Fingerprint recognition method, device and electronic device

Abstract

The embodiments of the present application provide a method, device and electronic device for fingerprint recognition, the method comprising: acquiring a first image captured by a fingerprint sensor at a first exposure time; determining whether to acquire a second image captured by the fingerprint sensor at a second exposure time based on the first image, the second exposure time and the first exposure time being continuous, and the length of the second exposure time being greater than or equal to the length of the first exposure time; performing fingerprint recognition based on the first image when it is determined not to acquire the second image; or performing fingerprint recognition based on the first image and the second image when it is determined to acquire the second image. The method, device and electronic device of the embodiments of the present application can take into account both the unlocking rate and the unlocking time, thereby improving the user's unlocking experience.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of fingerprint recognition, and more specifically, to a fingerprint recognition method, device and electronic device. Background Art

[0002] Nowadays, fingerprint recognition products are becoming more and more popular among people. Users have always been concerned about the speed of fingerprint unlocking and hope to unlock as "fast" as possible. The shorter the unlocking time, the better the user experience.

[0003] The current fingerprint sensor has a fixed exposure time, and in order to take into account the unlocking rate of the worst quality finger, the fingerprint sensor is usually set to a long exposure time, which results in a longer unlocking time and reduces the user's unlocking experience. Summary of the invention

[0004] The embodiments of the present application provide a fingerprint recognition method, device, and electronic device, which can take into account both the unlocking rate and the unlocking time, thereby improving the user's unlocking experience.

[0005] In a first aspect, a method for fingerprint recognition is provided, the method comprising: acquiring a first image captured by a fingerprint sensor at a first exposure time; determining, based on the first image, whether to acquire a second image captured by the fingerprint sensor at a second exposure time, the second exposure time and the first exposure time being continuous, and the length of the second exposure time being equal to or greater than the length of the first exposure time; in the case of determining not to acquire the second image, performing fingerprint recognition based on the first image; or, in the case of determining to acquire the second image, performing fingerprint recognition based on the first image and the second image.

[0006] In this embodiment, the fingerprint sensor is configured for continuous exposure. The processor can first determine whether to obtain the second image captured at the second exposure time based on the first image captured at the first exposure time. If it is determined that the second image captured at the second exposure time does not need to be acquired, fingerprint recognition is performed directly based on the first image. If it is determined that the second image captured at the second exposure time needs to be acquired, recognition is performed based on the first image and the second image. Since the fingerprint sensor supports continuous exposure, the processor is also acquiring and processing the first image while the fingerprint sensor is acquiring the second image. Compared with the technical solution in which the fingerprint sensor acquires the second image only when recognition based on the first image is unsuccessful, the unlocking time can be reduced, thereby improving the user unlocking experience.

[0007] Secondly, the length of the second exposure time is configured to be greater than the length of the first exposure time. In the case of fingerprint recognition based on the first image, the first exposure time is shorter, which can greatly reduce the unlocking time; and in the case of fingerprint recognition based on the first image and the second image, the fingerprint sensor is continuously exposed, that is, while the fingerprint sensor collects the second image, the processor is also acquiring and processing the first image, which can also reduce the unlocking time. Therefore, while taking into account the unlocking rate, it is beneficial to reduce the unlocking time, thereby improving the user unlocking experience.

[0008] In a possible implementation manner, the end time of the second exposure time is not earlier than the time when the second image is determined to be acquired.

[0009] In this embodiment, the occurrence of CRC errors can be avoided while using a fingerprint sensor with lower cost.

[0010] In a possible implementation, determining whether to acquire a second image captured by the fingerprint sensor at a second exposure time based on the first image includes: preprocessing the first image to acquire a corresponding fingerprint parameter value, the fingerprint parameter including any one of a fingerprint signal, a fingerprint image quality score, and pixel data of the fingerprint sensor when capturing the image; and determining to acquire the second image when determining that the value of the fingerprint parameter is less than a first threshold.

[0011] In this embodiment, preprocessing the first image is beneficial to the accuracy of fingerprint feature extraction. In addition, by comparing the value of the fingerprint parameter corresponding to the first image with the preset first threshold, the quality of the first image can be judged, that is, it can be judged whether the texture of the finger currently pressed by the user is clear. In the case where it is judged that the quality of the first image is good, fingerprint recognition can be performed directly based on the first image. Compared with the technical solution of directly using a long exposure time to capture images in the prior art, the time taken to judge the quality of the first image is much less than the time difference between the long exposure time and the short exposure time. Therefore, the unlocking time can be greatly reduced.

[0012] In a possible implementation, preprocessing the first image to obtain a value of a corresponding fingerprint parameter includes: when it is determined that the first image is not a fingerprint pattern, preprocessing the first image to obtain a value of a corresponding fingerprint parameter.

[0013] In this embodiment, once the processor determines that the first image is a fingerprint pattern, the processor can directly determine that the second image needs to be acquired without obtaining the value of the fingerprint parameter corresponding to the first image through preprocessing, thereby further reducing the unlocking time.

[0014] In a possible implementation, determining whether to acquire a second image captured by the fingerprint sensor at a second exposure time according to the first image includes: determining to acquire the second image when determining that the first image is a fingerprint pattern.

[0015] In a possible implementation, when it is determined that the second image is acquired, fingerprint recognition is performed based on the first image and the second image, including: when it is determined that the second image is acquired, determining whether an offset occurs between the second image and the first image; when it is determined that an offset occurs between the second image and the first image, fingerprint recognition is performed based on the image with higher quality between the first image and the second image.

[0016] In this embodiment, it is determined whether there is an offset between the second image and the first image, that is, it is determined whether the user's finger slides when the fingerprint sensor captures the second image and the second image. In the case that the user's finger slides, an image with better quality can be selected from the first image and the second image for fingerprint recognition.

[0017] In a possible implementation, determining whether an offset occurs between the second image and the first image when determining to acquire the second image includes: calculating a standard deviation between a plurality of pixel data at a preset position in the fingerprint sensor when acquiring the first image and a plurality of pixel data at the preset position in the fingerprint sensor when acquiring the second image when determining to acquire the second image; and determining that an offset occurs between the second image and the first image when the standard deviation is greater than a second threshold.

[0018] In a possible implementation manner, the preset position is located in a central area of ​​the fingerprint sensor.

[0019] In this embodiment, calculating the standard deviation between the pixel data of multiple pixels located in the central area of ​​the first image and the second image is beneficial to improving the accuracy of the processor in determining whether the second image and the first image are offset, thereby facilitating obtaining images of better quality to improve the success rate of user unlocking.

[0020] In a possible implementation, determining whether an offset occurs between the second image and the first image when determining to acquire the second image includes: determining an offset between the fingerprint patterns of the first image and the fingerprint patterns of the second image; and determining whether an offset occurs between the second image and the first image based on the offset.

[0021] In a possible implementation, when it is determined that the second image is acquired, fingerprint recognition is performed based on the first image and the second image, including: when it is determined that the second image is acquired and the first image is a fingerprint pattern, fingerprint recognition is performed based on the second image.

[0022] In a possible implementation, when it is determined that the second image is acquired, fingerprint recognition is performed based on the first image and the second image, including: when it is determined that the second image is acquired and the first image is not a fingerprint pattern, fusing the first image and the second image; and performing fingerprint recognition based on the fused first image and the second image.

[0023] In this embodiment, when the first image is a fingerprint pattern, the second image is more conducive to fingerprint recognition; and when the first image is not a fingerprint pattern, fusing the first image and the second image is more conducive to fingerprint recognition. Therefore, the technical solution provided in this embodiment is conducive to improving the success rate of user unlocking.

[0024] In a possible implementation manner, the fusing the first image and the second image includes: fusing the first image and the second image when it is determined that no offset occurs between the second image and the first image.

[0025] In a possible implementation manner, the fusing the first image and the second image includes: fusing a valid signal for fingerprint identification in the first image and a valid signal for fingerprint identification in the second image.

[0026] In this embodiment, the effective signal for fingerprint identification in the first image and the effective signal for fingerprint identification in the second image are fused to obtain an image of better quality, thereby facilitating improving the success rate of user unlocking.

[0027] In a possible implementation manner, the method further includes: dynamically adjusting the first threshold according to an unlocking rate of fingerprint recognition using the first image.

[0028] In this embodiment, the first threshold for determining whether to obtain the second image is dynamically adjusted according to the unlocking rate of fingerprint recognition using the first image, which can take into account both the unlocking rate and the unlocking time, thereby maximizing the user's unlocking experience.

[0029] In a possible implementation, the first threshold is dynamically adjusted according to the unlocking rate of fingerprint recognition using the first image, including: when the unlocking rate is greater than a third threshold, the first threshold is lowered by at least one level; or when the unlocking rate is less than a fourth threshold, the first threshold is raised by at least one level, and the third threshold is greater than or equal to the fourth threshold.

[0030] In a possible implementation, the third threshold is 85%, and the fourth threshold is 70%.

[0031] In a possible implementation, the method also includes: determining, based on the first image, whether the environment in which the fingerprint sensor is located is a strong light environment; determining, based on the first image, whether to obtain a second image collected by the fingerprint sensor at a second exposure time, includes: when it is determined that the environment in which the fingerprint sensor is located is not a strong light environment, determining, based on the first image, whether to obtain the second image collected by the fingerprint sensor at the second exposure time.

[0032] In a possible implementation, the method further includes: when determining that the environment in which the fingerprint sensor is located is a strong light environment, obtaining a third image of the fingerprint sensor at a third exposure time, the length of the third exposure time is equal to the length of the first exposure time, and the gain of the fingerprint sensor when collecting the third image is less than the gain of the fingerprint sensor when collecting the first image; and performing fingerprint recognition based on the third image.

[0033] In this embodiment, when it is determined based on the first image that the second image needs to be acquired, but at the same time the environment where the fingerprint sensor is located is also a strong light environment, the gain is preferentially reduced to re-acquire the third image, which can improve the dynamic range of image acquisition.

[0034] In a possible implementation, determining whether the environment in which the fingerprint sensor is located is a strong light environment based on the first image includes: when a proportion of all pixel data of the fingerprint sensor that is greater than a fifth threshold when the fingerprint sensor collects the first image exceeds a sixth threshold, determining that the environment in which the fingerprint sensor is located is a strong light environment.

[0035] In a possible implementation manner, the sixth threshold is 40%.

[0036] In a possible implementation manner, the length of the second exposure time is twice the length of the first exposure time.

[0037] In a second aspect, a fingerprint recognition device is provided, which is used to execute the method in the first aspect and any possible implementation manner thereof.

[0038] According to a third aspect, an electronic device is provided, including: a fingerprint sensor, used to capture a first image at a first exposure time and a second image at a second exposure time, wherein the second exposure time and the first exposure time are continuous, and the length of the second exposure time is greater than or equal to the length of the first exposure time; and a processor, used to: acquire the first image, determine whether to acquire the second image based on the first image, and perform fingerprint recognition based on the first image if it is determined not to acquire the second image, or perform fingerprint recognition based on the first image and the second image if it is determined to acquire the second image. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the optical fingerprint unlocking process.

[0040] Figure 2 It is a schematic block diagram of the fingerprint recognition method of an embodiment of the present application.

[0041] Figure 3 It is a schematic flow chart of the fingerprint recognition method based on intelligent exposure according to an embodiment of the present application.

[0042] Figure 4 It is a schematic block diagram of a fingerprint recognition device according to an embodiment of the present application.

[0043] Figure 5 It is a schematic block diagram of another device for fingerprint recognition according to an embodiment of the present application.

[0044] Figure 6 It is a schematic structural diagram of an electronic device according to an embodiment of the present application.

[0045] Figure 7 is another schematic structural diagram of an electronic device according to an embodiment of the present application.

[0046] Figure 8 is another schematic structural diagram of the electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0048] Nowadays, fingerprint recognition products are becoming more and more popular among people. Users have always been concerned about the speed of fingerprint unlocking and hope to unlock as "fast" as possible. The shorter the unlocking time, the better the user experience.

[0049] The complete unlocking process includes: Figure 1The steps shown are: mobile phone manufacturer time, chip exposure time, and algorithm matching time. Among them, the mobile phone manufacturer time includes detecting finger press and lighting the light spot; the chip exposure time includes chip exposure and data collection; and the algorithm matching time includes fingerprint matching and obtaining matching results (success / failure). The mobile phone manufacturer time is mainly determined by the mobile phone manufacturer, while the chip exposure time and algorithm matching time are determined by the chip system solution and algorithm capabilities. No matter which part of the time is reduced, the user's unlocking experience can be improved.

[0050] The current fingerprint sensor has a fixed exposure time, and in order to take into account the unlocking rate of the worst quality finger, the fingerprint sensor usually needs to be set to a long exposure time, which results in a longer unlocking time and reduces the user experience.

[0051] Through big data statistics, the applicant found that among the fingers with an unlocking rate greater than 80%, good quality fingers account for about 80%. For this reason, the embodiment of the present application provides a fingerprint recognition method that can take into account both the unlocking rate and the unlocking time, thereby improving the user's unlocking experience.

[0052] Figure 2 It is a schematic block diagram of a fingerprint recognition method 200 according to an embodiment of the present application. Figure 2 The method 200 shown can be executed by a processor, for example, by a main control processor of an electronic device or a microprocessor in a fingerprint recognition device (also referred to as a fingerprint recognition module, fingerprint module or fingerprint device, etc.), that is, the device for executing the fingerprint recognition method 200 of the embodiment of the present application can be packaged together with a fingerprint sensor, and the embodiment of the present application does not limit the execution subject of the method 200. Figure 2 As shown, method 200 may include some or all of the following steps.

[0053] S210: Acquire a first image captured by a fingerprint sensor at a first exposure time.

[0054] S220, determining whether to acquire a second image captured by the fingerprint sensor at a second exposure time according to the first image, the second exposure time being continuous with the first exposure time, and the length of the second exposure time being greater than or equal to the length of the first exposure time;

[0055] S230: If it is determined not to acquire the second image, fingerprint recognition is performed based on the first image; or, if it is determined to acquire the second image, fingerprint recognition is performed based on the first image and the second image.

[0056] First of all, it needs to be explained that the first exposure time and the second exposure time in the embodiment of the present application refer to specific time periods, and the two time periods are continuous. For example, the first exposure time may be 9:00:00-9:00:30 in the morning, and the second exposure time may be 9:00:30-9:01:10 in the morning. The length of the first exposure time may be referred to as the first exposure duration, the length of the second exposure time may be referred to as the second exposure duration, and the second exposure duration is greater than or equal to the first exposure duration. In other words, two frames of images exposed continuously may use one exposure duration; or two different exposure durations may be used, and the latter exposure duration is greater than the former exposure duration.

[0057] It should also be noted that the duration of the first exposure time in the embodiment of the present application is different from the long exposure time mentioned in the prior art, and may refer to the shortest exposure time used for a fingerprint image that can be successfully unlocked.

[0058] For the fingerprint sensor, no matter whether the processor acquires the second image or not, the fingerprint sensor will continue to acquire the second image at the second exposure time after acquiring the first image at the first exposure time.

[0059] It should be understood that in the embodiment of the present application, the fingerprint sensor may capture a first image at the first exposure time, which may be one frame of the first image or multiple frames of the first image. Similarly, the fingerprint sensor may capture a second image at the second exposure time, which may be one frame of the second image or multiple frames of the second image. The embodiment of the present application does not limit the number of frames of the first image and the second image captured.

[0060] For the processor, after acquiring the first image captured by the fingerprint sensor, that is, after the processor receives the first image transmitted by the fingerprint sensor, the processor can determine whether to acquire the second image captured by the fingerprint sensor based on the first image. For example, whether to acquire the second image can be determined based on the quality of the first image. When the processor determines that it is not necessary to acquire the second image, that is, the quality of the first image is acceptable and the probability of successful fingerprint recognition is high, the processor can perform fingerprint recognition based on the first image. When the processor determines that it is not necessary to acquire the second image, that is, the quality of the first image is poor and the probability of successful fingerprint recognition is low, then the processor needs to acquire the second image captured by the fingerprint sensor and perform fingerprint recognition based on the first image and the second image.

[0061] Therefore, in the fingerprint recognition method of the embodiment of the present application, the fingerprint sensor is configured for continuous exposure. The processor can first determine whether to obtain the second image captured at the second exposure time based on the first image captured at the first exposure time. If it is determined that the second image captured at the second exposure time does not need to be acquired, fingerprint recognition is performed directly based on the first image. If it is determined that the second image captured at the second exposure time needs to be acquired, recognition is performed based on the first image and the second image. Since the fingerprint sensor supports continuous exposure, the processor is also acquiring and processing the first image while the fingerprint sensor is acquiring the second image. Compared with the technical solution in which the fingerprint sensor acquires the second image only when recognition based on the first image is unsuccessful, the unlocking time can be reduced, thereby improving the user unlocking experience.

[0062] Secondly, the length of the second exposure time is configured to be greater than the length of the first exposure time. In this case, the length of the second exposure time can be referred to as the second exposure time, and the length of the first exposure time can be referred to as the first exposure time. In the case of fingerprint recognition based on the first image, since the first exposure time is shorter, the unlocking time can be greatly reduced; and in the case of fingerprint recognition based on the first image and the second image, since the fingerprint sensor is continuously exposed, that is, while the fingerprint sensor collects the second image, the processor is also acquiring and processing the first image, which can also reduce the unlocking time. Therefore, while taking into account the unlocking rate, it is beneficial to reduce the unlocking time, thereby improving the user unlocking experience.

[0063] Optionally, in an embodiment of the present application, the end time of the second exposure time is not earlier than the time when the second image is determined to be acquired.

[0064] First of all, it should be noted that the fingerprint sensor in the embodiment of the present application can be applied to various exposure methods. Usually, in order to reduce the exposure time, a rolling shutter exposure method can be adopted. For example, the fingerprint sensor array includes M rows × N columns of pixels. The pixels in the same row of the pixel array are exposed at the same time, and after the pixels in this row start to be exposed for a certain time, the pixels in the next row are exposed at the same time. Then, the subsequent rows of pixels are exposed in sequence. The time difference between the start time of exposure of two adjacent rows of pixels can, for example, usually be equal to the time for the processor to read the data of a row of pixels, so that the reading time of the exposed data of different pixel rows does not overlap. Then, the exposed data of the M rows of pixels are processed and spliced ​​to form a complete image.

[0065] However, for fingerprint sensors that expose row by row, the processor needs to obtain the data of each row of pixels after exposure in a timely manner, otherwise, the data of the next row of pixels after exposure will overwrite the data of the previous row of pixels after exposure. That is to say, in an embodiment of the present application, if the processor has not determined whether to obtain the second image based on the first image, and the fingerprint sensor has already acquired the second image, then when the processor needs to obtain the second image, the data of the second image has been damaged. That is, a cyclic redundancy check (CRC) error will occur. For example, the processor may only obtain the data of the last row of pixels exposed by the fingerprint sensor. Therefore, the second exposure duration can be configured to be at least greater than the duration for the processor to receive the first image. Furthermore, the second exposure duration can be configured to be greater than the total duration for the processor to receive and process the first image.

[0066] In other embodiments, if the cache in the fingerprint sensor is large enough to store the data of the entire frame of the image captured by the fingerprint sensor, then in this case, the second exposure time can also be configured to be less than the total time for the processor to receive and process the first image. In other words, after the fingerprint sensor captures the second image, the data of the second image is stored inside the fingerprint sensor, and the fingerprint sensor can stop working and wait for the processor to read the data of the second image.

[0067] Although the embodiments of the present application are described throughout this document using the example that the length of the second exposure time is greater than the length of the first exposure time, those skilled in the art understand that the embodiments of the present application are not limited thereto.

[0068] Optionally, in an embodiment of the present application, determining whether to obtain a second image captured by the fingerprint sensor at a second exposure time based on the first image includes: preprocessing the first image to obtain a value of a corresponding fingerprint parameter, where the fingerprint parameter is used to evaluate the quality of the image captured by the fingerprint sensor; and determining to obtain the second image when it is determined that the value of the fingerprint parameter is less than a first threshold.

[0069] Further, the fingerprint parameter may include any one of a fingerprint signal, a fingerprint image quality score, and pixel data of the fingerprint sensor when collecting images. Generally, the fingerprint signal is used to indicate the signal strength difference between the fingerprint ridge and the fingerprint valley. The fingerprint image quality score can be used to quantify the fingerprint image. For example, the fingerprint image can be divided into multiple levels according to the quality, and different levels represent fingerprint images of different quality. In addition, since the fingerprint sensor usually includes a pixel array, each pixel in the pixel array has a pixel data, that is, rawdata, when the fingerprint sensor collects an image. In the embodiment of the present application, it can be determined whether to obtain the second image based on any pixel data of the fingerprint sensor when collecting the first image; it can also be determined whether to obtain the second image based on a data obtained by processing the pixel data rawdata of the fingerprint sensor when collecting the image. For example, an average operation is performed on all the rawdata in the pixel array. For another example, a maximum operation is performed on all the rawdata in the pixel array. The embodiment of the present application is not limited to this.

[0070] Preprocessing the first image may include general fingerprint image preprocessing. For example, in the process of fingerprint collection, various noises are inevitably introduced, such as cross-connections and breakpoints in the image. These noises have a certain impact on the extraction of fingerprint feature information and may even produce many pseudo feature points. Therefore, before extracting fingerprint features, the fingerprint image needs to be filtered to remove useless information and enhance useful information. After obtaining the enhanced grayscale image, it needs to be further binarized to facilitate subsequent processing. Fingerprint image preprocessing includes fingerprint area detection, image quality judgment, directional map and frequency estimation, image enhancement, fingerprint image binarization and refinement, etc.

[0071] The preprocessing of the first image may also include data processing of the fingerprint image, for example, performing an average operation on all raw data of the pixel array, or performing a maximum operation on all raw data of the pixel array.

[0072] Different fingerprint parameters correspond to different first thresholds. For example, the fingerprint image quality score can be divided into 100 levels from 1 to 100, and the first threshold can be 50, for example. That is, if the value of the fingerprint image quality score of the first image is greater than 50, it is determined not to obtain the second image, that is, fingerprint recognition is performed based on the first image; if the value of the fingerprint image quality score of the first image is less than or equal to 50, it is determined to obtain the second image, that is, fingerprint recognition is performed based on the first image and the second image.

[0073] In this embodiment, preprocessing the first image is beneficial to the accuracy of fingerprint feature extraction. In addition, by comparing the value of the fingerprint parameter corresponding to the first image with the preset first threshold, the quality of the first image can be judged, that is, it can be judged whether the texture of the finger currently pressed by the user is clear. In the case where it is judged that the quality of the first image is good, fingerprint recognition can be performed directly based on the first image. Compared with the technical solution of directly using a long exposure time to capture images in the prior art, the time taken to judge the quality of the first image is much less than the time difference between the long exposure time and the short exposure time. Therefore, the unlocking time can be greatly reduced.

[0074] Optionally, in an embodiment of the present application, preprocessing the first image to obtain the value of the corresponding fingerprint parameter includes: when it is determined that the first image is not a fingerprint pattern, preprocessing the first image to obtain the value of the corresponding fingerprint parameter.

[0075] That is to say, before preprocessing the first image, the processor may first determine whether the first image is a fingerprint pattern. If it is determined that the first image is not a fingerprint pattern, the first image may be preprocessed. Usually in the under-screen optical fingerprint recognition technology, the pressing part will be prompted on the display screen, that is, the fingerprint pattern will be displayed on the display screen to guide the user to collect the fingerprint. The electronic device may pre-store the pattern of the fingerprint pattern. When the processor obtains the first image, the pattern of the first image can be matched with the pattern of the fingerprint pattern pre-stored in the electronic device. If the match is successful, it means that the first image is a fingerprint pattern; if the match is unsuccessful, it means that the first image is not a fingerprint pattern.

[0076] Optionally, in an embodiment of the present application, determining whether to acquire a second image captured by the fingerprint sensor at a second exposure time based on the first image includes: determining to acquire the second image when determining that the first image is a fingerprint pattern.

[0077] In this embodiment, once the processor determines that the first image is a fingerprint pattern, the processor can directly determine that the second image needs to be acquired without obtaining the value of the fingerprint parameter corresponding to the first image through preprocessing, thereby further reducing the unlocking time.

[0078] Optionally, in an embodiment of the present application, when it is determined that the second image is acquired, fingerprint recognition is performed based on the first image and the second image, including: when it is determined that the second image is acquired and the first image is a fingerprint pattern, fingerprint recognition is performed based on the second image.

[0079] Optionally, in an embodiment of the present application, when it is determined that the second image is acquired, fingerprint recognition is performed based on the first image and the second image, including: when it is determined that the second image is acquired and the first image is not a fingerprint pattern, fusing the first image and the second image; and performing fingerprint recognition based on the fused first image and second image.

[0080] When the processor determines to acquire the second image based on the various embodiments described above, the processor may further determine whether the first image is a fingerprint pattern. If the first image is a fingerprint pattern, the fingerprint recognition is performed directly based on the second image. For example, if the processor determines to acquire the second image based on the value of the fingerprint parameter corresponding to the first image, the processor may further determine whether the first image is a fingerprint pattern. Finally, if the processor determines that the first image is a fingerprint pattern, the fingerprint recognition is performed based on the second image. If the processor determines that the first image is not a fingerprint pattern, the first image and the second image may be fused, and the fingerprint recognition is performed based on the fused image. For another example, if the processor determines to acquire the second image based on the first image being a fingerprint pattern, the processor may perform fingerprint recognition directly based on the second image.

[0081] In this embodiment, when the first image is a fingerprint pattern, the second image is more conducive to fingerprint recognition; and when the first image is not a fingerprint pattern, fusing the first image and the second image is more conducive to fingerprint recognition. Therefore, the technical solution provided in this embodiment is conducive to improving the success rate of user unlocking.

[0082] Optionally, in an embodiment of the present application, when it is determined to obtain the second image, fingerprint recognition is performed based on the first image and the second image, including: when it is determined to obtain the second image, determining whether an offset occurs between the second image and the first image; when it is determined that an offset occurs between the second image and the first image, fingerprint recognition is performed based on the image with higher quality between the first image and the second image.

[0083] In this embodiment, it is determined whether there is an offset between the second image and the first image, that is, it is determined whether the user's finger slides when the fingerprint sensor captures the second image and the second image. In the case that the user's finger slides, an image with better quality can be selected from the first image and the second image for fingerprint recognition.

[0084] As an example, when it is determined that the second image is acquired, determining whether an offset occurs between the second image and the first image includes: when it is determined that the second image is acquired, calculating a standard deviation between a plurality of pixel data at a preset position in the fingerprint sensor when the first image is acquired and a plurality of pixel data at the preset position in the fingerprint sensor when the second image is acquired; when the standard deviation is greater than a second threshold, determining that an offset occurs between the second image and the first image.

[0085] It should be understood that the first image may include pixel data obtained for each pixel in the pixel array of the fingerprint sensor, and the second image may include pixel data obtained for each pixel in the pixel array of the fingerprint sensor. The processor may specify multiple pixels of the fingerprint sensor in advance, that is, the positions of the multiple pixels in the fingerprint sensor are fixed. After acquiring the first image and the second image, the processor may respectively acquire pixel data on the specified multiple pixels in the first image and pixel data on the specified multiple pixels in the second image, and calculate the standard deviation between the two. When the standard deviation is greater than a preset second threshold, it is determined that an offset occurs between the second image and the first image.

[0086] Optionally, the preset position is located in the central area of ​​the fingerprint sensor. For example, the plurality of pixels at the preset position includes 50*50 pixels in the central area of ​​the fingerprint sensor.

[0087] In this embodiment, calculating the standard deviation between the pixel data of multiple pixels located in the central area of ​​the first image and the second image is beneficial to improving the accuracy of the processor in determining whether the second image and the first image are offset, thereby facilitating obtaining images of better quality to improve the success rate of user unlocking.

[0088] As another example, when determining to acquire the second image, determining whether an offset occurs between the second image and the first image includes: determining an offset between the fingerprint patterns of the first image and the fingerprint patterns of the second image; and determining whether an offset occurs between the second image and the first image based on the offset.

[0089] Specifically, one of the first image and the second image may be fixed, and the other image may be moved so that the first image and the second image overlap, and the movement amount is the offset between the fingerprint pattern of the first image and the fingerprint pattern of the second image.

[0090] Optionally, determining whether an offset occurs between the second image and the first image based on the offset between the fingerprint patterns of the first image and the fingerprint patterns of the second image may include: determining that an offset occurs between the second image and the first image when the offset is greater than a certain threshold; and determining that no offset occurs between the second image and the first image when the offset is less than or equal to the certain threshold. For example, the certain threshold is 0. That is, if the offset is equal to 0, it is determined that no offset occurs between the second image and the first image; if the offset is greater than 0, it is determined that an offset occurs between the second image and the first image.

[0091] Optionally, the above-mentioned fusion of the first image and the second image may be performed when it is determined that there is no offset between the first image and the second image. In other words, when it is determined that there is no offset between the second image and the first image, the processor fuses the first image and the second image.

[0092] Optionally, the fusion of the first image and the second image described above may also be performed when it is determined that there is an offset between the first image and the second image. For example, if there is an offset between the first image and the second image, the first image (second image) may be fixed, and the second image (first image) may be moved so that the first image and the second image overlap, and the moved second image (first image) may be fused with the first image (second image).

[0093] Optionally, in the embodiment of the present application, fusing the first image and the second image includes: fusing a valid signal for fingerprint identification in the first image and a valid signal for fingerprint identification in the second image.

[0094] That is to say, before fusing the first image and the second image, it is necessary to extract the valid signal in the first image and the valid signal in the second image. The valid signal of the first image can be used alone for fingerprint recognition, and the valid signal of the second image can also be used alone for fingerprint recognition. The valid signal can be a signal from which noise is removed in the signal received by the fingerprint sensor.

[0095] In this embodiment, the effective signal for fingerprint identification in the first image and the effective signal for fingerprint identification in the second image are fused to obtain an image of better quality, thereby facilitating improving the success rate of user unlocking.

[0096] In other embodiments, the first image and the second image may not be processed and may be directly fused. For example, the pixel data of the first image and the pixel data of the second image may be directly added to obtain a fused image.

[0097] In another embodiment of the present application, when it is determined that the first image is not a fingerprint pattern, the processor may not fuse the first image and the second image, but directly select an image with better quality from the first image and the second image for fingerprint identification.

[0098] Optionally, in the embodiment of the present application, the method 200 further includes: dynamically adjusting the first threshold value according to an unlocking rate of fingerprint recognition using the first image.

[0099] When fingerprint recognition reaches stability after a certain period of use, the first threshold can be adjusted. Taking the first threshold corresponding to the fingerprint image quality score as an example, assuming that the first threshold is 26, the unlocking rate of fingerprint recognition using the first image is higher than 90%, but the proportion of fingerprint recognition using the first image in the embodiment of the present application is lower than 50%. Therefore, the first threshold can be dynamically adjusted according to the unlocking rate of fingerprints using the first image.

[0100] In this embodiment, the first threshold for determining whether to obtain the second image is dynamically adjusted according to the unlocking rate of fingerprint recognition using the first image, which can take into account both the unlocking rate and the unlocking time, thereby maximizing the user's unlocking experience.

[0101] In one example, the first threshold is dynamically adjusted based on the unlocking rate of fingerprint recognition using the first image, including: when the unlocking rate is greater than a third threshold, the first threshold is lowered by at least one level; or when the unlocking rate is less than a fourth threshold, the first threshold is raised by at least one level, and the third threshold is greater than or equal to the fourth threshold.

[0102] Optionally, the third threshold is 85% and the fourth threshold is 70%.

[0103] Taking the fingerprint parameter as the fingerprint image quality score as an example, assuming that the first threshold A is 26, the unlocking rate of fingerprint recognition using the first image for multiple consecutive times (for example, 100 times) is P1; if P1 is greater than 85%, A=A-1; if P1 is less than 70%, A=A+1.

[0104] It should be noted that the processor may also adjust the first threshold A down by multiple levels when the unlocking rate is particularly high. And when the unlocking rate is particularly low, the first threshold A is adjusted up by multiple levels. For example, if P1 is greater than 95%, then A=A-3; if P1 is less than 50%, then A=A+5.

[0105] Usually, the first threshold value has an upper limit and a lower limit, that is, the adjustment range of the first threshold value should be between the upper limit and the lower limit. For example, 15<first threshold value A<28, that is, the upper limit of the first threshold value A is 28 and the lower limit is 15. When the first threshold value A is lowered to the lower limit of 15, the first threshold value A is directly set to 15; when the first threshold value A is raised to the upper limit of 28, the first threshold value A is directly set to 28.

[0106] Optionally, in an embodiment of the present application, the method also includes: determining whether the environment in which the fingerprint sensor is located is a strong light environment based on the first image; and determining whether to obtain a second image collected by the fingerprint sensor at a second exposure time based on the first image, including: when it is determined that the environment in which the fingerprint sensor is located is not a strong light environment, determining whether to obtain the second image collected by the fingerprint sensor at the second exposure time based on the first image.

[0107] Optionally, in an embodiment of the present application, the method also includes: when it is determined that the environment in which the fingerprint sensor is located is a strong light environment, obtaining a third image of the fingerprint sensor at a third exposure time, the length of the third exposure time is equal to the length of the first exposure time, and the gain of the fingerprint sensor when collecting the third image is less than the gain of the fingerprint sensor when collecting the first image; and performing fingerprint recognition based on the third image.

[0108] That is, before the processor determines whether to acquire the second image based on the first image, the processor may first determine whether the environment in which the fingerprint sensor is located is a strong light environment based on the first image. Because the first image acquired by the fingerprint sensor may be overexposed in a strong light environment, resulting in weak fingerprint information in the first image, the fingerprint sensor needs to acquire a new image. But at the same time, since the weak fingerprint information in the first image may be only caused by the strong light environment in which the fingerprint sensor is located, the fingerprint sensor can use short exposure (i.e., the first exposure duration) again, and reduce the gain to capture the third image, and the processor can perform fingerprint recognition based on the third image. At this time, the processor can control the fingerprint sensor to capture the third image during the process of the fingerprint sensor capturing the second image. That is, once the processor determines that the environment in which the fingerprint sensor is located is a strong light environment, the processor can directly send instructions to the fingerprint sensor to configure the exposure duration of the fingerprint sensor to the first exposure duration again, and configure the gain of the fingerprint sensor to be lower than the gain when the first image is captured, and capture the third image under this configuration.

[0109] Optionally, in an embodiment of the present application, determining whether the environment in which the fingerprint sensor is located is a strong light environment based on the first image includes: when the proportion of all pixel data of the fingerprint sensor that is greater than a fifth threshold when the fingerprint sensor collects the first image exceeds a sixth threshold, determining that the environment in which the fingerprint sensor is located is a strong light environment.

[0110] Specifically, if the proportion of pixel data of the entire frame of pixels of the first image that is greater than the strong light threshold (ie, the fifth threshold) exceeds 40%, the processor may determine that the environment in which the fingerprint sensor is located is a strong light environment.

[0111] In this embodiment, when it is determined based on the first image that the second image needs to be acquired, but at the same time the environment where the fingerprint sensor is located is also a strong light environment, the gain is preferentially reduced to re-acquire the third image, which can improve the dynamic range of image acquisition.

[0112] Optionally, in an embodiment of the present application, the length of the second exposure time is twice the length of the first exposure time.

[0113] Figure 3 A timing diagram of a method for implementing fingerprint recognition based on adaptive exposure provided by an embodiment of the present application is shown. Specifically, the processor presets an exposure configuration, which includes two different exposure durations, and the fingerprint sensor supports continuous exposure. The fingerprint sensor preferentially acquires a frame of image under a short exposure duration, and the processor preprocesses the frame of image and determines the state of the finger. When the finger quality is good, the frame of image is used for fingerprint recognition, and at this time, the time consumption is shorter; when the finger quality is poor, a frame of image acquired under a long exposure duration continues to be acquired from the fingerprint sensor, and then the two frames of image are fused, and fingerprint recognition is performed based on the fused image to further improve the unlocking rate.

[0114] like Figure 3 As shown, the method includes:

[0115] S301, the fingerprint sensor downloads the exposure configuration in advance;

[0116] S302, the fingerprint sensor starts continuous exposure and collects the first frame image under the short exposure time, and the short exposure time is 22ms;

[0117] S303, after acquiring the first frame of image, the fingerprint sensor immediately acquires a second frame of image under a long exposure time, where the long exposure time is 44 ms;

[0118] S304, after the fingerprint sensor acquires the first frame of image, it immediately sends the first frame of image to the processor, that is, the processor immediately receives the first frame of image sent by the fingerprint sensor. This step takes about 18ms.

[0119] S305, after receiving the first frame of image, the processor may pre-process the first frame of image and determine the quality of the finger. This step takes about 6 ms.

[0120] S306, when it is determined that the finger quality is good, fingerprint recognition is performed based on the first frame image, and this step takes about 43ms;

[0121] S307, obtaining the recognition result in step S306;

[0122] S308, when it is determined that the finger quality is poor, the processor can control the fingerprint sensor to transmit a second frame of image to it, and this step takes about 18ms;

[0123] S309, the processor may perform fusion preprocessing on the first frame image and the second frame image to obtain a fused frame image, and this step takes about 6 ms;

[0124] S310, the processor performs fingerprint recognition based on the fused frame obtained in step S309, and this step takes about 43ms;

[0125] S311, obtaining the recognition result in step S310.

[0126] It should be noted that in the entire process, the total time consumed by the fingerprint sensor to transmit the image and the processor to perform preprocessing and finger judgment is less than the long exposure time to prevent the occurrence of CRC.

[0127] Optionally, in an embodiment of the present application, the fingerprint sensor can be configured in a multi-frame continuous exposure mode, and when the processor acquires each frame of image, it can use the technical solution provided in the embodiment of the present application to determine whether to acquire the next frame of image. For example, the first frame exposure time of the fingerprint sensor is t1, the second frame exposure time is t2, the third frame exposure time is t3, etc., wherein t1 can be less than or equal to t2, t2 can be less than or equal to t3, and so on. Furthermore, for each frame exposure time, it can also be set to be greater than or equal to the total time of reading, preprocessing, and finger judgment of the previous frame of image.

[0128] The fingerprint recognition method according to the embodiment of the present application is described in detail above. The fingerprint recognition device according to the embodiment of the present application will be described below in conjunction with Figure 4. The technical features described in the method embodiment are applicable to the following device embodiments.

[0129] Figure 4 FIG. 4 is a schematic block diagram of a fingerprint recognition device 400 according to an embodiment of the present application. Figure 4 As shown, the device 400 includes:

[0130] An acquisition unit 410 is configured to acquire a first image captured by a fingerprint sensor at a first exposure time;

[0131] A determination unit 420 is configured to determine, based on the first image, whether to acquire a second image captured by the fingerprint sensor at a second exposure time, where the second exposure time is continuous with the first exposure time, and a length of the second exposure time is greater than or equal to a length of the first exposure time;

[0132] The fingerprint recognition unit 430 is configured to perform fingerprint recognition based on the first image when it is determined not to acquire the second image; or to perform fingerprint recognition based on the first image and the second image when it is determined to acquire the second image.

[0133] Optionally, in an embodiment of the present application, the end time of the second exposure time is not earlier than the time when the second image is determined to be acquired.

[0134] Optionally, in an embodiment of the present application, the determination unit 420 is specifically used to: preprocess the first image to obtain a corresponding fingerprint parameter value, the fingerprint parameter including any one of a fingerprint signal, a fingerprint image quality score, and pixel data of the fingerprint sensor when acquiring the image; when it is determined that the value of the fingerprint parameter is less than a first threshold, determine to obtain the second image.

[0135] Optionally, in the embodiment of the present application, the determining unit 420 is specifically configured to: when it is determined that the first image is not a fingerprint pattern, pre-process the first image to obtain a value of a corresponding fingerprint parameter.

[0136] Optionally, in the embodiment of the present application, the determining unit 420 is specifically configured to: determine to acquire the second image when it is determined that the first image is a fingerprint pattern.

[0137] Optionally, in an embodiment of the present application, the determination unit 420 is further used to: when it is determined that the second image is acquired, determine whether an offset occurs between the second image and the first image; the fingerprint recognition unit 530 is specifically used to: when it is determined that an offset occurs between the second image and the first image, perform fingerprint recognition based on the image with higher quality between the first image and the second image.

[0138] Optionally, in an embodiment of the present application, the determination unit 420 is specifically used to: when determining to obtain the second image, calculate the standard deviation between multiple pixel data at a preset position in the fingerprint sensor when acquiring the first image and multiple pixel data at the preset position of the fingerprint sensor when acquiring the second image; when the standard deviation is greater than a second threshold, determine that an offset occurs between the second image and the first image.

[0139] Optionally, in an embodiment of the present application, the preset position is located in a central area of ​​the fingerprint sensor.

[0140] Optionally, in an embodiment of the present application, the determination unit 420 is specifically used to: determine the offset between the fingerprint patterns of the first image and the fingerprint patterns of the second image; and determine whether an offset occurs between the second image and the first image based on the offset.

[0141] Optionally, in the embodiment of the present application, the fingerprint recognition unit 430 is specifically configured to: when it is determined that the second image is acquired and the first image is a fingerprint pattern, perform fingerprint recognition based on the second image.

[0142] Alternatively, if Figure 5 As shown, the device 400 also includes: a fusion unit 440, which is used to fuse the first image and the second image when it is determined that the second image is obtained and the first image is not a fingerprint pattern; the fingerprint recognition unit 430 is specifically used to: perform fingerprint recognition based on the fused first image and the second image.

[0143] Optionally, in the embodiment of the present application, the fusion unit 440 is specifically used to: fuse the first image and the second image when it is determined that no offset occurs between the second image and the first image.

[0144] Optionally, in the embodiment of the present application, the fusion unit 440 is specifically used to: fuse the valid signal used for fingerprint identification in the first image and the valid signal used for fingerprint identification in the second image.

[0145] Alternatively, if Figure 5 As shown, the device 400 further includes: a threshold adjustment unit 450, configured to dynamically adjust the first threshold according to an unlocking rate of fingerprint recognition using the first image.

[0146] Optionally, in an embodiment of the present application, the dynamic adjustment unit 450 is specifically used to: when the unlocking rate is greater than a third threshold, lower the first threshold by at least one level; or when the unlocking rate is less than a fourth threshold, raise the first threshold by at least one level, and the third threshold is greater than or equal to the fourth threshold.

[0147] Optionally, in the embodiment of the present application, the third threshold is 85%, and the fourth threshold is 70%.

[0148] Optionally, in an embodiment of the present application, the determination unit 420 is also used to: determine whether the environment in which the fingerprint sensor is located is a strong light environment based on the first image; the determination unit 420 is specifically used to: when it is determined that the environment in which the fingerprint sensor is located is not a strong light environment, determine whether to obtain a second image captured by the fingerprint sensor at a second exposure time based on the first image.

[0149] Optionally, in an embodiment of the present application, the acquisition unit 410 is further used to: when it is determined that the environment in which the fingerprint sensor is located is a strong light environment, acquire a third image of the fingerprint sensor under a third exposure time, the length of the third exposure time is equal to the length of the first exposure time, and the gain of the fingerprint sensor when acquiring the third image is less than the gain of the fingerprint sensor when acquiring the first image; the fingerprint recognition unit 430 is further used to: perform fingerprint recognition based on the third image.

[0150] Optionally, in an embodiment of the present application, the determination unit 420 is specifically used to: determine that the environment in which the fingerprint sensor is located is a strong light environment when the proportion of all pixel data greater than the fifth threshold in the fingerprint sensor when collecting the first image exceeds a sixth threshold.

[0151] Optionally, in the embodiment of the present application, the sixth threshold is 40%.

[0152] Optionally, in an embodiment of the present application, the length of the second exposure time is twice the length of the first exposure time.

[0153] Figure 6 FIG. 6 is a schematic block diagram of an electronic device 600 according to an embodiment of the present application. Figure 6 As shown, the electronic device 600 includes: a sensor chip 610, which is used to collect a first image at a first exposure time and a second image at a second exposure time, wherein the second exposure time is continuous with the first exposure time, and the length of the second exposure time is greater than the length of the first exposure time. The electronic device 600 also includes a processor 620, which can call and run a computer program from a memory to implement the method in the embodiment of the present application.

[0154] Alternatively, if Figure 6 As shown, the electronic device 600 may further include a memory 630. The processor 620 may call and run a computer program from the memory 630 to implement the method in the embodiment of the present application.

[0155] The memory 630 may be a separate device independent of the processor 610 , or may be integrated into the processor 620 .

[0156] Figure 7 and Figure 8 A schematic structural diagram of an electronic device 600 in an embodiment of the present application is also shown.

[0157] in, Figure 7 is a front view of an electronic device 600, Figure 8 for Figure 7 The electronic device 600 is a schematic diagram of a partial cross-sectional structure along the line AA'. The electronic device 600 includes a display screen 640 and a fingerprint sensor 610 disposed below the display screen 640. The electronic device also includes Figure 6 The processor 620 shown may be packaged together with the fingerprint sensor 610 , or the processor 620 may be independent of the fingerprint sensor chip 610 . For example, the processor 620 is a main control processor of the electronic device 600 .

[0158] like Figure 8 As shown, the fingerprint sensor 610 includes a light detection part 611 and a light path guiding structure 612. The light path guiding structure 612 is arranged above the light detection part 611. The light detection part 611 includes a pixel array 601 composed of a plurality of pixels 6011, and a control circuit 602 connected to the pixel array 601. Figure 8 As shown, the area where the pixel array 601 is located or its sensing area is the fingerprint detection area 603 of the fingerprint sensor 611. The optical path guiding structure 612 is used to guide the optical signal returned by the finger on the fingerprint detection area 603 to the pixel array 601.

[0159] The embodiment of the present application does not impose any limitation on the optical path guiding structure 612 in the fingerprint sensor 610. For example, the optical path guiding structure 612 may include a microlens array composed of a plurality of microlenses. Furthermore, there may be at least one light-blocking layer below the microlens array, wherein each light-blocking layer is provided with a plurality of openings corresponding to the plurality of microlenses, and the pixel array 601 includes a plurality of pixels 6011 corresponding to the plurality of microlenses. Each microlens is used to converge the light signal returned by the finger to the corresponding opening in each light-blocking layer, so that the light signal passes through the corresponding opening in each light-blocking layer in turn and is transmitted to the corresponding pixel 6011 in the pixel array 601.

[0160] For another example, the light path guiding structure 612 may include a collimator layer made on a semiconductor silicon wafer, which has a plurality of collimating units or a micro-hole array, and the collimating unit may be a small hole.

[0161] For another example, the light path guiding structure 612 may include an optical lens layer having one or more lens units, and the lens unit may be a lens group composed of one or more aspherical lenses. For example, as shown in FIG8 , the light path guiding structure may include a lens 6121. The light emitted by the light emitting layer 1401 in the display screen illuminates the finger and the light returned by the finger can be converged to the pixel array 601 of the optical fingerprint sensor through the lens 6121.

[0162] When performing fingerprint detection, the display screen 140 emits a beam of light 111 to the finger 650 above the fingerprint detection area 603. The light 111 is reflected on the surface of the finger 650 to form reflected light or is scattered inside the finger 650 to form scattered light. Since the ridge 141 and valley 142 of the fingerprint have different reflective capabilities for light, the reflected light 151 from the fingerprint ridge and the reflected light 152 from the fingerprint valley have different light intensities. After the reflected light passes through the optical path guiding structure 612, it is received by the pixel array 601 and converted into a corresponding electrical signal, i.e., a fingerprint detection signal. Based on the fingerprint detection signal, the data of the fingerprint image can be obtained and further used for fingerprint matching and verification, thereby realizing the function of optical fingerprint detection in the electronic device 600.

[0163] Furthermore, the electronic device 600 may also include an excitation light source for fingerprint detection.

[0164] The display screen 640 may be a display screen with a self-luminous display unit, such as an organic light-emitting diode (OLED) display screen or a micro-LED display screen. Taking the OLED display screen as an example, the fingerprint sensor 610 may use the display unit located in the fingerprint detection area 603 of the OLED display screen 640 as an excitation light source for optical fingerprint detection.

[0165] As an example but not limitation, the electronic device in the embodiment of the present application can be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a laptop computer, a desktop computer, a gaming device, an in-vehicle electronic device or a wearable smart device, as well as other electronic devices such as an electronic database, a car, and an automated teller machine (ATM). The wearable smart device includes a device with full functions and large size that can realize full or partial functions without relying on a smart phone, such as a smart watch or smart glasses, and includes a device that only focuses on a certain type of application function and needs to be used in conjunction with other devices such as a smart phone, such as various types of smart bracelets and smart jewelry for vital sign monitoring.

[0166] An embodiment of the present application further provides a chip, which includes a processor, and the processor can call and run a computer program from a memory to implement the method in the embodiment of the present application.

[0167] Optionally, the chip can be applied to the device for collecting fingerprint images in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the device for collecting fingerprint images in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0168] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0169] Optionally, the embodiments of the present application further provide a computer-readable medium for storing a computer program to implement the method in the embodiments of the present application.

[0170] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0171] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0172] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0173] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0174] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0175] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0176] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A fingerprint recognition method, characterized in that: include: Acquire a first image captured by the fingerprint sensor at a first exposure time; Determine, according to the first image, whether to acquire a second image captured by the fingerprint sensor at a second exposure time, where the second exposure time and the first exposure time are continuous, and a length of the second exposure time is greater than or equal to a length of the first exposure time; If it is determined not to acquire the second image, fingerprint recognition is performed based on the first image; or, if it is determined to acquire the second image, fingerprint recognition is performed based on the first image and the second image; The end time of the second exposure time is not earlier than the time for determining to acquire the second image, and the duration of the second exposure time is at least configured to be greater than the duration for acquiring the first image.

2. The method according to claim 1, characterized in that The determining, according to the first image, whether to acquire a second image collected by the fingerprint sensor at a second exposure time includes: Preprocessing the first image to obtain a value of a corresponding fingerprint parameter, where the fingerprint parameter includes any one of a fingerprint signal, a fingerprint image quality score, and pixel data of the fingerprint sensor when acquiring the image; When it is determined that the value of the fingerprint parameter is less than the first threshold, it is determined to acquire the second image.

3. The method according to claim 2, characterized in that The preprocessing of the first image to obtain a value of a corresponding fingerprint parameter includes: When it is determined that the first image is not a fingerprint pattern, the first image is preprocessed to obtain a value of a corresponding fingerprint parameter.

4. The method according to claim 1, characterized in that: The determining, according to the first image, whether to acquire a second image collected by the fingerprint sensor at a second exposure time includes: In the case where it is determined that the first image is a fingerprint pattern, it is determined to acquire the second image.

5. The method according to claim 1, characterized in that The step of performing fingerprint recognition according to the first image and the second image when it is determined to acquire the second image includes: In the case of determining to acquire the second image, determining whether an offset occurs between the second image and the first image; In the case where it is determined that a shift occurs between the second image and the first image, fingerprint recognition is performed based on the image with higher quality between the first image and the second image.

6. The method according to claim 5, characterized in that The step of determining whether an offset occurs between the second image and the first image when it is determined to acquire the second image comprises: In the case of determining to acquire the second image, calculating a standard deviation between a plurality of pixel data at a preset position in the fingerprint sensor when acquiring the first image and a plurality of pixel data at the preset position in the fingerprint sensor when acquiring the second image; When the standard deviation is greater than a second threshold, it is determined that an offset occurs between the second image and the first image.

7. The method according to claim 6, characterized in that The preset position is located in the central area of ​​the fingerprint sensor.

8. The method according to claim 5, characterized in that The step of determining whether an offset occurs between the second image and the first image when it is determined to acquire the second image comprises: Determining an offset between the fingerprint patterns of the first image and the fingerprint patterns of the second image; According to the offset, it is determined whether an offset occurs between the second image and the first image.

9. The method according to claim 1, characterized in that: The step of performing fingerprint recognition according to the first image and the second image when it is determined to acquire the second image includes: When it is determined that the second image is acquired and the first image is a fingerprint pattern, fingerprint recognition is performed based on the second image.

10. The method according to claim 1, characterized in that The step of performing fingerprint recognition according to the first image and the second image when it is determined to acquire the second image includes: When it is determined that the second image is acquired and the first image is not a fingerprint pattern, fusing the first image and the second image; Fingerprint recognition is performed based on the fused first image and the second image.

11. The method according to claim 10, characterized in that The fusing the first image and the second image comprises: When it is determined that no offset occurs between the second image and the first image, the first image and the second image are fused.

12. The method according to claim 10, characterized in that The fusing the first image and the second image comprises: The effective signal used for fingerprint identification in the first image and the effective signal used for fingerprint identification in the second image are fused.

13. The method according to claim 2, characterized in that The method further comprises: The first threshold is dynamically adjusted according to an unlocking rate of fingerprint recognition using the first image.

14. The method according to claim 13, characterized in that The dynamically adjusting the first threshold according to the unlocking rate of fingerprint recognition using the first image includes: When the unlocking rate is greater than a third threshold, lowering the first threshold by at least one level; or When the unlocking rate is less than a fourth threshold, the first threshold is increased by at least one level, and the third threshold is greater than or equal to the fourth threshold.

15. The method according to claim 14, characterized in that The third threshold is 85%, and the fourth threshold is 70%.

16. The method according to claim 1, characterized in that The method further comprises: Determining, according to the first image, whether the environment in which the fingerprint sensor is located is a strong light environment; The determining, according to the first image, whether to acquire a second image collected by the fingerprint sensor at a second exposure time includes: When it is determined that the environment in which the fingerprint sensor is located is not a strong light environment, it is determined whether to obtain a second image captured by the fingerprint sensor at a second exposure time according to the first image.

17. The method according to claim 16, characterized in that The method further comprises: When it is determined that the environment in which the fingerprint sensor is located is a strong light environment, obtaining a third image of the fingerprint sensor under a third exposure time, wherein the length of the third exposure time is equal to the length of the first exposure time, and the gain of the fingerprint sensor when acquiring the third image is less than the gain of the fingerprint sensor when acquiring the first image; Fingerprint recognition is performed based on the third image.

18. The method according to claim 16, characterized in that The determining, according to the first image, whether the environment in which the fingerprint sensor is located is a strong light environment includes: When the proportion of all pixel data greater than the fifth threshold in the fingerprint sensor when collecting the first image exceeds the sixth threshold, it is determined that the environment in which the fingerprint sensor is located is a strong light environment.

19. The method according to claim 18, characterized in that The sixth threshold is 40%.

20. The method according to claim 1, characterized in that The length of the second exposure time is twice the length of the first exposure time.

21. A fingerprint recognition device, characterized in that: For carrying out the method according to any one of claims 1 to 20.

22. An electronic device, characterized in that: include: A fingerprint sensor, configured to capture a first image at a first exposure time and a second image at a second exposure time, wherein the second exposure time and the first exposure time are continuous, and a length of the second exposure time is greater than or equal to a length of the first exposure time; Processor for: acquiring the first image, determining whether to acquire the second image according to the first image, If it is determined not to acquire the second image, fingerprint recognition is performed based on the first image; or, if it is determined to acquire the second image, fingerprint recognition is performed based on the first image and the second image; The end time of the second exposure time is not earlier than the time for determining to acquire the second image, and the duration of the second exposure time is at least configured to be greater than the duration for acquiring the first image.

23. The electronic device according to claim 22, characterized in that: The processor is used to: Preprocessing the first image to obtain a value of a corresponding fingerprint parameter, where the fingerprint parameter includes any one of a fingerprint signal, a fingerprint image quality score, and pixel data of the fingerprint sensor when acquiring the image; When it is determined that the value of the fingerprint parameter is less than the first threshold, it is determined to acquire the second image.

24. The electronic device according to claim 23, characterized in that: The processor is used to: When it is determined that the first image is not a fingerprint pattern, the first image is preprocessed to obtain a value of a corresponding fingerprint parameter.

25. The electronic device according to claim 22, characterized in that: The processor is used to: In the case where it is determined that the first image is a fingerprint pattern, it is determined to acquire the second image.

26. The electronic device according to claim 22, characterized in that: The processor is used to: In the case of determining to acquire the second image, determining whether an offset occurs between the second image and the first image; In the case where it is determined that a shift occurs between the second image and the first image, fingerprint recognition is performed based on the image with higher quality between the first image and the second image.

27. The electronic device according to claim 26, characterized in that: The processor is used to: In the case of determining to acquire the second image, calculating a standard deviation between a plurality of pixel data at a preset position in the fingerprint sensor when acquiring the first image and a plurality of pixel data at the preset position in the fingerprint sensor when acquiring the second image; When the standard deviation is greater than a second threshold, it is determined that an offset occurs between the second image and the first image.

28. The electronic device according to claim 27, characterized in that: The preset position is located in the central area of ​​the fingerprint sensor.

29. The electronic device according to claim 26, characterized in that: The processor is used to: Determine an offset between the fingerprint patterns of the first image and the fingerprint patterns of the second image; and determine whether an offset occurs between the second image and the first image based on the offset.

30. The electronic device according to claim 22, characterized in that The processor is used to: When it is determined that the second image is acquired and the first image is a fingerprint pattern, fingerprint recognition is performed based on the second image.

31. The electronic device according to claim 22, characterized in that: The processor is used to: When it is determined that the second image is acquired and the first image is not a fingerprint pattern, fusing the first image and the second image; Fingerprint recognition is performed based on the fused first image and the second image.

32. The electronic device according to claim 31, characterized in that: The processor is used to: When it is determined that no offset occurs between the second image and the first image, the first image and the second image are fused.

33. The electronic device according to claim 31, characterized in that: The processor is used to: The effective signal used for fingerprint identification in the first image and the effective signal used for fingerprint identification in the second image are fused.

34. The electronic device according to claim 23, characterized in that: The processor is further configured to: The first threshold is dynamically adjusted according to an unlocking rate of fingerprint recognition using the first image.

35. The electronic device according to claim 34, characterized in that The processor is used to: When the unlocking rate is greater than a third threshold, lowering the first threshold by at least one level; or When the unlocking rate is less than a fourth threshold, the first threshold is increased by at least one level, and the third threshold is greater than or equal to the fourth threshold.

36. The electronic device according to claim 35, characterized in that: The third threshold is 85%, and the fourth threshold is 70%.

37. The electronic device according to claim 22, characterized in that: The processor is further configured to: Determining, according to the first image, whether the environment in which the fingerprint sensor is located is a strong light environment; The processor is used to: When it is determined that the environment in which the fingerprint sensor is located is not a strong light environment, it is determined whether to obtain a second image captured by the fingerprint sensor at a second exposure time according to the first image.

38. The electronic device according to claim 37, characterized in that: The processor is used to: When it is determined that the environment in which the fingerprint sensor is located is a strong light environment, obtaining a third image of the fingerprint sensor under a third exposure time, wherein the length of the third exposure time is equal to the length of the first exposure time, and the gain of the fingerprint sensor when acquiring the third image is less than the gain of the fingerprint sensor when acquiring the first image; Fingerprint recognition is performed based on the third image.

39. The electronic device according to claim 37, characterized in that: The processor is used to: When the proportion of all pixel data greater than the fifth threshold in the fingerprint sensor when collecting the first image exceeds the sixth threshold, it is determined that the environment in which the fingerprint sensor is located is a strong light environment.

40. The electronic device according to claim 39, characterized in that The sixth threshold is 40%.

41. The electronic device according to claim 22, characterized in that: The length of the second exposure time is twice the length of the first exposure time.

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