Calibration methods, apparatus, electronic devices and storage media for image sensor chips

Abstract

This invention discloses a calibration method, apparatus, electronic device, and storage medium for an image sensor chip. The calibration method includes: acquiring at least one frame of target image data of an optically dark area, and a digital signal reference value corresponding to the target image data; calibrating each first pixel unit according to the first image signal and digital signal reference value of the first pixel unit in the target image data to determine a reference pixel unit characterizing noise stripes; and calibrating each second pixel unit according to the reference pixel unit, based on the row or column distribution of noise stripes in the image sensor chip. This invention utilizes image data of the optically dark area to calibrate the row or column stripes of the image sensor chip, eliminating the need for calibration based on image data of the photosensitive area, reducing calibration computation, and effectively improving stripe calibration efficiency. Furthermore, calibration can be performed automatically in real time as needed, effectively improving stripe calibration accuracy.

Description

Technical Field

[0001] This invention relates to the field of image sensor technology, and more specifically to a calibration method, apparatus, electronic device, and storage medium for an image sensor chip. Background Technology

[0002] CMOS image sensor chips convert received light signals into analog electrical signals, which are then converted into digital signals by an analog-to-digital converter (ADC). Each column of pixels shares one ADC. Due to circuit mismatches, manufacturing process variations, and differences in ADC bias voltages, some columns of pixels may exhibit fixed-pattern noise or random noise, resulting in column stripes in the image. Furthermore, the presence of parasitic resistance and capacitance can cause inconsistent time delays in the output digital signals of different columns, leading to row stripes. When the sensor receives insufficient light and has a high internal gain, these row or column stripe problems can be amplified several times, significantly impacting the imaging quality of the CMOS image sensor chip. Therefore, correctly calibrating the positions of row or column stripes and employing appropriate methods is crucial to ensuring image quality.

[0003] In related technologies, the column coordinates of column stripes and the row coordinates of row stripes are usually calibrated by testing the CMOS image sensor chip before it leaves the factory. This is used for stripe calibration algorithms. However, this method cannot calibrate the row and column stripes that gradually increase after the chip ages. Summary of the Invention

[0004] This invention provides a calibration method, apparatus, electronic device, and storage medium for an image sensor chip, aiming to improve the stripe calibration accuracy of the image sensor chip.

[0005] In a first aspect, embodiments of the present invention provide a calibration method for an image sensor chip. The pixel array of the image sensor chip includes a photosensitive area and an optical dark area. The optical dark area includes a plurality of first pixel units arranged side by side, and the photosensitive area includes a plurality of second pixel units arranged side by side. The first pixel units and the second pixel units each include a plurality of pixels located in the same row or the same column. The calibration method includes:

[0006] Acquire at least one frame of target image data of the optical dark area, and the digital signal reference value corresponding to the target image data;

[0007] Based on the first image signal of the first pixel unit and the digital signal reference value in the target image data, each first pixel unit is calibrated to determine the reference pixel unit that represents the noise stripes.

[0008] Based on the fact that the noise stripes of the image sensor chip are distributed in rows or columns, each of the second pixel units is calibrated according to the reference pixel unit.

[0009] Secondly, embodiments of the present invention provide a calibration device for an image sensor chip. The pixel array of the image sensor chip includes a photosensitive area and an optical dark area. The optical dark area includes a plurality of first pixel units arranged side by side, and the photosensitive area includes a plurality of second pixel units arranged side by side. The first pixel units and the second pixel units each include a plurality of pixels located in the same row or column. The calibration device for the image sensor chip includes:

[0010] The acquisition module is used to acquire at least one frame of target image data of the optical dark area, and the digital signal reference value corresponding to the target image data;

[0011] The determination module is used to calibrate each first pixel unit according to the first image signal of the first pixel unit in the target image data and the digital signal reference value, and determine the reference pixel unit that represents the noise stripes.

[0012] The calibration module, based on the row or column distribution of the noise stripes in the image sensor chip, is used to calibrate each of the second pixel units according to the reference pixel unit.

[0013] Thirdly, embodiments of the present invention also provide an electronic device, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of any of the image sensor chip calibration methods provided in the embodiments of the present invention.

[0014] Fourthly, embodiments of the present invention also provide a computer-readable storage medium, which includes a computer program. When the computer program is run on an electronic device, the computer program is used to cause the electronic device to perform the steps of any of the image sensor chip calibration methods provided in the embodiments of the present invention.

[0015] The pixel array of the image sensor chip of the present invention includes a photosensitive area and an optically dark area. The optically dark area includes multiple first pixel units arranged side by side, and the photosensitive area includes multiple second pixel units arranged side by side. The first pixel units and the second pixel units each include multiple pixels located in the same row or column. The calibration method includes: calibrating each first pixel unit according to the first image signal of the first pixel unit in the target image data and the digital signal reference value to determine a reference pixel unit characterizing noise stripes; and calibrating each second pixel unit according to the reference pixel unit based on the row or column distribution of the noise stripes of the image sensor chip. Thus, the present invention uses image data from the optically dark area to calibrate the row or column stripes of the image sensor chip, eliminating the need for calibration based on image data from the photosensitive area, reducing calibration computation, and effectively improving stripe calibration efficiency. Simultaneously, calibration can be performed automatically in real time as needed, unaffected by equipment aging or inaccuracies after multi-level data processing, effectively improving the stripe calibration accuracy of the image sensor chip. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating one embodiment of the image sensor chip calibration method provided in this invention.

[0018] Figure 2 This is a schematic flowchart of another embodiment of the image sensor chip calibration method provided in this invention.

[0019] Figure 3 This is a first schematic diagram of the pixel array structure of the image sensor chip provided in this embodiment of the invention;

[0020] Figure 4 This is a second schematic diagram of the pixel array structure of the image sensor chip provided in this embodiment of the invention;

[0021] Figure 5 This is a schematic diagram of the stripe correction device for the image sensor chip provided in an embodiment of the present invention;

[0022] Figure 6 This is a first schematic diagram of the structure of the reference region in the pixel array provided in this embodiment of the invention;

[0023] Figure 7This is a second schematic diagram of the structure of the reference region in the pixel array provided in this embodiment of the invention;

[0024] Figure 8 This is a schematic diagram of the structure of the calibration device for the image sensor chip provided in an embodiment of the present invention;

[0025] Figure 9 This is a schematic diagram of the structure of the electronic device provided in the embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, in the description of the embodiments of the present invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Thus, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of the embodiments of the present invention, "multiple" means two or more, unless otherwise explicitly specified.

[0027] This invention provides a calibration method, apparatus, electronic device, and storage medium for an image sensor chip.

[0028] Specifically, this embodiment will be described from the perspective of the calibration device of the image sensor chip. The calibration device of the image sensor chip can be integrated into an electronic device. The electronic device can be a calibration device for the image sensor chip, an image sensor chip, or an image sensor, etc. That is, the calibration method of the image sensor chip in this embodiment can be executed by an electronic device.

[0029] The following detailed description is provided in conjunction with the accompanying drawings. In this embodiment, an electronic device is used as the execution subject. It should be noted that the order of description in the following embodiments is not intended to limit the preferred order of the embodiments. Although a logical order is shown in the flowcharts, in some cases, the steps shown or described may be performed in a different order than that shown in the accompanying drawings.

[0030] According to the background art description of the present invention, in related technologies, the column coordinates of rows or columns of stripes are generally calibrated by testing the CMOS image sensor chip before it leaves the factory, which is used for stripe calibration algorithms. However, this method cannot calibrate the column or row stripes that gradually increase after the chip ages, which affects the stripe calibration accuracy.

[0031] In other related solutions, the image output by the image sensor can be processed by an algorithm to calibrate the rows and columns of stripes. However, since the pixel data obtained by the algorithm in the image signal processing chip has been processed by multiple modules, it differs greatly from the original data read by the analog-to-digital converter, which will also affect the calibration accuracy.

[0032] Therefore, there is an urgent need for a simple, efficient, and effective image sensor chip stripe calibration technology.

[0033] To address the aforementioned problems, this invention discloses a calibration method for an image sensor chip. Please refer to [link / reference]. Figure 1 The specific process of the calibration method for this image sensor chip can be summarized in steps S10 to S30, wherein:

[0034] Step S10: Obtain at least one frame of target image data of the optical dark area, and the digital signal reference value corresponding to the target image data;

[0035] In this embodiment, an image signal can be obtained through photoelectric conversion by the image sensor chip, and then used for imaging. The image sensor chip can be a CMOS image sensor chip, such as... Figure 3 As shown, it includes a pixel array, which comprises multiple pixels arranged in an array. Each pixel can perform photoelectric conversion and output an image signal. The image signals output by each pixel at the same time or adjacent times can form a frame of image data. The image data is then processed and converted to achieve the imaging function.

[0036] In addition to the above, the image sensor chip also includes a driving circuit, a readout circuit, an analog-to-digital converter, and an image signal processor. Driven by the driving circuit, light-sensing sampling is performed through the pixel array. The analog sampling voltage of each pixel in the pixel array is read out by the readout circuit and converted into a digital signal by the analog-to-digital converter. The image signal processor then performs post-processing on the digital signal, such as dark field correction, linearity correction, bad pixel correction, digital gain control, white balance, automatic exposure control, autofocus data processing, noise reduction, data compression, etc., and outputs the final image.

[0037] The pixel array includes a photosensitive area and an optical dark area. Each of the photosensitive area and the optical dark area also includes multiple pixels arranged in an array. The photosensitive area is set to correspond to the aperture of the image sensor chip and is used for photosensitive sampling. Its corresponding image signal is used for imaging and display. The optical dark area is used to collect the black level generated by dark current in the area without light illumination. The black level can help reduce the dark current noise in the photosensitive area.

[0038] Within the photosensitive area, multiple pixels located in the same row or column can be selected to form a first pixel unit. Multiple pixels in multiple rows or columns can form multiple first pixel units, which are arranged side by side. Within the optically dark area, multiple pixels located in the same row or column can be selected to form a second pixel unit. Multiple pixels in multiple rows or columns can form multiple second pixel units, which are arranged side by side.

[0039] In some optional embodiments, the calibration mode of the image sensor chip can be divided into row calibration mode and column calibration mode. In row calibration mode, pixels in the optical dark area are grouped by row to obtain multiple first pixel units, and pixels in the photosensitive area are grouped by row to obtain multiple second pixel units. In row calibration mode, each first pixel unit and each second pixel unit includes multiple pixels in the same row. In column calibration mode, pixels in the optical dark area are grouped by column to obtain multiple first pixel units, and pixels in the photosensitive area are grouped by column to obtain multiple second pixel units. In column calibration mode, each first pixel unit and each second pixel unit includes multiple pixels in the same column. In both modes, the optical dark area includes multiple first pixel units arranged side-by-side, and the photosensitive area includes multiple second pixel units arranged side-by-side.

[0040] Optionally, the optical dark area is generally located at the outer edge of the photosensitive area, and its position may surround the photosensitive area. It is understood that the relative position of the optical dark area and the photosensitive dark area is not limited to... Figure 3 As shown, the optical dark area can also be positioned on one side, two sides, or three sides, not completely surrounding the photosensitive area. (Refer to...) Figure 4 .

[0041] In this embodiment, the image sensor chip may produce noise stripes. Based on the fact that the noise stripes of the image sensor chip are distributed in rows or columns, when the first pixel unit in the optical dark area produces noise stripes, the second pixel unit in the photosensitive area that is in the same row or column as the first pixel unit will also produce noise stripes accordingly.

[0042] It's important to note that both the optical dark area and the photosensitive area have image sensing capabilities. Each pixel in the optical dark area can output image signals during operation and can further be used for imaging. The difference lies in the fact that pixels in the photosensitive area are not obstructed; they can receive incident light from the environment to capture environmental images, and therefore their output image signal is primarily used for imaging. In contrast, the optical dark area is obstructed, and its pixels cannot receive incident light from the environment; instead, they output image signals based on dark current.

[0043] In this embodiment, the image signal output within the optical dark area is not used for imaging. Acquiring at least one frame of target image data of the optical dark area means acquiring target image data output by the optical dark area based on dark current at a certain moment. The target image data includes the image signal output by each pixel within the optical dark area.

[0044] It is understood that acquiring at least one frame of target image data in an optically dark area includes acquiring one frame of target image data in an optically dark area, or acquiring at least two frames of target image data in an optically dark area. Image signals belonging to the same frame of target image data are acquired at the same time.

[0045] In some embodiments, at least one frame of image data acquired by a pixel array can be obtained, and target image data of the optical dark area can be segmented from it. Further, the image data of the remaining photosensitive area can be used as display image data to be calibrated, which may include the second image signal of each second pixel unit of the photosensitive area. Thus, the stripes of the output image data of the photosensitive area can be calibrated in real time through the target image data of the optical dark area, thereby performing calibration.

[0046] For the acquired target image data, it is necessary to obtain the digital signal reference value corresponding to that frame of target image data. The digital signal reference value is the signal value of the standard image signal related to the optical dark area. It can actually exist, be calculated, theoretically derived, or pre-set. This digital signal reference value is the basis for column or row fringe calibration of the image. The digital signal reference value can be a signal reference value obtained based on the image signal corresponding to at least some pixels in the optical dark area. These image signals can come from the target image data or from historical frame image data before the target image data. Different sources result in different technical effects. This can be set according to theoretical calculations or usage requirements. The specific acquisition method is not limited here, as long as the digital signal reference value is related to the image signal corresponding to at least some pixels in the optical dark area, so that it can be used as a calibration basis.

[0047] Step S20: Based on the first image signal and digital signal reference value of the first pixel unit in the target image data, calibrate each first pixel unit to determine the reference pixel unit that represents the noise stripes.

[0048] In this embodiment, for each frame of target image data in the optical dark area, reference pixel units characterizing noise stripes are individually calibrated using the target image data. Specifically, the optical dark area includes multiple first pixel units. Using single-frame target image data and corresponding digital signal reference values, each first pixel unit in the optical dark area is calibrated to determine whether it is a reference pixel unit characterizing noise stripes. Based on the row or column distribution of noise stripes in the image sensor chip, the image signal corresponding to the pixel row or pixel column where the reference pixel unit is located in the pixel array will form noise stripes. Therefore, the row or column position that will generate noise stripes can be determined based on the reference pixel unit, thereby performing row or column stripe calibration processing on the second pixel unit in the photosensitive area.

[0049] From the target image data, the first image signal corresponding to multiple pixels in the same row or column within the first pixel unit can be obtained. The reference pixel unit can be identified from each first pixel unit by determining whether the first image signal corresponding to each first pixel unit is a stripe signal.

[0050] Specifically, for each first pixel unit, the first image signal of that first pixel unit can be obtained from at least one frame of target image data. Then, the signal value of the image signal of each pixel in that first pixel unit can be obtained. This signal is then calculated with a digital signal reference value, using either the offset trend statistical principle or the variance calibration principle. The calculation determines whether the first image signal in the optical dark area is a stripe signal. If so, the first pixel unit corresponding to that first image signal is set as the reference pixel unit. Single-frame calibration is performed using the offset trend statistical principle or the variance calibration principle, and multiple methods or angles are used for single-frame calibration, thus improving calibration accuracy.

[0051] Step S30: Based on the fact that the noise stripes of the image sensor chip are distributed in rows or columns, each second pixel unit is calibrated according to the reference pixel unit.

[0052] In this embodiment, based on the row or column distribution of noise stripes in the image sensor chip, if a noise stripe is generated in a first pixel unit in the optical dark area, then noise stripes will appear in the row or column where the first pixel unit is located in the pixel array. Correspondingly, noise stripes will also appear in the second pixel unit in the photosensitive area that belongs to the same row or column as the first pixel unit. Therefore, after determining the reference pixel unit representing the noise stripe in each first pixel unit in the optical dark area through calibration, the stripe position can be determined according to the row or column where the reference pixel unit representing the noise stripe is located. This allows for stripe calibration of the pixel array or the photosensitive area, specifically, stripe calibration of each second pixel unit in the photosensitive area. Based on the calibration results, the second image signal output by the calibrated second pixel unit can be calibrated to eliminate stripes when the second image signal composes the displayed image data.

[0053] Specifically, the target stripe pixel unit can be determined based on the row or column coordinates of the first pixel unit, corresponding to the reference pixel unit within the photosensitive area. After the first image signal corresponding to the reference pixel unit is calibrated as a stripe signal based on the digital signal reference value, since the stripes are linear, the second image signal corresponding to the second pixel unit in the photosensitive area that belongs to the same row or column as the reference pixel unit will also be calibrated as a stripe signal. Therefore, in single-frame calibration, there will be a reference pixel unit and the target stripe pixel unit in the image array that belong to the same row or column in the pixel array, meaning that the target stripe pixel unit in the photosensitive area can have the same row or column coordinates as a reference pixel unit in the optical dark area.

[0054] Optionally, after calibrating the second pixel unit of the photosensitive area according to the reference pixel unit, the calibration result can be saved. The second image signal acquired by the second pixel unit of the photosensitive area can then be calibrated over a subsequent period to eliminate stripe defects in the image acquired by the image sensor chip. In other words, the calibration method provided in this embodiment can be executed at intervals to update the stripe calibration results in the image sensor chip, thereby updating the calibration basis of the stripe calibration algorithm and improving calibration accuracy and imaging quality.

[0055] Based on this, embodiments of the present invention also provide a stripe correction device for an image sensor chip. (Refer to...) Figure 5Specifically, it may also include an automatic stripe calibration unit 51, a calibration result storage unit 52, and a stripe correction processing unit 53. The automatic stripe calibration unit 51 executes the calibration method of the image sensor chip provided in this embodiment. It can be a calibration device for the image sensor chip. The automatic stripe calibration unit 51 calibrates the target stripe pixel unit in the second pixel unit based on the reference pixel unit in each first pixel unit calibrated by single-frame calibration or multi-frame target image data. The second image signal corresponding to the target stripe pixel unit will form column stripes or row stripes. The calibration result is stored in the calibration result storage unit 52. The stripe correction processing unit 53 then retrieves the relevant information of the calibrated target stripe pixel unit from the calibration result storage unit 52, such as its column coordinates or row coordinates, and corrects the second image signal corresponding to the column coordinates or row coordinates, that is, the second image signal corresponding to the target stripe pixel unit, through a correction algorithm, so as to avoid it forming row stripes or column stripes in the imaging.

[0056] The stripe correction device of the image sensor chip can be integrated into the image sensor chip itself, such as within the image signal processor. This allows the image sensor chip to automatically calibrate and correct stripes.

[0057] Optionally, when calibrating the second pixel unit of the photosensitive area according to the reference pixel unit, real-time correction can also be performed based on the calibration result to obtain the display image data of the photosensitive area acquired in the same frame as the target image data. The display image data includes the second image signal of each second pixel unit of the photosensitive area. Then, the calibration result is used to calibrate the second image signal of the second pixel unit to eliminate stripes on the display image data in real time.

[0058] In the technical solution disclosed in this embodiment, an optical dark area is set on the image sensor chip, which can acquire target image data in real time. Based on the target image data of the optical dark area, real-time judgment is performed using the corresponding digital reference value and the first image signal of each first pixel unit in the target image data to calibrate the reference pixel unit in the optical dark area that represents noise stripes. The reference pixel unit can represent the noise stripes in the entire image sensor or photosensitive area, thereby realizing the calibration of the second pixel unit in the photosensitive area, so as to eliminate the stripes generated in the corresponding display image data of the photosensitive area in real time. Even if the data undergoes multi-level processing, it does not affect the calibration accuracy, and the calibration accuracy remains high. Based on the setting of the optical dark area, the calibration and correction processes can be performed at any time, and stripes added due to aging or other reasons can be calibrated and corrected in a timely manner, enabling real-time and efficient calibration of stripes generated by the image sensor chip.

[0059] Further, step S20 includes:

[0060] For each first pixel unit, comparing the signal values of each pixel in the first pixel unit with a digital signal reference value to determine the number of first target pixels and the number of second target pixels in the first pixel unit;

[0061] determining a reference pixel unit according to the number of first target pixels and the number of second target pixels in each first pixel unit;

[0062] wherein, the signal value of the first target pixel is lower than the digital signal reference value by more than a first threshold, and the signal value of the second target pixel is higher than the digital signal reference value by more than a second threshold.

[0063] In this embodiment, single-frame calibration is performed according to an offset trend statistics principle for each frame of target image data. The digital signals corresponding to each pixel in an optical dark area are operated with a digital reference value, and whether the first pixel unit is a reference pixel unit is calibrated one by one according to the operation result. That is, the digital signal reference value corresponding to the target image data is Refa, the signal value (denoted as Pn, 0 < n ≤ N, where N is the number of pixels in the first pixel unit) of each pixel of the first pixel unit is determined based on a first image signal, for each first pixel unit, subtraction operation is performed on Refa in the first image signal, the number Dn of first target pixels in which a difference value Refa-Pn is greater than a first threshold Dvd and the number Un of second target pixels in which a difference value Pn-Refa is greater than a second threshold Dvu are counted respectively in each first pixel unit. The first target pixel is an over-dark pixel point, and the second target pixel is an over-bright pixel point. Therefore, according to the number Dn of first target pixels and the number Un of second target pixels, based on a preset quantity threshold, the overall brightness offset condition of the first pixel unit can be determined. If the brightness offset condition of the first pixel unit exceeds the threshold, it indicates that the row or column where the first pixel unit is located is prominent, which may correspondingly generate stripes, and the first pixel unit is taken as a reference pixel unit for stripe calibration. Conversely, if the brightness offset condition does not exceed the threshold, it indicates that the row or column where the first pixel unit is located is not prominent, the risk of generating stripes is low, and the first pixel unit is not taken as a reference pixel unit.

[0064] In this way, single-frame calibration is performed through the offset trend statistics principle, which can accurately reflect the overall brightness offset condition of the first pixel unit. Based on this, the reference pixel unit can be determined more accurately, stripe calibration is performed, and the calibration accuracy is improved.

[0065] Further, the reference pixel units comprise a dark-biased noise reference pixel unit, a bright-biased noise reference pixel unit and a random noise reference pixel unit, and determining the reference pixel unit according to the number of first target pixels and the number of second target pixels in each first pixel unit comprises:

[0066] acquiring a bright-biased noise reference value, a dark-biased noise reference value and a random noise reference value corresponding to each first pixel unit;

[0067] For each first pixel unit, if the number of first target pixels in the first pixel unit is greater than the dark noise reference value, then the first pixel unit is set as the dark reference pixel unit.

[0068] For each first pixel unit, if the number of second target pixels in the first pixel unit is greater than the brightness noise reference value, then the first pixel unit is set as the brightness reference pixel unit.

[0069] For each first pixel unit, if the total number of first target pixels and second target pixels in the first pixel unit is greater than the random noise reference value, then the first pixel unit is set as the random noise reference pixel unit.

[0070] In this embodiment, the brightness trend reference value of each first pixel unit is obtained. The brightness trend reference value of each first pixel unit includes a fixed bright noise reference value Csnu that shifts towards brightness, a fixed dark noise reference value Csnd that shifts towards darkness, and a random noise reference value Csnr. The values ​​of Csnu, Csnd, and Csnr range from 1 to N. The specific values ​​are related to the analog gain and digital gain and can be obtained through testing and calibration.

[0071] Each first pixel unit is individually calibrated. The relative magnitudes of Un, Dn and Csnu, Csnd, and Csnr of the m-th first pixel unit (1≤m≤M) are compared. Based on the comparison results, it is determined whether noise stripes exist in each column. There are three possibilities for determining noise stripes:

[0072] If Un≥Csnu, then the row or column corresponding to the m-th first pixel unit can be identified as a fixed pattern noise row or column that is shifted towards brightness, and the m-th first pixel unit is set as a brighter reference pixel unit.

[0073] If Dn≥Csnd, then the row or column corresponding to the m-th first pixel unit can be identified as a fixed pattern noise row or column shifted towards darkness, and the m-th first pixel unit is set as a darker reference pixel unit.

[0074] If Un+Dn≥Csnr, then the row or column corresponding to the m-th first pixel unit can be identified as a random noise row or column, and the m-th first pixel unit is set as a random noise reference pixel unit.

[0075] In some embodiments, if any one of the above three conditions is met, the m-th first pixel unit is determined to be a reference pixel unit, and the corresponding row or column may have stripes. The stripe marker signal CSFm of its corresponding row or column can be set to 1. If none of the above three conditions are met, the m-th first pixel unit is determined to be a reference pixel unit, and the corresponding row or column has no stripe risk. The stripe marker signal CSFm of its corresponding row or column can be set to 0.

[0076] In some embodiments, the stripe marking signals CSFm of the rows or columns corresponding to the dark noise reference pixel units, bright noise reference pixel units and random noise reference pixel units can be distinguished. For example, the stripe marking signal CSFm of the row or column corresponding to a dark noise reference pixel unit is marked as 1, that corresponding to a bright noise reference pixel unit is marked as 2, that corresponding to a random noise reference pixel unit is marked as 3, and that corresponding to a pixel unit which is not any of the above reference pixel units is marked as 0. In this way, in the subsequent processing, the reference pixel units can be further distinguished, and a more appropriate calibration algorithm can be further selected to calibrate the second image signal of the second pixel unit corresponding to the reference pixel unit, so as to further improve the imaging quality.

[0077] Further, the above step S20 includes:

[0078] For each first pixel unit, perform a variance operation based on the digital signal reference value and the signal value of each pixel in the first pixel unit in the first image signal to obtain a target variance value of the first stripe pixel unit;

[0079] For each first pixel unit, if the target variance value of the first stripe pixel unit is greater than the variance reference value, set the first stripe pixel unit as a reference pixel unit.

[0080] In this embodiment, for each frame of target image data, the digital signal reference value Refa corresponding to the target image data is used as the average value of the first image signals of the first pixel units in the target image data, then a variance operation is performed on the signal values corresponding to multiple pixels in each first pixel unit to obtain the target variance value of the first stripe pixel unit, and the target variance value of the m-th first pixel unit is recorded as Sm.

[0081] The variance reference value Sref is obtained by means of test calibration, the magnitude of Sm of the m-th first pixel unit is compared with Sref, and whether there is a noise stripe in the row or column corresponding to the m-th first pixel unit is determined according to the comparison result:

[0082] If Sm<Sref, it is determined and calibrated that there is no noise stripe in the row or column corresponding to the m-th first pixel unit, the row or column stripe marking signal CSFm can be set to 0, and the m-th first stripe pixel unit is not calibrated as a reference pixel unit;

[0083] If Sm≥Sref, it is determined and calibrated that there may be a noise stripe in the row or column corresponding to the m-th first pixel unit, the row or column stripe marking signal CSFm can be set to 1, and the m-th first stripe pixel unit will be calibrated as a reference pixel unit.

[0084] The target variance value in column m represents the discreteness of the first pixel unit relative to the digital signal reference value Refa. If the variance value is small, it indicates that the relative dispersion is small and the difference is small, and it can be considered that there are no stripes. If the variance value is large, it indicates that the relative dispersion is large and the difference is large, and it can be considered that stripes may appear. In this way, the problem of stripe calibration caused by fixed pattern noise and random noise that are too bright or too dark can be solved at the same time, and the accuracy and efficiency of stripe calibration can be further improved.

[0085] Optionally, refer to Figure 2 Based on any of the above embodiments, in another embodiment of the calibration method for the image sensor chip of the present invention, in step S10, obtaining the digital signal reference value corresponding to the target image data includes:

[0086] Step S101: Obtain the reference image signal of the reference region within the optical dark area from the reference image data corresponding to the target image data;

[0087] In this embodiment, reference image data corresponding to the target image data is obtained. The reference image data also includes the image signal corresponding to each pixel in the optical dark area, from which the reference image signal output by the corresponding pixel in the reference region within the optical dark area can be obtained. The reference region is a region composed of at least some pixels within the optical dark area.

[0088] Step S102: Average the target signal values ​​in the reference image signal that are less than a preset threshold to obtain digital signal reference values.

[0089] In this embodiment, abnormal image signals with signal values ​​greater than or equal to a preset threshold in the reference image signal will be filtered out, while normal image signals with signal values ​​less than the preset threshold will be retained for further processing. The signal value of the normal image signal is the target signal value, which is understood to be less than the preset threshold. Then, the target signal is averaged to obtain the average signal value within the reference area, which serves as the digital signal reference value. The reference area is at least a portion of the optical dark area, is related to the optical dark area, and the average signal value of the reference area can characterize the normal display brightness of the optical dark area, thereby improving the accuracy of judging reference pixel units and performing stripe calibration.

[0090] In some embodiments, the edge region of the optical dark area and the preset region at the junction of the optical dark area and the photosensitive area may have inaccurate optical dark area pixel data due to light leakage or other reasons. Therefore, these parts are additionally set unusable optical dark areas and are generally not selected as reference areas. Thus, a portion of the optical dark area is selected as the reference area. This portion of the reference area is configurable. Apart from the unusable preset area, the remaining optical dark areas can be configured as needed to obtain the desired reference area, making the stripe calibration process more flexible.

[0091] It should be noted that when performing filtering based on a preset threshold, only the reference image signal of the reference area can be filtered to reduce the amount of data processing. However, the image signal corresponding to the optical area or even the entire pixel array can be filtered in advance, thereby making the reference area more selective and further increasing the flexibility of the calibration process.

[0092] It should be added that the reference area is divided based on the number of first pixel units in the optical dark area. When the first pixel unit includes multiple pixels in the same column within the optical dark area, the second pixel unit also includes multiple pixels in the same column within the photosensitive area. Currently, the image sensor chip is calibrated using column stripes, so the corresponding reference area should span a sufficiently large number of columns (i.e., the width M should be large enough for reference). Figure 6 This means the row-to-column ratio of the reference area is less than a first preset ratio, serving as the basis for horizontal comparison of each column pixel unit. Similarly, when the first pixel unit includes multiple pixels in the same row, the second pixel unit also includes multiple pixels in the same row within the photosensitive area. Currently, the image sensor chip is being calibrated using row stripes, so the corresponding reference area should span a sufficient number of rows (i.e., the height N should be large enough for comparison). Figure 7 The reference area has a row-to-column ratio greater than the second preset ratio, which serves as the basis for vertical comparison of each row of pixel units.

[0093] For example, refer to Figure 6 As shown, select as Figure 3 The optical dark area shown is located in the upper half of the photosensitive area. Its maximum width is W and its maximum height is H. The target image data or reference image data corresponding to the optical dark area are processed and filtered according to a preset threshold to remove abnormal image signals and retain only normal digital signals. Among them, image signals with signal values ​​less than the preset threshold are retained.

[0094] Within a W*H optical dark area, an M*N region within the optical dark area is selected as the reference region for stripe calibration of each frame of target image data. The width M of the reference region is less than or equal to the maximum width W of the optical dark area, and the height N of the reference region is less than or equal to the maximum height H of the optical dark area.

[0095] It should be noted that the width W, width M, height H, and height N are all relative to the size of a single pixel. Width W refers to the number of pixels arranged along the row direction, and height H refers to the number of pixels arranged along the column direction. In acquiring the reference image data, the image signals corresponding to the pixels within the M*N reference region are used as digital reference signals.

[0096] Furthermore, the reference image data is acquired earlier than the target image signal.

[0097] In this embodiment, each frame of target image data corresponds to a definite reference image data, and the reference image data corresponding to each frame of target image data can be different, so that each frame of target image data has a different data signal reference value.

[0098] In some embodiments, the target image data can be used as its own reference image data. By using the corresponding reference image signal of the reference region in the image data of the Nth frame to perform stripe calibration on the image data of the Nth frame, the calibration accuracy can be improved.

[0099] In some embodiments, to ensure real-time image data acquisition and computation, the target image data may not be used as its own reference image data. Instead, one or more frames of historical image data from the target image data are used as reference data frames for the target image data. That is, the digital signal reference value comes from the previous frame of historical image data of the target image data, or from the result of a comprehensive setting of digital signal reference values ​​corresponding to multiple consecutive frames of historical image data preceding the target image data. The acquisition time of the historical image frame is earlier than the acquisition time of the target image data; that is, the acquisition time of the reference image data is earlier than the acquisition time of the target image data.

[0100] Optionally, for column or row stripe calibration of the target image data, the digital reference values ​​used are uniformly denoted as Refa. When acquiring a target image data for single-frame calibration, the digital signal reference value Refa is equal to the digital signal reference value of the previous frame of historical image data. When acquiring at least two target image data for multi-frame correlation calibration, the digital signal reference values ​​corresponding to at least two consecutive frames of historical image data are registered. Then, the multiple digital signal reference values ​​of at least two consecutive frames are processed, for example, after removing the maximum and minimum values, a weighted average is performed to obtain the digital reference value obtained by combining the multiple digital signal reference values ​​as the digital signal reference value of the target image data.

[0101] This approach takes into account the real-time nature of the image data streams acquired by the chip's photosensitive and optically dark areas. The image signals flow through the processing unit sequentially, row by row and column by column. At any given moment, the processing unit can only receive one or a few consecutive image signals. When the digital reference value obtained by the chip's relevant processing unit comes from the Nth frame of image data, that frame may have already passed through the processing unit. Therefore, if the Nth frame needs to be set as its own reference image data, the chip needs to additionally store the real-time optically dark area signal image data to calculate the digital signal reference value. However, due to chip manufacturing cost considerations, data storage requires additional, larger storage units. Therefore, acquiring the reference image data earlier than acquiring the target image data, or using historical image data from the optically dark area as its reference image data, can reduce the chip's storage costs.

[0102] Optionally, based on any of the above embodiments, in another embodiment of the calibration method for the image sensor chip of the present invention, step S30 includes:

[0103] Based on the reference pixel units determined corresponding to at least two frames of target image data, the number of target reference pixel units corresponding to each second pixel unit in the photosensitive area is superimposed and counted, wherein the second pixel unit and its corresponding target reference pixel unit are in the same row or column.

[0104] If the number of target reference pixel units corresponding to the second pixel unit is greater than the marking threshold, the second pixel unit is marked as a target stripe pixel unit in order to calibrate the second image signal corresponding to the target stripe pixel unit.

[0105] In this embodiment, step S10 may include acquiring at least two frames of target image data of the optical dark area, and a digital signal reference value corresponding to the target image signal. The acquired multi-frame target image data of the optical dark area may be continuous multi-frame image data or discrete multi-frame images. Considering the influence of accidental external electromagnetic interference, optionally, the acquired at least two frames of target image data of the optical dark area are discrete images, that is, there is an interval between the acquisition times of the at least two frames of target image data of the optical dark area, in order to eliminate the influence of accidental interference factors.

[0106] Calibration is performed frame by frame using the digital signal reference value of the target image frame and the first image signal of the first pixel unit in the target image data to determine the reference pixel unit in the first pixel unit. Therefore, the reference pixel unit determined for each frame of target image data may differ between different frames of target image data. To avoid inaccurate calibration due to accidental interference or problems with the setting of the digital reference value Refa, it is necessary to superimpose the reference pixel units determined for multiple frames (at least two frames) of target image data for calibration.

[0107] In each frame of the target image, among the determined reference pixel units, reference pixel units belonging to the same first pixel unit are counted. These are designated as target reference pixel units corresponding to second pixel units within the photosensitive area that are in the same pixel column or row as the first pixel unit. The number of target reference pixel units corresponding to the second pixel unit is also counted. The second pixel unit and its corresponding target reference pixel unit are located in the same row or column. If the number of target reference pixel units corresponding to the second pixel unit in the photosensitive area is greater than a marking threshold, it is considered that most of the target image data indicates that the pixel row or column corresponding to the second pixel unit has stripes. This second pixel unit is then marked as a target stripe pixel unit, allowing subsequent calibration units to calibrate the second image signal corresponding to the target stripe pixel unit.

[0108] For example, 10 frames of target image data of the optical dark area were marked by single-frame calibration. A reference pixel unit was obtained based on each target image data, and the stripe marker signal CSFm (0 < m ≤ 10) corresponding to the pixel row or pixel column of the reference pixel unit was obtained. The stripe marker signals CSF2 of the second column in the 10 frames were superimposed to obtain the stripe marker signal CS2 = 7 of the second column. The stripe marker signals of the ninth column in the 10 frames were superimposed to obtain the stripe marker signal CS9 = 2 of the ninth column. The corresponding multi-frame marking threshold for column stripes is 6. Thus, it is determined that there are column stripes in the second column and no column stripes in the ninth column.

[0109] In the technical solution disclosed in this embodiment, reference pixel units calibrated by multi-frame target image data of the optical dark area are superimposed and statistically analyzed, and the target stripe pixel units corresponding to the photosensitive area are calibrated to avoid miscalibration and further improve calibration accuracy.

[0110] Thus, in the above-mentioned image sensor chip calibration method, the row or column stripes of the image sensor chip are calibrated using image data from the optical dark area, eliminating the need for calibration based on image data from the photosensitive area. This reduces the computational load and effectively improves stripe calibration efficiency. Calibration can be performed automatically in real time as needed. For example, if the calibration process is set on-chip, new stripes can be calibrated promptly even if the device ages and new stripes appear, effectively improving the stripe calibration accuracy of the image sensor chip. Simultaneously, the calibration process requires combining the digital signal reference value corresponding to the optical dark area. This involves a horizontal comparison between each row or column in the optical dark area and the digital signal reference value. The digital signal reference value can be acquired or set in real time. On one hand, the real-time acquired digital signal reference value also suffers from inaccuracy after multi-level processing. The inaccuracies from the multi-level processing of the real-time image signal and the digital signal reference value cancel each other out, effectively improving the stripe calibration accuracy of the image sensor chip. On the other hand, the real-time set digital signal reference value can be flexibly set, allowing for flexible adjustment of the stripe and non-stripe thresholds according to the application scenario, expanding the applicable scenarios of this stripe calibration method.

[0111] This embodiment also provides a calibration device for an image sensor chip, which can be integrated into an electronic device. For example, the pixel array of the image sensor chip includes a photosensitive area and an optically dark area, such as... Figure 8 As shown, the calibration device for the image sensor chip may include:

[0112] The acquisition module 1001 is used to acquire at least one frame of target image data of the optical dark area, and the digital signal reference value corresponding to the target image data;

[0113] The determination module 1002 is used to calibrate each first pixel unit according to the first image signal and digital signal reference value of the first pixel unit in the target image data, and determine the reference pixel unit that represents the noise stripe.

[0114] The calibration module 1003 is used to calibrate each second pixel unit according to the reference pixel unit, based on the row or column distribution of the noise stripes of the image sensor chip.

[0115] Optionally, the determining module 1002 is also used for:

[0116] For each first pixel unit, the signal value of each pixel in the first pixel unit is compared with the digital signal reference value to determine the number of first target pixels and the number of second target pixels in the first pixel unit;

[0117] The reference pixel unit is determined based on the number of first target pixels and the number of second target pixels in each first pixel unit;

[0118] Among them, the signal value of the first target pixel is lower than the digital signal reference value by more than a first threshold, and the signal value of the second target pixel is higher than the digital signal reference value by more than a second threshold.

[0119] Optionally, the determining module 1002 is also used for:

[0120] Obtain the reference values ​​for brighter noise, darker noise, and random noise corresponding to each first pixel unit;

[0121] For each first pixel unit, if the number of first target pixels in the first pixel unit is greater than the dark noise reference value, then the first pixel unit is set as the dark noise reference pixel unit.

[0122] For each first pixel unit, if the number of second target pixels in the first pixel unit is greater than the brightness noise reference value, then the first pixel unit is set as the brightness noise reference pixel unit.

[0123] For each first pixel unit, if the total number of first target pixels and second target pixels in the first pixel unit is greater than the random noise reference value, then the first pixel unit is set as the random noise reference pixel unit.

[0124] Optionally, the determining module 1002 is also used for:

[0125] For each first pixel unit, variance calculation is performed based on the digital signal reference value and the signal values ​​of each pixel in the first pixel unit in the first image signal to obtain the target variance value of the first stripe pixel unit.

[0126] For each first pixel unit, if the target variance value of the first stripe pixel unit is greater than the variance reference value, then the first stripe pixel unit is set as the reference pixel unit.

[0127] Optionally, the acquisition module 1001 is also used for:

[0128] Acquire the reference image signal of the reference region within the optical dark area from the reference image data corresponding to the target image data;

[0129] The target signal values ​​in the reference image signal that are less than a preset threshold are averaged to obtain digital signal reference values.

[0130] Optionally, the reference image data is acquired earlier than the target image data.

[0131] Optionally, the calibration module 1003 is also used for:

[0132] Based on the reference pixel units determined corresponding to at least two frames of target image data, the number of target reference pixel units corresponding to each second pixel unit in the photosensitive area is superimposed and counted, wherein the second pixel unit and its corresponding target reference pixel unit are in the same row or column.

[0133] If the number of target reference pixel units corresponding to the second pixel unit is greater than the marking threshold, then the second pixel unit is marked as a target stripe pixel unit.

[0134] In this embodiment, the pixel array of the image sensor chip includes a photosensitive area and an optical dark area. The optical dark area includes multiple first pixel units arranged side by side, and the photosensitive area includes multiple second pixel units arranged side by side. Each first pixel unit and second pixel unit includes multiple pixels located in the same row or column. The calibration method includes: calibrating each first pixel unit based on the first image signal and digital signal reference value of the first pixel unit in the target image data to determine a reference pixel unit characterizing noise stripes; and calibrating each second pixel unit according to the reference pixel unit, based on the row or column distribution of the noise stripes in the image sensor chip. Thus, by using the target image data obtained through the optical dark area of ​​the image sensor chip and the corresponding digital reference value, the reference pixel unit characterizing the noise stripes is determined. Given the row or column distribution of the noise stripes in the image sensor chip, the reference pixel unit can be used to characterize the row and column positions where stripes will appear. Therefore, the reference pixel unit can be used to perform stripe calibration on the second pixel units within the photosensitive area in real time, unaffected by equipment aging or other issues, thereby improving the stripe calibration accuracy of the image sensor chip.

[0135] like Figure 9 As shown, Figure 9This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. The electronic device 1100 includes a processor 1101 with one or more processing cores, a memory 1102 with one or more computer-readable storage media, and a computer program stored on the memory 1102 and executable on the processor. The processor 1101 and the memory 1102 are electrically connected. Those skilled in the art will understand that the electronic device structure shown in the figure does not constitute a limitation on the electronic device, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0136] The processor 1101 is the control center of the electronic device 1100. It connects various parts of the electronic device 1100 via various interfaces and lines. By running or loading software programs and / or units stored in the memory 1102, and by calling data stored in the memory 1102, it executes various functions of the electronic device 1100 and processes data, thereby providing overall monitoring of the electronic device 1100. The processor 1101 can be a CPU, GPU, network processor (NP), etc., and can implement or execute the methods, steps, and logic diagrams disclosed in the embodiments of this invention.

[0137] In this embodiment of the invention, the processor 1101 in the electronic device 1100 loads the instructions corresponding to the processes of one or more applications into the memory 1102 according to the following steps, and the processor 1101 runs the applications stored in the memory 1102 to realize various functions, such as:

[0138] Acquire at least one frame of target image data for the optically dark area, and the corresponding digital signal reference value for the target image data;

[0139] Based on the first image signal and digital signal reference value of the first pixel unit in the target image data, each first pixel unit is calibrated to determine the reference pixel unit that represents the noise stripes.

[0140] Based on the row or column distribution of noise stripes in the image sensor chip, each second pixel unit is calibrated according to the reference pixel unit.

[0141] For details on the implementation of each of the above operations, please refer to the previous examples, which will not be repeated here.

[0142] Optional, such as Figure 9As shown, the electronic device 1100 also includes: a touch display screen 1103, a radio frequency circuit 1104, an audio circuit 1105, an input unit 1106, and a power supply 1107. The processor 1101 is electrically connected to the touch display screen 1103, the radio frequency circuit 1104, the audio circuit 1105, the input unit 1106, and the power supply 1107. Those skilled in the art will understand that... Figure 9 The electronic device structure shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0143] The touch display screen 1103 can be used to display a graphical user interface (GUI) and receive operation commands generated by the user interacting with the GUI. The touch display screen 1103 may include a display panel and a touch panel. The display panel can be used to display information input by the user or information provided to the user, as well as various graphical user interfaces of the electronic device. These graphical user interfaces can be composed of graphics, text, icons, video, and any combination thereof. Optionally, the display panel can be configured using a liquid crystal display (LCD), organic light-emitting diode (OLED), or other similar technologies. The touch panel can be used to collect touch operations performed by the user on or near it (such as operations performed by the user using a finger, stylus, or any suitable object or accessory on or near the touch panel), generate corresponding operation commands, and execute the corresponding program according to the operation commands. Optionally, the touch panel may include a touch detection device and a touch controller. The touch detection device detects the user's touch location and the signal generated by the touch operation, transmitting the signal to the touch controller. The touch controller receives touch information from the touch detection device, converts it into touch point coordinates, and sends it to the processor 1101. It can also receive and execute commands from the processor 1101. The touch panel can cover the display panel. When the touch panel detects a touch operation on or near it, it transmits the information to the processor 1101 to determine the type of touch event. Subsequently, the processor 1101 provides corresponding visual output on the display panel based on the type of touch event. In this embodiment, the touch panel and the display panel can be integrated into the touch display screen 1103 to achieve input and output functions. However, in some embodiments, the touch panel and the touch display screen 1103 can be used as two independent components to achieve input and output functions. That is, the touch display screen 1103 can also be used as part of the input unit 1106 to achieve input functions.

[0144] The radio frequency circuit 1104 can be used to transmit and receive radio frequency signals to establish wireless communication with network devices or other electronic devices, and to transmit and receive signals with network devices or other electronic devices.

[0145] Audio circuit 1105 can be used to provide an audio interface between a user and an electronic device via a speaker and a microphone. Audio circuit 1105 can convert received audio data into electrical signals and transmit them to the speaker, where the speaker converts them into sound signals for output. Conversely, the microphone converts collected sound signals into electrical signals, which are then received by audio circuit 1105, converted back into audio data, and then processed by processor 1101 before being transmitted via radio frequency circuit 1104 to, for example, another electronic device, or output to memory 1102 for further processing. Audio circuit 1105 may also include an earphone jack to provide communication between peripheral headphones and electronic devices.

[0146] The input unit 1106 can be used to receive input numbers, characters, or user characteristic information (such as fingerprints, iris, facial information, etc.), and to generate keyboard, mouse, joystick, optical, or trackball signal inputs related to user settings and function control.

[0147] Power supply 1107 is used to supply power to various components of electronic device 1100. Optionally, power supply 1107 can be logically connected to processor 1101 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. Power supply 1107 may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

[0148] although Figure 9 As not shown in the diagram, the electronic device 1100 may also include a camera, sensor, wireless fidelity module, Bluetooth module, etc., which will not be described in detail here.

[0149] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0150] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0151] To this end, embodiments of the present invention provide a computer-readable storage medium storing a plurality of computer programs, which can be loaded by a processor to execute any of the image sensor chip calibration methods provided in the embodiments of the present invention. The computer program can execute the following steps of the image sensor chip calibration method:

[0152] Acquire at least one frame of target image data for the optically dark area, and the corresponding digital signal reference value for the target image data;

[0153] Based on the first image signal and digital signal reference value of the first pixel unit in the target image data, each first pixel unit is calibrated to determine the reference pixel unit that represents the noise stripes.

[0154] Based on the row or column distribution of noise stripes in the image sensor chip, each second pixel unit is calibrated according to the reference pixel unit.

[0155] For details on the implementation of each of the above operations, please refer to the previous examples, which will not be repeated here.

[0156] The computer-readable storage medium may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0157] Since the computer program stored in the computer-readable storage medium can execute any of the image sensor chip calibration methods provided in the embodiments of the present invention, the beneficial effects that any of the image sensor chip calibration methods provided in the embodiments of the present invention can achieve can be realized, as detailed in the preceding embodiments, and will not be repeated here.

[0158] In the above embodiments of the image sensor chip calibration device, computer-readable storage medium, electronic device, and computer program product, the descriptions of each embodiment have different focuses. Parts not described in detail in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process and beneficial effects of the image sensor chip calibration device, computer-readable storage medium, computer program product, electronic device, and their corresponding units described above can be referred to the description of the image sensor chip calibration method in the above embodiments, and will not be repeated here.

[0159] The foregoing has provided a detailed description of the image sensor chip calibration method, image sensor chip calibration device, electronic device, computer-readable storage medium, and computer program product provided by the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A calibration method for an image sensor chip, characterized in that, The pixel array of the image sensor chip includes a photosensitive area and an optical dark area. The optical dark area includes multiple first pixel units arranged side by side, and the photosensitive area includes multiple second pixel units arranged side by side. The first pixel units and the second pixel units each include multiple pixels located in the same row or column. The calibration method includes: Acquire at least one frame of target image data of the optical dark area, and the digital signal reference value corresponding to the target image data; Based on the first image signal of the first pixel unit and the digital signal reference value in the target image data, each first pixel unit is calibrated to determine the reference pixel unit that represents the noise stripes. Based on the fact that the noise stripes of the image sensor chip are distributed in rows or columns, each of the second pixel units is calibrated according to the reference pixel unit; The step of calibrating each first pixel unit based on the first image signal of the first pixel unit in the target image data and the digital signal reference value to determine the reference pixel unit characterizing the noise stripes includes: For each first pixel unit, the signal value of each pixel in the first pixel unit is compared with the digital signal reference value to determine the number of first target pixels and the number of second target pixels in the first pixel unit; The reference pixel unit is determined based on the number of first target pixels and the number of second target pixels within each first pixel unit; Wherein, the signal value of the first target pixel is lower than the digital signal reference value by more than a first threshold, and the signal value of the second target pixel is higher than the digital signal reference value by more than a second threshold.

2. The calibration method as described in claim 1, characterized in that, The reference pixel unit includes a dark noise reference pixel unit, a bright noise reference pixel unit, and a random noise reference pixel unit. Determining the reference pixel unit based on the number of first target pixels and the number of second target pixels within each first pixel unit includes: Obtain the reference values ​​for brighter noise, darker noise, and random noise corresponding to each of the first pixel units; For each first pixel unit, if the number of first target pixels in the first pixel unit is greater than the dark noise reference value, then the first pixel unit is set as the dark noise reference pixel unit. For each of the first pixel units, if the number of the second target pixels in the first pixel unit is greater than the brightness noise reference value, then the first pixel unit is set as the brightness noise reference pixel unit. For each first pixel unit, if the total number of the first target pixels and the number of the second target pixels in the first pixel unit is greater than the random noise reference value, then the first pixel unit is set as the random noise reference pixel unit.

3. The calibration method as described in claim 1, characterized in that, The step of calibrating each first pixel unit based on the first image signal of the first pixel unit in the target image data and the digital signal reference value, and determining the reference pixel unit representing the noise stripes, includes: For each of the first pixel units, variance calculation is performed based on the digital signal reference value and the signal values ​​of each pixel in the first pixel unit in the first image signal to obtain the target variance value of the first stripe pixel unit. For each of the first pixel units, if the target variance value of the first stripe pixel unit is greater than the variance reference value, then the first stripe pixel unit is set as the reference pixel unit.

4. The calibration method as described in claim 1, characterized in that, Obtaining the digital signal reference value corresponding to the target image data includes: Obtain the reference image signal of the reference region within the optical dark area from the reference image data corresponding to the target image data; The target signal values ​​in the reference image signal that are less than a preset threshold are averaged to obtain the digital signal reference value.

5. The calibration method as described in claim 4, characterized in that, The reference image data was acquired earlier than the target image data.

6. The calibration method as described in claim 1, characterized in that, Based on the row or column distribution of noise stripes in the image sensor chip, the step of calibrating each of the second pixel units according to the reference pixel units includes: Based on the reference pixel units determined corresponding to at least two frames of target image data, the number of target reference pixel units corresponding to each second pixel unit in the photosensitive area is superimposed and counted, wherein the second pixel unit and its corresponding target reference pixel unit are in the same row or column. If the number of target reference pixel units corresponding to the second pixel unit is greater than the marking threshold, then the second pixel unit is marked as a target stripe pixel unit.

7. A calibration device for an image sensor chip, characterized in that, The pixel array of the image sensor chip includes a photosensitive area and an optical dark area. The optical dark area includes multiple first pixel units arranged side by side, and the photosensitive area includes multiple second pixel units arranged side by side. The first pixel units and the second pixel units each include multiple pixels located in the same row or column. The calibration device of the image sensor chip includes: The acquisition module is used to acquire at least one frame of target image data of the optical dark area, and the digital signal reference value corresponding to the target image data; The determination module is used to calibrate each first pixel unit according to the first image signal of the first pixel unit in the target image data and the digital signal reference value, and determine the reference pixel unit that represents the noise stripes. The calibration module is used to calibrate each of the second pixel units according to the reference pixel unit, based on the fact that the noise stripes of the image sensor chip are distributed in rows or columns. The determining module is further configured to, for each first pixel unit, compare the signal value of each pixel in the first pixel unit with the digital signal reference value to determine the number of first target pixels and the number of second target pixels in the first pixel unit; and determine the reference pixel unit based on the number of first target pixels and the number of second target pixels in each first pixel unit; wherein the signal value of the first target pixel is lower than the digital signal reference value by more than a first threshold, and the signal value of the second target pixel is higher than the digital signal reference value by more than a second threshold.

8. An electronic device, characterized in that, It includes a processor and a memory, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the calibration method for any one of the image sensor chips according to claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a computer program that, when run on an electronic device, causes the electronic device to perform the steps of the calibration method for any one of the image sensor chips of claims 1-6.

Images