Exposure readout control method, image sensor, electronic apparatus, and vehicle

Abstract

The invention discloses an exposure read-out control method, an image sensor, electronic equipment and a vehicle, the method is used for a pixel array, each pixel unit of the pixel array comprises a first-class photoelectric conversion unit and a second-class photoelectric conversion unit which are different in photosensitive area, and the method comprises the following steps: controlling the first-class photoelectric conversion unit to perform exposure, and controlling the second-class photoelectric conversion unit to perform exposure; reading pixel signals of the first type of photoelectric conversion units; after the pixel signals of the first type of photoelectric conversion units are read out, the second type of photoelectric conversion units are controlled to be exposed, and the pixel signals of the second type of photoelectric conversion units are read out. According to the method, the column consistency of the output image of the pixel unit can be improved, the column FPN is reduced, and the image quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of image processing, and in particular to an exposure readout control method, an image sensor, an electronic device and a vehicle. Background Art

[0002] In the related art, for the structure of the pixel unit of the image sensor including photoelectric conversion units with different photosensitive areas, for example, including a large photoelectric conversion unit with a relatively large photosensitive area and a small photoelectric conversion unit with a relatively small photosensitive area, the exposure and readout sequence is: first expose the large photoelectric conversion unit and the small photoelectric conversion unit at the same time, and then read out the image signals one by one in sequence. The current exposure method causes the image column consistency to deteriorate, which is manifested as uneven brightness in the vertical direction of the output image, that is, vertical stripes with light and dark changes appear in the image. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the first object of the present invention is to propose an exposure readout control method, which can improve the column consistency of the pixel unit output image, make the brightness of the output image more uniform in the vertical direction, reduce the vertical stripes of light and dark changes in the output image, and improve the image quality.

[0004] A second objective of the present invention is to provide an image sensor.

[0005] A third objective of the present invention is to provide an electronic device.

[0006] A fourth object of the present invention is to provide a vehicle.

[0007] In order to achieve the above-mentioned object, an exposure readout control method according to a first aspect of an embodiment of the present invention is used for a pixel array, wherein each pixel unit in the pixel array includes a first type of photoelectric conversion unit and a second type of photoelectric conversion unit with different photosensitive areas, and the exposure readout control method includes:

[0008] Controlling the first type of photoelectric conversion unit to be exposed and reading out the pixel signal of the first type of photoelectric conversion unit; and after reading out the pixel signal of the first type of photoelectric conversion unit, controlling the second type of photoelectric conversion unit to be exposed and reading out the pixel signal of the second type of photoelectric conversion unit.

[0009] The exposure and readout control method of the embodiment of the present invention controls the exposure and readout processes of photoelectric conversion units with different photosensitive areas, i.e., large and small pixels, separately, first performs exposure and readout control on one type of photoelectric conversion units, and then performs exposure and readout control on the other type of photoelectric conversion units. By adjusting the exposure and readout sequence of large and small pixels, the deviation of the time difference between the exposure time and the readout time of large and small pixels can be reduced, thereby improving the column consistency of the final imaging, improving the uniformity of the brightness in the vertical direction of the image, and improving the imaging quality.

[0010] In some embodiments, the time difference between the readout time and the exposure time of the pixel signal of the first type of photoelectric conversion unit is a first time difference, and the time difference between the readout time and the exposure time of the pixel signal of the second type of photoelectric conversion unit is a second time difference, and the absolute value of the difference between the first time difference and the second time difference is within the image column consistency tolerance difference range.

[0011] Among them, the difference between the exposure and readout time of the photoelectric conversion units with different photosensitive areas is within the tolerance difference range of the image column consistency, so that the difference between the exposure time and the readout time of the photoelectric conversion units with different photosensitive areas can be reduced, and the column consistency of the pixel array output image can be improved, that is, the uniformity of the brightness of the output image in the vertical direction is improved, the column FPN is reduced, and the imaging quality is improved.

[0012] In some embodiments, the first time difference is equal to the second time difference.

[0013] In some embodiments, the exposure readout control method further includes: if it is determined that the absolute value of the difference between the first time difference and the second time difference exceeds the image sequence consistency tolerance difference range, then the pixel signal of the current frame is abandoned.

[0014] In some embodiments, the photosensitive area of ​​the first type of photoelectric conversion unit is larger than the photosensitive area of ​​the second type of photoelectric conversion unit, and the first type of photoelectric conversion unit is controlled to be exposed, and the pixel signal of the first type of photoelectric conversion unit is read out, including: controlling the first type of photoelectric conversion unit to be exposed, and recording the exposure time of the first type of photoelectric conversion unit; sequentially reading out the low gain reset signal of the first type of photoelectric conversion unit, the high gain reset signal of the first type of photoelectric conversion unit, the high gain image signal of the first type of photoelectric conversion unit, and the low gain image signal of the first type of photoelectric conversion unit, and recording the readout time of the pixel signal of the first type of photoelectric conversion unit.

[0015] In some embodiments, controlling the second type of photoelectric conversion unit to be exposed and reading out the pixel signal of the second type of photoelectric conversion unit includes: controlling the second type of photoelectric conversion unit to be exposed and recording the exposure time of the second type of photoelectric conversion unit; sequentially reading out the high gain reset signal of the second type of photoelectric conversion unit, the high gain image signal of the second type of photoelectric conversion unit, the low gain image signal of the second type of photoelectric conversion unit and the low gain reset signal of the second type of photoelectric conversion unit, and recording the readout time of the pixel signal of the second type of photoelectric conversion unit.

[0016] In some embodiments, the pixel unit is a 7T structure, and each column of the pixel units is connected to a first column-level analog-to-digital conversion circuit and a second column-level analog-to-digital conversion circuit through a column line, respectively. The first column-level analog-to-digital conversion circuit is used to convert the low-gain signal of the corresponding column of pixel units, and the second column-level analog-to-digital conversion circuit is used to convert the high-gain signal of the corresponding column of pixel units. Reading out the pixel signal of the first type of photoelectric conversion unit includes: controlling the reset tube to start resetting, and controlling the gain conversion tube, the source follower tube and the selection tube to be turned on to obtain the first reset signal of the first type of photoelectric conversion unit; inputting the first reset signal of the first type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; comparing the first reset signal of the first type of photoelectric conversion unit with the first low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain reset signal of the first type of photoelectric conversion unit.

[0017] In some embodiments, reading out the pixel signal of the first type of photoelectric conversion unit also includes: controlling the gain conversion tube to turn off to obtain a second reset signal of the first type of photoelectric conversion unit; inputting the second reset signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the second reset signal of the first type of photoelectric conversion unit with the first high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain reset signal of the first type of photoelectric conversion unit.

[0018] In some embodiments, reading out the pixel signal of the first type of photoelectric conversion unit also includes: controlling the image signal transmission tube connected to the first type of photoelectric conversion unit with a first pulse signal to obtain a first image signal of the first type of photoelectric conversion unit; inputting the first image signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the first image signal of the first type of photoelectric conversion unit with a second high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain image signal of the first type of photoelectric conversion unit.

[0019] In some embodiments, reading out the pixel signal of the first type of pixel unit also includes: controlling the gain conversion tube to be turned on, and controlling the image signal transmission tube connected to the first type of photoelectric conversion unit to be turned on with a first pulse signal to obtain a second image signal of the first type of photoelectric conversion unit; inputting the second image signal of the first type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; comparing the second image signal of the first type of photoelectric conversion unit with a second low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain image signal of the first type of photoelectric conversion unit.

[0020] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit includes: controlling the reset tube to be turned on, and controlling the gain conversion tube and the reset signal transmission tube of the second type of photoelectric conversion unit to be turned on, so as to obtain a first reset signal of the second type of photoelectric conversion unit; inputting the first reset signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the first reset signal of the second type of photoelectric conversion unit with the third high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain reset signal of the second type of photoelectric conversion unit.

[0021] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit also includes: controlling the image signal transmission tube connected to the second type of photoelectric conversion unit to be turned on with a second pulse signal, and controlling the gain conversion tube and the reset signal transmission tube of the second type of photoelectric conversion unit to remain turned on to obtain a first image signal of the second type of photoelectric conversion unit; inputting the first image signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the first image signal of the second type of photoelectric conversion unit with a fourth high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain image signal of the second type of photoelectric conversion unit.

[0022] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit also includes: controlling the image signal transmission tube connected to the second type of photoelectric conversion unit to be turned on with a second pulse signal, and controlling the gain conversion tube to remain turned on, so as to obtain a second image signal of the second type of photoelectric conversion unit; inputting the second image signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; and comparing the second image signal of the second type of photoelectric conversion unit with a third low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain image signal of the second type of photoelectric conversion unit.

[0023] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit also includes: controlling the reset tube to start resetting to obtain a second reset signal of the second type of photoelectric conversion unit; inputting the second reset signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; comparing the second reset signal of the second type of photoelectric conversion unit with the fourth low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain reset signal of the second type of photoelectric conversion unit.

[0024] In some embodiments, the photosensitive area of ​​the second type of photoelectric conversion unit is larger than the photosensitive area of ​​the first type of photoelectric conversion unit, and controlling the first type of photoelectric conversion unit to be exposed and reading out the pixel signal of the first type of photoelectric conversion unit includes: controlling the first type of photoelectric conversion unit to be exposed and recording the exposure time of the first type of photoelectric conversion unit; sequentially reading out the high-gain reset signal of the first type of photoelectric conversion unit, the high-gain image signal of the first type of photoelectric conversion unit, the low-gain image signal of the first type of photoelectric conversion unit and the low-gain reset signal of the first type of photoelectric conversion unit, and recording the readout time of the pixel signal of the first type of photoelectric conversion unit.

[0025] In some embodiments, controlling the second type of photoelectric conversion unit to be exposed and reading out the pixel signal of the second type of photoelectric conversion unit includes: controlling the second type of photoelectric conversion unit to be exposed and recording the exposure time of the second type of photoelectric conversion unit; sequentially reading out the low gain reset signal of the second type of photoelectric conversion unit, the high gain reset signal of the second type of photoelectric conversion unit, the high gain image signal of the second type of photoelectric conversion unit and the low gain image signal of the second type of photoelectric conversion unit, and recording the readout time of the pixel signal of the second type of photoelectric conversion unit.

[0026] In some embodiments, the pixel unit is a 7T structure, and each column of the pixel units is connected to a first column-level analog-to-digital conversion circuit and a second column-level analog-to-digital conversion circuit through a column line, respectively. The first column-level analog-to-digital conversion circuit is used to convert the low gain signal of the corresponding column of pixel units, and the second column-level analog-to-digital conversion circuit is used to convert the high gain signal of the pixel units of the corresponding column, and read out the pixel signal of the first type of photoelectric conversion unit, including: controlling the reset tube to start resetting, controlling the source follower tube and the selection tube to be turned on, and controlling the gain conversion tube and the reset signal transmission tube of the first type of photoelectric conversion unit to be turned on, so as to obtain the first reset signal of the first type of photoelectric conversion unit; inputting the first reset signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the first reset signal of the first type of photoelectric conversion unit with the third high gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high gain reset signal of the first type of photoelectric conversion unit.

[0027] In some embodiments, reading out the pixel signal of the first type of photoelectric conversion unit also includes: controlling the image signal transmission tube of the first type of photoelectric conversion unit to be turned on with a second pulse signal, and controlling the gain conversion tube and the reset signal transmission tube of the first type of photoelectric conversion unit to remain turned on, so as to obtain the first image signal of the second type of photoelectric conversion unit; inputting the first image signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the first image signal of the first type of photoelectric conversion unit with a fourth high-gain ramp signal through the second column-level analog-to-digital conversion circuit, so as to obtain a high-gain image signal of the first type of photoelectric conversion unit.

[0028] In some embodiments, reading out the pixel signal of the first type of photoelectric conversion unit also includes: controlling the image signal transmission tube of the first type of photoelectric conversion unit to be turned on with a second pulse signal, and controlling the gain conversion tube to remain turned on, to obtain a second image signal of the first type of photoelectric conversion unit; inputting the second image signal into the first column-level analog-to-digital conversion circuit; and comparing the second image signal of the first type of photoelectric conversion unit with a third low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain image signal of the first type of photoelectric conversion unit.

[0029] In some embodiments, reading out the pixel signal of the first type of photoelectric conversion unit also includes: controlling the reset tube to start resetting to obtain a second reset signal of the first type of photoelectric conversion unit; inputting the second reset signal of the first type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; comparing the second reset signal of the first type of photoelectric conversion unit with the fourth low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain reset signal of the first type of photoelectric conversion unit.

[0030] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit includes: controlling the reset tube to start resetting to obtain a first reset signal of the second type of photoelectric conversion unit; inputting the first reset signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; comparing the first reset signal of the first type of photoelectric conversion unit with the first low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain reset signal of the second type of photoelectric conversion unit.

[0031] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit also includes: controlling the gain conversion tube to turn off to obtain a second reset signal of the second type of photoelectric conversion unit; inputting the second reset signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the second reset signal of the second type of photoelectric conversion unit with the first high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain reset signal of the second type of photoelectric conversion unit.

[0032] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit also includes: controlling the image signal transmission tube connected to the second type of photoelectric conversion unit with a first pulse signal to obtain a first image signal of the second type of photoelectric conversion unit; inputting the first image signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; comparing the first image signal of the second type of photoelectric conversion unit with a second high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain image signal of the second type of photoelectric conversion unit.

[0033] In some embodiments, reading out the pixel signal of the second type of photoelectric conversion unit also includes: controlling the gain conversion tube to be turned on, and controlling the image signal transmission tube connected to the second type of photoelectric conversion unit to be in a turned-on state with a first pulse signal to obtain a second image signal of the second type of photoelectric conversion unit; inputting the second image signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; comparing the second image signal of the second type of photoelectric conversion unit with a second low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain image signal of the second type of photoelectric conversion unit.

[0034] In order to achieve the above-mentioned purpose, an image sensor according to an embodiment of the second aspect of the present invention includes: a pixel array, the pixel array includes at least one column of pixel units, each pixel unit includes a first type of photoelectric conversion unit and a second type of photoelectric conversion unit, the first type of photoelectric conversion unit and the second type of photoelectric conversion unit have different photosensitive areas, and the pixel units in each column of the pixel array are connected to the same column line; an analog-to-digital conversion module, the analog-to-digital conversion module is connected to each column of pixel units in the pixel array, and is used to convert pixel analog signals of the pixel units in each column into pixel digital signals; an image processing module, the image processing module is respectively connected to the pixel array and the analog-to-digital conversion module, and is used to control the pixel array and the analog-to-digital conversion module according to the exposure readout control method.

[0035] The image sensor of the embodiment of the present invention controls the pixel array and the analog-to-digital conversion module according to the exposure and readout control method of the above embodiment, thereby realizing separate and independent control of the exposure and readout of large and small pixels in the pixel array, and can reduce the difference in the exposure time and readout time of the photoelectric conversion units with different photosensitive areas, thereby improving the column consistency of the pixel array output image, that is, improving the uniformity of the brightness of the output image in the vertical direction, reducing the column FPN, and improving the imaging quality.

[0036] In some embodiments, the analog-to-digital conversion module includes: a first column-level analog-to-digital conversion circuit and a second column-level analog-to-digital conversion circuit arranged corresponding to each column of pixel units; a first input end of the first column-level analog-to-digital conversion circuit is connected to a column line of the corresponding column of pixel units, a second input end of the first column-level analog-to-digital conversion circuit is suitable for inputting a low-gain ramp signal, an output end of the first column-level analog-to-digital conversion circuit is connected to the image processing module, for comparing the low-gain signal of the column line with the low-gain ramp signal and outputting a digitized low-gain signal; a first input end of the second column-level analog-to-digital conversion circuit is connected to a column line of the corresponding column of pixel units, a second input end of the second column-level analog-to-digital conversion circuit is suitable for inputting a high-gain ramp signal, an output end of the second column-level analog-to-digital conversion circuit is connected to the image processing module, for comparing the high-gain signal of the column line with the high-gain ramp signal and outputting a digitized high-gain signal.

[0037] In some embodiments, the analog-to-digital conversion module also includes: a first switch arranged at the first input end of the first column-level analog-to-digital conversion circuit and the second input end of the first column-level analog-to-digital conversion circuit, the first switch being used to control the input of the first column-level analog-to-digital conversion circuit; a second switch arranged at the first input end of the second column-level analog-to-digital conversion circuit and the second input end of the second column-level analog-to-digital conversion circuit, the second switch being used to control the input of the second column-level analog-to-digital conversion circuit.

[0038] In some embodiments, the image sensor further includes: a first column exchange module, a first end of the first column exchange module is connected to the column line of the pixel array, a second end of the first column exchange module is connected to the input end of the first column-level analog-to-digital conversion circuit, and is used to switch the output of the low-gain signal on the column line of the pixel array; a second column exchange module, a first end of the second column exchange module is connected to the column line of the pixel array, a second end of the second column exchange module is connected to the input end of the second column-level analog-to-digital conversion circuit, and is used to switch the output of the high-gain signal on the column line of the pixel array.

[0039] In some embodiments, the pixel unit includes a 7T structure.

[0040] In order to achieve the above objective, a third aspect of the present invention provides an electronic device, which includes the image sensor of the above embodiment.

[0041] According to the electronic device according to the embodiment of the present invention, by adopting the image sensor of the above embodiment, the deviation of the exposure and readout time difference between large and small pixels can be reduced, the column consistency of the final imaging can be improved, the uniformity of the brightness in the vertical direction of the image can be improved, the imaging quality can be improved, and the image processing capability of the device can be improved.

[0042] In order to achieve the above objective, a fourth aspect of the present invention provides a vehicle, which includes the image sensor of the above embodiment.

[0043] According to the vehicle of the embodiment of the present invention, by adopting the image sensor of the above embodiment, the deviation of the exposure and readout time difference between large and small pixels can be reduced, the column consistency of the final imaging can be improved, the uniformity of the brightness in the vertical direction of the image can be improved, data support can be provided for the control strategy based on the image processing results in the vehicle, and the vehicle performance can be improved.

[0044] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0046] Figure 1 is a flow chart of an exposure readout control method according to an embodiment of the present invention;

[0047] Figure 2 is a schematic diagram of a circuit structure of a pixel unit according to an embodiment of the present invention;

[0048] Figure 3is a schematic diagram of a pixel unit and an analog-to-digital conversion module connected thereto according to an embodiment of the present invention;

[0049] Figure 4 is a schematic diagram of an exposure readout control timing according to an embodiment of the present invention;

[0050] Figure 5 is a block diagram of an image sensor according to an embodiment of the present invention;

[0051] Figure 6 is a block diagram of an electronic device according to an embodiment of the present invention;

[0052] Figure 7 is a block diagram of a vehicle according to one embodiment of the present invention.

[0053] Figure Number:

[0054] Vehicle 1;

[0055] Electronic equipment 1000;

[0056] Image sensor 100;

[0057] The pixel array 10 , the analog-to-digital conversion module 20 , the image processing module 30 , the pixel unit 11 , the first column-level analog-to-digital conversion circuit 21 , the second column-level analog-to-digital conversion circuit 22 , the first column switching module 40 and the second column switching module 50 . DETAILED DESCRIPTION

[0058] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0059] The first aspect of the present invention provides an exposure readout control method, which is used for a pixel array, wherein the pixel array includes at least one column of pixel units, each pixel unit includes a first type of photoelectric conversion unit and a second type of photoelectric conversion unit, wherein the photoelectric conversion unit can be a photodiode or other device that can realize photoelectric conversion, and the photosensitive area of ​​the first type of photoelectric conversion unit is different from the photosensitive area of ​​the second type of photoelectric conversion unit. For example, in some embodiments, the photosensitive area of ​​the first type of photoelectric conversion unit is larger than the photosensitive area of ​​the second type of photoelectric conversion unit, or the photosensitive area of ​​the second type of photoelectric conversion unit is larger than the photosensitive area of ​​the first type of photoelectric conversion unit. In the following embodiments, the photoelectric conversion unit with a larger photosensitive area in the pixel unit can be called a large pixel, and the photoelectric conversion unit with a smaller photosensitive area in the pixel unit can be called a small pixel.

[0060] In order to improve the consistency of exposure and readout time of photoelectric conversion units with different photosensitivity areas in a pixel array and reduce column FPN (Fixed Pattern Noise), the exposure and readout control method of an embodiment of the present invention improves the exposure and readout process of photoelectric conversion units with different photosensitivity areas. The exposure and readout control method according to an embodiment of the first aspect of the present invention is described below with reference to the accompanying drawings.

[0061] Figure 1 FIG. 1 is a flow chart of an exposure readout control method according to an embodiment of the present invention. Figure 1 As shown, the exposure readout control method according to the embodiment of the present invention includes steps S1-S2.

[0062] S1, controlling the first type of photoelectric conversion unit to perform exposure, and reading out the pixel signal of the first type of photoelectric conversion unit.

[0063] S2, after reading out the pixel signals of the first type of photoelectric conversion unit, controlling the second type of photoelectric conversion unit to be exposed, and reading out the pixel signals of the second type of photoelectric conversion unit.

[0064] In an embodiment, the large pixel may be exposed first and its pixel signal may be read out, and then the small pixel may be controlled to be exposed and its pixel signal may be read out. Alternatively, the small pixel may be exposed first and its pixel signal may be read out, and then the large pixel may be controlled to be exposed and its pixel signal may be read out.

[0065] Furthermore, in an embodiment, the time difference between the readout time of the pixel signal of the first type of photoelectric conversion unit and the exposure time of the first type of photoelectric conversion unit is the first time difference; the time difference between the readout time of the pixel signal of the second type of photoelectric conversion unit and the exposure time of the second type of photoelectric conversion unit is the second time difference. The difference between the first time difference and the second time difference is within the image column consistency tolerance difference range, which can be understood as making the column consistency of the image output by the pixel unit high, and the difference between the two within this range can prevent the vertical stripes of the light and dark changes of the graphics. For example, the image column consistency tolerance difference can be a value close to zero or slightly greater than zero, that is, the difference between the first time difference and the second time difference is equal, or the two are basically equal, that is, the difference is not much, compared with the exposure readout control in the prior art, it can improve the consistency of the exposure and readout time of large and small pixels, reduce the column FPN, and improve the imaging quality.

[0066] Furthermore, if it is determined that the absolute value of the difference between the first time difference and the second time difference exceeds the tolerance difference range of the image column consistency, it is considered that there is column inconsistency in the image of the current frame, and the imaging will have uneven brightness in the vertical direction, that is, the image will have vertical stripes with light and dark variations. In this case, the pixel signal of the current frame is discarded, and the exposure and pixel signal readout control are re-performed to obtain the pixel signal of the next frame, so as to obtain a higher quality image.

[0067] In some embodiments, the first time difference is equal to the second time difference, thereby completely eliminating the column inconsistency of the output image of the photoelectric conversion units with different photosensitive areas, making the brightness of the output image more uniform in the vertical direction, preventing the vertical stripes of light and dark changes from appearing in the pixel array output image, and improving the pixel quality.

[0068] The process of first controlling the exposure and readout of large pixels and then controlling the exposure and readout of small pixels is described below in different embodiments.

[0069] In some embodiments, the photosensitive area of ​​the first type of photoelectric conversion unit is larger than the photosensitive area of ​​the second type of photoelectric conversion unit, that is, the first type of photoelectric conversion unit may be a large pixel, and the second type of photoelectric conversion unit may be a small pixel.

[0070] Wherein, controlling the first type of photoelectric conversion unit to be exposed and reading out the pixel signal of the first type of photoelectric conversion unit includes: controlling the first type of photoelectric conversion unit to be exposed and recording the exposure time of the first type of photoelectric conversion unit; sequentially reading out the low gain reset signal of the first type of photoelectric conversion unit, the high gain reset signal of the first type of photoelectric conversion unit, the high gain image signal of the first type of photoelectric conversion unit and the low gain image signal of the first type of photoelectric conversion unit, and recording the readout time of the pixel signal of the first type of photoelectric conversion unit. Wherein, the first time difference can be obtained based on the exposure time of the first type of photoelectric conversion unit and the readout time of the pixel signal.

[0071] Furthermore, the difference between the low-gain image signal and the low-gain reset signal of the first type of photoelectric conversion unit is obtained, that is, the image quantization value of the correlated double sampling of the first type of photoelectric conversion unit in the low-gain conversion mode; and the difference between the high-gain image signal and the high-gain reset signal of the first type of photoelectric conversion unit is obtained, that is, the image quantization value of the correlated double sampling of the first type of photoelectric conversion unit in the high-gain conversion mode.

[0072] Controlling the second type of photoelectric conversion unit to be exposed and reading out the pixel signal of the second type of photoelectric conversion unit includes: controlling the second type of photoelectric conversion unit to be exposed and recording the exposure time of the second type of photoelectric conversion unit; sequentially reading out the high gain reset signal of the second type of photoelectric conversion unit, the high gain image signal of the second type of photoelectric conversion unit, the low gain image signal of the second type of photoelectric conversion unit and the low gain reset signal of the second type of photoelectric conversion unit, and recording the readout time of the pixel signal of the second type of photoelectric conversion unit. The second time difference can be obtained based on the exposure time of the second type of photoelectric conversion unit and the readout time of the pixel signal.

[0073] Furthermore, the difference between the high-gain image signal and the high-gain reset signal of the second type of photoelectric conversion unit is obtained, that is, the correlated double-sampled image quantization value of the second type of photoelectric conversion unit in the high-gain conversion mode; and the difference between the low-gain image signal and the low-gain reset signal of the second type of photoelectric conversion unit is obtained, that is, the non-correlated double-sampled image quantization value of the second type of photoelectric conversion unit in the low-gain conversion mode.

[0074] As described above, before performing quantization conversion, it can be determined whether the absolute value of the difference between the first time difference and the second time difference exceeds the image column consistency tolerance difference range. If it is within the image column consistency tolerance difference range, further image quantization processing is performed; otherwise, the pixel signal of the current frame is discarded and the pixel signal is reacquired to obtain a higher quality image.

[0075] Different from the related art, the exposure readout control method of the embodiment of the present invention separates the exposure process of the pixel signal of the large pixel and the pixel signal of the small pixel in time sequence, and performs the large pixel exposure->large pixel readout, small pixel exposure->small pixel readout process in sequence. That is, the timing diagram of the readout circuit of the large pixel is not always continuous, and the interval time is the exposure reset time of the small pixel signal, thereby reducing the difference between the exposure time and the readout time of the large and small pixels, reducing the column FPN, and improving the imaging quality.

[0076] In an embodiment of the present invention, the pixel unit may include but is not limited to a 7T structure, and may also include other pixel units including photoelectric conversion circuits with different photosensitivity areas, and may adopt the exposure readout control logic of an embodiment of the present invention to achieve the effect of reducing column FPN.

[0077] Take the pixel unit as 7T structure as an example. Figure 2 FIG. 1 is a schematic diagram of a circuit structure of a pixel unit according to an embodiment of the present invention. Figure 2As shown, each pixel unit includes photoelectric conversion units with different photosensitive areas, such as large pixel LPD and small pixel SPD, and transistors M1, M2, M3, M4, M5, M6, and M7. Among them, M5, M6, and M7 are transmission transistors, and the control signals are FCG, TXS, and TXL respectively; M1 is a reset transistor, and the control signal is RST; M3 is a source follower buffer amplifier; M4 is a row selection transistor, and the control signal is RS; M2 is a high and low gain selection transistor, and the control signal is DCG. VDDD is a reset voltage provided.

[0078] Among them, transistor M1 resets the voltage of FD1 point to VDDD with RST reset signal as input. DCG pulse control signal enables the pixel unit to work in low conversion gain mode or high conversion gain mode. RS pulse signal controls the signal output of a certain row of selected pixels. Pulse control signals TXL and TXS control the image signal transmission of large pixel LPD and small pixel SPD respectively. Small pixel SPD and large pixel LPD convert the incident light signal into an electrical signal, and the output pixel signal is Vpix.

[0079] In some embodiments, Figure 3 FIG. 1 is a schematic diagram showing the structure and connection of a pixel array and an analog-to-digital conversion module according to an embodiment of the present invention. Figure 3 As shown, each column of pixel units is connected to a first column-level analog-to-digital conversion circuit 21, such as an ADC (analog to digital converter) circuit, and a second column-level analog-to-digital conversion circuit 22, such as an ADC circuit, through column lines. The first column-level analog-to-digital conversion circuit 21 is used to convert the low-gain signal of the corresponding column of pixel units 11, and the second column-level analog-to-digital conversion circuit 22 is used to convert the high-gain signal of the corresponding column of pixel units 11. That is, two column-level analog-to-digital conversion circuits for high- and low-gain signal conversion are set corresponding to each column of pixel units, and the column-level analog-to-digital conversion circuit includes a comparator and a counter. Among them, switches SW1 and SW2 control the transmission of pixel signals to the high- and low-gain analog-to-digital converters, and AZ_CMPT1 and AZ_CMPB1 are reset signals of the analog-to-digital converters, respectively. The low-gain reset signal and the low-gain image signal of the pixel signal are transmitted to the low-gain analog-to-digital converter through the switch, that is, they are compared and converted with the low-gain ramp through the first column-level analog-to-digital conversion circuit 21; the high-gain reset signal and the high-gain image signal are transmitted to the high-gain analog-to-digital converter through the switch, that is, they are compared and converted with the high-gain ramp through the second column-level analog-to-digital conversion circuit, so as to obtain the image quantization value output by the pixel unit.

[0080] like Figure 2 and Figure 3As shown, for the case where the photosensitive area of ​​the first type of photoelectric conversion unit is larger than the photosensitive area of ​​the second type of photoelectric conversion unit, that is, the first type of photoelectric conversion unit is a large pixel and the second type of photoelectric conversion unit is a small pixel.

[0081] When reading out the pixel signal of the first type of photoelectric conversion unit, the low-gain reset signal of the first type of photoelectric conversion unit is first read out in the order of the above embodiments. Specifically, the reset tube M1 is controlled to start resetting, and the gain conversion tube M2, the source follower tube M3 and the selection tube M4 are controlled to be turned on to obtain the first reset signal of the first type of photoelectric conversion unit, i.e., the large pixel LPD; and the first reset signal of the first type of photoelectric conversion unit is input into the first column-level analog-to-digital conversion circuit 21; the first reset signal of the first type of photoelectric conversion unit is compared with the first low-gain ramp signal through the first column-level analog-to-digital conversion circuit 21 to obtain the low-gain reset signal of the first type of photoelectric conversion unit.

[0082] For example, Figure 4 As shown, it is a timing diagram of the pixel control timing and signal readout timing according to an embodiment of the present invention. At t1, the RST reset signal changes from a high level to a low level. At this time, the pixel signal outputs a reset signal in a low-gain mode, the switch SW1 is turned on, and the pixel signal is input to the left plate of the sampling capacitor of the first column-level analog-to-digital conversion circuit, i.e., the low-gain analog-to-digital converter. The reset signal AZ_CMPT1 resets the input end of the comparator in the first column-level analog-to-digital conversion circuit, i.e., the right plate of the sampling capacitor, to a fixed voltage value. The ramp signal Vramp rises by a fixed voltage value ΔV1 at t2 and then slopes down. When the voltage at the input end of the comparator is equal, the output voltage of the comparator changes from a high potential to a low potential, and the counter in the first column-level analog-to-digital conversion circuit stops counting. At this time, the low-gain reset signal conversion quantization of the large pixel is completed, i.e., the low-gain reset signal of the first photoelectric conversion unit is obtained.

[0083] Then, the high-gain reset signal of the first type of photoelectric conversion unit is read out. Specifically, the gain conversion tube DCG is controlled to be turned off to obtain the second reset signal of the first type of photoelectric conversion unit; and the second reset signal of the first type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit 22; the second reset signal of the first type of photoelectric conversion unit is compared with the first high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high-gain reset signal of the first type of photoelectric conversion unit.

[0084] For example, Figure 4 As shown, at time t3, switch SW2 is turned on first, and then the DCG signal changes from a high level to a low level, and the gain conversion tube M2 is turned off. At this time, the high-gain reset signal of the large pixel is transmitted to the second column-level analog-to-digital conversion circuit, i.e., the high-gain analog-to-digital converter, to complete the conversion and quantization of the high-gain reset signal of the large pixel, i.e., to obtain the high-gain reset signal of the large pixel.

[0085] Further, the high gain image signal of the first type of photoelectric conversion unit is read out. Specifically, the image signal transmission tube connected to the first type of photoelectric conversion unit is controlled by the first pulse signal TXL. Figure 2 M7 in is turned on to obtain the first image signal of the first type of photoelectric conversion unit; and the first image signal of the first type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit, that is, the high-gain analog converter; the first image signal of the first type of photoelectric conversion unit is compared with the second high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high-gain image signal of the first type of photoelectric conversion unit.

[0086] For example, Figure 4 As shown, at time t4, the TXL signal is a high pulse, the M7 tube is turned on, and the high-gain image signal of the large pixel is output to the second column-level analog-to-digital conversion circuit, that is, the high-gain analog-to-digital converter (in Figure 4 The conversion is completed in the column-level analog-to-digital converter in the middle and lower part), and then the ramp signal begins to decrease. When the high-gain image signal overlaps with the ramp signal, that is, when the voltages of the two input terminals of the comparator in the second column-level analog-to-digital conversion circuit are equal, the comparator output signal changes from a high level to a low level, and the counter in the second column-level analog-to-digital conversion circuit stops working. Then, the difference between the image signal and the reset signal under large pixel high conversion gain is obtained, and the conversion and quantization of the signal are completed, that is, the image quantization value of the correlated double sampling under high conversion gain is obtained.

[0087] Further, the low-gain image signal of the first type of photoelectric conversion unit is read out. Specifically, the gain conversion tube M2 is controlled to be turned on, and the image signal transmission tube connected to the first type of photoelectric conversion unit is controlled to be turned on with the first pulse signal TXL to obtain the second image signal of the first type of photoelectric conversion unit; and the second image signal of the first type of photoelectric conversion unit is input into the first column-level analog-to-digital conversion circuit 21, i.e., the low-gain analog-to-digital converter; the second image signal of the first type of photoelectric conversion unit is compared with the second low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain image signal of the first type of photoelectric conversion unit.

[0088] like Figure 4 As shown, at time t5, the pixel unit is converted from high gain mode to low gain mode, at which time the switch SW1 is turned on, and at time t6, the TXL pulse is at a high level, transmitting the image signal of the large pixel in low gain mode to the left side of the sampling capacitor of the first column-level analog-to-digital conversion circuit, i.e., the low gain analog-to-digital converter. Then the slope begins to decrease, and when the voltage at the input end of the comparator in the first column-level analog-to-digital conversion circuit overlaps, the counter in the first column-level analog-to-digital conversion circuit stops working. Then, the difference between the image signal of the large pixel in low gain mode and the reset signal is obtained, i.e., the image quantization value of the correlated double sampling of the large pixel at low conversion gain.

[0089] The above is the process of reading out the pixel signal of the large pixel. In the embodiment of the present invention, the exposure and readout process of the large pixel and the small pixel are controlled separately. The following describes the reading out of the pixel signal of the second type of photoelectric conversion unit, namely the small pixel.

[0090] Reading out the pixel signal of the second type of photoelectric conversion unit includes first reading out the high gain reset signal of the second type of photoelectric conversion unit. Specifically, the reset tube M1 is controlled to be turned on, and the gain conversion tube DCG and the reset signal transmission tube M5 of the second type of photoelectric conversion unit are controlled to be turned on to obtain the first reset signal of the second type of photoelectric conversion unit; and the first reset signal of the second type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit; the first reset signal of the second type of photoelectric conversion unit is compared with the third high gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high gain reset signal of the second type of photoelectric conversion unit.

[0091] For example, Figure 4 As shown, at time t8, after the RST pulse is reset, the FCG controls the transmission tube M5 to be turned on, and the pixel unit outputs the reset signal of the small pixel SPD in the high gain mode. At this time, the AZ_CMPT1 pulse resets the right plate of the sampling capacitor of the second column-level analog-to-digital conversion circuit, i.e., the high gain analog-to-digital converter. The ramp signal rises from the original voltage value by a fixed voltage ΔV2 to the initial voltage, and then when the ramp falls and overlaps with the pixel signal, the counter stops working, and the conversion and quantization completes the reset signal of the small pixel in the high gain mode, that is, the high gain reset signal of the second type of photoelectric conversion unit is obtained.

[0092] Furthermore, the image signal transmission tube M6 connected to the second type of photoelectric conversion unit is controlled to be turned on by the second pulse signal TXS, and the gain conversion tube M2 and the reset signal transmission tube M5 of the second type of photoelectric conversion unit are controlled to remain turned on to obtain the first image signal of the second type of photoelectric conversion unit; and the first image signal of the second type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit; the first image signal of the second type of photoelectric conversion unit is compared with the fourth high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high-gain image signal of the second type of photoelectric conversion unit.

[0093] For example, Figure 4 As shown, at time t9, the TXS signal is a high pulse, and the M2, M5 and M6 tubes are turned on, and the high-gain image signal of the small pixel SPD is output to the second column-level analog-to-digital conversion circuit, that is, the high-gain analog-to-digital converter. After the output is completed, the ramp signal begins to decrease. When the pixel signal overlaps with the ramp signal, that is, when the voltages of the two input terminals of the comparator are equal, the comparator output signal changes from a high level to a low level, and the counter stops working, obtaining a high-gain image signal of the small pixel. Then, the image quantization value of the correlated double sampling under the high conversion gain of the small photodiode can be obtained.

[0094] Further, the low-gain image signal of the small pixel is read out. Specifically, after the second pulse signal TXS controls the image signal transmission tube M6 connected to the second type of photoelectric conversion unit to be turned on, the gain conversion tube M2 is controlled to remain turned on to obtain the second image signal of the second type of photoelectric conversion unit; and the second image signal of the second type of photoelectric conversion unit is input into the first column-level analog-to-digital conversion circuit, i.e., the low-gain analog-to-digital converter; the second image signal of the second type of photoelectric conversion unit is compared with the third low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain image signal of the second type of photoelectric conversion unit.

[0095] For example, Figure 4 As shown, at time t10, the pixel unit is converted from high gain mode to low gain mode, and the switch SW_1 is turned on to input the image signal of the small pixel in low gain mode into the first column-level analog-to-digital conversion circuit, i.e., the low gain analog-to-digital converter. After the output is completed, the rear ramp signal begins to decrease. When the pixel signal overlaps with the ramp signal, that is, the voltages at the two input terminals of the comparator are equal, the counter stops timing, and the conversion and quantization of the low gain image signal of the small photodiode of the pixel is completed.

[0096] Further, the low-gain reset signal of the small pixel is read out. Specifically, the reset tube M1 is controlled to start resetting, and the second reset signal of the second type of photoelectric conversion unit, i.e., the small pixel, is obtained; and the second reset signal of the second type of photoelectric conversion unit is input into the first column-level analog-to-digital conversion circuit, i.e., the low-gain analog-to-digital converter; the second reset signal of the second type of photoelectric conversion unit is compared with the fourth low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain reset signal of the second type of photoelectric conversion unit.

[0097] For example, Figure 4 As shown in the figure, at time t11, the RST signal changes from low level to high level. At this time, the pixel unit outputs a reset signal in low gain mode, and the pixel signal is input to the left plate of the sampling capacitor of the low gain analog-to-digital converter. After that, the slope begins to decrease. When the voltage at the input of the comparator overlaps, the counter stops working and obtains a low gain reset signal for a small pixel. Then, the difference between the image signal and the reset signal in low gain mode can be obtained, that is, the image quantization value of the small pixel under low conversion gain.

[0098] The above embodiment takes the photosensitive area of ​​the first type of pixel unit as an example to illustrate the exposure readout control process of the embodiment of the present invention. The following takes the photosensitive area of ​​the second type of photoelectric conversion unit as an example to illustrate the exposure readout control process of the embodiment of the present invention.

[0099] That is, in the following embodiments, the second type of photoelectric conversion unit is a large pixel, and the first type of photoelectric conversion unit is a small pixel.

[0100] In an embodiment, controlling the first type of photoelectric conversion unit to be exposed and reading out the pixel signal of the first type of photoelectric conversion unit includes: controlling the first type of photoelectric conversion unit to be exposed and recording the exposure time of the first type of photoelectric conversion unit; sequentially reading out the high gain reset signal of the first type of photoelectric conversion unit, the high gain image signal of the first type of photoelectric conversion unit, the low gain image signal of the first type of photoelectric conversion unit and the low gain reset signal of the first type of photoelectric conversion unit, and recording the readout time of the pixel signal of the first type of photoelectric conversion unit. The first time difference can be obtained based on the exposure time of the first type of photoelectric conversion unit and the readout time of the pixel signal.

[0101] In an embodiment, controlling the second type of photoelectric conversion unit to be exposed and reading out the pixel signal of the second type of photoelectric conversion unit includes: controlling the second type of photoelectric conversion unit to be exposed and recording the exposure time of the second type of photoelectric conversion unit; sequentially reading out the low gain reset signal of the second type of photoelectric conversion unit, the high gain reset signal of the second type of photoelectric conversion unit, the high gain image signal of the second type of photoelectric conversion unit and the low gain image signal of the second type of photoelectric conversion unit, and recording the readout time of the pixel signal of the second type of photoelectric conversion unit. Wherein, the second time difference can be obtained based on the exposure time of the second type of photoelectric conversion unit and the readout time of the pixel signal.

[0102] Furthermore, it can be determined whether the absolute value of the difference between the first time difference and the second time difference exceeds the image column consistency tolerance difference range. If it is within the image column consistency tolerance difference range, further image quantization processing is performed; otherwise, the pixel signal of the current frame is discarded and the pixel signal is reacquired to obtain a higher quality image.

[0103] Specifically, still as Figure 2 Take the 7T structure of the pixel structure as an example. Figure 3 As shown, each column of pixel units is connected to a first column-level analog-to-digital conversion circuit 21 and a second column-level analog-to-digital conversion circuit 22 through column lines, respectively. The first column-level analog-to-digital conversion circuit 21 is used to convert the low-gain signal of the corresponding column of pixel units, and the second column-level analog-to-digital conversion circuit 22 is used to convert the high-gain signal of the corresponding column of pixel units.

[0104] As in the order of reading out the pixel signals of the small pixels in the above embodiments, reading out the pixel signals of the first type of photoelectric conversion unit includes reading out the high-gain reset signal of the small pixels. Specifically, the reset tube M1 is controlled to start resetting, the source follower tube M3 and the selection tube M4 are controlled to be turned on, and the gain conversion tube M2 and the reset signal transmission tube M5 of the first type of photoelectric conversion unit are controlled to be turned on to obtain the first reset signal of the first type of photoelectric conversion unit; and the first reset signal of the first type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit, i.e., the high-gain analog-to-digital converter; the first reset signal of the first type of photoelectric conversion unit is compared with the third high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high-gain reset signal of the first type of photoelectric conversion unit. Figure 4 As shown, in this embodiment, the high gain reset signal for reading out the small pixel corresponds to Figure 4 The timing control process at time t8.

[0105] Then, the high-gain image signal of the first type of photoelectric conversion unit, i.e., the small pixel, is read out. Specifically, the image signal transmission tube M6 of the first type of photoelectric conversion unit is controlled to be turned on by the second pulse signal TXS, and the gain conversion tube M2 and the reset signal transmission tube M5 of the first type of photoelectric conversion unit are controlled to remain turned on to obtain the first image signal of the second type of photoelectric conversion unit; and the first image signal of the first type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit, i.e., the high-gain analog-to-digital converter; the first image signal of the first type of photoelectric conversion unit is compared with the fourth high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high-gain image signal of the first type of photoelectric conversion unit. Figure 4 As shown, the process is Figure 4 The timing control process at time t9.

[0106] Then, the low-gain image signal of the small pixel is read out. Specifically, the image signal transmission tube M6 of the first type of photoelectric conversion unit is controlled to be turned on by the second pulse signal TXS, and the gain conversion tube M2 is controlled to remain turned on to obtain the second image signal of the first type of photoelectric conversion unit; and the second image signal is input into the first column-level analog-to-digital conversion circuit, i.e., the low-gain analog-to-digital converter; the second image signal of the first type of photoelectric conversion unit is compared with the third low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain image signal of the first type of photoelectric conversion unit. This process is just like Figure 4 Timing control at moment t10.

[0107] Further, the low-gain reset signal of the small pixel is read out, specifically, the reset tube M1 is controlled to start the reset, and the second reset signal of the first type of photoelectric conversion unit is obtained; and the second reset signal of the first type of photoelectric conversion unit is input into the first column-level analog-to-digital conversion circuit, that is, the low-gain analog-to-digital converter; the second reset signal of the first type of photoelectric conversion unit is compared with the fourth low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain reset signal of the first type of photoelectric conversion unit. Figure 4 As shown, the process is Figure 4 Timing control at moment t11.

[0108] Furthermore, according to the difference between the low-gain image signal and the low-gain reset signal of the first type of photoelectric conversion unit, the image quantization value under low conversion gain is obtained.

[0109] The following is an explanation of the pixel signal readout process of the second type of photoelectric conversion unit, namely the large pixel.

[0110] First, the low-gain reset signal of the second type of photoelectric conversion unit, i.e., the large pixel, is read out. Specifically, the reset tube M1 is controlled to start the reset to obtain the first reset signal of the second type of photoelectric conversion unit; and the first reset signal of the second type of photoelectric conversion unit is input into the first column-level analog-to-digital conversion circuit, i.e., the low-gain analog-to-digital converter; the first reset signal of the first type of photoelectric conversion unit is compared with the first low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain reset signal of the second type of photoelectric conversion unit. Figure 4 As shown, this process is Figure 4 The timing control process at moments t1 and t2.

[0111] Then, the high-gain reset signal of the second type of photoelectric conversion unit is read out. Specifically, the gain conversion tube M2 is controlled to be turned off to obtain the second reset signal of the second type of photoelectric conversion unit; and the second reset signal of the second type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit, i.e., the high-gain analog-to-digital converter; the second reset signal of the second type of photoelectric conversion unit is compared with the first high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain the high-gain reset signal of the second type of photoelectric conversion unit. Figure 4 As shown, the control sequence of this process is Figure 4 At moment t3.

[0112] Further, the high-gain image signal of the second type of photoelectric conversion unit is read out. Specifically, the image signal transmission tube M7 connected to the second type of photoelectric conversion unit is controlled to be turned on by the first pulse signal TXL to obtain the first image signal of the second type of photoelectric conversion unit; and the first image signal of the second type of photoelectric conversion unit is input into the second column-level analog-to-digital conversion circuit, i.e., the high-gain analog-to-digital converter; the first image signal of the second type of photoelectric conversion unit is compared with the second high-gain ramp signal by the second column-level analog-to-digital conversion circuit to obtain the high-gain image signal of the second type of photoelectric conversion unit. Figure 4 As shown, the process control sequence is just as Figure 4 The timing control process at time t4.

[0113] Furthermore, the difference between the image signal and the reset signal of the second type of photoelectric conversion unit at high conversion gain is obtained, and the signal conversion and quantization are completed, that is, the image quantization value of the correlated double sampling at high conversion gain of the large pixel is obtained.

[0114] Further, the low-gain image signal of the second type of photoelectric conversion unit is read out, specifically, the gain conversion tube M2 is controlled to be turned on, and the image signal transmission tube M7 connected to the second type of photoelectric conversion unit is controlled to be in a conducting state by the first pulse signal TXL to obtain the second image signal of the second type of photoelectric conversion unit; and the second image signal of the second type of photoelectric conversion unit is input into the first column-level analog-to-digital conversion circuit, i.e., the low-gain analog-to-digital converter; the second image signal of the second type of photoelectric conversion unit is compared with the second low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain image signal of the second type of photoelectric conversion unit. Figure 4 As shown, the timing control process of this process is just as Figure 4 Timing control at time t5.

[0115] Furthermore, the difference between the image signal and the reset signal of the large pixel in the low gain mode is obtained, that is, the image quantization value of the correlated double sampling of the second type of photoelectric conversion unit under the low conversion gain is obtained.

[0116] In summary, the exposure readout control method of the embodiment of the present invention optimizes the exposure readout process of the pixel signal so that the large and small pixel signals are independently exposed and read out in the circuit. Also, by controlling the large pixel exposure time τ1, the readout time τ2, the small pixel exposure time τ3, the readout time τ4, and ensuring that τ2-τ1=τ4-τ3, the interference caused by the inconsistency between the readout of the large and small pixel signals and the difference in exposure time is greatly reduced, the column consistency of the CIS is improved, and the imaging effect is improved.

[0117] Based on the exposure readout method of the above embodiment, a second embodiment of the present invention provides an image sensor.

[0118] Figure 5 is a functional block diagram of an image sensor according to an embodiment of the present invention. Figure 5 As shown, the image sensor 100 includes a pixel array 10 , an analog-to-digital conversion module 20 and an image processing module 30 .

[0119] The pixel array 10 includes at least one column of pixel units 11, each pixel unit 11 includes a first type of photoelectric conversion unit and a second type of photoelectric conversion unit, the first type of photoelectric conversion unit and the second type of photoelectric conversion unit have different photosensitive areas, and the pixel units in each column of the pixel array are connected to the same column line LOL so that the analog signal of the pixel signal output by the pixel unit is transmitted to the column line LOL.

[0120] The analog-to-digital conversion module 20 is connected to each column of pixel units in the pixel array, and is used to convert the pixel analog signal of each column of pixel units into a pixel digital signal.

[0121] The image processing module 30 is connected to the pixel array 10 and the analog-to-digital conversion module 20, respectively, and is used to control the pixel array 10 and the analog-to-digital conversion module 20 according to the exposure and readout control method of the above embodiment, so as to realize separate and independent control of the exposure and readout of large and small pixels in the pixel array 10, which can reduce the difference in the exposure time and readout time of the photoelectric conversion units with different photosensitive areas, thereby improving the column consistency of the pixel array output image, that is, improving the uniformity of the brightness of the output image in the vertical direction, reducing the column FPN, and improving the imaging quality.

[0122] Furthermore, if Figure 3 As shown, the analog-to-digital conversion module 20 includes a first column-level analog-to-digital conversion circuit 21 and a second column-level analog-to-digital conversion circuit 22 which are arranged corresponding to each column of pixel units.

[0123] The first input terminal of the first column-level analog-to-digital conversion circuit 21 is connected to the column line of the corresponding column of pixel units, and the second input terminal of the first column-level analog-to-digital conversion circuit 21 is suitable for inputting a low-gain ramp signal such as Figure 3 The black dotted line in the middle of the column line LOL is connected to input the ramp signal, and the output end of the first column-level analog-to-digital conversion circuit 21 is connected to the image processing module 30, which is used to compare the low-gain signal of the column line LOL with the low-gain ramp signal and output a digitized low-gain signal. In an embodiment, the first column-level analog-to-digital conversion circuit 21 may include a comparator and a counter.

[0124] The first input terminal of the second column-level analog-to-digital conversion circuit 22 is connected to the column line LOL of the corresponding column of pixel units. The second input terminal of the second column-level analog-to-digital conversion circuit 22 is suitable for inputting a high-gain ramp signal such as Figure 3The middle black dotted line, the output end of the second column-level analog-to-digital conversion circuit 22 is connected to the image processing module 30, which is used to compare the high-gain signal of the column line with the high-gain ramp signal and output the digitized high-gain signal. In an embodiment, the second column-level analog-to-digital conversion circuit 22 may include a comparator and a counter.

[0125] In an embodiment, Figure 3 As shown, the analog-to-digital conversion module 20 may further include a first switch SW1 disposed at a first input terminal of the first column-level analog-to-digital conversion circuit 21 and a second input terminal of the first column-level analog-to-digital conversion circuit 21, and the first switch SW1 is used to control the input of the first column-level analog-to-digital conversion circuit 21. The analog-to-digital conversion module 20 may further include a second switch SW2 disposed at a first input terminal of the second column-level analog-to-digital conversion circuit 22 and a second input terminal of the second column-level analog-to-digital conversion circuit 22, and the second switch SW2 is used to control the input of the second column-level analog-to-digital conversion circuit 22.

[0126] like Figure 3 As shown, the image sensor 100 further includes a first column switching module 40 and a second column switching module 50 .

[0127] Among them, the first end of the first column exchange module 40 is connected to the column line LOL of the pixel array 10, and the second end of the first column exchange module 40 is connected to the input end of the first column-level analog-to-digital conversion circuit 21, which is used to switch the output of the low-gain signal on the column line LOL of the pixel array; the first end of the second column exchange module 50 is connected to the column line of the pixel array 10, and the second end of the second column exchange module 50 is connected to the input end of the second column-level analog-to-digital conversion circuit 22, which is used to switch the output of the high-gain signal on the column line LOL of the pixel array 10.

[0128] In the embodiment of the present invention, the pixel unit may include but is not limited to a 7T structure, and may also include other pixel unit structures having two photoelectric conversion units with different photosensitive areas, which are not specifically limited here.

[0129] For the structure of the pixel unit of the 7T structure, Figure 2 As shown, the specific control of exposure and readout of large and small pixels can refer to the description of the above embodiments.

[0130] In general, the exposure and readout control method and image sensor 100 of the embodiment of the present invention achieve relative consistency in exposure and readout time of large and small pixels by separately controlling the exposure and readout processes of pixel signals of large pixels and small pixels, thereby reducing column FPN and improving imaging quality.

[0131] Based on the image sensor of the above embodiment, the third aspect of the present invention further provides an electronic device.

[0132] Figure 6is a block diagram of an electronic device according to an embodiment of the present invention, such as Figure 6 As shown, the electronic device 1000 of the embodiment of the present invention includes the image sensor 100 of the above embodiment. The specific structure of the image sensor 100 can refer to the description of the above embodiment, which will not be described again.

[0133] In an embodiment, the electronic device 1000 may include but is not limited to a smart phone, a tablet, or a vehicle-mounted image acquisition device and other devices with an image acquisition function.

[0134] According to the electronic device 1000 of the embodiment of the present invention, by adopting the image sensor 100 of the above embodiment, it is possible to reduce the deviation of the exposure and readout time difference between large and small pixels, improve the column consistency of the final imaging, improve the uniformity of the brightness in the vertical direction of the image, improve the imaging quality, and improve the image processing capability of the device.

[0135] Based on the image sensor of the above embodiment, a fourth aspect of the present invention further provides a vehicle.

[0136] Figure 7 is a block diagram of a vehicle according to an embodiment of the present invention, such as Figure 7 As shown, the vehicle 1 includes the image sensor 100 of the above embodiment.

[0137] In an embodiment, the image sensor 100 may be an image sensor on a vehicle-mounted camera or a vehicle-mounted tablet, or an image sensor 100 of a vehicle-mounted device having an image acquisition function.

[0138] According to the vehicle 1 of the embodiment of the present invention, by adopting the image sensor 100 of the above embodiment, the deviation of the exposure and readout time difference between large and small pixels can be reduced, the column consistency of the final imaging can be improved, the uniformity of the brightness in the vertical direction of the image can be improved, data support can be provided for the control strategy based on the image processing results in the vehicle, and the vehicle performance can be improved.

[0139] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0140] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An exposure readout control method, characterized in that: For a pixel array, each pixel unit in the pixel array includes a first type of photoelectric conversion unit and a second type of photoelectric conversion unit with different photosensitive areas, and the exposure readout control method includes: controlling the first type of photoelectric conversion unit to perform exposure, and reading out pixel signals of the first type of photoelectric conversion unit; and After the pixel signals of the first-type photoelectric conversion units are read out, the second-type photoelectric conversion units are controlled to be exposed, and the pixel signals of the second-type photoelectric conversion units are read out.

2. The exposure readout control method according to claim 1, characterized in that: The time difference between the readout time and the exposure time of the pixel signal of the first type of photoelectric conversion unit is a first time difference, and the time difference between the readout time and the exposure time of the pixel signal of the second type of photoelectric conversion unit is a second time difference. The absolute value of the difference between the first time difference and the second time difference is within the tolerance difference range of image column consistency.

3. The exposure readout control method according to claim 2, characterized in that: The first time difference is equal to the second time difference.

4. The exposure readout control method according to claim 2, characterized in that: The exposure readout control method further includes: If it is determined that the absolute value of the difference between the first time difference and the second time difference exceeds the image sequence consistency tolerance difference range, the pixel signal of the current frame is discarded.

5. The exposure readout control method according to any one of claims 1 to 4, characterized in that: The photosensitive area of ​​the first type of photoelectric conversion unit is larger than the photosensitive area of ​​the second type of photoelectric conversion unit, and the first type of photoelectric conversion unit is controlled to be exposed, and the pixel signal of the first type of photoelectric conversion unit is read out, including: Controlling the first type of photoelectric conversion unit to perform exposure, and recording the exposure time of the first type of photoelectric conversion unit; Sequentially read out a low-gain reset signal of the first type of photoelectric conversion unit, a high-gain reset signal of the first type of photoelectric conversion unit, a high-gain image signal of the first type of photoelectric conversion unit, and a low-gain image signal of the first type of photoelectric conversion unit, and record the readout time of the pixel signal of the first type of photoelectric conversion unit.

6. The exposure readout control method according to claim 5, characterized in that: Controlling the second-type photoelectric conversion unit to perform exposure, and reading out the pixel signal of the second-type photoelectric conversion unit, comprising: controlling the second-type photoelectric conversion unit to perform exposure, and recording the exposure time of the second-type photoelectric conversion unit; Sequentially read out the high-gain reset signal of the second-type photoelectric conversion unit, the high-gain image signal of the second-type photoelectric conversion unit, the low-gain image signal of the second-type photoelectric conversion unit and the low-gain reset signal of the second-type photoelectric conversion unit, and record the readout time of the pixel signal of the second-type photoelectric conversion unit.

7. The exposure readout control method according to claim 6, characterized in that: The pixel unit is a 7T structure, and each column of the pixel units is connected to a first column-level analog-to-digital conversion circuit and a second column-level analog-to-digital conversion circuit through column lines, respectively. The first column-level analog-to-digital conversion circuit is used to convert a low-gain signal of the corresponding column of pixel units, and the second column-level analog-to-digital conversion circuit is used to convert a high-gain signal of the corresponding column of pixel units, and read out the pixel signal of the first type of photoelectric conversion unit, including: Controlling the reset tube to start resetting, and controlling the gain conversion tube, the source follower tube and the selection tube to be turned on, so as to obtain a first reset signal of the first type of photoelectric conversion unit; Inputting a first reset signal of the first type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; The first column-level analog-to-digital conversion circuit compares the first reset signal of the first type of photoelectric conversion unit with the first low-gain ramp signal to obtain a low-gain reset signal of the first type of photoelectric conversion unit.

8. The exposure readout control method according to claim 7, characterized in that: Reading out the pixel signal of the first type of photoelectric conversion unit also includes: Controlling the gain conversion tube to turn off, so as to obtain a second reset signal of the first type of photoelectric conversion unit; inputting the second reset signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The second reset signal of the first type of photoelectric conversion unit is compared with the first high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain reset signal of the first type of photoelectric conversion unit.

9. The exposure readout control method according to claim 8, characterized in that: Reading out the pixel signal of the first type of photoelectric conversion unit also includes: Using a first pulse signal to control the image signal transmission tube connected to the first type of photoelectric conversion unit to be turned on, so as to obtain a first image signal of the first type of photoelectric conversion unit; inputting the first image signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The first image signal of the first type of photoelectric conversion unit is compared with the second high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain image signal of the first type of photoelectric conversion unit.

10. The exposure readout control method according to claim 9, characterized in that: Reading out the pixel signal of the first type of pixel unit also includes: Controlling the gain conversion tube to be turned on, and controlling the image signal transmission tube connected to the first type of photoelectric conversion unit to be turned on with a first pulse signal, so as to obtain a second image signal of the first type of photoelectric conversion unit; inputting the second image signal of the first type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; The second image signal of the first type of photoelectric conversion unit is compared with the second low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain image signal of the first type of photoelectric conversion unit.

11. The exposure readout control method according to claim 10, characterized in that: Reading out the pixel signal of the second type of photoelectric conversion unit includes: Controlling the reset tube to be turned on, and controlling the gain conversion tube and the reset signal transmission tube of the second type of photoelectric conversion unit to be turned on, so as to obtain a first reset signal of the second type of photoelectric conversion unit; inputting the first reset signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The first reset signal of the second type of photoelectric conversion unit is compared with the third high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain reset signal of the second type of photoelectric conversion unit.

12. The exposure readout control method according to claim 11, characterized in that: Reading out the pixel signal of the second type of photoelectric conversion unit also includes: Using a second pulse signal to control the image signal transmission tube connected to the second type of photoelectric conversion unit to be turned on, and controlling the gain conversion tube and the reset signal transmission tube of the second type of photoelectric conversion unit to remain turned on, so as to obtain a first image signal of the second type of photoelectric conversion unit; inputting the first image signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The first image signal of the second type of photoelectric conversion unit is compared with the fourth high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain image signal of the second type of photoelectric conversion unit.

13. The exposure readout control method according to claim 12, characterized in that: Reading out the pixel signal of the second type of photoelectric conversion unit also includes: Using a second pulse signal to control the image signal transmission tube connected to the second type of photoelectric conversion unit to be turned on, and controlling the gain conversion tube to remain turned on, to obtain a second image signal of the second type of photoelectric conversion unit; inputting the second image signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; The second image signal of the second type of photoelectric conversion unit is compared with the third low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain image signal of the second type of photoelectric conversion unit.

14. The exposure readout control method according to claim 13, characterized in that: Reading out the pixel signal of the second type of photoelectric conversion unit also includes: Controlling the reset tube to start resetting, and obtaining a second reset signal of the second type of photoelectric conversion unit; inputting a second reset signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; The second reset signal of the second type of photoelectric conversion unit is compared with the fourth low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain reset signal of the second type of photoelectric conversion unit.

15. The exposure readout control method according to any one of claims 1 to 4, characterized in that: The photosensitive area of ​​the second type of photoelectric conversion unit is larger than the photosensitive area of ​​the first type of photoelectric conversion unit, and controlling the first type of photoelectric conversion unit to be exposed and reading out the pixel signal of the first type of photoelectric conversion unit includes: Controlling the first type of photoelectric conversion unit to perform exposure, and recording the exposure time of the first type of photoelectric conversion unit; Sequentially read out a high-gain reset signal of the first type of photoelectric conversion unit, a high-gain image signal of the first type of photoelectric conversion unit, a low-gain image signal of the first type of photoelectric conversion unit, and a low-gain reset signal of the first type of photoelectric conversion unit, and record the readout time of the pixel signal of the first type of photoelectric conversion unit.

16. The exposure readout control method according to claim 15, characterized in that: Controlling the second-type photoelectric conversion unit to perform exposure, and reading out the pixel signal of the second-type photoelectric conversion unit includes: controlling the second-type photoelectric conversion unit to perform exposure, and recording the exposure time of the second-type photoelectric conversion unit; Sequentially read out a low-gain reset signal of the second-type photoelectric conversion unit, a high-gain reset signal of the second-type photoelectric conversion unit, a high-gain image signal of the second-type photoelectric conversion unit, and a low-gain image signal of the second-type photoelectric conversion unit, and record the readout time of the pixel signal of the second-type photoelectric conversion unit.

17. The exposure readout control method according to claim 16, characterized in that: The pixel unit is a 7T structure, and each column of the pixel units is connected to a first column-level analog-to-digital conversion circuit and a second column-level analog-to-digital conversion circuit through column lines, respectively. The first column-level analog-to-digital conversion circuit is used to convert low-gain signals of the pixel units in the corresponding column, and the second column-level analog-to-digital conversion circuit is used to convert high-gain signals of the pixel units in the corresponding column, and read out pixel signals of the first type of photoelectric conversion unit, including: Controlling the reset tube to start resetting, controlling the source follower tube and the selection tube to be turned on, and controlling the gain conversion tube and the reset signal transmission tube of the first type of photoelectric conversion unit to be turned on, so as to obtain a first reset signal of the first type of photoelectric conversion unit; Inputting the first reset signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The first reset signal of the first type of photoelectric conversion unit is compared with the third high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain reset signal of the first type of photoelectric conversion unit.

18. The exposure readout control method according to claim 17, characterized in that: Reading out the pixel signal of the first type of photoelectric conversion unit also includes: Using a second pulse signal to control the image signal transmission tube of the first type of photoelectric conversion unit to be turned on, and controlling the gain conversion tube and the reset signal transmission tube of the first type of photoelectric conversion unit to remain turned on, so as to obtain a first image signal of the second type of photoelectric conversion unit; inputting the first image signal of the first type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The first image signal of the first type of photoelectric conversion unit is compared with the fourth high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain image signal of the first type of photoelectric conversion unit.

19. The exposure readout control method according to claim 18, characterized in that: Reading out the pixel signal of the first type of photoelectric conversion unit also includes: Using a second pulse signal to control the image signal transmission tube of the first type of photoelectric conversion unit to be turned on, and controlling the gain conversion tube to remain turned on, to obtain a second image signal of the first type of photoelectric conversion unit; inputting the second image signal into the first column-level analog-to-digital conversion circuit; The second image signal of the first type of photoelectric conversion unit is compared with the third low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain image signal of the first type of photoelectric conversion unit.

20. The exposure readout control method according to claim 19, characterized in that: Reading out the pixel signal of the first type of photoelectric conversion unit also includes: Controlling the reset tube to start resetting, and obtaining a second reset signal of the first type of photoelectric conversion unit; inputting the second reset signal of the first type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; The second reset signal of the first type of photoelectric conversion unit is compared with the fourth low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain a low-gain reset signal of the first type of photoelectric conversion unit.

21. The exposure readout control method according to claim 20, characterized in that: Reading out the pixel signal of the second-type photoelectric conversion unit includes: Controlling the reset tube to start resetting, so as to obtain a first reset signal of the second type of photoelectric conversion unit; inputting a first reset signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; The first column-level analog-to-digital conversion circuit compares the first reset signal of the first type of photoelectric conversion unit with the first low-gain ramp signal to obtain a low-gain reset signal of the second type of photoelectric conversion unit.

22. The exposure readout control method according to claim 21, characterized in that: Reading out the pixel signal of the second type of photoelectric conversion unit also includes: Controlling the gain conversion tube to turn off, so as to obtain a second reset signal of the second type of photoelectric conversion unit; inputting the second reset signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The second reset signal of the second type of photoelectric conversion unit is compared with the first high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain reset signal of the second type of photoelectric conversion unit.

23. The exposure readout control method according to claim 22, characterized in that: Reading out the pixel signal of the second type of photoelectric conversion unit also includes: Using a first pulse signal to control the image signal transmission tube connected to the second type of photoelectric conversion unit to be turned on, so as to obtain a first image signal of the second type of photoelectric conversion unit; inputting the first image signal of the second type of photoelectric conversion unit into the second column-level analog-to-digital conversion circuit; The first image signal of the second type of photoelectric conversion unit is compared with the second high-gain ramp signal through the second column-level analog-to-digital conversion circuit to obtain a high-gain image signal of the second type of photoelectric conversion unit.

24. The exposure readout control method according to claim 23, characterized in that: Reading out the pixel signal of the second type of photoelectric conversion unit also includes: Controlling the gain conversion tube to be turned on, and controlling the image signal transmission tube connected to the second type of photoelectric conversion unit to be turned on with a first pulse signal, so as to obtain a second image signal of the second type of photoelectric conversion unit; inputting the second image signal of the second type of photoelectric conversion unit into the first column-level analog-to-digital conversion circuit; The second image signal of the second type of photoelectric conversion unit is compared with the second low-gain ramp signal through the first column-level analog-to-digital conversion circuit to obtain the low-gain image signal of the second type of photoelectric conversion unit.

25. An image sensor, characterized in that: include: A pixel array, the pixel array comprising at least one column of pixel units, each pixel unit comprising a first type of photoelectric conversion unit and a second type of photoelectric conversion unit, the first type of photoelectric conversion unit and the second type of photoelectric conversion unit having different photosensitive areas, and the pixel units in each column of the pixel array are connected to the same column line; An analog-to-digital conversion module, connected to each column of pixel units in the pixel array, and configured to convert pixel analog signals of each column of the pixel units into pixel digital signals; An image processing module, wherein the image processing module is connected to the pixel array and the analog-to-digital conversion module respectively, and is used to control the pixel array and the analog-to-digital conversion module according to the exposure readout control method according to any one of claims 1 to 24.

26. The image sensor according to claim 25, characterized in that The analog-to-digital conversion module comprises: A first column-level analog-to-digital conversion circuit and a second column-level analog-to-digital conversion circuit are arranged corresponding to each column of pixel units; The first input end of the first column-level analog-to-digital conversion circuit is connected to the column line of the corresponding column pixel unit, the second input end of the first column-level analog-to-digital conversion circuit is suitable for inputting a low-gain ramp signal, and the output end of the first column-level analog-to-digital conversion circuit is connected to the image processing module, for comparing the low-gain signal of the column line with the low-gain ramp signal and outputting a digitized low-gain signal; A first input end of the second column-level analog-to-digital conversion circuit is connected to a column line of a corresponding column of pixel units, a second input end of the second column-level analog-to-digital conversion circuit is suitable for inputting a high-gain ramp signal, and an output end of the second column-level analog-to-digital conversion circuit is connected to the image processing module, for comparing the high-gain signal of the column line with the high-gain ramp signal and outputting a digitized high-gain signal.

27. The image sensor according to claim 26, characterized in that The analog-to-digital conversion module also includes: a first switch provided at a first input end of the first column-level analog-to-digital conversion circuit and a second input end of the first column-level analog-to-digital conversion circuit, wherein the first switch is used to control an input of the first column-level analog-to-digital conversion circuit; A second switch is provided between the first input terminal of the second column-level analog-to-digital conversion circuit and the second input terminal of the second column-level analog-to-digital conversion circuit, and the second switch is used to control the input of the second column-level analog-to-digital conversion circuit.

28. The image sensor according to claim 26, characterized in that The image sensor further comprises: A first column switching module, wherein a first end of the first column switching module is connected to a column line of the pixel array, and a second end of the first column switching module is connected to an input end of the first column-level analog-to-digital conversion circuit, and is used to switch the output of a low-gain signal on the column line of the pixel array; A second column exchange module, wherein a first end of the second column exchange module is connected to a column line of the pixel array, and a second end of the second column exchange module is connected to an input end of the second column-level analog-to-digital conversion circuit, for switching the output of a high-gain signal on the column line of the pixel array.

29. The image sensor according to any one of claims 25 to 28, characterized in that: The pixel unit includes a 7T structure.

30. An electronic device, characterized in that: An image sensor comprising any one of claims 25-29.

31. A vehicle, characterized in that: An image sensor comprising any one of claims 25-29.

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