfully matched based on the fingerprint signal at time M and the reference signal at time M-1. If the match is successful, the fingerprint contrast of the multiple time interval windows is calculated. Specifically, the fingerprint contrast of the four time interval windows is calculated, and the time interval window with the largest fingerprint contrast among the four time interval windows is selected to update the screen echo delay New_delay.

[0094] The method for adjusting the integral window delay in this application embodiment can reduce signal attenuation and signal-to-noise ratio reduction caused by changes in the state of the screen protector.

[0095] In another specific implementation of the embodiments of this application, see [link to relevant documentation]. Figure 12 Step S40 further includes:

[0096] S408. Obtain the reference signal at time M corresponding to the time interval window with the maximum fingerprint contrast.

[0097] S409. Determine the saturation of the screen echo signal based on the reference signal at time M.

[0098] S4010. Adjust the number of integrations of the fingerprint signal according to the saturation of the screen echo signal;

[0099] S4011. Update the configuration of the number of points during the time interval window when the fingerprint contrast is the largest;

[0100] S4012. Control the ultrasonic sensor array to adaptively adjust according to the screen echo delay and the number of integrations.

[0101] Because the amplitude of the full-screen echo signal attenuates before and after the screen protector changes state, this can lead to a decrease in image quality. To ensure optimal image quality, the number of integration iterations can be adjusted appropriately, provided that the upper and lower peak values ​​of the full-screen echo signal amplitude do not saturate. The number of integration iterations can be increased as much as possible while preventing upper and lower saturation; if upper and lower saturation occurs, the number of integration iterations can be decreased appropriately.

[0102] Specifically, the reference signal at time M corresponding to the time interval window with the maximum fingerprint contrast is obtained. The saturation of the screen echo signal, i.e. the magnitude of the screen echo signal amplitude, is determined based on the reference signal at time M. The number of integrations that the fingerprint signal should increase or decrease is determined based on the magnitude of the screen echo signal amplitude. The determined number of integrations is updated at the time interval window with the maximum fingerprint contrast. The ultrasonic sensor array is controlled to adaptively adjust according to the screen echo delay and the number of integrations, thereby realizing the recalibration of the ultrasonic sensor array.

[0103] The aforementioned ultrasonic sensor array recalibration method reduces signal attenuation caused by changes in the screen protector state by adjusting the integration window delay and the number of integrations. Furthermore, it can quickly and adaptively adjust the configuration of the ultrasonic sensor array during the process of re-pressing the finger after determining that the screen protector state has changed, thus rapidly performing the recalibration process to adapt to different screen protectors, improve fingerprint recognition rate, and enhance user experience.

[0104] To better implement the above methods, this application also provides an ultrasonic sensor array adaptive control device, which can be integrated into an ultrasonic fingerprint recognition system. The main modules of the fingerprint recognition system include an ultrasonic sensor array, a high-precision analog-to-digital converter, a storage unit, and a data processing center. They are all connected to the central controller and are used to excite the ultrasonic array, receive the echo signal, convert the analog echo signal intensity into a digital signal, send the data to the data processing center via the storage unit, complete the preliminary processing of the fingerprint data, and then further process it through the fingerprint recognition algorithm to complete related fingerprint registration, fingerprint recognition unlocking, and other functions.

[0105] Reference Figure 13 An adaptive control device 130 for an ultrasonic sensor array according to an embodiment of this application is shown. The device includes:

[0106] The first data acquisition module 1302 is used to acquire the pressure data of the ultrasonic sensor array when the finger is pressed and the non-pressing data when the finger is lifted.

[0107] The data processing module 1303 is used to perform data processing based on the pressed data and non-pressed data to determine whether the screen protector has changed;

[0108] The calibration module 1304 is used to adaptively adjust the configuration of the ultrasonic sensor array according to the changes.

[0109] In another implementation of this application, the first data acquisition module 1302 is further configured to:

[0110] The Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press are obtained from the ultrasonic sensor array, where N is a positive integer;

[0111] The N-1 fingerprint signal under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th finger press are obtained from the ultrasonic sensor array.

[0112] In another implementation of this application, it also includes:

[0113] The fingerprint matching and judgment module is used to determine whether the fingerprint is successfully matched based on the Nth fingerprint signal and the (N-1)th reference signal.

[0114] The contrast calculation module, if the fingerprint matching judgment module determines that the fingerprint matching is successful, is used to calculate the fingerprint contrast based on the Nth fingerprint signal and the (N-1)th reference signal.

[0115] The screen protector state determination module determines that the screen protector state has changed if the ratio of the fingerprint contrast of the Nth fingerprint signal to the (N-1)th reference signal is less than a first threshold.

[0116] In another implementation of this application, it also includes:

[0117] The trigger module is used to determine when the screen protector changes and trigger the recalibration process.

[0118] The detection module is also used to detect finger pressing and lifting operations;

[0119] The second data acquisition module is used to acquire the fingerprint signal and the reference signal at time M of multiple time interval windows, where M is a positive integer.

[0120] The calibration parameter calculation module is used to calculate the screen echo delay after the state of the screen protective film changes, based on the film thickness and film sound velocity.

[0121] The fingerprint matching and judgment module is also used to determine whether the fingerprint is successfully matched based on the fingerprint signal at time M and the reference signal at time M-1.

[0122] If a match is successful, the contrast calculation module is also used to calculate the fingerprint contrast of the multiple time interval windows.

[0123] The calibration module is also used to select the time interval window with the highest fingerprint contrast to update the screen echo delay configuration.

[0124] In another implementation of this application, it also includes:

[0125] The second data acquisition module is also used to acquire the reference signal at time M corresponding to the time interval window with the largest fingerprint contrast.

[0126] The calibration parameter calculation module is also used to determine the saturation of the screen echo signal based on the reference signal at time M; and to adjust the number of integrations of the fingerprint signal based on the saturation of the screen echo signal.

[0127] A calibration module is used to update the configuration of the integration count during the time interval window when the fingerprint contrast is at its maximum; and to control the ultrasonic sensor array to adaptively adjust according to the screen echo delay and the integration count.

[0128] The apparatus in this embodiment is used to implement the corresponding methods in the foregoing multiple method embodiments and has the beneficial effects of the corresponding method embodiments, which will not be repeated here. The electronic devices to which the above apparatus is applied may be, for example, portable or mobile computing devices such as smartphones, laptops, tablets, and gaming devices, etc., and this application embodiment is not limited to this.

[0129] This application provides a chip including a processor for calling and running a computer program from a memory, causing a device equipped with the chip to perform an ultrasonic sensor array adaptive control method as described in any of the foregoing methods.

[0130] This chip can be applied to the ultrasonic sensor array adaptive control device or electronic device in the embodiments of this application, and can implement the corresponding processes implemented by the ultrasonic sensor array adaptive control device or electronic device in the various methods of the embodiments of this application, and achieve the corresponding effects. For the sake of brevity, it will not be described in detail here.

[0131] It should be noted that, depending on the implementation needs, the various components / steps described in the embodiments of this application can be broken down into more components / steps, or two or more components / steps or parts of the operation of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of this application.

[0132] The methods described in the embodiments of this application can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium (such as a CD-ROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code downloaded over a network that is originally stored in a remote recording medium or a non-transitory machine-readable medium and will be stored in a local recording medium. Thus, the methods described herein can be processed by software stored on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It is understood that the computer, processor, microprocessor controller, or programmable hardware includes storage components (e.g., RAM, ROM, flash memory, etc.) capable of storing or receiving software or computer code that, when accessed and executed by the computer, processor, or hardware, implements the checksum generation method described herein. Furthermore, when a general-purpose computer accesses code used to implement the checksum generation method shown herein, the execution of the code transforms the general-purpose computer into a dedicated computer for executing the checksum generation method shown herein.

[0133] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0134] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. An adaptive control method for an ultrasonic sensor array, wherein the ultrasonic sensor array is disposed beneath a screen protector, characterized in that, include: Acquire the pressure data of the ultrasonic sensor array when the finger is pressed and the non-pressing data when the finger is lifted; Based on the pressed data and non-pressed data, data processing is performed to determine whether the state of the screen protector has changed; The configuration of the ultrasonic sensor array is adaptively adjusted according to the changes. The step of acquiring the ultrasonic sensor array's pressure data under finger pressure and non-pressure data when the finger is lifted also includes: The Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press are obtained from the ultrasonic sensor array, where N is a positive integer; Acquire the N-1th fingerprint signal under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th finger press by the ultrasonic sensor array; The step of determining whether the screen protector state has changed based on the press data and non-press data through data processing also includes: Data processing is performed based on the Nth fingerprint signal and the (N-1)th reference signal to determine whether the screen protector state has changed; or... The step of acquiring the ultrasonic sensor array's pressure data under finger pressure and non-pressure data when the finger is lifted also includes: The Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press are obtained from the ultrasonic sensor array, where N is a positive integer; Acquire the N-1th fingerprint signal under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th finger press by the ultrasonic sensor array; The step of determining whether the screen protector state has changed based on the press data and non-press data through data processing also includes: Data processing is performed based on the Nth reference signal and the (N-1)th reference signal to determine whether the state of the screen protector has changed.

2. The adaptive control method for an ultrasonic sensor array according to claim 1, characterized in that, The step of determining whether the screen protector state has changed by processing data based on the Nth fingerprint signal and the (N-1)th reference signal further includes: Determine whether the fingerprint matches successfully based on the Nth fingerprint signal and the (N-1)th reference signal; If a match is successful, the fingerprint contrast is calculated based on the Nth fingerprint signal and the (N-1)th reference signal. If the ratio of the fingerprint contrast of the Nth fingerprint signal to the (N-1)th reference signal is less than the first threshold, it is determined that the state of the screen protector has changed.

3. The adaptive control method for an ultrasonic sensor array according to claim 1, characterized in that, The step of determining whether the screen protector state has changed by processing data based on the Nth reference signal and the (N-1)th reference signal further includes: The spatial regions of the Nth reference signal and the (N-1)th reference signal are inconsistent. If the ratio of the spatial region inconsistency of the Nth reference signal to the spatial region inconsistency of the (N-1)th reference signal is less than the second threshold; The screen protector's condition has changed.

4. The adaptive control method for an ultrasonic sensor array according to claim 3, characterized in that, Also includes: If the ratio of the spatial region inconsistency of the Nth reference signal to the spatial region inconsistency of the (N-1)th reference signal is not less than the second threshold; Spatial region inconsistency is calculated based on the difference between the Nth reference signal and the (N-1)th reference signal; If the spatial inconsistency of the difference is greater than the third threshold; The screen protector's condition has changed.

5. The adaptive control method for an ultrasonic sensor array according to claim 1, characterized in that, When N is 1, the first fingerprint signal under the first finger press and the first reference signal when the finger is lifted after the first finger press are obtained by the ultrasonic sensor array; Acquire the initial reference signal of the ultrasonic sensor array before the first finger press-and-release operation; The screen protector's state is determined by performing data processing on the first fingerprint signal, the first reference signal, and the initial reference signal.

6. The adaptive control method for an ultrasonic sensor array according to any one of claims 1-5, characterized in that, The changes include one of installing, removing, or replacing the screen protector.

7. The adaptive control method for an ultrasonic sensor array according to any one of claims 1-5, characterized in that, The adaptive adjustment of the configuration of the ultrasonic sensor array according to the changes further includes: A recalibration process is triggered when a change is detected in the screen protector. Detects finger pressing and lifting operations; Collect the fingerprint signal and the reference signal at time M of multiple time interval windows, where M is a positive integer; Calculate the screen echo delay after the screen protector's state changes based on the film thickness and film sound velocity; Determine whether the fingerprint matches successfully based on the fingerprint signal at time M and the reference signal at time M-1. If a match is successful, calculate the fingerprint contrast of the multiple time interval windows; The screen echo delay is updated by selecting the time interval window with the highest fingerprint contrast.

8. The adaptive control method for an ultrasonic sensor array according to claim 7, characterized in that, The calculation of screen echo delay after a change in the state of the screen protector based on film thickness and film sound velocity further includes: The screen echo delay after the screen protector state changes is equal to the screen echo delay before the screen protector state changes, plus or minus the echo time for different film thicknesses.

9. The adaptive control method for an ultrasonic sensor array according to claim 8, characterized in that, Obtain the reference signal at time M corresponding to the time interval window with the highest fingerprint contrast; The saturation of the screen echo signal is determined based on the reference signal at time M. The number of integrations of the fingerprint signal is adjusted according to the saturation of the screen echo signal; The number of integrations is updated during the time interval window when the fingerprint contrast is at its maximum. The ultrasonic sensor array is controlled to adaptively adjust based on the screen echo delay and the number of integrations.

10. An adaptive control device for an ultrasonic sensor array, wherein the ultrasonic sensor array is disposed below a screen protector, characterized in that, include: The first data acquisition module is used to acquire the pressure data of the ultrasonic sensor array when the finger is pressed and the non-pressing data when the finger is lifted. The data processing module is used to process the pressed data and non-pressed data to determine whether the state of the screen protector has changed. A calibration module is used to adaptively adjust the configuration of the ultrasonic sensor array according to the changes; The first data acquisition module is also used for: The Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press are obtained from the ultrasonic sensor array, where N is a positive integer; Acquire the (N-1)th fingerprint signal under the (N-1)th finger press and the (N-1)th reference signal when the finger is released after the (N-1)th finger press; or, The first data acquisition module is also used for: The Nth fingerprint signal under the Nth finger press and the Nth reference signal when the finger is lifted after the Nth finger press are obtained from the ultrasonic sensor array, where N is a positive integer; Acquire the N-1th fingerprint signal under the N-1th finger press and the N-1th reference signal when the finger is lifted after the N-1th finger press by the ultrasonic sensor array; The step of determining whether the screen protector state has changed based on the press data and non-press data through data processing also includes: Data processing is performed based on the Nth reference signal and the (N-1)th reference signal to determine whether the state of the screen protector has changed.

11. The adaptive control device for an ultrasonic sensor array according to claim 10, characterized in that, Also includes: The fingerprint matching and judgment module is used to determine whether the fingerprint is successfully matched based on the Nth fingerprint signal and the (N-1)th reference signal. The contrast calculation module, if the fingerprint matching judgment module determines that the fingerprint matching is successful, is used to calculate the fingerprint contrast based on the Nth fingerprint signal and the (N-1)th reference signal. The screen protector state determination module determines that the screen protector state has changed if the ratio of the fingerprint contrast of the Nth fingerprint signal to the (N-1)th reference signal is less than a first threshold.

12. The adaptive control device for an ultrasonic sensor array according to claim 10 or 11, characterized in that, include: The trigger module is used to determine when the screen protector changes and trigger the recalibration process. The detection module is also used to detect finger pressing and lifting operations; The second data acquisition module is used to acquire the fingerprint signal and the reference signal at time M of multiple time interval windows, where M is a positive integer. The calibration parameter calculation module is used to calculate the screen echo delay after the state of the screen protective film changes, based on the film thickness and film sound velocity. The fingerprint matching and judgment module is also used to determine whether the fingerprint is successfully matched based on the fingerprint signal at time M and the reference signal at time M-1. If a match is successful, the contrast calculation module is also used to calculate the fingerprint contrast of the multiple time interval windows. The calibration module is also used to select the time interval window with the highest fingerprint contrast to update the screen echo delay configuration.

13. The adaptive control device for an ultrasonic sensor array according to claim 12, characterized in that, The second data acquisition module is also used to acquire the reference signal at time M corresponding to the time interval window with the largest fingerprint contrast. The calibration parameter calculation module is also used to determine the saturation of the screen echo signal based on the reference signal at time M; and to adjust the number of integrations of the fingerprint signal based on the saturation of the screen echo signal. A calibration module is used to update the configuration of the integration count during the time interval window when the fingerprint contrast is at its maximum; and to control the ultrasonic sensor array to adaptively adjust according to the screen echo delay and the integration count.

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