WO2022104659A1 - 指纹检测的方法、指纹检测装置和电子设备 - Google Patents

指纹检测的方法、指纹检测装置和电子设备 Download PDF

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Publication number
WO2022104659A1
WO2022104659A1 PCT/CN2020/130205 CN2020130205W WO2022104659A1 WO 2022104659 A1 WO2022104659 A1 WO 2022104659A1 CN 2020130205 W CN2020130205 W CN 2020130205W WO 2022104659 A1 WO2022104659 A1 WO 2022104659A1
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Prior art keywords
pixels
row
data
exposure
difference
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PCT/CN2020/130205
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English (en)
French (fr)
Inventor
胡泽望
沈健
姚国峰
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深圳市汇顶科技股份有限公司
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Priority to PCT/CN2020/130205 priority Critical patent/WO2022104659A1/zh
Publication of WO2022104659A1 publication Critical patent/WO2022104659A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1318—Sensors therefor using electro-optical elements or layers, e.g. electroluminescent sensing

Definitions

  • the embodiments of the present application relate to the field of information technology, and more particularly, to a fingerprint detection method, a fingerprint detection apparatus, and an electronic device.
  • the pixel array in the image sensor is connected to the row decoder control and column readout circuit.
  • the row decoder can control each row of pixels to reset and start exposure. After exposure, the column readout circuit reads out the signal of each pixel. After all the row pixels are exposed and the data is read out, the fingerprint image of the finger to be tested can be obtained according to the data.
  • Embodiments of the present application provide a fingerprint detection method, a fingerprint detection device, and an electronic device, which can improve the performance of fingerprint detection without increasing the number of transistors in an image sensor, which has become an urgent problem to be solved.
  • a method for fingerprint detection comprising:
  • each row of pixels in the pixel array used for fingerprint detection is sequentially exposed, wherein the exposure sequences of two specific adjacent rows of pixels in the pixel array are not adjacent, or the pixels A particular row of pixels in the array is exposed twice;
  • the data of each row of pixels is read at the end of the exposure of each row of pixels, wherein the difference between the data of the two adjacent rows of pixels or the difference between the data of the specific row of pixels after two exposures , for determining whether the finger moves during the exposure process of the pixel array;
  • the data of the pixel array is not used for the fingerprint detection of the finger when the finger moves, and/or the data of the pixel array is used for the fingerprint detection of the finger when the finger does not move.
  • the method further includes: according to the difference between the data of the two adjacent rows of pixels, or the difference between the data of the specific row of pixels after two exposures, determine Whether the finger moves during the exposure process of the pixel array.
  • the determining whether the finger moves during the exposure process of the pixel array according to the difference between the data of the pixels in the two adjacent rows includes: if the difference is greater than a threshold, then: determining that the finger has moved; and/or, if the difference is less than the threshold, determining that the finger has not moved.
  • the pixel array includes M rows ⁇ N columns of pixels, and the two adjacent rows of pixels are respectively the first row of pixels exposed and the last row of pixels exposed in the pixel array; wherein, According to the predetermined exposure sequence, sequentially exposing each row of pixels in the pixel array used for fingerprint detection, including: sequentially starting exposure from the Kth row of pixels in the M rows of pixels to the M-1th row of pixels, K ⁇ 0 and K is less than M; after the elapse of time T, the exposure is sequentially performed from the pixels of the 0th row to the K-1th row of pixels, where T is equal to the reading time of the data of a row of pixels, or T is greater than the data of a row of pixels read time.
  • the difference between the data of the two adjacent rows of pixels includes: the difference between the data of N pairs of pixels located in the same column in the Kth row of pixels and the K-1th row of pixels average or weighted average.
  • the difference of the data of each pair of pixels in the N pairs of pixels includes: the difference of the data of each pair of pixels; or, the rate of change of the data of each pair of pixels, wherein, The rate of change is a ratio between the difference of the data of each pair of pixels and the data of one of the pixels.
  • the weight corresponding to the pixel located in the middle area among the N pairs of pixels is greater than the weight corresponding to the pixel located in the edge area.
  • the pixel array includes M rows ⁇ N columns of pixels, and the first row of pixels to be exposed and the last row of pixels to be exposed in the pixel array are the specific row that has been exposed twice. Pixels; wherein, according to a predetermined exposure sequence, sequentially exposing each row of pixels in the pixel array for fingerprint detection, including: starting from the Kth row of pixels in the M rows of pixels to the M-1th row of pixels. Exposure is performed, and K is less than M; then exposure is performed sequentially from the pixels in the 0th row to the Kth row of pixels.
  • the starting time of the second exposure of the pixels in the Kth row is after the data read after the first exposure of the pixels in the Kth row is completed, and the second exposure of the pixels in the Kth row is completed.
  • the reading time of the subsequent data does not overlap with the reading time of the data of the pixels of the other rows in the M rows of pixels.
  • the difference between the data of the specific row of pixels after two exposures includes: the data of the N pixels in the Kth row of pixels after the second exposure and the data of the first row of pixels after the second exposure The average or weighted average of the differences between the post-exposure data.
  • the difference between the data of each pixel in the N pixels after the second exposure and the data after the first exposure includes: The difference between the data after the first exposure and the data after the first exposure; or, the rate of change between the data after the second exposure and the data after the first exposure of each pixel, wherein the The rate of change is the ratio between the difference between the data of each pixel after the second exposure and the data after the first exposure, and the data after one of the exposures.
  • the weight corresponding to the pixel located in the middle area among the N pixels is greater than the weight corresponding to the pixel located in the edge area.
  • the method further includes: performing fingerprint detection on the finger according to the data of the pixels in the M rows that have been read while exposing the pixels in the Kth row for the second time.
  • the pixel array includes M rows ⁇ N columns of pixels, the M rows ⁇ N columns of pixels include a first subarray and a second subarray, and the first subarray includes the 0th row to the M-1th row and the 0th column to the P-1th column, the second subarray includes the 0th row to the M-1th row and the Pth column to the N-1th column; exposure sequence, sequentially exposing each row of pixels in the pixel array used for fingerprint detection, including: sequentially starting exposure from the 0th row of pixels to the K-1th row of pixels in the first sub-array, and simultaneously starting from the 0th row of pixels to the K-1th row of pixels.
  • the pixels in the M-1th row to the M-Kth row of pixels in the second subarray start to be exposed in sequence; after the elapse of time T, the exposure is sequentially performed from the M-1th row of pixels to the Kth row of pixels in the first subarray, At the same time, exposure is sequentially performed from the 0th row of pixels to the M-K-1th row of pixels in the second sub-array, wherein T is equal to the reading time of data of a single pixel, or T is greater than the reading time of data of a single pixel.
  • the difference between the data of the pixels in the Pth column and the data of the pixels in the P-1th column and the difference between the data of the pixels in the two adjacent rows are jointly used to determine the pixel array Whether the finger moves during the exposure process of The average or weighted average of the differences between the data of N pairs of pixels located in the same column in the M-K-th row of pixels and the M-K-1-th row of pixels of the subarray;
  • the difference between the data includes: the average value or the weighted average value of the difference between the data of M pairs of pixels located in the same row in the pixel in the P-th column and the pixel in the P-1-th column.
  • the difference between the data of each pair of pixels among the N pairs of pixels and the M pairs of pixels includes: a difference value of the data of each pair of pixels; or, the difference of the data of each pair of pixels
  • the rate of change of the data is the ratio between the difference of the data of each pair of pixels and the data of one of the pixels.
  • the weight corresponding to the pixel located in the middle area among the N pairs of pixels is greater than the weight corresponding to the pixel located in the edge area; and, among the M pairs of pixels, the pixel located in the middle area corresponds to The weight is greater than the weight corresponding to the pixel located in the edge area.
  • the time interval between the start moments of exposure of two adjacent rows of pixels in the exposure sequence is greater than or equal to the data of one row of pixels
  • the time interval between the start of exposure of two adjacent rows of pixels in the exposure sequence is greater than or equal to the reading time of the data of one row of pixels in the 0th row of pixels to the K-1th row of pixels.
  • a fingerprint detection device in a second aspect, includes an image sensor, and the image sensor includes:
  • the row decoder is used to sequentially start exposing each row of pixels in the pixel array used for fingerprint detection according to a predetermined exposure sequence, wherein the exposure sequence of specific adjacent two rows of pixels in the pixel array is different from each other. adjacent, or double exposure of a particular row of pixels in the pixel array; and,
  • a column reading circuit configured to read the data of each row of pixels at the end of exposure of each row of pixels, wherein the difference between the data of the two adjacent rows of pixels or the two exposures of the specific row of pixels The difference between the latter data is used to determine whether the finger moves during the exposure process of the pixel array;
  • the data of the pixel array is not used for the fingerprint detection of the finger when the finger moves, and/or the data of the pixel array is used for the fingerprint detection of the finger when the finger does not move.
  • the fingerprint detection apparatus further includes a processing module, and the processing module is configured to: according to the difference between the data of the pixels of the two adjacent rows, or the difference between the pixels of the specific row of pixels The difference between the data after the sub-exposure determines whether the finger moves during the exposure process of the pixel array.
  • the processing module is specifically configured to: if the difference is greater than a threshold, determine that the finger moves; and/or, if the difference is less than the threshold, determine that the finger No movement occurred.
  • the pixel array includes M rows ⁇ N columns of pixels, and the two adjacent rows of pixels are respectively the first row of pixels exposed and the last row of pixels exposed in the pixel array; wherein,
  • the row decoder is specifically used to: sequentially start exposure from the Kth row of pixels in the M rows of pixels to the M-1th row of pixels, where K ⁇ 0 and K is less than M; after the elapse of time T, from the 0th row Pixels to the K-1th row of pixels are sequentially exposed, wherein T is equal to the reading time of data of one row of pixels, or T is greater than the reading time of data of one row of pixels.
  • the difference between the data of the two adjacent rows of pixels includes: the difference between the data of N pairs of pixels located in the same column in the Kth row of pixels and the K-1th row of pixels average or weighted average.
  • the difference of the data of each pair of pixels in the N pairs of pixels includes: the difference of the data of each pair of pixels; or, the rate of change of the data of each pair of pixels, wherein, The rate of change is a ratio between the difference of the data of each pair of pixels and the data of one of the pixels.
  • the weight corresponding to the pixel located in the middle area among the N pairs of pixels is greater than the weight corresponding to the pixel located in the edge area.
  • the pixel array includes M rows ⁇ N columns of pixels, and the first row of pixels to be exposed and the last row of pixels to be exposed in the pixel array are the specific row that has been exposed twice. pixel; wherein, the row decoder is specifically used to: sequentially start exposure from the Kth row of pixels in the M rows of pixels to the M-1th row of pixels, and K is less than M; then from the 0th row of pixels to the Kth row of pixels Pixels sequentially start to be exposed.
  • the starting time of the second exposure of the pixels in the Kth row is after the data read after the first exposure of the pixels in the Kth row is completed, and the second exposure of the pixels in the Kth row is completed.
  • the reading time of the subsequent data does not overlap with the reading time of the data of the pixels of the other rows in the M rows of pixels.
  • the difference between the data of the specific row of pixels after two exposures includes: the data of the N pixels in the Kth row of pixels after the second exposure is different from the data after the second exposure of the pixels in the Kth row.
  • the average or weighted average of the differences between the data after an exposure includes: the data of the N pixels in the Kth row of pixels after the second exposure is different from the data after the second exposure of the pixels in the Kth row.
  • the difference between the data of each pixel in the N pixels after the second exposure and the data after the first exposure includes: The difference between the data after the first exposure and the data after the first exposure; or, the rate of change between the data after the second exposure and the data after the first exposure for each pixel, wherein the The rate of change is the ratio between the difference between the data of each pixel after the second exposure and the data after the first exposure, and the data after one of the exposures.
  • the weight corresponding to the pixel located in the middle area among the N pixels is greater than the weight corresponding to the pixel located in the edge area.
  • the method further includes: performing fingerprint detection on the finger according to the data of the pixels in the M rows that have been read while exposing the pixels in the Kth row for the second time.
  • the pixel array includes M rows ⁇ N columns of pixels, the M rows ⁇ N columns of pixels include a first subarray and a second subarray, and the first subarray includes the 0th row to the M-1th row and the 0th column to the P-1th column, the second subarray includes the 0th row to the M-1th row and the Pth column to the N-1th column; wherein, the row translation The encoder is specifically used for: sequentially starting exposure from the 0th row of pixels to the K-1th row of pixels in the first subarray, and simultaneously sequentially from the M-1th row of pixels to the M-Kth row of pixels in the second subarray.
  • Exposure is started; after the elapse of time T, exposure is sequentially performed from the pixels in the M-1th row to the Kth row of pixels in the first subarray, and simultaneously from the 0th row of pixels in the second subarray to the M-K-th row of pixels. 1 row of pixels starts to be exposed in sequence, wherein T is equal to the reading time of the data of a single pixel, or T is greater than the reading time of the data of a single pixel.
  • the difference between the data of the pixels in the Pth column and the data of the pixels in the P-1th column and the difference between the data of the pixels in the two adjacent rows are jointly used to determine the pixel array Whether the finger moves during the exposure process of The average or weighted average of the differences between the data of N pairs of pixels located in the same column in the M-K-th row of pixels and the M-K-1-th row of pixels of the subarray;
  • the difference between the data includes: the average value or the weighted average value of the difference between the data of M pairs of pixels located in the same row in the pixel in the P-th column and the pixel in the P-1-th column.
  • the difference between the data of each pair of pixels among the N pairs of pixels and the M pairs of pixels includes: a difference value of the data of each pair of pixels; or, the difference of the data of each pair of pixels
  • the rate of change of the data is the ratio between the difference of the data of each pair of pixels and the data of one of the pixels.
  • the weight corresponding to the pixel located in the middle area among the N pairs of pixels is greater than the weight corresponding to the pixel located in the edge area; and, among the M pairs of pixels, the pixel located in the middle area corresponds to The weight is greater than the weight corresponding to the pixel located in the edge area.
  • the time interval between the start moments of exposure of two adjacent rows of pixels in the exposure sequence is greater than or equal to the data of one row of pixels
  • the time interval between the start of exposure of two adjacent rows of pixels in the exposure sequence is greater than or equal to the reading time of the data of one row of pixels in the 0th row of pixels to the K-1th row of pixels.
  • the fingerprint detection device further includes an optical path guiding structure disposed above the image sensor, the optical path guiding structure includes: a microlens array including a plurality of microlenses; and a plurality of blocking A light layer is arranged below the microlens array, wherein each light blocking layer is provided with a plurality of openings corresponding to the plurality of microlenses respectively; wherein, the microlenses are used to return the finger
  • the light signals are converged to the corresponding openings in the plurality of light blocking layers, and transmitted to the pixel array through the corresponding openings in the plurality of light blocking layers.
  • an electronic device including the fingerprint detection apparatus in the second aspect or any possible implementation manner of the second aspect.
  • each row of pixels in the pixel array used for fingerprint detection is sequentially exposed, and the exposure sequences of specific adjacent two rows of pixels in the pixel array are not adjacent to each other, so that Increase the time difference between the exposure start moments of two adjacent rows of pixels, or make a specific row of pixels in the pixel array perform two exposures, so that the difference between the data of the specific adjacent two rows of pixels can be used, or according to The difference between the data after two exposures of the particular row of pixels effectively determines whether the finger moves.
  • the difference between the data of the specific two adjacent lines of pixels or the difference between the data after two exposures of the specific line of pixels will be small or even no difference; if the finger moves , the difference will be more obvious.
  • the data of the pixel array will not be used for subsequent fingerprint detection, thereby avoiding unnecessary false detection, improving the accuracy of fingerprint detection, and improving the performance of fingerprint detection.
  • FIG. 1 is a schematic diagram of an image sensor.
  • FIG. 2 is a schematic diagram of the exposure timing of each row of pixels when a global shutter is used.
  • FIG. 3 is a schematic diagram of the exposure timing of each row of pixels when a rolling shutter is used.
  • FIG. 4 is a schematic diagram of the exposure sequence of each row of pixels in FIG. 3 .
  • FIG. 5 is a schematic flowchart of a method for fingerprint detection according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a specific exposure sequence based on the fingerprint detection method shown in FIG. 5 .
  • FIG. 7 is a schematic diagram of the exposure sequence of each row of pixels in FIG. 6 .
  • FIG. 8 is a schematic diagram of a fingerprint image of a moving finger obtained based on the exposure sequence shown in FIG. 6 .
  • FIG. 9 is a schematic diagram of a fingerprint image of a stationary finger obtained based on the exposure sequence shown in FIG. 6 .
  • FIG. 10 is a schematic diagram of a specific exposure sequence based on the fingerprint detection method shown in FIG. 5 .
  • FIG. 11 is a schematic diagram of a possible fingerprint detection process based on the exposure sequence shown in FIG. 6 .
  • FIG. 12 is a schematic diagram of a specific exposure sequence based on the fingerprint detection method shown in FIG. 5 .
  • FIG. 13 is a schematic diagram of a possible fingerprint detection process based on the exposure sequence shown in FIG. 12 .
  • FIG. 14 is a schematic diagram of a first sub-array and a second sub-array divided based on a specific exposure sequence of the fingerprint detection method shown in FIG. 5 .
  • FIG. 15 is a schematic diagram of the exposure sequence of each row of pixels in the first sub-array.
  • FIG. 16 is a schematic diagram of the exposure sequence of each row of pixels in the second sub-array.
  • FIG. 17 is a schematic diagram of the exposure sequence of each row of pixels in FIGS. 15 and 16 .
  • FIG. 18 is a schematic block diagram of a fingerprint detection apparatus according to an embodiment of the present application.
  • FIG. 19 is a schematic diagram of a possible electronic device in an embodiment of the present application.
  • FIG. 20 is a schematic structural diagram of a possible fingerprint detection apparatus according to an embodiment of the present application.
  • the embodiments of the present application can be applied to an optical fingerprint detection system.
  • the optical fingerprint system can be applied to smart phones, tablet computers, and other mobile terminals or other electronic devices with display screens.
  • the optical fingerprint system can be set on the display of the electronic device. Part of or all of the area below the screen to form an under-screen optical fingerprint system.
  • the image sensor starts to collect the fingerprint image of the finger to be tested, and then the processing module pre-processes the fingerprint image, and then extracts the feature information of the pre-processed fingerprint image, and extracts the feature information from the extracted feature information. Match with the feature information of the fingerprint stored in the fingerprint database. If the matching is successful, it is determined that the fingerprint detection is successful, and the corresponding operation is performed.
  • the fuzzy fingerprint image In the process of pre-processing the fingerprint image, for the fuzzy fingerprint image, its signal-to-noise ratio is low, and the characteristic information of the fingerprint is easily lost in the process of pre-processing and feature information extraction, and the feature information is too small.
  • the fuzzy fingerprint image will cause the increase of false feature information, which will cause the matching process of feature information. Mismatches lead to an increase in the False Acceptance Rate (FAR). Therefore, in the fingerprint detection process, the fingerprint image collected by the image sensor is expected to be as clear as possible.
  • FIG. 1 is a schematic diagram of an image sensor.
  • the image sensor includes a pixel array composed of M rows ⁇ N columns of pixels, a row decoder, and a column readout circuit.
  • the pixel array is controlled by a row decoder, which can control the reset and exposure of each row of pixels.
  • the pixels in the row will convert optical signals into electrical signals through photoelectric conversion, and the photoelectrically converted electrical signals are read out by the column readout circuit.
  • the fingerprint image of the finger can be obtained according to the data.
  • FIG. 2 shows the exposure timing for each row of pixels when a global shutter is used. As shown in FIG. 2 , all pixels in the pixel array are reset at the same time and begin to be exposed. After all the pixels are exposed, the column reading circuit sequentially reads the exposed data of each row of pixels. Since all the pixels are exposed at the same time, this shutter method is not sensitive to the movement of the finger when the fingerprint is imaged, and the obtained fingerprint image is clearer.
  • the disadvantage of the global shutter is that additional transistors or storage capacitors need to be set in the pixel circuit corresponding to each pixel to store the data of the pixels waiting to be read. The ratio of the effective imaging area of the pixel is lower.
  • the effective imaging area refers to the ratio between the area of the area where photoelectric conversion is actually performed and the area of the entire pixel.
  • the noise read by the column reading circuit is larger, and the noise carried in the fingerprint image collected by the image sensor is more serious.
  • Figure 3 shows the exposure timing for each row of pixels when a rolling shutter is used.
  • the pixels in the same row start to be reset and exposed at the same time. After a certain period of time after the start of exposure of the pixels in the row, the pixels in the next row are reset and exposed.
  • the time difference between, for example, is usually equal to the reading time of the data of a single row of pixels.
  • reset, expose, and read data for subsequent rows of pixels in sequence As shown in Figure 4, the image sensor using the rolling shutter starts to expose the pixels of each row according to the exposure sequence of the pixels in the 0th row, the first row of pixels, the second row of pixels, ..., the M-1th row of pixels.
  • the advantage of the rolling shutter is that there is no need to set additional transistors or storage capacitors for storing pixel data, and the number of transistors required in the pixel circuit corresponding to each pixel is less, so the effective imaging of a single pixel is The ratio of the area is higher and the noise read by the column read circuit is lower.
  • the fingerprint image collected by the image sensor is expected to be as clear as possible.
  • one way is to use the above-mentioned global shutter method to obtain a clearer fingerprint image, but it increases the number of transistors or storage capacitors in the pixel circuit, which not only affects the area of the effective imaging area of the pixel, but also increases The noise in the fingerprint image affects the result of fingerprint detection.
  • Another way is to use a rolling shutter, but it must be judged that the finger does not move during the exposure process, so as to ensure that the fingerprint image formed based on the data of the exposed pixels is clear.
  • the embodiments of the present application provide a solution for fingerprint detection, which can improve the performance of fingerprint detection.
  • the scheme designs the exposure timing of each row of pixels, so that it can accurately judge whether the finger has moved during the exposure process according to the data of the pixels of a specific row after exposure, and determine whether the finger has not moved according to the data of the specific row of pixels after exposure.
  • the data of the pixels read when moving is used for fingerprint detection. In this way, the blurring of the fingerprint image caused by the movement of the finger can be avoided, and the influence on the false rejection rate and false recognition rate of the fingerprint detection process can be reduced.
  • there is no need to add additional transistors and storage capacitors in the pixel circuit which increases the effective imaging area of the image sensor, and reduces the noise carried in the read pixel data. the accuracy of fingerprint detection.
  • the touch detection function in the electronic device is used to determine the position of the finger on the screen, so as to determine whether the finger moves.
  • the sensitivity of touch detection is low, and the refresh rate is low, so it is impossible to accurately judge whether the finger moves during the exposure process.
  • some special types of finger movements such as finger rotation, cannot be recognized by means of touch detection.
  • two fingerprint images can be continuously collected, and whether the finger has moved is determined according to the difference between the two fingerprint images. However, this will consume more time, increase the fingerprint detection time, and reduce the user experience.
  • FIG. 5 is a schematic flowchart of a method for fingerprint detection according to an embodiment of the present application. As shown in FIG. 5 , the method 500 for fingerprint detection includes some or all of the following steps.
  • step 510 in accordance with a predetermined exposure sequence, exposure of each row of pixels in the pixel array used for fingerprint detection is started sequentially.
  • the exposure sequences of specific two adjacent rows of pixels in the pixel array are not adjacent to each other, for example, the two adjacent rows of pixels are respectively the first exposed row of pixels and the last exposed row of pixels in the pixel array; or , a specific row of pixels in the pixel array is exposed twice.
  • the first exposed row of pixels and the last exposed row of pixels in the pixel array are the specific row of pixels in the pixel array that have been exposed twice. .
  • step 520 the data of each row of pixels is read at the end of the exposure of each row of pixels.
  • the difference between the data of the two adjacent rows of pixels is used to determine whether the finger moves during the exposure process of the pixel array; or, the difference between the data of the specific row of pixels after two exposures , which is used to determine whether the finger moves during the exposure of the pixel array.
  • the data of the pixel array is not used for fingerprint detection of the finger when the finger moves, and/or the data of the pixel array is used for fingerprint detection of the finger when the finger does not move.
  • the method may further include step 530 .
  • step 530 it is determined whether the finger moves during the exposure of the pixel array according to the difference between the data of the two adjacent rows of pixels, or the difference between the data of the particular row of pixels after two exposures.
  • the finger has moved; and/or, if the difference between the data of the specific two adjacent rows of pixels is less than the threshold, it is determined that the finger has not moved.
  • the finger has moved; and/or, if the data of the specific row of pixels after the two exposures respectively If the difference is smaller than the threshold, it is determined that the finger has not moved.
  • steps 510 and 520 may be performed by an image sensor in the fingerprint detection device.
  • the fingerprint detection device includes the image sensor and a processing module.
  • the image sensor includes a pixel array (or sensor array), a row decoder, a column readout circuit, and the like.
  • the row decoder can control the pixel array to perform a corresponding exposure operation, that is, the above-mentioned step 510; and the column reading circuit can read the data output by the exposed pixel array, that is, the above-mentioned step 520.
  • the above-mentioned step 530 may be performed by the processing module.
  • the processing module may be a processor of the fingerprint detection apparatus, such as an MCU.
  • the processing module can control the row decoder to perform a corresponding exposure operation, and control the column read circuit to perform a corresponding data read operation. Further, optionally, the processing module can also judge the finger during the exposure process based on the data of the specific two adjacent rows of pixels read by the column decoder, or based on the data of the two exposures of the specific row of pixels. whether movement has occurred.
  • the processing module may also be a processor of an electronic device, such as a CPU or the like.
  • the row decoder and the column decoder can be controlled by the processor of the fingerprint detection apparatus, such as the MCU, to execute the above-mentioned steps 510 and 520 respectively.
  • the processing module can obtain the data of the exposed pixel array from the fingerprint detection device, so as to judge the process of exposure based on the data of the specific two adjacent rows of pixels, or based on the data of the two exposures of the specific row of pixels. Whether the finger has moved.
  • the processing module can also perform a corresponding fingerprint detection operation on the finger based on the data of the exposed pixel array.
  • the data of each pixel in the pixel array in the embodiments of the present application refers to the electrical signal formed by photoelectric conversion after the pixel is exposed to light.
  • the grayscale of a pixel of the fingerprint image here. value, the fingerprint image can be formed based on the data of all pixels in the pixel array.
  • the fingerprint detection operation described in the embodiments of the present application includes, for example, preprocessing the data of the fingerprint image, extracting the feature information of the fingerprint based on the preprocessed data, and combining the extracted feature information with the data stored in the fingerprint database.
  • the feature information of the fingerprint is matched and other operations are performed.
  • each row of pixels in the pixel array used for fingerprint detection is sequentially exposed, and the exposure sequences of specific two adjacent rows of pixels in the pixel array are not adjacent to each other, so that Increase the time difference between the exposure start moments of two adjacent rows of pixels, or make a specific row of pixels in the pixel array perform two exposures, so that the difference between the data of the specific adjacent two rows of pixels can be used, or according to The difference between the data after two exposures of the particular row of pixels effectively determines whether the finger moves.
  • the difference between the data of the specific two adjacent lines of pixels or the difference between the data after two exposures of the specific line of pixels will be small or even no difference; if the finger moves , the difference will be more obvious.
  • the data of the pixel array will not be used for subsequent fingerprint detection, thereby avoiding unnecessary false detection, improving the accuracy of fingerprint detection, and improving the performance of fingerprint detection.
  • the exposure sequence is not adjacent, which may mean that there is an interval between the positions of the pixels in each row arranged in the exposure sequence in terms of time sequence. For example, taking the K-1th row of pixels and the Kth row of pixels adjacent to the M rows of pixels as an example, if the Kth row of pixels is the i-th pixel row that starts exposure, then the K-1th row of pixels can be is the i+Qth pixel row where exposure begins, where Q is greater than or equal to 2.
  • the present application provides three specific implementation manners for judging whether the finger moves during the exposure process of the pixel array.
  • the exposure methods for the pixel array in methods 1 to 3 are all improvements based on the exposure methods of the rolling shutter shown in FIG. 3 and FIG. 4 , so the advantage lies in the pixel corresponding to each pixel. Fewer transistors or capacitors are required in the circuit, a higher proportion of the active imaging area of a single pixel, and lower noise read by the column read circuit.
  • the pixel array in the image sensor includes M rows by N columns of pixels.
  • step 510 sequentially exposing each row of pixels in the pixel array used for fingerprint detection, including: sequentially from the Kth row of pixels in the M rows of pixels to the M-1th row of pixels. Exposure is started; after the elapse of time T, exposure is sequentially started from the pixels in the 0th row to the K-1th row of pixels.
  • the pixel array can be regarded as two parts, the upper part includes pixels in row 0 to row K-1, and the lower half includes pixels in row K to M-1 row.
  • the upper part includes pixels in row 0 to row K-1
  • the lower half includes pixels in row K to M-1 row.
  • the exposure sequence of two adjacent rows of pixels starts at the beginning of exposure.
  • the time interval between the moments should be equal to or greater than the reading time t of the data of one row of pixels; in the pixels of the 0th row to the K-1th row of pixels, the exposure starting moments of the two adjacent rows of pixels in the exposure sequence are between the exposure times.
  • the time interval should be equal to or greater than the reading time t of the data of one row of pixels.
  • the exposure mode in Mode 1 is essentially the exposure mode of the rolling shutter, except that the exposure sequence for exposing each row of pixels is different from the exposure sequence of the traditional rolling shutter. Compared with the global shutter, fewer transistors are required in the pixel circuit corresponding to each pixel, the ratio of the effective imaging area of a single pixel is higher, and the noise read by the column readout circuit is also lower.
  • the responses of two adjacent rows of pixels will be very similar; when imaging a moving object such as a moving finger, since the exposure start time of each row of pixels is different, the adjacent rows of pixels will have different responses. There will be differences in the response of the two rows of pixels.
  • the exposure sequence of each row of pixels is readjusted in this embodiment, so that the first exposed row of pixels and the last exposed row of pixels are adjacent to each other. Two rows of pixels.
  • the first row of pixels to be exposed is the K-th row of pixels
  • the last row of pixels to be exposed is the K-1-th row of pixels
  • the time difference is equal to or greater than (M-1) ⁇ t.
  • the data corresponding to the fingerprint image between the pixels in the Kth row and the K-1th row should be very close. , that is, the difference is small, and the movement of the finger will cause a significant difference between the data of two adjacent rows of pixels.
  • the magnitude of the difference between the data output by the pixels in the K-th row and the K-1-th row of pixels after exposure it can be determined whether the finger moves during the above-mentioned exposure process.
  • the finger has not moved; if the first exposed pixel of the K-th row is If the difference between the data of the last exposed row K-1 and the pixel data of the K-1 row is greater than the preset threshold, it is considered that the finger has moved.
  • the first row of pixels to be exposed may be any row of pixels in the M rows of pixels except for the 0th row of pixels.
  • M is an even number
  • FIG. 7 wherein the solid arrows in FIG. 7 represent the exposure sequence of the pixel array exposed first, and the dotted arrows represent the exposure sequence of the pixel array exposed later.
  • the exposure sequence is specifically the M/2th row, the M/2+1th row, the M/2+2th row, ..., the M-1th row, the 0th row, the 1st row, the 2nd row, ..., Line M/2-1.
  • the exposure sequence is different, but the total time spent exposing M rows of pixels is the same, so method 1 does not increase additional exposure time.
  • the upper and lower half of the fingerprint image will have obvious boundaries.
  • This boundary is a deliberate boundary in this embodiment.
  • the two rows of pixels corresponding to the two sides of the boundary are the Kth
  • the time difference between the exposure start instants of the pixels of the -1 row and the Kth row of pixels is at least (M-1)*t. Then, for the moving finger, this significant time difference will result in a significant difference in the response of the pixels in the K-1 row and the K-th row to the movement of the finger in space, so that the results shown in Figure 8 can be obtained.
  • the fingerprint image is displayed, and the fingerprint image has obvious differences on the boundary corresponding to the pixel in the K-1th row and the pixel in the Kth row.
  • the fingerprint image shown in Figure 9 is obtained. It can be seen from the comparison that the fingerprint image of the stationary finger shown in Figure 8 has basically no difference on both sides of the middle boundary line, while the fingerprint image of the moving finger shown in Figure 9 is discontinuous on both sides of the middle boundary line. .
  • T is equal to the reading time t of data of one row of pixels, or T is greater than the reading time t of data of one row of pixels.
  • the exposure of the 0th row of pixels is started.
  • T is equal to the reading time t of the data of a row of pixels
  • the exposure of the pixels of the 0th row can be started, as shown in the above-mentioned FIG. 6 .
  • the time difference (M-1) ⁇ t between the exposure start moments of the pixels in the Kth row and the K-1th row of pixels may not be enough to judge whether the finger is Therefore, T can be set to be greater than the reading time t of the data of one row of pixels, then the time difference between the exposure start time of the Kth row of pixels and the K-1th row of pixels will be greater than (M-1) ⁇ t, so that the difference between the data of the Kth row of pixels and the K-1th row of pixels is more obvious, and it is easier to judge whether the finger is moving.
  • the time difference T between the exposure start time of the pixels in the 0th row and the exposure start time of the pixels in the M ⁇ 1th row is greater than the reading time t of the data of the pixels in one row.
  • the exposure time is much longer than the reset time and the data read time.
  • the reset time of each row of pixels can be, for example, 10us
  • the exposure time can be, for example, 30ms
  • the data read time can be, for example, is 30us. Therefore, in each schematic diagram of the exposure sequence in the various embodiments of the present application, the reset time, the exposure time and the data reading time are only schematic representations of relative positions. These drawings are mainly for explaining the exposure sequence of each row of pixels, and do not represent the reset time. The relative length between time, exposure time, and data readout time.
  • the data of the pixel array obtained according to the exposure method of Mode 1 can form the fingerprint images shown in FIG. 8 and FIG. 9 .
  • the fingerprint detection process has not yet entered, so the fingerprint image has not been formed yet.
  • the fingerprint images of FIG. 8 and FIG. 9 are only used to illustrate the influence of the exposure mode according to Mode 1 on the finally obtained fingerprint image.
  • step 530 other methods are needed to obtain a parameter representing the difference between the data of two adjacent rows of pixels, and based on the parameter, it is determined whether the finger moves during the exposure of the pixel array.
  • whether the finger moves may be determined according to the average value of the difference between the data of N pairs of pixels located in the same column in the Kth row of pixels and the K-1th row of pixels. For example, when the average value is greater than the threshold value, it is considered that the finger has moved; when the average value is smaller than the threshold value, it is considered that the finger has not moved.
  • the edge of the fingerprint image is relatively blurred. Therefore, when calculating the weighted average, a larger weight or even 100% can be assigned to the pixel located in the middle area among the N pairs of pixels, and a smaller weight or even a smaller weight can be assigned to the pixel located in the edge area among the N pairs of pixels 0. For example, for a pixel array of 200 rows by 200 columns, it is possible to determine whether or not the finger moves by using only the data of the pixels located in the 50th to 150th columns in the middle.
  • whether the finger moves can also be determined according to the sum, variance, standard deviation, etc. of the difference between the data of N pairs of pixels located in the same column in the K-th row of pixels and the K-1-th row of pixels.
  • This embodiment does not limit this, and any parameter that can be used to represent the degree of difference between the data of two adjacent rows of pixels can be used in this embodiment to determine whether the finger moves.
  • Factors such as the number of pixel rows and pixel columns in the pixel array, the reset time of each row of pixels, the exposure time, and the data reading time can be considered when determining the above-mentioned threshold for judging whether the finger moves. For example, assuming a pixel array of 200 rows ⁇ 200 columns, the reset time of each row of pixels is 10us, the exposure time is 30ms, and the data reading time is 30us, then the threshold may be 20%.
  • the difference between the data of each pair of pixels in the N pairs of pixels located in the same column in the Kth row of pixels and the K-1th row of pixels may be the difference of the data of each pair of pixels; or the difference between the data of each pair of pixels;
  • the rate of change of the pixel's data is the ratio between the difference between the data of each pair of pixels and the data of one of the pixels.
  • the values of the data output by the two pixels in the pair of pixels in the i-th column after exposure are A i and B i , i is any integer between 0 and N-1. Then, according to and the corresponding threshold to determine whether the finger has moved; or The size between the corresponding threshold value determines whether the finger moves.
  • the above description only takes the calculation of the data difference of the pixel pairs located in the same column in the adjacent two rows of pixels as an example.
  • the difference determines whether the finger has moved.
  • FIG. 11 shows a possible fingerprint detection process based on Mode 1. As shown in Figure 11, the following steps are included.
  • step 1101 exposure and data reading are performed on the pixel array.
  • each row of pixels in the pixel array is sequentially exposed, and the data of each row of pixels is read at the end of exposure of each row of pixels.
  • step 1102 the data of the K-th row of pixels and the K-1-th row of pixels is processed.
  • the degree of difference between the data of the pixel in row K and the pixel in row K-1 can be determined, for example, the difference between the data of N pairs of pixels located in the same column in the pixel in row K and the pixel in row K-1 can be determined.
  • the average or weighted average, or the average or weighted average of the rate of change of the data for N pairs of pixels can be determined.
  • step 1103 it is determined whether the finger moves.
  • step 1102 it is determined whether the finger moves. Wherein, when the average value or the weighted average value is smaller than the corresponding threshold, it is considered that the finger has not moved, and step 1104 is executed, that is, the process of fingerprint detection is entered.
  • step 1104 the data of the pixel array is processed to extract characteristic information of the fingerprint.
  • the data of each row of pixels in the pixel array is processed, and the characteristic information of the fingerprint is extracted.
  • step 1105 the feature information of the fingerprints is matched.
  • step 1106 it is determined whether there is a match.
  • step 1105 the feature information of the fingerprint obtained in step 1105 is compared with the feature information of the fingerprint stored in the fingerprint database, and if there is matching feature information, step 1107 is performed; otherwise, step 1108 is performed.
  • step 1107 the fingerprint detection is successful.
  • step 1108 fingerprint detection fails.
  • step 1103 if the average value or the weighted average value is greater than the corresponding threshold, it is considered that the finger has moved, so the data of the pixel array will not be used for fingerprint detection in subsequent steps. At this time, the user may be prompted to place the finger again or not to move the finger, and then steps 1101 to 1103 are performed again until it is determined that the finger has not moved.
  • the user's finger may not be placed stably at this time, but the pixel array has been exposed and read data. Therefore, it is determined that the finger has moved and the user is prompted to place the finger again, which may interrupt the above process and affect the user experience. Therefore, when it is determined that the finger moves, preferably, the user may not be prompted, but immediately re-enter the process of exposure and data reading of the pixel array.
  • step 1103 if the average value or the weighted average value is greater than the predetermined threshold, the pixel array will be exposed and data read again until it is determined that the finger has not moved. That is, steps 1101 and 1102 are re-executed until it is determined that the finger has not moved, and then the process of fingerprint detection is entered, that is, steps 1104 to 1108 .
  • each row of pixels in the pixel array used for fingerprint detection is sequentially exposed, and the first row of pixels exposed in the pixel array and the last row of pixels exposed are the same in the pixel array.
  • the subsequent fingerprint detection will not be performed, but the pixel array will be re-exposed and data read to ensure more effective pixel data and avoid pixel data caused by finger movement during fingerprint detection. False detections caused by inaccuracy.
  • the pixel array in the image sensor includes M rows by N columns of pixels.
  • step 510 sequentially exposing each row of pixels in the pixel array for fingerprint detection according to a predetermined exposure sequence, including: starting from the Kth row of pixels in the M rows of pixels to the M-1th row of pixels in sequence Exposure is performed; then exposure is performed sequentially from the 0th row of pixels to the Kth row of pixels.
  • the pixel array can be regarded as two parts, the upper part includes pixels in row 0 to row K-1, and the lower half includes pixels in row K to M-1 row.
  • the upper part includes pixels in row 0 to row K-1
  • the lower half includes pixels in row K to M-1 row.
  • exposing the pixel array first start from the Kth row of pixels in the lower half, and sequentially expose the Kth row of pixels to the M-1th row of pixels, and then start from the 0th row of the upper half.
  • the pixels in the 0th row to the Kth row of pixels are exposed.
  • the difference from the method 1 is that after exposing the pixels in the K-1th row in the upper half, in the method 2, a second exposure is performed on the pixels in the Kth row in the lower half.
  • the exposure mode of Mode 2 is It is more accurate when judging whether the finger is moving.
  • different pixel rows have different exposure start times.
  • the exposure sequence of two adjacent rows of pixels starts at the beginning of exposure.
  • the time interval between the moments should be equal to or greater than the reading time t of the data of one row of pixels; in the pixels of the 0th row to the K-1th row of pixels, the exposure starting moments of the two adjacent rows of pixels in the exposure sequence are between the exposure times.
  • the time interval should be equal to or greater than the reading time t of the data of one row of pixels. In this way, after the column reading circuit has read the data of the pixels in the previous row, it can continue to read the data of the pixels in the next row.
  • the essence of the exposure mode in Mode 2 is also the exposure mode of the rolling shutter, except that the exposure sequence for exposing each row of pixels is different from that of the traditional rolling shutter. Compared with the global shutter, fewer transistors are required in the pixel circuit corresponding to each pixel, the ratio of the effective imaging area of a single pixel is higher, and the noise read by the column readout circuit is also lower.
  • the responses of two adjacent rows of pixels will be very similar; when imaging a moving object such as a moving finger, since the exposure start time of each row of pixels is different, the adjacent rows of pixels will have different responses. There will be differences in the response of the two rows of pixels.
  • the exposure sequence of each row of pixels is readjusted in this embodiment, so that the first exposed row of pixels and the last exposed row of pixels are the same row of pixels .
  • the first row of pixels to be exposed is the Kth row of pixels
  • the last row of pixels to be exposed is also the Kth row of pixels
  • the start time of the second exposure of the Kth row of pixels is the same as the start of the first exposure.
  • the time difference between the start times includes at least the reset time, exposure time and data reading time of a single row of pixels.
  • the start time of the second exposure of the pixels in the Kth row is located after the data reading after the first exposure of the pixels in the Kth row is completed.
  • the read time of the data after the second exposure of the pixels in the Kth row should also be the same as the data in the other rows of the pixels in the M rows. The read times of the data do not overlap.
  • the second exposure of the K-th row of pixels can be started immediately after the data reading of the K-th row of pixels after the first exposure is completed, provided that the data after the second exposure is read. It will not overlap with the data read time from the pixels in the row K to the pixels in the M-1 row, and the data read time from the pixels in the row 0 to the pixels in the K-1 row, otherwise, the second exposure of the pixels in the K row
  • the starting time should be shifted backward relative to the completion time of data reading after the first exposure, for example, until the data read time after the second exposure of the Kth row of pixels is located at the K-1th row of pixels. After the read time of the data.
  • the data corresponding to the fingerprint images of the pixels of the Kth row after two exposures should be very close, that is, the difference is small, and the movement of the finger will cause the There is a clear difference between the data after two exposures for K rows of pixels.
  • the magnitude of the difference between the data of the Kth row of pixels after two exposures it can be determined whether the finger moves during the above exposure process.
  • the finger has not moved; if the difference between the K-th row of pixels after the two exposures is greater than If the preset threshold is set, it is considered that the finger has moved.
  • K can be any integer less than M. That is, a row of pixels exposed first and last exposed may be any row of pixels in M rows of pixels, that is, a row of pixels exposed twice may be any row of pixels in M rows of pixels.
  • M is an even number
  • the exposure sequence is specifically the M/2th row, the M/2+1th row, the M/2+2th row, ..., the M-1th row, the 0th row, the 1st row, the 2nd row, ..., Lines M/2-1, and Lines M/2.
  • the exposure sequence for each row is the same, but one more exposure is performed for M/2 rows of pixels.
  • the interval between the start time of the second exposure of the pixels in the M/2 row and the exposure start time of the pixels in the M/2-1 row shown in FIG. 12 is the data reading time of one row of pixels, so as to avoid the The data reading of the pixels in the M/2-1 row is affected.
  • the reading time of the data after the second exposure of the pixels in the M/2 row will not be the same as the data reading of the pixels in other rows
  • the pixels in the M/2 row can be reset and exposed.
  • the reset time of each row of pixels is 10us
  • the exposure time is 30ms
  • the data reading time is 30us
  • the time difference between the exposure start moments of two adjacent rows of pixels in the exposure sequence is 30us.
  • Mode 2 requires one more exposure of the Kth row, so the time consumption is slightly longer than that of Mode 1.
  • fingerprint detection may be performed on the finger according to the data of the pixels in the M rows that have been read.
  • the operations related to fingerprint detection such as pixel data processing and feature extraction, can be started first, and at the same time, the pixels in the Kth row can be processed for the second time in parallel at a suitable time. exposure, thus saving time.
  • FIG. 13 it is a possible fingerprint detection process based on Mode 2. As shown in Figure 13, the following steps are included.
  • step 1301 exposure and data reading are performed on the pixel array.
  • each row of pixels in the pixel array is sequentially exposed, and the data of each row of pixels is read when the exposure of each row of pixels ends.
  • step 1302 the data of the pixel array is processed to extract characteristic information of the fingerprint.
  • the data of each row of pixels in the pixel array is processed, and the characteristic information of the fingerprint is extracted.
  • step 1303 the feature information of the fingerprint is matched.
  • step 1304 a second exposure is performed on the Kth row of pixels.
  • step 1305 data obtained after two exposures of the pixels in the Kth row are processed.
  • Method 1 Similar processing methods as in Method 1 can be used to determine the degree of difference between the data obtained after two exposures of the pixels in the Kth row.
  • steps 1302 to 1303, and steps 1304 to 1305 can be performed in parallel.
  • step 1306 it is determined whether the characteristic information of the fingerprint matches and whether the finger moves.
  • step 1305 it is determined whether the finger moves. And, the feature information of the fingerprint obtained in step 1303 is compared with the feature information of the fingerprint stored in the fingerprint database. Among them, if the difference between the data of the Kth row of pixels after two exposures is less than the corresponding threshold, it is considered that the finger has not moved. At this time, if it is also determined that there is feature information matching the fingerprint of the finger in the fingerprint database, step 1307 is performed; otherwise, step 1308 is performed.
  • step 1307 the fingerprint detection is successful.
  • step 1308 fingerprint detection fails.
  • step 1306 if the difference between the data of the Kth row of pixels after two exposures is greater than the corresponding threshold, it is considered that the finger has moved, so the data of the pixel array will not be used for the fingerprint in the subsequent steps. detection.
  • the ongoing step 1302 or 1303 can be terminated, and the user is prompted to place the finger again or not to move the finger, and then re-execute steps 1301 to 1305 until it is determined that the finger has not moved.
  • the user's finger may not be placed stably at this time, but the pixel array has been exposed and read data. Therefore, it is determined that the finger has moved and the user is prompted to place the finger again, which may interrupt the above process and affect the user experience. Therefore, when it is determined that the finger moves, preferably, the user may not be prompted, but immediately re-enter the process of exposure and data reading of the pixel array.
  • step 1303 if the difference between the data of the Kth row of pixels after two exposures is greater than the threshold, the pixel array will be exposed and data read again until it is determined that the finger has not moved. That is, steps 1301 to 1305 are re-executed until it is determined that the finger has not moved.
  • steps 1301 to 1305 are re-executed until it is determined that the finger has not moved.
  • the exposure method of Mode 2 is used to sequentially expose each row of pixels in the pixel array used for fingerprint detection, and make the first exposed row of pixels in the pixel array and the last exposed row of pixels in the pixel array.
  • the same row of pixels can effectively determine whether the finger moves according to the difference between the data of the row of pixels after two exposures.
  • subsequent fingerprint detection will not be performed, but the pixel array will be re-exposed and data read to ensure more effective pixel data and avoid inconsistencies in pixel data caused by finger movement during fingerprint detection. False detections caused by accuracy.
  • the first exposure of the pixels in the Kth row is the first exposure in the pixel array
  • the second exposure is the last exposure in the pixel array.
  • the exposure sequences of the two exposures of the pixels in the Kth row may or may not be adjacent.
  • the time difference between the start times of the two exposures includes, for example, the reset time, exposure time, and data readout time of a row of pixels.
  • this time difference is sufficient to determine whether the finger moves.
  • whether the finger moves may be determined according to the average value of the difference between the data of the N pixels in the Kth row after the second exposure and the data after the first exposure. For example, when the average value is greater than the threshold value, it is considered that the finger has moved; when the average value is smaller than the threshold value, it is considered that the finger has not moved.
  • the edge of the fingerprint image is relatively blurred. Therefore, when calculating the weighted average, it is possible to assign a larger weight value or even 100% to the pixel located in the middle area among the N pixels of the Kth row of pixels, and assign a larger weight value to the pixel located in the edge area among the N pixels. Small weights even 0. For example, for a pixel array of 400 rows ⁇ 400 columns, it can be determined whether or not the finger moves by using only the data of the pixels located in the 50th to 350th columns in the middle.
  • whether the finger moves can also be determined according to the sum, variance, standard deviation, etc. of the difference between the data after the second exposure and the data after the first exposure of the N pixels in the Kth row.
  • This embodiment does not limit this, and any parameter that can be used to represent the degree of difference between the data of the same row of pixels after two exposures can be used in this embodiment to determine whether the finger moves.
  • Factors such as the number of pixel rows and pixel columns in the pixel array, the reset time of each row of pixels, the exposure time, and the data reading time can be considered when determining the above-mentioned threshold for judging whether the finger moves. For example, assuming a pixel array of 400 rows ⁇ 400 columns, the reset time of each row of pixels is 10us, the exposure time is 30ms, and the data reading time is 30us, then the threshold may be 10%.
  • the difference between the data of each pixel in the Kth row after two exposures may be the difference between the data of each pixel after the second exposure and the data after the first exposure value; or the rate of change of the data after the second exposure and the data after the first exposure for each pixel.
  • the change rate is the ratio between the difference between the data of each pixel after two exposures and the data of one pixel.
  • the value of the data output by the i-th pixel in the K-th row of pixels after the first exposure and the second exposure are A i and B i , respectively, and i is any integer between 0 and N-1 . Then, according to and the corresponding threshold to determine whether the finger has moved; or The size between the corresponding threshold value determines whether the finger moves.
  • the second exposure may be selectively performed on the pixels in the Kth row.
  • the Kth row of pixels may not be exposed for the second time, that is, steps 1304 and 1305 in FIG. 13 are not performed, and in step 1306 it is not determined whether the finger is movement; however, in scenarios with a high security level such as payment, the second exposure is performed on the pixels in the Kth row, and it is judged whether the finger has moved.
  • the pixel array in the image sensor includes M rows by N columns of pixels.
  • the M rows ⁇ N columns of pixels include a first sub-array and a second sub-array, the first sub-array includes rows 0 to M-1 and columns 0 to P-1, and the first sub-array includes rows 0 to M-1 and columns 0 to P-1.
  • the two sub-arrays include rows 0 to M-1 and columns P to N-1.
  • Fig. 14 it is equivalent to dividing the pixel array into a first sub-array and a second sub-array which are located on the left and right sides respectively.
  • the number of rows and columns of the pixel array in FIG. 14 the number of rows and columns in the first sub-array, and the number of rows and columns in the second sub-array are all schematic. In practical applications, the number of rows and columns in the pixel array is much larger than this, and the number of columns included in the first subarray and the number of columns included in the second subarray may or may not be equal.
  • step 510 sequentially exposing each row of pixels in the pixel array used for fingerprint detection according to a predetermined exposure sequence, including: sequentially from the 0th row of pixels to the K-1th row of pixels in the first subarray Exposure is started, and at the same time, exposure is started sequentially from the pixels in the M-1th row to the M-Kth row of pixels in the second subarray; after the elapse of time T, from the M-1th row of pixels in the first subarray to the The K rows of pixels start to be exposed in sequence, and at the same time, the exposure is performed from the 0th row of pixels to the M-K-1th row of pixels in the second sub-array.
  • Mode 3 The difference from Mode 1 is that the fingerprint image finally obtained by using the exposure mode of Mode 3 may have a vertical border as well as a horizontal border such as shown in FIG. 8 .
  • two row decoders need to be set, one row decoder is used to control the exposure of each row of pixels in the first sub-array, and the other is used to control the exposure of each row of pixels in the second sub-array.
  • the first sub-array can be regarded as two parts, the upper part includes pixels in row 0 to row K-1, and the lower half includes pixels in row K to M-1 row; Considering the second sub-array as two parts, similarly, the upper half includes pixels in rows 0 to M-K-1, and the lower half includes pixels in rows M-K to M-1.
  • first simultaneously from the 0th row of pixels of the first sub-array to the K-1th row of pixels, and from the M-1th row of pixels of the second sub-array to the The pixels in the M-K row are exposed in sequence; secondly, simultaneously from the pixels in the M-1 row of the first sub-array to the pixels in the K-th row, and the pixels in the 0-th row of the second sub-array to the pixels in the M-K-1 row, sequentially Start taking exposures.
  • the exposure start times of different pixel rows of the first sub-array are different, and the exposure start times of different pixel rows of the second sub-array are different.
  • the column reading circuit can simultaneously read data of a total of N pixels in the pixel rows in the first subarray and the second subarray that start to be exposed at the same time, therefore, in the 0th subarray of the first subarray From the row of pixels to the K-1th row of pixels, the time interval between the start moments of exposure of two adjacent rows of pixels in the exposure sequence should be equal to or greater than the reading time t of the data of a single pixel; in the first sub-array In the M-1th row of pixels to the Kth row of pixels, the time interval between the starting moments of exposure of two adjacent rows of pixels in the exposure sequence should be equal to or greater than the reading time t of the data of a single pixel; Among the pixels in the M-1th row to the M-Kth row of pixels in the two sub
  • the essence of the exposure mode in Mode 3 is also the exposure mode of the rolling shutter, except that the exposure sequence of exposing each row of pixels is different from that of the traditional rolling shutter. Compared with the global shutter, fewer transistors are required in the pixel circuit corresponding to each pixel, the ratio of the effective imaging area of a single pixel is higher, and the noise read by the column readout circuit is also lower.
  • the responses of two adjacent rows of pixels will be very similar; when imaging a moving object such as a moving finger, since the exposure start time of each row of pixels is different, the adjacent rows of pixels will have different responses. There will be differences in the response of the two rows of pixels.
  • the exposure sequence of each row of pixels is readjusted in this embodiment, so that the exposure sequences of two adjacent rows of pixels are not adjacent to each other, and
  • the first sub-array and the second sub-array use different exposure sequences.
  • the first row of pixels to be exposed is the 0th row of pixels, and the last row of pixels to be exposed is the Kth row of pixels; in the second subarray, the first row of pixels to be exposed is the first row of pixels.
  • M-1 row of pixels, the last exposed row of pixels is the M-K-1 row of pixels.
  • the time difference between the exposure start instants of the pixels in the K-1th row and the Kth row of pixels is equal to or greater than t ⁇ (M-K); in the second subarray, the M-K-1th row of pixels
  • the time difference from the exposure start time of the pixels in the M-Kth row is equal to or greater than t ⁇ (M-K), where t is the data reading time of a single pixel.
  • Two thresholds can be configured, a first threshold and a second threshold. For example, if the difference between the data of pixels in row K and row K-1 of the first subarray, and the difference between row M-K and row M-K-1 of the second subarray, is greater than the first threshold , and the difference between the data of the pixel in the Pth column and the pixel in the P-1th column is greater than the second threshold, it is considered that the finger has moved during the above exposure process; The difference between the data of row pixels, and the difference between the M-Kth row and the M-K-1th row of the second subarray, is less than the first threshold, and the difference between the data of the Pth column pixel and the P-1th column pixel If the difference is less than the second threshold, it is considered that the finger did not move during the above exposure process.
  • K can be any integer less than M
  • P can be any integer less than N.
  • M is an even number
  • FIG. 15 when exposing the M rows of pixels in the first subarray, firstly, the pixels in the 0th row to the M/2-1th row of pixels located in the upper half of the pixel array are sequentially exposed. After all pixel rows in the half have been exposed, starting from the M-1 row pixels located in the lower half, the exposure is sequentially performed on the M-1 row pixels to the M/2 row pixels.
  • FIG. 17 wherein the solid arrows in FIG.
  • the exposure sequence of the first sub-array is specifically row 0, row 1, row 2, ..., row M/2-1, row M-1, row M-2, ..., row M/ 2 lines.
  • FIG. 16 when exposing the M rows of pixels in the second sub-array, start from the M-1 row pixels in the lower half, and sequentially start from the M-1 row pixels to the M/2 row pixels. Exposure is performed. After all the pixel rows in the lower half have started to be exposed, starting from the 0th row of pixels located in the upper half, the 0th row of pixels to the M/2-1th row of pixels are sequentially exposed.
  • FIG. 17 For the specific exposure sequence, reference may be made to FIG. 17 , wherein the two solid line arrows in FIG. 17 represent the pixel arrays that are exposed in parallel at the same time, and the two dotted line arrows represent the pixel arrays that are exposed in parallel.
  • the exposure sequence of the second subarray is specifically the M-1th row, the M-2th row, the M-3th row, ..., the M/2th row, the 0th row, the 1st row, the 2nd row, ... , line M/2-1.
  • the upper and lower halves of the fingerprint image will have a clear boundary, and the left and right halves will also have a clear boundary.
  • the horizontal and vertical boundaries are the implementation of the For the deliberately created boundary in the example, the time difference between the exposure start times of the two rows of pixels corresponding to both sides of the horizontal boundary is at least t ⁇ (M/2), and the difference between the exposure start times of the two columns of pixels corresponding to both sides of the vertical boundary is at least t ⁇ (M/2). The time difference between them is at least t ⁇ (M/2). Then, for a moving finger, such a significant time difference can cause significant differences in the responses of adjacent pixel rows and adjacent pixel columns to the spatial movement of the finger. For a stationary finger, even if there is a significant time difference, there is no spatial movement of the finger, so adjacent pixel rows and adjacent pixel columns do not have significant differences in the response to the finger movement.
  • Exposure begins at row 0 of the array.
  • T is equal to the reading time t of the data of a single pixel
  • the exposure of the pixels in the M-1th row of the first subarray can start to be exposed.
  • the exposure of the pixels in the 0th row of the second sub-array can be started, for example, as shown in the above-mentioned Figure 16 .
  • T can be set to be greater than the data reading time t of a single pixel, then the K-1 row of pixels and the Kth row of pixels can be set.
  • the time difference between the exposure start times of the pixels is increased and the time difference between the exposure start times of the pixels in the P-th column and the P-1-th column is increased. Therefore, the difference between the data of two adjacent rows of pixels is more obvious, and it is easier to judge whether the finger moves.
  • the column reading circuit can simultaneously read data of a row of pixels, that is, read data of N pixels at the same time. Therefore, the reading time of a single pixel described here is equal to the reading time of a row of pixels.
  • the pixel array is divided into a first sub-array and a second sub-array, and each row of pixels in the first sub-array and each row of pixels in the second sub-array are respectively subjected to different exposure sequences.
  • Each row of pixels starts to be exposed in sequence, so that the exposure sequences of two specific adjacent rows of pixels in the first sub-array are not adjacent to each other, and the exposure sequences of specific two adjacent rows of pixels in the second sub-array are not adjacent to each other.
  • the exposure sequences of specific two adjacent columns of pixels are not adjacent, so that whether the finger moves or not can be effectively determined according to the difference between the two adjacent rows of pixels and the difference between the two adjacent columns of pixels.
  • the subsequent fingerprint detection will not be performed, but the pixel array will be re-exposed and data read to ensure more effective pixel data and avoid pixel data caused by finger movement during fingerprint detection. False detections caused by inaccuracy.
  • the pixels in the Kth row of the first subarray and the pixels in the K-1th row are located in the same column, and the pixels in the M-Kth row and the M-K-1th row of the pixels in the second subarray are located in the same column.
  • Parameters such as the average or weighted average of the differences between the data of the N pairs of pixels, and the average or weighted average of the differences between the data of the M pairs of pixels in the same row in the pixels in the P-1 column value and other parameters to determine whether the finger moves. For example, when the value of this parameter is greater than the threshold, it is considered that the finger has moved; when the value of this parameter is less than the threshold, it is considered that the finger has not moved.
  • the edge of the fingerprint image is relatively blurred. Therefore, when calculating this weighted average, it is possible to assign a larger weight or even 100% to the pixels in the middle area, and assign a smaller weight or even 0 to the pixels of the edge area. For example, for a pixel array with 200 rows and 200 columns, it is possible to use only the data of the pixels located in the 50th to 150th columns in the middle and the data of the pixels in the 50th to 150th rows in the middle to determine whether the finger has occurred move.
  • the finger can also be determined according to parameters such as the sum, variance or standard deviation of the difference between the data of two adjacent rows of pixels, and the sum, variance or standard deviation of the difference between the data of two adjacent columns of pixels, etc. whether movement has occurred.
  • This embodiment does not limit this. Any parameter that can be used to characterize the degree of difference between the data of two adjacent rows of pixels, and any parameter that can be used to characterize the degree of difference between the data of two adjacent columns of pixels, can be used. It is applied in this embodiment to determine whether the finger moves.
  • Factors such as the number of pixel rows and pixel columns in the pixel array, the reset time of each row of pixels, the exposure time, and the data reading time can be considered when determining the above-mentioned threshold for judging whether the finger moves.
  • the difference between the data of each pair of pixels in the N pairs of pixels located in the same column in two adjacent rows of pixels may be the difference value of the data of each pair of pixels; or the rate of change of the data of each pair of pixels .
  • the rate of change is the ratio between the difference between the data of each pair of pixels and the data of one of the pixels.
  • the difference between the data of each pair of pixels in the M pairs of pixels located in the same row in two adjacent columns of pixels may be the difference value of the data of each pair of pixels; or the rate of change of the data of each pair of pixels.
  • the rate of change is the ratio between the difference between the data of each pair of pixels and the data of one of the pixels.
  • the values of data output by two pixels in a pair of pixels in the i-th column after exposure are A i and B i respectively, and i is any integer between 0 and N-1.
  • the values of the data output by the two pixels in the pair of pixels in the j-th row after exposure are C j and D j respectively.
  • j is any integer between 0 and M-1. Then, according to and threshold Q1, and and the threshold Q2, to determine whether the finger moves; alternatively, it can be determined according to or and the magnitude between the threshold Q3, and according to or The size between the threshold Q4 determines whether the finger moves.
  • An embodiment of the present application further provides a fingerprint detection device, which can perform the fingerprint detection method in any of the foregoing embodiments.
  • a fingerprint detection device which can perform the fingerprint detection method in any of the foregoing embodiments.
  • the fingerprint detection apparatus 1800 includes an image sensor 1810, and the image sensor 1810 includes:
  • the row decoder is used to sequentially start exposing each row of pixels in the pixel array used for fingerprint detection according to a predetermined exposure sequence, wherein the exposure sequence of specific adjacent two rows of pixels in the pixel array is different from each other. adjacent, or double exposure of a particular row of pixels in the pixel array; and,
  • a column reading circuit configured to read the data of each row of pixels at the end of exposure of each row of pixels, wherein the difference between the data of the two adjacent rows of pixels, or the two times of the specific row of pixels The difference between the exposed data is used to determine whether the finger moves during the exposure process of the pixel array;
  • the data of the pixel array is not used for the fingerprint detection of the finger when the finger moves, and/or the data of the pixel array is used for the fingerprint detection of the finger when the finger does not move.
  • the fingerprint detection device can sequentially start exposing each row of pixels in the pixel array used for fingerprint detection according to a predetermined exposure sequence, so that the exposure sequences of two specific adjacent rows of pixels in the pixel array are not adjacent to each other, Or make a specific row of pixels in the pixel array to be exposed twice, so that it can be based on the difference between the data of the specific adjacent two rows of pixels, or the difference between the data after two exposures of the specific row of pixels , effectively determine whether the finger moves. If the finger does not move, the difference between the data of the specific two adjacent lines of pixels or the difference between the data after two exposures of the specific line of pixels will be small or even no difference; if the finger moves , the difference will be more obvious. When it is determined that the finger moves, the data of the pixel array will not be used for subsequent fingerprint detection, thereby avoiding unnecessary false detection and improving the accuracy of fingerprint detection.
  • the fingerprint detection apparatus 1800 further includes a processing module 1820, and the processing module 1820 is configured to: according to the difference between the data of the two adjacent rows of pixels, or the The difference between the data after the two exposures determines whether the finger moves during the exposure of the pixel array.
  • the processing module 1820 is specifically configured to: if the difference is greater than a threshold, determine that the finger moves; and/or, if the difference is less than the threshold, determine the The fingers have not moved.
  • the pixel array includes M rows ⁇ N columns of pixels, and the two adjacent rows of pixels are respectively the first exposed row of pixels and the last exposed row of pixels in the pixel array;
  • the row decoder is specifically used to: start exposure sequentially from the Kth row of pixels in the M rows of pixels to the M-1th row of pixels, where K ⁇ 0 and K is less than M; Exposure is performed sequentially from the pixels of the 0th row to the K-1th row of pixels, wherein T is equal to the reading time of the data of one row of pixels, or T is greater than the reading time of the data of one row of pixels.
  • the difference between the data of the two adjacent rows of pixels includes: between the data of the Kth row of pixels and the data of N pairs of pixels located in the same column in the K-1th row of pixels. The average or weighted average of the differences.
  • the difference of the data of each pair of pixels in the N pairs of pixels includes: the difference of the data of each pair of pixels; or, the rate of change of the data of each pair of pixels, Wherein, the rate of change is the ratio between the difference between the data of each pair of pixels and the data of one of the pixels.
  • the weight corresponding to the pixel located in the middle area is greater than the weight corresponding to the pixel located in the edge area.
  • the pixel array includes M rows ⁇ N columns of pixels, and the first row of pixels to be exposed and the last row of pixels to be exposed in the pixel array are the specific ones that have been exposed twice.
  • the starting time of the second exposure of the pixels in the Kth row is after the data read after the first exposure of the pixels in the Kth row is completed, and the second exposure of the pixels in the Kth row is completed.
  • the reading time of the data after the sub-exposure does not overlap with the reading time of the data of the other rows of pixels in the M rows of pixels.
  • the difference between the data of the specific row of pixels after two exposures includes: the data of the N pixels in the Kth row of pixels after the second exposure and the data after the second exposure.
  • the difference between the data after the second exposure and the data after the first exposure of each pixel in the N pixels includes: The difference between the data after the second exposure and the data after the first exposure; or, the rate of change between the data after the second exposure and the data after the first exposure of each pixel, wherein, The rate of change is a ratio between the difference between the data of each pixel after the second exposure and the data after the first exposure and the data after one exposure.
  • the weight corresponding to the pixel located in the middle area among the N pixels is greater than the weight corresponding to the pixel located in the edge area.
  • the method further includes: performing fingerprint detection on the finger according to the data of the pixels in the M rows that have been read while exposing the pixels in the K th row for the second time.
  • the pixel array includes M rows ⁇ N columns of pixels, the M rows ⁇ N columns of pixels include a first subarray and a second subarray, and the first subarray includes a first subarray. row 0 to row M-1 and column 0 to column P-1, the second subarray includes row 0 to row M-1 and column P to column N-1; wherein, the The row decoder is specifically used for: sequentially starting exposure from the 0th row of pixels to the K-1th row of pixels in the first subarray, and simultaneously from the M-1th row of pixels in the second subarray to the M-Kth row of pixels
  • the pixels start to be exposed in sequence; after the elapse of time T, the exposure is sequentially performed from the pixels in the M-1th row to the Kth row of pixels in the first subarray, and simultaneously from the 0th row of pixels in the second subarray to the Kth row of pixels. Pixels of rows M-K-1 start to be exposed in sequence, wherein T is equal to the reading
  • the difference between the data of the pixels in the Pth column and the data of the pixels in the P-1th column and the difference between the data of the pixels in the two adjacent rows are jointly used to determine the Whether the finger moves during the exposure process of the pixel array; wherein, the difference between the data of the two adjacent rows of pixels includes: the pixels in the Kth row of the first subarray and the K-1th row of pixels are located in the same column and The average or weighted average of the differences between the data of N pairs of pixels located in the same column among the pixels in the M-Kth row and the M-K-1th row of the second subarray; The difference between the data of the pixels includes: the average value or the weighted average value of the difference between the data of M pairs of pixels located in the same row in the pixel in the Pth column and the pixel in the P-1th column.
  • the difference between the data of each pair of pixels in the N pairs of pixels and the M pairs of pixels includes: a difference value of the data of each pair of pixels; or, the each pair of pixels The rate of change of the data of the pixels, wherein the rate of change is the ratio between the difference of the data of each pair of pixels and the data of one of the pixels.
  • the weights corresponding to the pixels located in the middle area among the N pairs of pixels are greater than the weights corresponding to the pixels located in the edge area; and, among the M pairs of pixels, the weights located in the middle area.
  • the weight corresponding to the pixel is greater than the weight corresponding to the pixel located in the edge area.
  • the time interval between the start moments of exposure of two adjacent rows of pixels in the exposure sequence is greater than or equal to one row of pixels.
  • the reading time of the data; in the 0th row of pixels to the K-1th row of pixels, the time interval between the exposure start times of two adjacent rows of pixels in the exposure sequence is greater than or equal to the readout of the data of one row of pixels. Take time.
  • the fingerprint detection device further includes an optical path guiding structure disposed above the image sensor, the optical path guiding structure including: a microlens array, including a plurality of microlenses; and a plurality of microlenses; a plurality of light-blocking layers are arranged below the microlens array, wherein each light-blocking layer is provided with a plurality of openings corresponding to the plurality of microlenses respectively; wherein, the microlenses are used for the finger
  • the returned optical signals are converged to the corresponding openings in the plurality of light blocking layers, and transmitted to the pixel array through the corresponding openings in the plurality of light blocking layers.
  • optical path guiding structure is only an example, and in some scenarios, a lens or an array of collimating pinholes may also be used to guide the optical signal returned by the finger to the pixel array in the image sensor.
  • An embodiment of the present application further provides an electronic device, including the fingerprint detection apparatus described in any of the foregoing embodiments.
  • FIG. 19 and FIG. 20 show a possible structure of the fingerprint detection apparatus according to the embodiment of the present application.
  • FIG. 19 is a schematic view of the orientation of the electronic device 10
  • FIG. 20 is a schematic partial cross-sectional view of the electronic device 10 shown in FIG. 19 along the direction A-A'.
  • the electronic device 10 includes a display screen 120 and a fingerprint detection device 1800 .
  • the fingerprint detection apparatus 1800 includes an image sensor 1810 including a pixel array 133 having a plurality of pixels 131, a row decoder, a column readout circuit, and the like. The area where the pixel array 133 is located or its sensing area is the fingerprint detection area 103 of the fingerprint detection device 1800 .
  • the processing module 1820 is not shown in FIGS. 19 and 20 , and the processing module 1820 may be, for example, the MUC of the fingerprint detection apparatus 1800 . In practical applications, the processing module 1820 may be disposed below the image sensor 1810 .
  • the fingerprint detection device 1800 further includes an optical path guiding structure 1830 disposed above the image sensor 1810 .
  • the light path guiding structure 1830 is used to guide the light signal returned by the finger to the image sensor 1810 .
  • the optical path guiding structure 1830 may include a microlens array composed of a plurality of microlenses.
  • at least one light-blocking layer may be provided 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 133 includes a plurality of openings corresponding to the plurality of microlenses.
  • Each microlens is used to condense the optical signal returned by the finger to the corresponding opening in each light blocking layer, so that the optical signal passes through the corresponding opening in each light blocking layer in turn and is transmitted to the corresponding pixel in the pixel array 133 131.
  • the optical path guiding structure 1830 may include a collimator layer fabricated on a semiconductor silicon wafer, which has a plurality of collimation units or an array of micro holes, and the collimation units may be small holes.
  • the optical path guiding structure 1830 may include an optical lens layer having one or more lens units, and the lens units may be a lens group composed of one or more aspherical lenses.
  • the display screen 120 emits a beam of light 111 to the finger 140 above the fingerprint detection area 103.
  • the light 111 is reflected on the surface of the finger 140 to form reflected light or scattered inside the finger 140 to form scattered light. Since the ridges 141 and valleys 142 of the fingerprint have different reflection capabilities for light, the reflected light 151 from the fingerprint ridge and the reflected light 152 from the fingerprint valley have different light intensities, and the reflected light passes through the optical path guiding structure After 1830, it is received by the pixel array 133 in the image sensor 1810 and converted into a corresponding electrical signal, that is, 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, so as to realize the optical fingerprint detection function in the electronic device 10 .
  • the electronic device 10 may further include an excitation light source for fingerprint detection.
  • the display screen 120 may be a display screen having a self-luminous display unit, such as an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display screen or a micro-light-emitting diode (Micro-LED) display screen.
  • OLED Organic Light-Emitting Diode
  • Micro-LED micro-light-emitting diode
  • the optical fingerprint module 130 can use the display unit located in the fingerprint detection area 103 in the OLED display screen 120 as an excitation light source for optical fingerprint detection.
  • the fingerprint detection device 1800 can also be applied to a display screen that is not self-illuminating, such as a liquid crystal display screen.
  • a built-in light source or an external light source can be used to provide an optical signal for fingerprint detection.
  • the excitation light source for fingerprint detection can be an infrared light source or a light source of non-visible light with a specific wavelength, which can be arranged below the backlight module of the liquid crystal display or The edge area provided under the protective cover of the electronic device 10 .
  • the electronic device in the embodiment of the present application may be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a notebook computer, a desktop computer, a game device, a vehicle-mounted electronic device, or a wearable smart device, and Electronic databases, automobiles, bank ATMs (Automated Teller Machine, ATM) and other electronic devices.
  • the wearable smart devices include devices with full functions and large sizes that can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as devices that only focus on a certain type of application function and need to communicate with other devices such as smartphones.
  • Compatible devices such as various types of smart bracelets, smart jewelry and other devices for physical sign monitoring.
  • the systems, devices, and methods disclosed in the embodiments of the present application may be implemented in other manners. For example, some features of the method embodiments described above may be omitted or not implemented.
  • the device embodiments described above are only illustrative, and the division of units is only a logical function division. In actual implementation, there may be other division methods, and multiple units or components may be combined or integrated into another system.
  • the coupling between the various units or the coupling between the various components may be direct coupling or indirect coupling, and the above-mentioned coupling includes electrical, mechanical or other forms of connection.

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Abstract

本申请提供一种指纹检测的方法、指纹检测装置和电子设备，能够提高指纹检测的性能。该方法包括：按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，其中，所述像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，或者对所述像素阵列中特定的一行像素进行两次曝光；在每行像素曝光结束时读取所述每行像素的数据，其中，所述相邻两行像素的数据之间的差异或者所述特定的一行像素的两次曝光后的数据之间的差异，用于确定所述像素阵列的曝光过程中手指是否发生移动。

Description

指纹检测的方法、指纹检测装置和电子设备 技术领域
本申请实施例涉及信息技术领域，并且更具体地，涉及一种指纹检测的方法、指纹检测装置和电子设备。
背景技术
图像传感器中的像素阵列与行译码器控制和列读取电路相连，行译码器可以控制各行像素进行复位并开始曝光，在曝光结束后，列读取电路将各个像素的信号读出。在所有的行像素进行曝光并读出数据后，就可以根据这些数据获取待测手指的指纹图像。
目前的图像传感器在获取指纹图像时采用的快门方式包括全局快门(global shutter)和卷帘快门(rolling shutter)两种。其中，采用全局快门的方式时，图像传感器中需要设置更多的晶体管或存储电容，从而导致列读取电路读出的噪声更大，会对指纹检测的结果造成影响，并且降低了单个像素的有效成像区域的面积；而采用卷帘快门的方式时，容易因手指的移动导致最终获取的指纹图像出现模糊和畸变，同样影响指纹检测的结果。因此，如何在不增加图像传感器中的晶体管数量的情况下提高指纹检测的性能，成为亟待解决的问题。
发明内容
本申请实施例提供一种指纹检测的方法、指纹检测装置和电子设备，能够在不增加图像传感器中的晶体管数量的情况下提高指纹检测的性能，成为亟待解决的问题。
第一方面，提供了一种指纹检测的方法，所述方法包括：
按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，其中，所述像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，或者所述像素阵列中特定的一行像素进行了两次曝光；
在每行像素曝光结束时读取所述每行像素的数据，其中，所述相邻两行像素的数据之间的差异或者所述特定的一行像素的两次曝光后的数据之间的差异，用于确定所述像素阵列的曝光过程中手指是否发生移动；
其中，所述手指发生移动时所述像素阵列的数据不用于所述手指的指纹检测，和/或，所述手指未发生移动时所述像素阵列的数据用于所述手指的指纹检测。
在一种可能的实现方式中，所述方法还包括：根据所述相邻两行像素的数据之间的差异，或者所述特定的一行像素的两次曝光后的数据之间的差异，确定所述像素阵列的曝光过程中手指是否发生移动。
在一种可能的实现方式中，所述根据所述相邻两行像素的数据之间的差异，确定所述像素阵列的曝光过程中手指是否发生移动，包括：若所述差异大于阈值，则确定所述手指发生移动；和/或，若所述差异小于所述阈值，则确定所述手指未发生移动。
在一种可能的实现方式中，所述像素阵列包括M行×N列像素，所述相邻两行像素分别为所述像素阵列中最先曝光的一行像素与最后曝光的一行像素；其中，所述按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K≠0且K小于M；在经过时间T之后，从第0行像素至第K-1行像素依次开始进行曝光，其中，T等于一行像素的数据的读取时间，或者T大于一行像素的数据的读取时间。
在一种可能的实现方式中，所述相邻两行像素的数据之间的差异，包括：第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值。
在一种可能的实现方式中，所述N对像素中每对像素的数据的差异包括：所述每对像素的数据的差值；或者，所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
在一种可能的实现方式中，所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
在一种可能的实现方式中，所述像素阵列包括M行×N列像素，所述像素阵列中最先曝光的一行像素与最后曝光的一行像素为进行了两次曝光的所述特定的一行像素；其中，所述按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K小于M；接着从第0行像素至 第K行像素依次开始进行曝光。
在一种可能的实现方式中，第K行像素的第二次曝光的起始时刻位于第K行像素的第一次曝光后的数据读取完成之后，且第K行像素的第二次曝光后的数据的读取时间，与M行像素中其他各行像素的数据的读取时间均不重叠。
在一种可能的实现方式中，所述特定的一行像素的两次曝光后的数据之间的差异，包括：第K行像素中的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的平均值或者加权平均值。
在一种可能的实现方式中，所述N个像素中每个像素在第二次曝光后的数据和在第一次曝光后的数据之间的差异，包括：所述每个像素在第二次曝光后的数据与在第一次曝光后的数据的差值；或者，所述每个像素在第二次曝光后的数据与在第一次曝光后的数据的变化率，其中，所述变化率为所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的差值，与其中一次曝光后的数据之间的比值。
在一种可能的实现方式中，所述N个像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
在一种可能的实现方式中，所述方法还包括：在对第K行像素进行第二次曝光的同时，根据已读取的M行像素的数据，对所述手指进行指纹检测。
在一种可能的实现方式中，所述像素阵列包括M行×N列像素，所述M行×N列像素包括第一子阵列和第二子阵列，所述第一子阵列包括第0行至第M-1行以及第0列至第P-1列，所述第二子阵列包括第0行至第M-1行以及第P列至第N-1列；其中，所述按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：从第一子阵列中的第0行像素至第K-1行像素依次开始进行曝光，并同时从第二子阵列中的第M-1行像素至第M-K行像素依次开始进行曝光；在经过时间T之后，从第一子阵列中的第M-1行像素至第K行像素依次开始进行曝光，并同时从第二子阵列中的第0行像素至第M-K-1行像素依次开始进行曝光，其中，T等于单个像素的数据的读取时间，或者T大于单个像素的数据的读取时间。
在一种可能的实现方式中，第P列像素与第P-1列像素的数据之间的差异，与所述相邻两行像素的数据之间的差异，共同用于确定所述像素阵列的曝光过程中手指是否发生移动；其中，所述相邻两行像素的数据之间的差异， 包括：第一子阵列的第K行像素与第K-1行像素中位于相同列以及第二子阵列的第M-K行像素和第M-K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值；以及，第P列像素与第P-1列像素的数据之间的差异，包括：第P列像素与第P-1列像素中位于相同行的M对像素的数据之间的差异的平均值或者加权平均值。
在一种可能的实现方式中，所述N对像素和所述M对像素中的每对像素的数据的差异包括：所述每对像素的数据的差值；或者，所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
在一种可能的实现方式中，所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值；以及，所述M对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
在一种可能的实现方式中，P为偶数，P＝N/2；或者，P为奇数，P＝(N-1)/2或者P＝(N+1)/2。
在一种可能的实现方式中，M为偶数，K＝M/2；或者，M为奇数，K＝(M-1)/2或者K＝(M+1)/2。
在一种可能的实现方式中，在第K行像素至第M-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间；在第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间。
第二方面，提供了一种指纹检测装置，所述指纹检测装置包括图像传感器，所述图像传感器包括：
像素阵列；
行译码器，用于按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，其中，所述像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，或者对所述像素阵列中特定的一行像素进行两次曝光；以及，
列读取电路，用于在每行像素曝光结束时读取所述每行像素的数据，其中，所述相邻两行像素的数据之间的差异或者所述特定的一行像素的两次曝光后的数据之间的差异，用于确定所述像素阵列的曝光过程中手指是否发生 移动；
其中，所述手指发生移动时所述像素阵列的数据不用于所述手指的指纹检测，和/或，所述手指未发生移动时所述像素阵列的数据用于所述手指的指纹检测。
在一种可能的实现方式中，所述指纹检测装置还包括处理模块，所述处理模块用于：根据所述相邻两行像素的数据之间的差异，或者所述特定的一行像素的两次曝光后的数据之间的差异，确定所述像素阵列的曝光过程中手指是否发生移动。
在一种可能的实现方式中，所述处理模块具体用于：若所述差异大于阈值，则确定所述手指发生移动；和/或，若所述差异小于所述阈值，则确定所述手指未发生移动。
在一种可能的实现方式中，所述像素阵列包括M行×N列像素，所述相邻两行像素分别为所述像素阵列中最先曝光的一行像素与最后曝光的一行像素；其中，所述行译码器具体用于：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K≠0且K小于M；在经过时间T之后，从第0行像素至第K-1行像素依次开始进行曝光，其中，T等于一行像素的数据的读取时间，或者T大于一行像素的数据的读取时间。
在一种可能的实现方式中，所述相邻两行像素的数据之间的差异，包括：第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值。
在一种可能的实现方式中，所述N对像素中每对像素的数据的差异包括：所述每对像素的数据的差值；或者，所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
在一种可能的实现方式中，所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
在一种可能的实现方式中，所述像素阵列包括M行×N列像素，所述像素阵列中最先曝光的一行像素与最后曝光的一行像素为进行了两次曝光的所述特定的一行像素；其中，所述行译码器具体用于：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K小于M；接着从第0行像素至第K行像素依次开始进行曝光。
在一种可能的实现方式中，第K行像素的第二次曝光的起始时刻位于第K行像素的第一次曝光后的数据读取完成之后，且第K行像素的第二次曝光后的数据的读取时间，与M行像素中其他各行像素的数据的读取时间均不重叠。
在一种可能的实现方式中，所述特定的一行像素的两次曝光后的数据之间的差异异，包括：第K行像素中的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的平均值或者加权平均值。
在一种可能的实现方式中，所述N个像素中每个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异，包括：所述每个像素在第二次曝光后的数据与在第一次曝光后的数据的差值；或者，所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的变化率，其中，所述变化率为所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的差值，与其中一次曝光后的数据之间的比值。
在一种可能的实现方式中，所述N个像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
在一种可能的实现方式中，所述方法还包括：在对第K行像素进行第二次曝光的同时，根据已读取的M行像素的数据，对所述手指进行指纹检测。
在一种可能的实现方式中，所述像素阵列包括M行×N列像素，所述M行×N列像素包括第一子阵列和第二子阵列，所述第一子阵列包括第0行至第M-1行以及第0列至第P-1列，所述第二子阵列包括第0行至第M-1行以及第P列至第N-1列；其中，所述行译码器具体用于：从第一子阵列中的第0行像素至第K-1行像素依次开始进行曝光，并同时从第二子阵列中的第M-1行像素至第M-K行像素依次开始进行曝光；在经过时间T之后，从第一子阵列中的第M-1行像素至第K行像素依次开始进行曝光，并同时从第二子阵列中的第0行像素至第M-K-1行像素依次开始进行曝光，其中，T等于单个像素的数据的读取时间，或者T大于单个像素的数据的读取时间。
在一种可能的实现方式中，第P列像素与第P-1列像素的数据之间的差异，与所述相邻两行像素的数据之间的差异，共同用于确定所述像素阵列的曝光过程中手指是否发生移动；其中，所述相邻两行像素的数据之间的差异，包括：第一子阵列的第K行像素与第K-1行像素中位于相同列以及第二子阵列的第M-K行像素和第M-K-1行像素中位于相同列的N对像素的数据之间 的差异的平均值或者加权平均值；以及，第P列像素与第P-1列像素的数据之间的差异，包括：第P列像素与第P-1列像素中位于相同行的M对像素的数据之间的差异的平均值或者加权平均值。
在一种可能的实现方式中，所述N对像素和所述M对像素中的每对像素的数据的差异包括：所述每对像素的数据的差值；或者，所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
在一种可能的实现方式中，所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值；以及，所述M对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
在一种可能的实现方式中，P为偶数，P＝N/2；或者，P为奇数，P＝(N-1)/2或者P＝(N+1)/2。
在一种可能的实现方式中，M为偶数，K＝M/2；或者，M为奇数，K＝(M-1)/2或者K＝(M+1)/2。
在一种可能的实现方式中，在第K行像素至第M-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间；在第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间。
在一种可能的实现方式中，所述指纹检测装置还包括设置在所述图像传感器上方的光路引导结构，所述光路引导结构包括：微透镜阵列，包括多个微透镜；以及，多个挡光层，设置在所述微透镜阵列下方，其中每个挡光层上设置有与所述多个微透镜分别对应的多个开孔；其中，所述微透镜用于将所述手指返回的光信号会聚到所述多个挡光层中的对应的开孔，并通过所述多个挡光层中的对应的开孔，传输至所述像素阵列。
第三方面，提供了一种电子设备，包括上述第二方面或第二方面的任一可能的实现方式中的指纹检测装置。
基于上述技术方案，按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，并使得像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，以增加相邻两行像素的曝光起始时刻之间的时间差，或者使得像素阵列中特定的一行像素进行两次曝光，从而能够根据该特定的 相邻两行像素的数据之间的差异，或者根据该特定的一行像素的两次曝光后的数据之间的差异，有效地判断手指是否发生移动。如果手指未发生移动，则该特定的相邻两行像素的数据之间的差异或者该特定的一行像素的两次曝光后的数据之间的差异会很小，甚至没有差异；如果手指发生移动，则该差异会较为明显。当确定手指发生移动时，像素阵列的数据就不会用于进行后续的指纹检测，从而避免不必要的误检测，提高了指纹检测的准确性，提高了指纹检测的性能。
附图说明
图1是图像传感器的示意图。
图2是采用全局快门时对各行像素的曝光时序的示意图。
图3是采用卷帘快门时对各行像素的曝光时序的示意图。
图4是图3中的各行像素的曝光顺序的示意图。
图5是本申请实施例的指纹检测的方法的示意性流程图。
图6是基于图5所示的指纹检测方法的一种具体的曝光顺序的示意图。
图7是图6中的各行像素的曝光顺序的示意图。
图8是基于图6所示的曝光顺序得到的移动手指的指纹图像的示意图。
图9是基于图6所示的曝光顺序得到的静止手指的指纹图像的示意图。
图10是基于图5所示的指纹检测方法的一种具体的曝光顺序的示意图。
图11是基于图6所示的曝光顺序的一种可能的指纹检测过程的示意图。
图12是基于图5所示的指纹检测方法的一种具体的曝光顺序的示意图。
图13是基于图12所示的曝光顺序的一种可能的指纹检测过程的示意图。
图14是基于图5所示的指纹检测方法的一种具体的曝光顺序所划分的第一子阵列和第二子阵列的示意图。
图15是第一子阵列中各行像素的曝光顺序的示意图。
图16是第二子阵列中各行像素的曝光顺序的示意图。
图17是图15和图16中的各行像素的曝光顺序的示意图。
图18是本申请实施例的指纹检测装置的示意性框图。
图19是本申请实施例中一种可能的电子设备的示意图。
图20是本申请实施例的一种可能的指纹检测装置的示意性结构图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
本申请实施例可以应用于光学指纹检测系统中，该光学指纹系统可以应用在智能手机、平板电脑以及其他具有显示屏的移动终端或者其他电子设备中，该光学指纹系统可以设置在电子设备的显示屏下方的局部区域或者全部区域，从而形成屏下光学指纹系统。
在进行光学指纹检测时，图像传感器开始采集待测手指的指纹图像，然后由处理模块对指纹图像进行前处理，接着对经过前处理的指纹图像进行特征信息的提取，并将提取到的特征信息与指纹库中存储的指纹的特征信息进行匹配，如果匹配成功，则判定指纹检测成功，从而执行相应的操作。
在对指纹图像进行前处理的过程中，对于模糊的指纹图像而言，其信噪比较低，在进行前处理和特征信息提取的过程中容易导致指纹的特征信息丢失，而特征信息过少会造成指纹识检测程中的拒真率(False RejectionRate，FRR)的提升；另外，在前处理的过程中，模糊的指纹图像会引起伪特征信息的增多，在特征信息的匹配过程中会造成误匹配，导致认假率(False Acceptance Rate，FAR)的提升。因此，在指纹检测过程中，期望图像传感器采集的指纹图像尽量清晰。
图1为图像传感器的示意图。图像传感器包括由M行×N列像素组成的像素阵列、行译码器以及列读取电路。该像素阵列由行译码器控制，行译码器可以控制每行像素的复位并对该行像素进行曝光。在该行像素曝光过程中，该行中的像素会通过光电转换将光信号转换为电信号，并由列读取电路将光电转换后的电信号读取出来。在对M行像素进行曝光并读取数据后，就可以根据这些数据获取手指的指纹图像。
目前的图像传感器在获取指纹图像时采用的快门方式包括全局快门和卷帘快门两种。图2示出了采用全局快门时对各行像素的曝光时序。如图2所示，像素阵列中的所有像素同时复位并开始曝光，当所有像素曝光结束后，列读取电路按顺序依次对各行像素曝光后的数据进行读取。由于所有像素同时进行曝光，因此，在对指纹进行成像时，这种快门方式对手指的移动并不敏感，得到的指纹图像更为清晰。但是，全局快门的缺点在于，每个像素对应的像素电路中需要额外设置晶体管或存储电容，以用于对等待被读取的像素的数据进行存储，所以采用全局快门方式的图像传感器中的单个像素的有 效成像区域的比例更低。该有效成像区域是指实际进行光电转换区域的面积与整个像素的面积之间的比例。另外，由于图像传感器中设置了更多的晶体管或存储电容，导致列读取电路读取到的噪声更大，图像传感器采集到的指纹图像中携带的噪声更为严重。
图3示出了采用卷帘快门时对各行像素的曝光时序。如图3所示，同一行中的像素同时开始复位并进行曝光，在该行像素的开始曝光一定时间后，对下一行像素开始复位并进行曝光，这两行像素的曝光的起始时刻之间的时间差例如通常等于单行像素的数据的读取时间。接着，按顺序对后面的各行像素开始复位、曝光和读取数据。如图4所示，采用卷帘快门的图像传感器，按照第0行像素、第1行像素、第2行像素、……、第M-1行像素的曝光顺序，对各行像素开始进行曝光，图4中箭头方向指示各行像素的曝光顺序。并且，如图3所示，各行像素实际开始进行曝光的时刻各不相同，相邻两行像素的曝光的起始时刻之间存在一定的时间差。这样，在对移动的手指进行成像时，由于各行像素的曝光的起始时刻对应的手指的实际位置存在偏差，采集到的指纹图像容易模糊和畸变。但是，相比于全局快门的方式，卷帘快门的优势在于，无需额外设置存储像素数据的晶体管或存储电容，每个像素对应的像素电路中需要的晶体管数目更少，因此单个像素的有效成像区域的比例更高，列读取电路所读取的噪声也更低。
在指纹检测过程中，期望图像传感器采集的指纹图像尽量清晰。为此，一种方式是，采用上述的全局快门的方式可以获得更清晰的指纹图像，但是却使得像素电路中的晶体管或存储电容的数量增加，不仅影响像素的有效成像区域的面积，更增加了指纹图像中的噪声，影响指纹检测的结果。另一种方式是，采用卷帘快门的方式，但是要判断在曝光过程中手指未发生移动，才能确保基于曝光后的像素的数据形成的指纹图像是清晰的。
本申请实施例提供了一种指纹检测的方案，能够提高指纹检测的性能。
该方案在卷帘快门的基础上，对各行像素的曝光时序进行了设计，从而能够根据曝光后的特定行的像素的数据，准确地判断曝光过程中手指是否发生了移动，并根据手指未发生移动时读取的像素的数据，进行指纹检测。这样，能够避免手指移动引起的指纹图像的模糊，降低对指纹检测过程的拒真率和认假率的影响。同时，由于是基于卷帘快门的改进，因此无需在像素电路中增加额外的晶体管和存储电容，增加了图像传感器的有效成像区域，且 使读取的像素的数据中携带的噪声更低，提高了指纹检测的准确性。
当然，也可以采用其他方式判断像素阵列曝光过程中手指是否发生移动。例如，利用电子设备中的触摸检测功能，确定手指在屏幕上的位置，从而判断手指是否发生移动。但是触摸检测的灵敏度较低，刷新频率较低，无法准确地判断曝光过程中手指是否发生移动。而且，利用触摸检测的方式无法识别某些特殊类型的手指移动，例如手指旋转等。又例如，可以连续采集两幅指纹图像，并根据两幅指纹图像的差异，判断手指是否发生了移动。但这样会耗费更多的时间，增加了指纹检测的时长，降低了用户体验。
图5是本申请实施例的指纹检测的方法的示意性流程图。如图5所示，指纹检测的方法500包括以下步骤中的部分或全部。
在步骤510中，按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光。
其中，该像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，例如，该相邻两行像素分别为该像素阵列中最先曝光的一行像素与最后曝光的一行像素；或者，对该像素阵列中特定的一行像素进行了两次曝光，例如，该像素阵列中最先曝光的一行像素与最后曝光的一行像素，是该像素阵列中进行了两次曝光的特定的一行像素。
在步骤520中，在每行像素曝光结束时读取每行像素的数据。
其中，所述相邻两行像素的数据之间的差异，用于确定该像素阵列的曝光过程中手指是否发生移动；或者，所述特定的一行像素的两次曝光后的数据之间的差异，用于确定该像素阵列的曝光过程中手指是否发生移动。
该手指发生移动时该像素阵列的数据不用于该手指的指纹检测，和/或，该手指未发生移动时该像素阵列的数据用于该手指的指纹检测。
进一步地，该方法还可以包括步骤530。
在步骤530中，根据该相邻两行像素的数据之间的差异，或者该特定的一行像素的两次曝光后的数据之间的差异，确定该像素阵列的曝光过程中手指是否发生移动。
例如，若该特定的相邻两行像素的数据之间的差异，大于阈值，则确定该手指发生移动；和/或，若该特定的相邻两行像素的数据之间的差异，小于该阈值，则确定该手指未发生移动。
又例如，若该特定的一行像素分别在两次曝光后的数据之间的差异，大 于阈值，则确定该手指发生移动；和/或，若该特定的一行像素分别在两次曝光后的数据之间的差异，小于该阈值，则确定该手指未发生移动。
应理解，上述步骤510和520可以由指纹检测装置中的图像传感器执行。
其中，该指纹检测装置包括该图像传感器和处理模块。该图像传感器包括像素阵列(或者称感应阵列)、行译码器和列读取电路等。其中，行译码器可以控制像素阵列执行相应的曝光操作，即上述步骤510；而列读取电路可以读取曝光后的像素阵列输出的数据，即上述步骤520。
上述步骤530可以由处理模块执行。
其中，该处理模块可以是指纹检测装置的处理器，例如MCU。这时，该处理模块可以控制行译码器执行相应的曝光操作，以及控制列读取电路执行相应的数据读取操作。进一步地，可选地，该处理模块还可以基于列译码器读取的该特定的相邻两行像素的数据，或者基于该特定的一行像素的两次曝光的数据，判断曝光过程中手指是否发生移动。
该处理模块也可以是电子设备的处理器，例如CPU等。这时，可以由指纹检测装置的处理器例如MCU控制行译码器和列译码器分别执行上述步骤510和步骤520。该处理模块可以从该指纹检测装置中获取曝光后的像素阵列的数据，从而基于该特定的相邻两行像素的数据，或者基于该特定的一行像素的两次曝光的数据，判断曝光过程中手指是否发生移动。并且，该处理模块还可以基于曝光后的像素阵列的数据，对该手指进行相应的指纹检测操作。
本申请实施例中的像素阵列中每个像素的数据，是指该像素曝光后，通过光电转换而形成的电信号，为了便于理解，这里也可以将其理解为指纹图像的一个像素的灰度值，基于该像素阵列中所有像素的数据可以形成该指纹图像。
本申请实施例中所述的指纹检测操作，例如包括对指纹图像的数据进行前处理、基于经过前处理的数据进行指纹的特征信息的提取、以及将提取到的特征信息与指纹库中存储的指纹的特征信息进行匹配等操作。
该实施例中，按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，并使得像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，以增加相邻两行像素的曝光起始时刻之间的时间差，或者使得像素阵列中特定的一行像素进行两次曝光，从而能够根据该特定的相邻两 行像素的数据之间的差异，或者根据该特定的一行像素的两次曝光后的数据之间的差异，有效地判断手指是否发生移动。如果手指未发生移动，则该特定的相邻两行像素的数据之间的差异或者该特定的一行像素的两次曝光后的数据之间的差异会很小，甚至没有差异；如果手指发生移动，则该差异会较为明显。当确定手指发生移动时，像素阵列的数据就不会用于进行后续的指纹检测，从而避免不必要的误检测，提高了指纹检测的准确性，提高了指纹检测的性能。
本申请实施例中，曝光顺序不相邻，可以是指按照该曝光顺序排列的各行像素在时序上的位置之间存在间隔。举例来说，以M行像素中相邻的第K-1行像素和第K行像素为例，如果第K行像素是第i个开始进行曝光的像素行，那么第K-1行像素可以是第i+Q个开始进行曝光的像素行，其中Q大于或者等于2。
本申请提供三种具体的实现方式，用以判断像素阵列的曝光过程中手指是否发生移动。以下，结合图6至图17分别进行描述。其中，方式1至方式3中对像素阵列的曝光方式，均是在对图3和图4所示的卷帘快门的曝光方式的基础上进行的改进，因此其优势在于每个像素对应的像素电路中需要的晶体管的数目或电容的数目更少，单个像素的有效成像区域的比例更高，列读取电路所读取的噪声也更低。
方式1
图像传感器中的该像素阵列包括M行×N列像素。
其中，在步骤510中，按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光；在经过时间T之后，从第0行像素至第K-1行像素依次开始进行曝光。
该实施例中，可以将像素阵列看作两部分，上半部分包括第0行像素至第K-1行像素，下半部分包括第K行像素至第M-1行像素。在对像素阵列进行曝光时，先从下半部分的第K行像素开始，依次对第K行像素至第M-1行像素进行曝光，其次再从上半部分的第0行开始，依次对第0行像素至第K-1行像素进行曝光。
其中，在对像素阵列进行曝光时，不同的像素行的曝光起始时刻均不同。其中，由于M行像素共用相同的列读取电路对各自的数据进行读取，因此， 在第K行像素至第M-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于一行像素的数据的读取时间t；在第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于一行像素的数据的读取时间t。这样，列读取电路在读取完上一行像素的数据之后，就可以接着读取下一行像素的数据。
可见，方式1中的曝光方式的实质是卷帘快门的曝光方式，只是对各行像素进行曝光的曝光顺序与传统的卷帘快门的曝光顺序不同。相对于全局快门而言，每个像素对应的像素电路中需要的晶体管数目更少，单个像素的有效成像区域的比例更高，列读取电路所读取的噪声也更低。
对静止的物体例如静止的手指进行成像时，相邻的两行像素的响应会很相近；而对运动的物体例如移动的手指进行成像时，由于各行像素的曝光起始时刻不同，因此相邻的两行像素的响应会存在差异。
为了使这种差异能够被辨识出来并能够用于判断手指是否发生移动，该实施例中重新调整了对各行像素的曝光顺序，使得最先曝光的一行像素与最后曝光的一行像素为相邻的两行像素。
该实施例中，最先曝光的一行像素为第K行像素，最后曝光的一行像素就为第K-1行像素，那么第K行像素和第K-1行像素的曝光起始时刻之间的时间差就等于或者大于(M-1)×t。
由于第K行像素与第K-1行像素是相邻的两行像素，因此，手指未发生移动时，第K行像素和第K-1行像素之间的指纹图像对应的数据应当很接近，即差异很小，而手指的移动会导致相邻两行像素的数据之间存在明显差异。这时，通过对比第K行像素和第K-1行像素在曝光后输出的数据之间的差异的大小，就可以判断在上述曝光过程中手指是否发生移动。如果最先曝光的第K行像素的数据，与最后曝光的第K-1行像素的数据之间的差异小于预设的阈值，则认为手指未发生移动；如果最先曝光的第K行像素的数据，与最后曝光的第K-1行像素的数据之间的差异大于预设的阈值，则认为手指发生了移动。
其中，K≠0且K小于M。也就是说，最先曝光的一行像素可以M行像素中除了第0行像素之外的任意一行像素。
优选地，M为偶数时，K＝M/2；或者，M为奇数时，K＝(M-1)/2或者 K＝(M+1)/2。
如图6所示，假设像素阵列包括偶数行像素，即M为偶数，且K＝M/2。在对M行像素进行曝光时，先对像素阵列中位于下半部分的第M/2行像素至第M-1行像素依次开始进行曝光，当下半部分的所有像素行都已经开始进行曝光之后，再对位于上半部分的第0行像素至第M/2-1行像素依次开始进行曝光。具体的曝光顺序可以参考图7，其中，图7中的实线箭头表示先曝光的像素阵列的曝光顺序，虚线箭头表示后曝光的像素阵列的曝光顺序。曝光顺序具体为第M/2行、第M/2+1行、第M/2+2行、……、第M-1行、第0行、第1行、第2行、……、第M/2-1行。与图3的现有的卷帘快门的曝光方式相比，曝光顺序不同，但是对M行像素曝光所耗费的总时长是相等的，因此方式1并没有增加额外的曝光时间。
采用图6和图7所示的方式，指纹图像的上半部分和下半部分会产生明显边界，这个边界是该实施例中刻意制造的边界，该边界两侧对应的两行像素即第K-1行像素和第K行像素的曝光起始时刻之间的时间差至少为(M-1)×t。那么，对于移动的手指而言，这一显著的时间差会导致第K-1行像素和第K行像素对手指在空间上的位置移动所产生的响应具有明显差异，从而可以得到如图8所示指纹图像，该指纹图像在第K-1行像素和第K行像素对应的边界上出现明显差异。而对于静止的手指，即使存在显著的时间差，但是不存在手指在空间上的位置移动，因此第K-1行像素和第K行像素不会对该手指移动产生的响应具有明显差异，从而可以得到如图9所示指纹图像。对比可以看出，图8所示的静止手指的指纹图像在中间的边界线的两侧基本没有差异，而图9所示的移动手指的指纹图像在中间的边界线的两侧表现为不连续。
该实施例中，第M-1行像素开始曝光后的时间T之后，从第0行像素至第K-1行像素依次开始进行曝光。这里，T等于一行像素的数据的读取时间t，或者，T大于一行像素的数据的读取时间t。
也就是说，从下半部分的最后一行像素即第M-1行像素的曝光起始时刻起的时间T之后，开始对第0行像素进行曝光。T等于一行像素的数据的读取时间t时，第M-1行像素的开始曝光后经过时间T，就可以对第0行像素开始进行曝光，例如上述的图6所示。
但是，对于一些情况，例如行数较少的像素阵列，第K行像素和第K-1 行像素的曝光起始时刻之间的时间差(M-1)×t可能不足够用来判断手指是否移动，因此，可以将T设置为大于一行像素的数据的读取时间t，那么第K行像素和第K-1行像素的曝光起始时刻之间的时间差就会大于(M-1)×t，从而使第K行像素和第K-1行像素的数据之间的差异更加明显，更容易判断手指是否移动。例如图10所示，第0行像素的曝光起始时刻与第M-1行像素的曝光起始时刻之间的时间差T大于一行像素的数据的读取时间t。
通常，曝光时间比复位时间和数据读取时间长很多，例如对于400×400的像素阵列而言，每行像素的复位时间例如可以是10us，曝光时间例如可以是30ms，数据读取时间例如可以是30us。因此，本申请各个实施例中的曝光顺序的各个示意图中，复位时间、曝光时间和数据读取时间仅仅是相对位置的示意，这些附图主要是为了说明各行像素的曝光顺序，并不表示复位时间、曝光时间和数据读取时间之间的相对长度。
按照方式1的曝光方式得到的像素阵列的数据可以形成图8和图9所示的指纹图像。但是，在判断手指是否移动时，此时还未进入指纹检测流程，因此暂时还没有形成指纹图像。图8和图9的指纹图像仅仅是为了说明按照方式1的曝光方式对最终得到的指纹图像的影响。
因此，在步骤530中，需要采用其他方式，获取用于表征相邻两行像素的数据之间的差异的参数，并基于该参数确定像素阵列的曝光过程中手指是否发生移动。
该实施例中，可以根据第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的平均值，确定手指是否发生移动。例如，该平均值大于阈值时，认为手指发生移动；该平均值小于阈值时，认为手指未发生移动。
或者，也可以根据第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的加权平均值，确定手指是否发生移动。例如，该加权平均值大于阈值时，认为手指发生移动；该加权平均值小于阈值时，认为手指未发生移动。
其中，考虑到像素阵列的边界上的像素容易受到外界环境光的影响，使得指纹图像的边缘较为模糊。因此，在计算该加权平均值时，可以为该N对像素中位于中间区域的像素分配较大的权值甚至100％，并为该N对像素中位于边缘区域的像素分配较小权值甚至0。例如，对于200行×200列的像 素阵列，可以仅利用位于中间的第50列至第150列的像素的数据来判断手指是否发生移动。
当然，对于某些特殊情况，也可能设置该N对像素中位于中间区域的像素具有较小的权值，而设置该N对像素中位于边缘区域的像素具有较大的权值，该实施例对此不作限定。
此外，也可以根据第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的总和、方差、标准差等，确定手指是否发生移动。该实施例对此不做限定，任何能够用来表征相邻两行像素的数据之间的差异程度的参数，都可以应用在该实施例中，以判断手指是否发生移动。
在确定上述用于判断手指是否发生移动的阈值，可以考虑像素阵列中的像素行和像素列的数量、每行像素的复位时间、曝光时间和数据读取时间等因素。例如，假设200行×200列的像素阵列，每行像素的复位时间10us，曝光时间30ms，数据读取时间30us，那么，该阈值可以是20％。
该实施例中，第K行像素与第K-1行像素中位于相同列的N对像素中每对像素的数据之间的差异，可以是每对像素的数据的差值；或者是每对像素的数据的变化率。其中，该变化率为每对像素的数据的差值与其中一个像素的数据之间的比值。
例如，在第K行像素与第K-1行像素中位于相同列的N对像素中，假设第i列的一对像素中的两个像素在曝光后输出的数据的值分别为A i和B i，i为0至N-1之间的任意整数。那么，可以根据
Figure PCTCN2020130205-appb-000001
与相应阈值之间的大小，确定手指是否发生移动；或者，可以根据
Figure PCTCN2020130205-appb-000002
或者
Figure PCTCN2020130205-appb-000003
与相应阈值之间的大小，确定手指是否发生移动。
上面仅以计算相邻两行像素中位于同一列的像素对的数据差异为例进行描述，实际应用中，也可以使用相邻两行像素中位于相邻列或附近列的像素对的数据的差异判断手指是否发生移动。
图11示出了基于方式1的一种可能的指纹检测的过程。如图11所示，包括以下步骤。
在步骤1101中，对像素阵列进行曝光和数据读取。
具体地，按照方式1中的曝光顺序，依次对像素阵列中的各行像素开始 进行曝光，并在每行像素曝光结束时读取每行像素的数据。
在步骤1102中，对第K行像素和第K-1行像素的数据进行处理。
具体地，可以确定第K行像素和第K-1行像素的数据之间的差异程度，例如第K行像素和第K-1行像素中位于相同列的N对像素的数据的差值的平均值或者加权平均值，或者N对像素的数据的变化率的平均值或者加权平均值。
在步骤1103中，判断手指是否发生移动。
具体地，根据步骤1102中计算得到的平均值或者加权平均值，判断手指是否发生移动。其中，该平均值或者加权平均值小于相应的阈值时，则认为手指未发生移动，执行步骤1104，即进入指纹检测的流程。
在步骤1104中，对像素阵列的数据进行处理，以提取指纹的特征信息。
具体地，对像素阵列中各行像素的数据进行处理，并提取指纹的特征信息。
在步骤1105中，对指纹的特征信息进行匹配。
在步骤1106中，判断是否匹配。
具体地，将在步骤1105中得到的指纹的特征信息与指纹库中存储的指纹的特征信息进行比对，如果存在匹配的特征信息，则执行步骤1107，否则执行步骤1108。
在步骤1107中，指纹检测成功。
接着可以执行用户的相关操作，例如解锁等。
在步骤1108中，指纹检测失败。
接着可以拒绝执行用户的相关操作，例如解锁等，并且还可以提示用户重新放置手指或者提示用户保持手指不要移动。
应理解，在步骤1103中，如果该平均值或者加权平均值大于相应的阈值，则认为手指发生了移动，因此像素阵列的数据不会用于后续步骤中的指纹检测。此时，则可以提示用户重新放置手指或者提示用户不要移动手指，然后重新执行步骤1101至步骤1103，直至判断手指没有发生移动。
但是，在实际应用中，此时用户的手指可能还没有放置稳定，但是像素阵列已经曝光和读取完数据，因此判定手指发生移动并提示用户重新放置手指，可能会造成上述过程的中断，影响用户体验。所以，在判定手指发生移动时，优选地，可以不对用户进行提示，而是立即重新进入像素阵列的曝光 和数据读取的过程。
也就是说，在步骤1103中，如果该平均值或者加权平均值大于预定的阈值，会重新对像素阵列进行曝光和数据读取，直至判断手指没有发生移动。也即，重新执行步骤1101和步骤1102，直至判断手指没有发生移动后，再进入指纹检测的流程，即步骤1104至步骤1108。
可以看出，采用方式1的曝光方式，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，并使得像素阵列中最先曝光的一行像素与最后曝光的一行像素为像素阵列中相邻的两行像素，从而能够针对该相邻两行像素的数据之间的差异，有效地判断手指是否发生移动。当确定手指发生移动时，则不会进行后续的指纹检测，而是对像素阵列进行重新曝光和数据读取，以确保获得更有效的像素数据，避免指纹检测过程中手指移动引起的像素数据的不准确所导致的误检测。
应理解，可以选择性地判断手指是否发生移动。例如，在安全等级较低的场景下比如指纹解锁等场景下，可以不判断手指是否发生移动，而是在获取M行像素的数据后直接进行指纹检测；而在支付等安全等级高的场景下，才判断手指是否发生移动。
方式2
图像传感器中的该像素阵列包括M行×N列像素。
其中，在步骤510中，按照预定的曝光顺序依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光；接着从第0行像素至第K行像素依次开始进行曝光。
该实施例中，可以将像素阵列的看作两部分，上半部分包括第0行像素至第K-1行像素，下半部分包括第K行像素至第M-1行像素。在对像素阵列进行曝光时，先从下半部分的第K行像素开始，依次对第K行像素至第M-1行像素进行曝光，其次再从上半部分的第0行开始，依次对第0行像素至第K行像素进行曝光。与方式1不同之处在于，在对上半部分的第K-1行像素进行曝光之后，方式2中会对下半部分的第K行像素进行第二次曝光。
这时，在判断曝光过程中手指是否发生移动时，利用的是同一行像素即第K行像素在两次曝光后的数据之间的差异，因此相比于方式1，方式2的曝光方式在判断手指是否发生运动时更加准确。
其中，在对像素阵列进行曝光时，不同的像素行的曝光起始时刻均不同。其中，由于M行像素共用相同的列读取电路对各自的数据进行读取，因此，在第K行像素至第M-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于一行像素的数据的读取时间t；在第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于一行像素的数据的读取时间t。这样，列读取电路在读取完上一行像素的数据之后，就可以接着读取下一行像素的数据。
方式2中的曝光方式的实质也是卷帘快门的曝光方式，只是对各行像素进行曝光的曝光顺序与传统的卷帘快门的曝光顺序不同。相对于全局快门而言，每个像素对应的像素电路中需要的晶体管数目更少，单个像素的有效成像区域的比例更高，列读取电路所读取的噪声也更低。
对静止的物体例如静止的手指进行成像时，相邻的两行像素的响应会很相近；而对运动的物体例如移动的手指进行成像时，由于各行像素的曝光起始时刻不同，因此相邻的两行像素的响应会存在差异。
为了使这种差异能够被辨识出来并能够用于判断手指是否发生移动，该实施例中重新调整了对各行像素的曝光顺序，使得最先曝光的一行像素与最后曝光的一行像素为同一行像素。
该实施例中，最先曝光的一行像素为第K行像素，最后曝光的一行像素也为第K行像素，那么第K行像素的第二次曝光的起始时刻与第一次曝光的起始时刻之间的时间差至少包括单行像素的复位时间、曝光时间和数据读取时间。换句话说，第K行像素的第二次曝光的起始时刻位于第K行像素的第一次曝光后的数据读取完成之后。并且，由于M行像素共用相同的列读取电路对各自的数据进行读取，因此第K行像素的第二次曝光后的数据的读取时间，还应当与M行像素中其他各行像素的数据的读取时间均不重叠。
例如，可以在对第K行像素进行第一次曝光后的数据读取完成后立即开始对第K行像素进行第二次曝光，前提是第二次曝光后的数据在进行数据读取时，不会与第K行像素至第M-1行像素的数据读取时间，以及第0行像素至第K-1行像素的数据读取时间重叠，否则，第K行像素的第二次曝光的起始时刻应当相对于第一次曝光后的数据读取完成时刻向后推移，例如推移至使得第K行像素的第二次曝光后的数据的读取时间位于第K-1行像素的数 据的读取时间之后。
对于同一行像素即第K行像素而言，当手指未发生移动时，第K行像素在两次曝光后的指纹图像对应的数据应当很接近，即差异很小，而手指的移动会导致第K行像素在两次曝光后的数据之间存在明显差异。这时，通过对比第K行像素在两次曝光后的数据之间的差异的大小，就可以判断在上述曝光过程中手指是否发生移动。如果第K行像素在两次曝光后的数据之间的差异小于预设的阈值，则认为手指未发生移动；如果第K行像素在两次曝光后的数据之间的差异之间的差异大于预设的阈值，则认为手指发生了移动。
其中，K可以为小于M的任意整数。也就是说，最先曝光和最后曝光的一行像素可以是M行像素中的任意一行像素，即，进行两次曝光的像素行可以是M行像素中的任意一行像素。
应理解，该实施例中，仅以对第K行像素进行两次曝光为例进行说明，在实际应用中，也可以对多行像素进行两次曝光，以提升判断手指是否移动的准确性，对这些像素行的相关操作均可以参考对第K行的描述。
优选地，M为偶数时，K＝M/2；或者，M为奇数时，K＝(M-1)/2或者K＝(M+1)/2。
如图12所示，假设像素阵列包括偶数行像素，即M为偶数，且K＝M/2。在对M行像素进行曝光时，先对像素阵列中位于下半部分的第M/2行像素至第M-1行像素依次开始进行曝光，当下半部分的所有像素行都已经开始进行曝光之后，对位于上半部分的第0行像素至第M/2-1行像素依次开始进行曝光，最后对第M/2行像素进行第二次曝光。曝光顺序具体为第M/2行、第M/2+1行、第M/2+2行、……、第M-1行、第0行、第1行、第2行、……、第M/2-1行、以及第M/2行。与方式1的曝光方式相比，对各行的曝光顺序相同，但是对M/2行像素多进行了一次曝光。
图12所示的第M/2行像素的第二次曝光的起始时刻与第M/2-1行像素的曝光起始时刻之间的间隔了一行像素的数据读取时间，以避免对第M/2-1行像素的数据读取造成影响。但在实际应用中例如行数较少或者曝光时间较长的情况下，如果第M/2行像素的第二次曝光后的数据的读取时间，不会与其他行的像素的数据读取时间发生重叠，那么在第M/2行像素的第一次曝光后的数据的读取完成之后，就可以开始对第M/2行像素进行复位并曝光。
例如，假设400行×400列的像素阵列，每行像素的复位时间是10us， 曝光时间是30ms，数据读取时间是30us，曝光顺序相邻的两行像素的曝光起始时刻之间的时间差为30us。当第M/2-1行像素开始曝光时，第M/2行像素的第一次曝光进行了11.97ms，第M/2行像素的曝光还并没有结束，因此，M/2行的第二次曝光需要等待M/2行的第一次曝光和数据读取结束，那么第M/2行的第二次曝光和第一次曝光的起始时刻之间的时间差至少等于30.04ms。
方式2由于需要多对第K行进行一次曝光，因此耗时会比方式1的耗时略微长一点。这时，可选地，在对第K行像素进行第二次曝光的同时，可以根据已读取的M行像素的数据，对手指进行指纹检测。
也就是说，当M行像素的数据读取完成时，可以先开始进行像素数据的处理和特征提取等与指纹检测相关的操作，同时在合适的时间并行地对第K行像素进行第二次曝光，从而节省时间。
例如图13所示，为基于方式2的一种可能的指纹检测的过程。如图13所示，包括以下步骤。
在步骤1301中，对像素阵列进行曝光和数据读取。
具体地，按照方式2中的曝光顺序，依次对像素阵列中的各行像素开始进行曝光，并在每行像素曝光结束时读取每行像素的数据。
在步骤1302中，对像素阵列的数据进行处理，以提取指纹的特征信息。
具体地，对像素阵列中各行像素的数据进行处理，并提取指纹的特征信息。
在步骤1303中，对指纹的特征信息进行匹配。
在步骤1304中，对第K行像素进行第二次曝光。
在步骤1305中，对第K行像素的两次曝光后得到的数据进行处理。
可以采用与方式1中类似的处理方式，确定第K行像素在两次曝光后得到的数据之间的差异程度。
其中，步骤1302至步骤1303，以及步骤1304至步骤1305可以并行地执行。
在步骤1306中，判断指纹的特征信息是否匹配以及手指是否发生移动。
根据步骤1305中计算得到的第K行像素在两次曝光后的数据之间的差异，判断手指是否发生移动。并且，将步骤1303中得到的指纹的特征信息与指纹库中存储的指纹的特征信息进行比对。其中，如果第K行像素在两次 曝光后的数据之间的差异小于相应的阈值，则认为手指未发生移动。这时，如果还确定指纹库中存在与该手指的指纹匹配的特征信息，那么执行步骤1307，否则执行步骤1308。
在步骤1307中，指纹检测成功。
接着可以执行用户的相关操作，例如解锁等。
在步骤1308中，指纹检测失败。
接着可以拒绝执行用户的相关操作，例如解锁等，并且还可以提示用户重新放置手指或者提示用户保持手指不要移动。
应理解，在步骤1306中，如果第K行像素在两次曝光后的数据之间的差异大于相应的阈值，则认为手指发生了移动，因此像素阵列的数据不会用于后续步骤中的指纹检测。此时，可以终止正在进行的步骤1302或者1303，并提示用户重新放置手指或者提示用户不要移动手指，然后重新执行步骤1301至步骤1305，直至判断手指没有发生移动。
但是，在实际应用中，此时用户的手指可能还没有放置稳定，但是像素阵列已经曝光和读取完数据，因此判定手指发生移动并提示用户重新放置手指，可能会造成上述过程的中断，影响用户体验。所以，在判定手指发生移动时，优选地，可以不对用户进行提示，而是立即重新进入像素阵列的曝光和数据读取的过程。
也就是说，在步骤1303中，如果第K行像素在两次曝光后的数据之间的差异大于该阈值，会重新对像素阵列进行曝光和数据读取，直至判断手指没有发生移动。也即，重新执行步骤1301至步骤1305，直至判断手指没有发生移动。当判断手指没有发生移动时，等待处理模块对步骤1303的判断结果，如果特征信息匹配成功，则进入指纹检测的流程，即步骤1306至步骤1308。
可以看出，采用方式2的曝光方式，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，并使得像素阵列中最先曝光的一行像素与最后曝光的一行像素为像素阵列中的同一行像素，从而能够针对该行像素在两次曝光后的数据之间的差异，有效地判断手指是否发生移动。当确定手指发生移动时，不会进行后续的指纹检测，而是对像素阵列进行重新曝光和数据读取，以确保获得更有效的像素数据，避免指纹检测过程中手指移动引起的像素数据的不准确所导致的误检测。
应理解，在方式2中，第K行像素的第一次曝光是像素阵列中的最先进行曝光的，第二次曝光是像素阵列中最后进行曝光的。这样可以尽可能地增加第K行像素的两次曝光的起始时刻之间的时间差，以使其对手指的移动更加敏感。
但实际上，第K行像素的两次曝光的曝光顺序之间可以相邻，也可以不相邻。当第K行像素的两次曝光的曝光顺序相邻时，两次曝光的起始时刻之间的时间差例如包括一行像素的复位时间、曝光时间、以及数据读取时间，对于某些像素阵列，例如对于每行像素的曝光时间较长的像素阵列而言，这段时间差足够用于判断手指是否移动。特殊地，当K＝M-1时，即选定进行两次曝光的像素行为像素阵列中的最后一行像素，那么，可以对最后一行像素进行连续两次曝光。
与方式1类似，在衡量第K行像素在两次曝光后的数据之间的差异程度时，需要采用其他方式，获取用于表征第K行像素在两次曝光后的数据之间的差异的参数，并基于该参数确定像素阵列的曝光过程中手指是否发生移动。
该实施例中，可以根据第K行像素的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的平均值，确定手指是否发生移动。例如，该平均值大于阈值时，认为手指发生移动；该平均值小于阈值时，认为手指未发生移动。
或者，也可以根据第K行像素的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的加权平均值，确定手指是否发生移动。例如，该平均值大于阈值时，认为手指发生移动；该平均值小于阈值时，认为手指未发生移动。
其中，考虑到像素阵列的边界上的像素容易受到外界环境光的影响，使得指纹图像的边缘较为模糊。因此，在计算该加权平均值时，可以为第K行像素的N个像素中位于中间区域的像素分配较大的权值甚至100％，并为该N个像素中位于边缘区域的像素分配较小权值甚至0。例如，对于400行×400列的像素阵列，可以仅利用位于中间的第50列至第350列的像素的数据来判断手指是否发生移动。
当然，对于某些特殊情况，也可能设置该N个像素中位于中间区域的像素具有较小的权值，而设置该N个像素中位于边缘区域的像素具有较大的权值，该实施例对此不作限定。
此外，也可以根据第K行像素的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的总和、方差、标准差等，确定手指是否发生移动。该实施例对此不做限定，任何能够用来表征同一行像素在两次曝光后的数据之间的差异程度的参数，都可以应用在该实施例中，以判断手指是否发生移动。
在确定上述用于判断手指是否发生移动的阈值，可以考虑像素阵列中的像素行和像素列的数量、每行像素的复位时间、曝光时间和数据读取时间等因素。例如，假设400行×400列的像素阵列，每行像素的复位时间10us，曝光时间30ms，数据读取时间30us，那么，该阈值可以是10％。
该实施例中，第K行像素中的每个像素在两次曝光后的数据之间的差异，可以是每个像素在第二次曝光后的数据和在第一次曝光后的数据的差值；或者是每个像素在第二次曝光后的数据和在第一次曝光后的数据的变化率。其中，该变化率为每个像素的数据在两次曝光后的数据的差值，与其中一个像素的数据之间的比值。
例如，假设第K行像素中的第i个像素在第一次曝光和第二次曝光后输出的数据的值，分别为A i和B i，i为0至N-1之间的任意整数。那么，可以根据
Figure PCTCN2020130205-appb-000004
与相应阈值之间的大小，确定手指是否发生移动；或者，可以根据
Figure PCTCN2020130205-appb-000005
或者
Figure PCTCN2020130205-appb-000006
与相应阈值之间的大小，确定手指是否发生移动。
应理解，可以选择性地对第K行像素进行第二次曝光。例如，在安全等级较低的场景下比如指纹解锁等场景下，可以不对第K行像素进行第二次曝光，即不执行图13中的步骤1304和步骤1305，在步骤1306中不判断手指是否发生移动；而在支付等安全等级高的场景下，才对第K行像素进行第二次曝光，并判断手指是否发生移动。
方式3
图像传感器中的该像素阵列包括M行×N列像素。
其中，该M行×N列像素包括第一子阵列和第二子阵列，所述第一子阵列包括第0行至第M-1行以及第0列至第P-1列，所述第二子阵列包括第0行至第M-1行以及第P列至第N-1列。
例如图14所示，相当于将该像素阵列划分成，分别位于左侧和右侧的 第一子阵列和第二子阵列。图14中的像素阵列的行数和列数、第一子阵列中的行数和列数、以及第二子阵列中的行数和列数均为示意。实际应用中，像素阵列中的行数和列数远远多于此，第一子阵列中包括的列数和第二子阵列中包括的列数可以相等，也可以不相等。
其中，在步骤510中，按照预定的曝光顺序依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：从第一子阵列中的第0行像素至第K-1行像素依次开始进行曝光，并同时从第二子阵列中的第M-1行像素至第M-K行像素依次开始进行曝光；在经过时间T之后，从第一子阵列中的第M-1行像素至第K行像素依次开始进行曝光，并同时从第二子阵列中的第0行像素至第M-K-1行像素进行曝光。
与方式1不同之处在于，采用方式3的曝光方式最后得到的指纹图像除了可以具有例如图8所示的横向的边界，还可以具有纵向的边界。方式3中需要设置两个行译码器，其中一个行译码器用于控制第一子阵列中各行像素的曝光，另一个译码器用于控制第二子阵列中各行像素的曝光。
该实施例中，可以将第一子阵列的看作两部分，上半部分包括第0行像素至第K-1行像素，下半部分包括第K行像素至第M-1行像素；可以将第二子阵列的看作两部分，同样，上半部分包括第0行像素至第M-K-1行像素，下半部分包括第M-K行像素至第M-1行像素。
在对第一子阵列和第二子阵列进行曝光时，首先，同时从第一子阵列的第0行像素至第K-1行像素，以及从第二子阵列的第M-1行像素至第M-K行像素，依次开始进行曝光；其次，同时从第一子阵列的第M-1行像素至第K行像素，以及第二子阵列的第0行像素至第M-K-1行像素，依次开始进行曝光。
其中，在对像素阵列进行曝光时，第一子阵列的不同像素行的曝光起始时刻不同，第二子阵列的不同像素行的曝光起始时刻不同。其中，由于列读取电路每次可以对第一子阵列和第二子阵列中同时开始曝光的像素行中的一共N个像素的数据同时进行读取，因此，在第一子阵列的第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于单个像素的数据的读取时间t；在第一子阵列的第M-1行像素至第K行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于单个像素的数据的读取时间t；在第二子阵列的 第M-1行像素至第M-K行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于单个像素的数据的读取时间t；在第二子阵列的第0行像素至第M-K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，应当等于或者大于单个像素的数据的读取时间t。这样，列读取电路在读取完上一行像素的数据之后，就可以接着读取下一行像素的数据。
方式3中的曝光方式的实质也是卷帘快门的曝光方式，只是对各行像素进行曝光的曝光顺序与传统的卷帘快门的曝光顺序不同。相对于全局快门而言，每个像素对应的像素电路中需要的晶体管数目更少，单个像素的有效成像区域的比例更高，列读取电路所读取的噪声也更低。
对静止的物体例如静止的手指进行成像时，相邻的两行像素的响应会很相近；而对运动的物体例如移动的手指进行成像时，由于各行像素的曝光起始时刻不同，因此相邻的两行像素的响应会存在差异。
为了使这种差异能够被辨识出来并能够用于判断手指是否发生移动，该实施例中重新调整了对各行像素的曝光顺序，使得相邻的两行像素的曝光顺序之间不相邻，并且第一子阵列和第二子阵列采用不同的曝光顺序。
该实施例中，在第一子阵列中，最先曝光的一行像素为第0行像素，最后曝光的一行像素为第K行像素；在第二子阵列中，最先曝光的一行像素为第M-1行像素，最后曝光的一行像素为第M-K-1行像素。那么，在第一阵列中，第K-1行像素和第K行像素的曝光起始时刻之间的时间差等于或者大于t×(M-K)；在第二子阵列中，第M-K-1行像素和第M-K行像素的曝光起始时刻之间的时间差等于或者大于t×(M-K)，其中t为单个像素的数据读取时间。并且，第P列像素和第P-1列像素的曝光起始时刻之间也存在一定的时间差。因此，可以根据横向的相邻两行像素的数据的差异，以及竖向的相邻两行像素的数据的差异，共同判断手指是否发生移动，提高了对手指是否移动进行判断的准确性。
可以配置两个阈值，即第一阈值和第二阈值。例如，如果第一子阵列的第K行像素和第K-1行像素的数据之间的差异，以及第二子阵列的第M-K行和第M-K-1行之间的差异，大于第一阈值，且第P列像素和第P-1列像素的数据之间的差异大于第二阈值，则认为上述曝光过程中手指发生了移动；如果第一子阵列的第K行像素和第K-1行像素的数据之间的差异，以及第二 子阵列的第M-K行和第M-K-1行之间的差异，小于第一阈值，且第P列像素和第P-1列像素的数据之间的差异小于第二阈值，则认为上述曝光过程中手指未发生移动。
其中，K可以为小于M的任意整数，P可以为小于N的任意整数。
优选地，M为偶数时，K＝M/2；或者，M为奇数时，K＝(M-1)/2或者K＝(M+1)/2。
优选地，P为偶数时，P＝N/2；或者，P为奇数时，P＝(N-1)/2或者P＝(N+1)/2。
如图15和图16所示，假设像素阵列包括偶数行像素，即M为偶数，且K＝M/2。如图15所示，在对第一子阵列的M行像素进行曝光时，先对像素阵列中位于上半部分的第0行像素至第M/2-1行像素依次开始进行曝光，当上半部分的所有像素行都已经开始进行曝光之后，再从位于下半部分的第M-1行像素开始，依次开始对第M-1行像素至第M/2行像素进行曝光。具体的曝光顺序可以参考图17，其中，图17中的实线箭头表示先曝光的像素阵列的曝光顺序，虚线箭头表示后曝光的像素阵列的曝光顺序。第一子阵列的曝光顺序具体为第0行、第1行、第2行、……、第M/2-1行、第M-1行、第M-2行、……、第M/2行。如图16所示，在对第二子阵列的M行像素进行曝光时，先从下半部分的第M-1行像素开始，对第M-1行像素至第M/2行像素依次开始进行曝光，当下半部分的所有像素行都已经开始进行曝光之后，再从位于上半部分的第0行像素开始，依次开始对第0行像素至第M/2-1行像素进行曝光。具体的曝光顺序可以参考图17，其中，图17中的两个实线箭头表示同时并行进行曝光的像素阵列，两个虚线箭头表示并行曝光的像素阵列。第二子阵列的曝光顺序具体为第M-1行、第M-2行、第M-3行、……、第M/2行、第0行、第1行、第2行、……、第M/2-1行。
采用图15和图16所示的方式，指纹图像的上半部分和下半部分会产生一个明显边界，并且左半部分与右半部分也会产生一个明显边界，横向边界和纵向边界是该实施例中刻意制造的边界，横向边界两侧对应的两行像素的曝光起始时刻之间的时间差至少为t×(M/2)，纵向边界两侧对应的两列像素的曝光起始时刻之间的时间差至少为t×(M/2)。那么，对于移动的手指而言，这种显著的时间差会导致相邻像素行和相邻像素列对手指在空间上的位置移动所产生的响应具有明显差异。而对于静止的手指，即使存在显著的 时间差，但是不存在手指在空间上的位置移动，因此相邻像素行和相邻像素列不会对该手指移动产生的响应具有明显差异。
该实施例中，第一子阵列的第K-1行像素和第二子阵列的第K行像素开始曝光后的时间T之后，对第一子阵列的第M-1行像素和第二子阵列的第0行像素开始进行曝光。T等于单个像素的数据的读取时间t时，第一子阵列的第K-1行像素的开始曝光后经过时间T，就可以开始对第一子阵列的第M-1行像素开始进行曝光，例如上述的图15所示；第二子阵列的第M-K行像素的开始曝光后经过时间T，就可以开始对第二子阵列的第0行像素开始进行曝光，例如上述的图16所示。
但是，对于一些情况，例如行数或列数较少的像素阵列，第K-1行像素和第K行像素的曝光起始时刻之间的时间差以及第P列像素和第P-1列像素的曝光起始时刻之间的时间差，可能不足够用来判断手指是否移动，因此，可以将T设置为大于单个像素的数据读取时间t，那么可以使第K-1行像素和第K行像素的曝光起始时刻之间的时间差增大以及使第P列像素和第P-1列像素的曝光起始时刻之间的时间差增大。从而使相邻两行像素的数据之间的差异更加明显，更容易判断手指是否移动。
应理解，本申请实施例中，由于列读取电路能够同时读取一行像素的数据，即同时读取N个像素的数据。因此，这里所述的单个像素的读取时间，就等于一行像素的读取时间。
可以看出，采用方式3的曝光方式，将像素阵列划分为第一子阵列和第二子阵列，并按照不同的曝光顺序，分别对第一子阵列中的各行像素和第二子阵列中的各行像素依次开始进行曝光，并使得第一子阵列中特定的相邻两行像素的曝光顺序之间不相邻，第二子阵列中特定的相邻两行像素的曝光顺序之间不相邻，以及特定的相邻两列像素的曝光顺序不相邻，从而能够针对该相邻两行像素之间的差异以及该相邻两列像素之间的差异，有效地判断手指是否发生移动。当确定手指发生移动时，则不会进行后续的指纹检测，而是对像素阵列进行重新曝光和数据读取，以确保获得更有效的像素数据，避免指纹检测过程中手指移动引起的像素数据的不准确所导致的误检测。
与方式1类似，在衡量相邻两行像素的数据之间的差异程度以及相邻两列像素的数据之间的差异程度时，需要采用其他方式，获取用于表征该相邻两行像素的数据之间差异的参数以及该相邻两列像素的数据之间差异的参 数，并基于该参数确定像素阵列的曝光过程中手指是否发生移动。
该实施例中，可以根据第一子阵列的第K行像素与第K-1行像素中位于相同列以及第二子阵列的第M-K行像素和第M-K-1行像素中位于相同列的一共N对像素的数据之间的差异的平均值或者加权平均值等参数，以及P列像素与第P-1列像素中位于相同行的M对像素的数据之间的差异的平均值或者加权平均值等参数，确定手指是否发生移动。例如，该参数的值大于阈值时，认为手指发生移动；该参数的值小于阈值时，认为手指未发生移动。
其中，考虑到像素阵列的边界上的像素容易受到外界环境光的影响，使得指纹图像的边缘较为模糊。因此，在计算该加权平均值时，可以为中间区域的像素分配较大的权值甚至100％，并为边缘区域的像素分配较小权值甚至0。例如，对于200行×200列的像素阵列，可以仅利用位于中间的第50列至第150列的像素的数据，以及位于中间的第50行至第150行像素的数据，来判断手指是否发生移动。
当然，对于某些特殊情况，也可能设置中间区域的像素具有较小的权值，而设置边缘区域的像素具有较大的权值，该实施例对此不作限定。
此外，也可以根据相邻两行像素的数据之间的差异的总和、方差或者标准差等参数，以及相邻两列像素的数据之间的差异的总和、方差或者标准差等参数，确定手指是否发生移动。该实施例对此不做限定，任何能够用来表征相邻两行像素的数据之间的差异程度的参数，以及用来表征相邻两列像素的数据之间的差异程度的参数，都可以应用在该实施例中，以判断手指是否发生移动。
在确定上述用于判断手指是否发生移动的阈值，可以考虑像素阵列中的像素行和像素列的数量、每行像素的复位时间、曝光时间和数据读取时间等因素。
该实施例中，相邻两行像素中位于相同列的N对像素中每对像素的数据之间的差异，可以是每对像素的数据的差值；或者是每对像素的数据的变化率。其中，该变化率为每对像素的数据的差值与其中一个像素的数据之间的比值。
相邻两列像素中位于相同行的M对像素中每对像素的数据之间的差异，可以是每对像素的数据的差值；或者是每对像素的数据的变化率。其中，该变化率为每对像素的数据的差值与其中一个像素的数据之间的比值。
例如，在第一子阵列的第K行像素与第K-1行像素中位于相同列以及第二子阵列的第M-K行像素和第M-K-1行像素中位于相同列的一共N对像素中，假设第i列的其中一对像素中的两个像素在曝光后输出的数据的值分别为A i和B i，i为0至N-1之间的任意整数。在第P列像素与第P-1列像素中位于相同行的M对像素中，假设第j行的一对像素中的两个像素在曝光后输出的数据的值分别为C j和D j，j为0至M-1之间的任意整数。那么，可以根据
Figure PCTCN2020130205-appb-000007
与阈值Q1之间的大小，以及
Figure PCTCN2020130205-appb-000008
与阈值Q2之间的大小，确定手指是否发生移动；或者，可以根据
Figure PCTCN2020130205-appb-000009
或者
Figure PCTCN2020130205-appb-000010
与阈值Q3之间的大小，以及根据
Figure PCTCN2020130205-appb-000011
或者
Figure PCTCN2020130205-appb-000012
与阈值Q4之间的大小，确定手指是否发生移动。
方式3中针对第一子阵列中各行像素和第二子阵列中各行像素的曝光过程以及数据计算过程的其他相关描述，可以参考针对方式1的相关描述，为了简洁，这里不再赘述。
本申请实施例还提供一种指纹检测的装置，该指纹检测装置可以执行上述任意实施例中的指纹检测的方法，对该指纹检测装置的详细描述可以参考针对前述指纹检测的方法的描述。
如图18所示，该指纹检测装置1800包括图像传感器1810，该图像传感器1810包括：
像素阵列；
行译码器，用于按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，其中，所述像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，或者对所述像素阵列中特定的一行像素进行两次曝光；以及，
列读取电路，用于在每行像素曝光结束时读取所述每行像素的数据，其中，所述相邻两行像素的数据之间的差异，或者所述特定的一行像素的两次曝光后的数据之间的差异，用于确定所述像素阵列的曝光过程中手指是否发生移动；
其中，所述手指发生移动时所述像素阵列的数据不用于所述手指的指纹 检测，和/或，所述手指未发生移动时所述像素阵列的数据用于所述手指的指纹检测。
因此，指纹检测装置能够按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，并使得像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，或者使得像素阵列中特定的一行像素进行两次曝光，从而能够根据该特定的相邻两行像素的数据之间的差异，或者根据该特定的一行像素的两次曝光后的数据之间的差异，有效地判断手指是否发生移动。如果手指未发生移动，则该特定的相邻两行像素的数据之间的差异或者该特定的一行像素的两次曝光后的数据之间的差异会很小，甚至没有差异；如果手指发生移动，则该差异会较为明显。当确定手指发生移动时，像素阵列的数据就不会用于进行后续的指纹检测，从而避免不必要的误检测，提高了指纹检测的准确性。
可选地，在一种实现方式中，指纹检测装置1800还包括处理模块1820，处理模块1820用于：根据所述相邻两行像素的数据之间的差异，或者所述特定的一行像素的两次曝光后的数据之间的差异，确定所述像素阵列的曝光过程中手指是否发生移动。
可选地，在一种实现方式中，处理模块1820具体用于：若所述差异大于阈值，则确定所述手指发生移动；和/或，若所述差异小于所述阈值，则确定所述手指未发生移动。
可选地，在一种实现方式中，所述像素阵列包括M行×N列像素，所述相邻两行像素分别为所述像素阵列中最先曝光的一行像素与最后曝光的一行像素；其中，所述行译码器具体用于：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K≠0且K小于M；在经过时间T之后，从第0行像素至第K-1行像素依次开始进行曝光，其中，T等于一行像素的数据的读取时间，或者T大于一行像素的数据的读取时间。
可选地，在一种实现方式中，所述相邻两行像素的数据之间的差异，包括：第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值。
可选地，在一种实现方式中，所述N对像素中每对像素的数据的差异包括：所述每对像素的数据的差值；或者，所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的 比值。
可选地，在一种实现方式中，所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
可选地，在一种实现方式中，所述像素阵列包括M行×N列像素，所述像素阵列中最先曝光的一行像素与最后曝光的一行像素为进行了两次曝光的所述特定的一行像素；其中，所述行译码器具体用于：从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K小于M；接着从第0行像素至第K行像素依次开始进行曝光。
可选地，在一种实现方式中，第K行像素的第二次曝光的起始时刻位于第K行像素的第一次曝光后的数据读取完成之后，且第K行像素的第二次曝光后的数据的读取时间，与M行像素中其他各行像素的数据的读取时间均不重叠。
可选地，在一种实现方式中，所述特定的一行像素的两次曝光后的数据之间的差异，包括：第K行像素中的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的平均值或者加权平均值。
可选地，在一种实现方式中，所述N个像素中每个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异，包括：所述每个像素在第二次曝光后的数据与在第一次曝光后的数据的差值；或者，所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的变化率，其中，所述变化率为所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的差值，与其中一次曝光后的数据之间的比值。
可选地，在一种实现方式中，所述N个像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
可选地，在一种实现方式中，所述方法还包括：在对第K行像素进行第二次曝光的同时，根据已读取的M行像素的数据，对所述手指进行指纹检测。
可选地，在一种实现方式中，所述像素阵列包括M行×N列像素，所述M行×N列像素包括第一子阵列和第二子阵列，所述第一子阵列包括第0行至第M-1行以及第0列至第P-1列，所述第二子阵列包括第0行至第M-1行以及第P列至第N-1列；其中，所述行译码器具体用于：从第一子阵列中的第0行像素至第K-1行像素依次开始进行曝光，并同时从第二子阵列中的 第M-1行像素至第M-K行像素依次开始进行曝光；在经过时间T之后，从第一子阵列中的第M-1行像素至第K行像素依次开始进行曝光，并同时从第二子阵列中的第0行像素至第M-K-1行像素依次开始进行曝光，其中，T等于单个像素的数据的读取时间，或者T大于单个像素的数据的读取时间。
可选地，在一种实现方式中，第P列像素与第P-1列像素的数据之间的差异，与所述相邻两行像素的数据之间的差异，共同用于确定所述像素阵列的曝光过程中手指是否发生移动；其中，所述相邻两行像素的数据之间的差异，包括：第一子阵列的第K行像素与第K-1行像素中位于相同列以及第二子阵列的第M-K行像素和第M-K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值；以及，第P列像素与第P-1列像素的数据之间的差异，包括：第P列像素与第P-1列像素中位于相同行的M对像素的数据之间的差异的平均值或者加权平均值。
可选地，在一种实现方式中，所述N对像素和所述M对像素中的每对像素的数据的差异包括：所述每对像素的数据的差值；或者，所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
可选地，在一种实现方式中，所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值；以及，所述M对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
可选地，在一种实现方式中，P为偶数，P＝N/2；或者，P为奇数，P＝(N-1)/2或者P＝(N+1)/2。
可选地，在一种实现方式中，M为偶数，K＝M/2；或者，M为奇数，K＝(M-1)/2或者K＝(M+1)/2。
可选地，在一种实现方式中，在第K行像素至第M-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间；在第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间。
可选地，在一种实现方式中，所述指纹检测装置还包括设置在所述图像传感器上方的光路引导结构，所述光路引导结构包括：微透镜阵列，包括多个微透镜；以及，多个挡光层，设置在所述微透镜阵列下方，其中每个挡光 层上设置有与所述多个微透镜分别对应的多个开孔；其中，所述微透镜用于将所述手指返回的光信号会聚到所述多个挡光层中的对应的开孔，并通过所述多个挡光层中的对应的开孔，传输至所述像素阵列。
其中，该光路引导结构仅为示例，在一些场景下，也可以利用透镜或者准直小孔阵列将手指返回的光信号引导至图像传感器中的该像素阵列。
本申请实施例还提供了一种电子设备，包括上述任一实施例中所述的指纹检测装置。
图19和图20给出了本申请实施例的指纹检测装置的一种可能的结构。图19为电子设备10的定向示意图，图20为图19所示的电子设备10沿A-A’方向的部分剖面示意图。
电子设备10包括显示屏120和指纹检测装置1800。指纹检测装置1800包括图像传感器1810，该图像传感器1810包括具有多个像素131的像素阵列133、行译码器以及列读取电路等。其中，像素阵列133所在区域或者其感应区域为指纹检测装置1800的指纹检测区域103。图19和图20中未示出处理模块1820，该处理模块1820例如可以是指纹检测装置1800的MUC。在实际应用中，处理模块1820可以设置在图像传感器1810下方。
如图20所示，指纹检测装置1800还包括设置在图像传感器1810上方的光路引导结构1830。光路引导结构1830用于将手指返回的光信号引导至图像传感器1810。
本申请实施例对指纹检测装置1800中的光路引导结构1830不做任何限定。例如，光路引导结构1830可以包括由多个微透镜组成的微透镜阵列。进一步地，在微透镜阵列的下方还可以具有至少一个挡光层，其中每个挡光层上设置有与该多个微透镜分别对应的多个开孔，并且像素阵列133包括与该多个微透镜对应的多个像素131。每个微透镜用于将手指返回的光信号会聚到各个挡光层中对应的开孔，以使该光信号依次通过各个挡光层中对应的开孔，传输至像素阵列133中对应的像素131。
又例如，光路引导结构1830可以包括在半导体硅片制作而成的准直器层，其具有多个准直单元或者微孔阵列，该准直单元可以是小孔。
又例如，光路引导结构1830可以包括光学透镜层，其具有一个或多个透镜单元，该透镜单元可以是由一个或多个非球面透镜组成的透镜组。
显示屏120向指纹检测区域103上方的手指140发出一束光线111，光 线111在手指140的表面发生反射形成反射光或者经过手指140内部散射而形成散射光。由于指纹的脊(ridge)141与谷(valley)142对于光线的反射能力不同，因此，来自指纹脊的反射光151和来自指纹谷的反射光152具有不同的光强，反射光经过光路引导结构1830后，被图像传感器1810中的像素阵列133接收并转换为相应的电信号，即指纹检测信号。基于该指纹检测信号便可以获得指纹图像的数据，并进一步用于指纹匹配和验证，从而在电子设备10中实现光学指纹检测功能。
进一步地，电子设备10还可以包括用于指纹检测的激励光源。
其中，显示屏120可以采用具有自发光显示单元的显示屏，比如有机发光二极管(Organic Light-Emitting Diode，OLED)显示屏或者微型发光二极管(Micro-LED)显示屏。以采用OLED显示屏为例，光学指纹模组130可以利用该OLED显示屏120中位于指纹检测区域103的显示单元作为光学指纹检测的激励光源。
指纹检测装置1800也可以应用于非自发光的显示屏，例如液晶显示屏。这时，可以采用内置光源或者外置光源来提供用于进行指纹检测的光信号。以应用在具有背光模组和液晶面板的液晶显示屏为例，用于指纹检测的激励光源可以具体为红外光源或者特定波长非可见光的光源，其可以设置在液晶显示屏的背光模组下方或者设置在电子设备10的保护盖板下方的边缘区域。
作为示例而非限定，本申请实施例中的电子设备可以为终端设备、手机、平板电脑、笔记本电脑、台式机电脑、游戏设备、车载电子设备或穿戴式智能设备等便携式或移动计算设备，以及电子数据库、汽车、银行自动柜员机(Automated Teller Machine，ATM)等其他电子设备。该穿戴式智能设备包括功能全、尺寸大、可不依赖智能手机实现完整或部分功能的设备，例如智能手表或智能眼镜等，以及包括只专注于某一类应用功能并且需要和其它设备如智能手机配合使用的设备，例如各类进行体征监测的智能手环、智能首饰等设备。
需要说明的是，在不冲突的前提下，本申请描述的各个实施例和/或各个实施例中的技术特征可以任意的相互组合，组合之后得到的技术方案也应落入本申请的保护范围。
本申请实施例中所揭露的系统、装置和方法，可以通过其它方式实现。例如，以上所描述的方法实施例的一些特征可以忽略或者不执行。以上所描 述的装置实施例仅仅是示意性的，单元的划分仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，多个单元或组件可以结合或者可以集成到另一个系统。另外，各单元之间的耦合或各个组件之间的耦合可以是直接耦合，也可以是间接耦合，上述耦合包括电的、机械的或其它形式的连接。
应理解，本申请实施例中的具体的例子只是为了帮助本领域技术人员更好地理解本申请实施例，而非限制本申请实施例的范围，本领域技术人员可以在上述实施例的基础上进行各种改进和变形，而这些改进或者变形均落在本申请的保护范围内。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (42)

  1. 一种指纹检测的方法，其特征在于，所述方法包括：
    按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，其中，所述像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，或者对所述像素阵列中特定的一行像素进行两次曝光；
    在每行像素曝光结束时读取所述每行像素的数据，其中，所述相邻两行像素的数据之间的差异或者所述特定的一行像素的两次曝光后的数据之间的差异，用于确定所述像素阵列的曝光过程中手指是否发生移动；
    其中，所述手指发生移动时所述像素阵列的数据不用于所述手指的指纹检测，和/或，所述手指未发生移动时所述像素阵列的数据用于所述手指的指纹检测。
  2. 根据权利要求1所述的方法，其特征在于，所述方法还包括：
    根据所述相邻两行像素的数据之间的差异，或者所述特定的一行像素的两次曝光后的数据之间的差异，确定所述像素阵列的曝光过程中手指是否发生移动。
  3. 根据权利要求2所述的方法，其特征在于，所述根据所述相邻两行像素的数据之间的差异，确定所述像素阵列的曝光过程中手指是否发生移动，包括：
    若所述差异大于阈值，则确定所述手指发生移动；和/或，
    若所述差异小于所述阈值，则确定所述手指未发生移动。
  4. 根据权利要求1至3中任一项所述的方法，其特征在于，所述像素阵列包括M行×N列像素，所述相邻两行像素分别为所述像素阵列中最先曝光的一行像素与最后曝光的一行像素；
    其中，所述按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：
    从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K≠0且K小于M；
    在经过时间T之后，从第0行像素至第K-1行像素依次开始进行曝光，其中，T等于一行像素的数据的读取时间，或者T大于一行像素的数据的读取时间。
  5. 根据权利要求4所述的方法，其特征在于，所述相邻两行像素的数 据之间的差异，包括：
    第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值。
  6. 根据权利要求5所述的方法，其特征在于，所述N对像素中每对像素的数据的差异包括：
    所述每对像素的数据的差值；或者，
    所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
  7. 根据权利要求5所述的方法，其特征在于，所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
  8. 根据权利要求1至3中任一项所述的方法，其特征在于，所述像素阵列包括M行×N列像素，所述像素阵列中最先曝光的一行像素与最后曝光的一行像素为进行了两次曝光的所述特定的一行像素；
    其中，所述按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：
    从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K小于M；
    接着从第0行像素至第K行像素依次开始进行曝光。
  9. 根据权利要求8所述的方法，其特征在于，第K行像素的第二次曝光的起始时刻位于第K行像素的第一次曝光后的数据读取完成之后，且第K行像素的第二次曝光后的数据的读取时间，与M行像素中其他各行像素的数据的读取时间均不重叠。
  10. 根据权利要求8或9所述的方法，其特征在于，所述特定的一行像素的两次曝光后的数据之间的差异，包括：
    第K行像素中的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的平均值或者加权平均值。
  11. 根据权利要求10所述的方法，其特征在于，所述N个像素中每个像素在第二次曝光后的数据和在第一次曝光后的数据之间的差异，包括：
    所述每个像素在第二次曝光后的数据与在第一次曝光后的数据的差值；或者，
    所述每个像素在第二次曝光后的数据与在第一次曝光后的数据的变化 率，其中，所述变化率为所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的差值，与其中一次曝光后的数据之间的比值。
  12. 根据权利要求11所述的方法，其特征在于，所述N个像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
  13. 根据权利要求8至11中任一项所述的方法，其特征在于，所述方法还包括：
    在对第K行像素进行第二次曝光的同时，根据已读取的M行像素的数据，对所述手指进行指纹检测。
  14. 根据权利要求1至3中任一项所述的方法，其特征在于，所述像素阵列包括M行×N列像素，所述M行×N列像素包括第一子阵列和第二子阵列，所述第一子阵列包括第0行至第M-1行以及第0列至第P-1列，所述第二子阵列包括第0行至第M-1行以及第P列至第N-1列；
    其中，所述按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，包括：
    从第一子阵列中的第0行像素至第K-1行像素依次开始进行曝光，并同时从第二子阵列中的第M-1行像素至第M-K行像素依次开始进行曝光；
    在经过时间T之后，从第一子阵列中的第M-1行像素至第K行像素依次开始进行曝光，并同时从第二子阵列中的第0行像素至第M-K-1行像素依次开始进行曝光，其中，T等于单个像素的数据的读取时间，或者T大于单个像素的数据的读取时间。
  15. 根据权利要求14所述的方法，其特征在于，第P列像素与第P-1列像素的数据之间的差异，与所述相邻两行像素的数据之间的差异，共同用于确定所述像素阵列的曝光过程中手指是否发生移动，
    其中，所述相邻两行像素的数据之间的差异，包括：
    第一子阵列的第K行像素与第K-1行像素中位于相同列以及第二子阵列的第M-K行像素和第M-K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值；以及，
    第P列像素与第P-1列像素的数据之间的差异，包括：
    第P列像素与第P-1列像素中位于相同行的M对像素的数据之间的差异的平均值或者加权平均值。
  16. 根据权利要求15所述的方法，其特征在于，所述N对像素和所述 M对像素中的每对像素的数据的差异包括：
    所述每对像素的数据的差值；或者，
    所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
  17. 根据权利要求16所述的方法，其特征在于，
    所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值；以及，
    所述M对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
  18. 根据权利要求14至17中任一项所述的方法，其特征在于，
    P为偶数，P＝N/2；或者，
    P为奇数，P＝(N-1)/2或者P＝(N+1)/2。
  19. 根据权利要求4至18中任一项所述的方法，其特征在于，
    M为偶数，K＝M/2；或者，
    M为奇数，K＝(M-1)/2或者K＝(M+1)/2。
  20. 根据权利要求4至13中任一项所述的方法，其特征在于，
    在第K行像素至第M-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间；
    在第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间。
  21. 一种指纹检测装置，其特征在于，所述指纹检测装置包括图像传感器，所述图像传感器包括：
    像素阵列；
    行译码器，用于按照预定的曝光顺序，依次对用于指纹检测的像素阵列中的各行像素开始进行曝光，其中，所述像素阵列中特定的相邻两行像素的曝光顺序之间不相邻，或者对所述像素阵列中特定的一行像素进行两次曝光；以及，
    列读取电路，用于在每行像素曝光结束时读取所述每行像素的数据，其中，所述相邻两行像素的数据之间的差异或者所述特定的一行像素的两次曝光后的数据之间的差异，用于确定所述像素阵列的曝光过程中手指是否发生移动；
    其中，所述手指发生移动时所述像素阵列的数据不用于所述手指的指纹检测，和/或，所述手指未发生移动时所述像素阵列的数据用于所述手指的指纹检测。
  22. 根据权利要求21所述的指纹检测装置，其特征在于，所述指纹检测装置还包括处理模块，所述处理模块用于：
    根据所述相邻两行像素的数据之间的差异，或者所述特定的一行像素的两次曝光后的数据之间的差异，确定所述像素阵列的曝光过程中手指是否发生移动。
  23. 根据权利要求22所述的指纹检测装置，其特征在于，所述处理模块具体用于：
    若所述差异大于阈值，则确定所述手指发生移动；和/或，
    若所述差异小于所述阈值，则确定所述手指未发生移动。
  24. 根据权利要求21至23中任一项所述的指纹检测装置，其特征在于，所述像素阵列包括M行×N列像素，所述相邻两行像素分别为所述像素阵列中最先曝光的一行像素与最后曝光的一行像素；
    其中，所述行译码器具体用于：
    从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K≠0且K小于M；
    在经过时间T之后，从第0行像素至第K-1行像素依次开始进行曝光，其中，T等于一行像素的数据的读取时间，或者T大于一行像素的数据的读取时间。
  25. 根据权利要求24所述的指纹检测装置，其特征在于，所述相邻两行像素的数据之间的差异，包括：
    第K行像素与第K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值。
  26. 根据权利要求25所述的指纹检测装置，其特征在于，所述N对像素中每对像素的数据的差异包括：
    所述每对像素的数据的差值；或者，
    所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
  27. 根据权利要求26所述的指纹检测装置，其特征在于，所述N对像 素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
  28. 根据权利要求21至23中任一项所述的指纹检测装置，其特征在于，所述像素阵列包括M行×N列像素，所述像素阵列中最先曝光的一行像素与最后曝光的一行像素为进行了两次曝光的所述特定的一行像素；
    其中，所述行译码器具体用于：
    从M行像素中的第K行像素至第M-1行像素依次开始进行曝光，K小于M；
    接着从第0行像素至第K行像素依次开始进行曝光。
  29. 根据权利要求28所述的指纹检测装置，其特征在于，第K行像素的第二次曝光的起始时刻位于第K行像素的第一次曝光后的数据读取完成之后，且第K行像素的第二次曝光后的数据的读取时间，与M行像素中其他各行像素的数据的读取时间均不重叠。
  30. 根据权利要求28或29所述的指纹检测装置，其特征在于，所述特定的一行像素的两次曝光后的数据之间的差异，包括：
    第K行像素中的N个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异的平均值或者加权平均值。
  31. 根据权利要求30所述的指纹检测装置，其特征在于，所述N个像素中每个像素在第二次曝光后的数据与在第一次曝光后的数据之间的差异，包括：
    所述每个像素在第二次曝光后的数据与在第一次曝光后的数据的差值；或者，
    所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的变化率，其中，所述变化率为所述每个像素在第二次曝光后的数据和在第一次曝光后的数据的差值，与其中一次曝光后的数据之间的比值。
  32. 根据权利要求31所述的指纹检测装置，其特征在于，所述N个像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
  33. 根据权利要求28至31中任一项所述的指纹检测装置，其特征在于，所述方法还包括：
    在对第K行像素进行第二次曝光的同时，根据已读取的M行像素的数据，对所述手指进行指纹检测。
  34. 根据权利要求21至23中任一项所述的指纹检测装置，其特征在于， 所述像素阵列包括M行×N列像素，所述M行×N列像素包括第一子阵列和第二子阵列，所述第一子阵列包括第0行至第M-1行以及第0列至第P-1列，所述第二子阵列包括第0行至第M-1行以及第P列至第N-1列；
    其中，所述行译码器具体用于：
    从第一子阵列中的第0行像素至第K-1行像素依次开始进行曝光，并同时从第二子阵列中的第M-1行像素至第M-K行像素依次开始进行曝光；
    在经过时间T之后，从第一子阵列中的第M-1行像素至第K行像素依次开始进行曝光，并同时从第二子阵列中的第0行像素至第M-K-1行像素依次开始进行曝光，其中，T等于单个像素的数据的读取时间，或者T大于单个像素的数据的读取时间。
  35. 根据权利要求34所述的指纹检测装置，其特征在于，第P列像素与第P-1列像素的数据之间的差异，与所述相邻两行像素的数据之间的差异，共同用于确定所述像素阵列的曝光过程中手指是否发生移动，
    其中，所述相邻两行像素的数据之间的差异，包括：
    第一子阵列的第K行像素与第K-1行像素中位于相同列以及第二子阵列的第M-K行像素和第M-K-1行像素中位于相同列的N对像素的数据之间的差异的平均值或者加权平均值；以及，
    第P列像素与第P-1列像素的数据之间的差异，包括：
    第P列像素与第P-1列像素中位于相同行的M对像素的数据之间的差异的平均值或者加权平均值。
  36. 根据权利要求35所述的指纹检测装置，其特征在于，所述N对像素和所述M对像素中的每对像素的数据的差异包括：
    所述每对像素的数据的差值；或者，
    所述每对像素的数据的变化率，其中，所述变化率为所述每对像素的数据的差值与其中一个像素的数据之间的比值。
  37. 根据权利要求36所述的指纹检测装置，其特征在于，
    所述N对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值；以及，
    所述M对像素中位于中间区域的像素对应的权值，大于位于边缘区域的像素对应的权值。
  38. 根据权利要求34至37中任一项所述的指纹检测装置，其特征在于，
    P为偶数，P＝N/2；或者，
    P为奇数，P＝(N-1)/2或者P＝(N+1)/2。
  39. 根据权利要求24至38中任一项所述的指纹检测装置，其特征在于，
    M为偶数，K＝M/2；或者，
    M为奇数，K＝(M-1)/2或者K＝(M+1)/2。
  40. 根据权利要求24至33中任一项所述的指纹检测装置，其特征在于，
    在第K行像素至第M-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间；
    在第0行像素至第K-1行像素中，曝光顺序相邻的两行像素的曝光的起始时刻之间的时间间隔，大于或等于一行像素的数据的读取时间。
  41. 根据权利要求21至40中任一项所述的指纹检测装置，其特征在于，所述指纹检测装置还包括设置在所述图像传感器上方的光路引导结构，所述光路引导结构包括：
    微透镜阵列，包括多个微透镜；以及，
    多个挡光层，设置在所述微透镜阵列下方，其中每个挡光层上设置有与所述多个微透镜分别对应的多个开孔；
    其中，所述微透镜用于将所述手指返回的光信号会聚到所述多个挡光层中的对应的开孔，并通过所述多个挡光层中的对应的开孔，传输至所述像素阵列。
  42. 一种电子设备，其特征在于，包括上述权利要求21至41中任一项所述的指纹检测装置。
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