A method for reducing pulse crosstalk in TDI CCD vertical drive

Abstract

This invention proposes a method to reduce crosstalk from vertical drive pulses in a TDI CCD. The method includes: controlling the TDI CCD to be in continuous transfer mode and acquiring the continuous transfer timing signal in this mode; adjusting the phases of multiple vertical drive pulses based on a preset number of vertical transfer phases within the horizontal transfer row period, thereby generating multiple vertical drive level transition moments; and controlling the horizontal drive pulses and reset pulses to be in a horizontal transfer stopped state based on the vertical drive level transition moments, thereby reducing crosstalk generated by the vertical drive pulse transition edges on the currently horizontally readout pixels. This method eliminates the reliance on independent debugging of individual circuits, achieving active suppression of crosstalk at its source, possessing good reproducibility and portability, and fully meeting the engineering consistency requirements of mass production of modules.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic imaging technology, and in particular to a method for reducing crosstalk of vertical drive pulses in a TDI CCD. Background Technology

[0002] In high-resolution Earth imaging applications in space, there is high-speed relative motion between remote sensing satellites and the ground. Therefore, Time Delay Integration Charge Coupled Devices (TDI CCDs) are typically used as image detectors to achieve push-broom imaging of ground scenes. Compared to ordinary linear charge-coupled devices, TDI CCDs offer advantages such as high responsivity, large dynamic range, and high signal-to-noise ratio. By using delay integration technology to accumulate multiple exposures of the same target, they effectively extend the exposure time and increase the image plane energy, thereby reducing the relative aperture of the optical system and the volume of the rocket payload, showing broad application prospects in the field of space optical remote sensing. However, in the traditional burst transfer drive mode, pixels in the previous row are forcibly transferred to the next row in a very short time. This is mismatched with the continuously moving scene on the focal plane, easily causing image shift and reducing the system's modulation transfer function (MTF). To reduce the impact of image shift, continuous transfer mode is often used in engineering practice to replace the traditional burst transfer mode.

[0003] While continuous transfer mode can improve the modulation transfer function, it also introduces new technical challenges. Limited by the system's line frequency, the rising and falling edges of the vertical drive pulse inevitably fall within the horizontal drive transfer time window of the charge-coupled device (CCD), causing crosstalk to the amplifier performing charge transfer readout. This crosstalk manifests as spikes and glitches in the spectral curve and as alternating bright and dark stripes in the image, belonging to inherent circuit interference that does not change with the optical signal. Existing technologies primarily employ two methods to eliminate this interference: hardware and software. Hardware methods artificially extend the rising and falling edge times of the drive signal by adding a filter network to the vertical drive pulse circuit, reducing transient energy. Software methods fine-tune the phase relationship between the rising and falling edges of the vertical drive pulse and the horizontal drive pulse multiple times to select the phase configuration that minimizes crosstalk to the image. However, due to significant individual differences in the hardware circuits of different CCDs, both methods require individual debugging for each specific circuit, making them unsuitable for mass production and manufacturing, resulting in poor engineering practicality. Summary of the Invention

[0004] This invention provides a method for reducing crosstalk of vertical drive pulses in TDI CCDs, thereby solving the technical problems mentioned above, such as low debugging efficiency and poor consistency of hardware and software crosstalk elimination methods in continuous transfer mode, which cannot meet the production and manufacturing needs of batch modules and have poor engineering practicality.

[0005] In a first aspect, the present invention provides a method for reducing crosstalk of vertical drive pulses in a TDI CCD, comprising: The TDI CCD is controlled to be in continuous transfer mode, and the continuous transfer timing signal is acquired, which includes a vertical drive pulse, a horizontal drive pulse, and a reset pulse; Within the horizontal transfer cycle, the phases of multiple vertical drive pulses are adjusted according to a preset number of vertical transfer phases to generate multiple vertical drive level transition moments; Based on the vertical drive level transition time, the horizontal drive pulse and the reset pulse are controlled to be in a horizontal transfer stop state to reduce the crosstalk generated by the vertical drive pulse transition edge on the currently horizontally readout pixel.

[0006] In one embodiment of the present invention, adjusting the phases of multiple vertical drive pulses according to a preset vertical transfer phase number to generate multiple vertical drive level transition times includes: dividing the horizontal transfer line period based on the preset vertical transfer phase number to determine multiple candidate times; adjusting the phases of the multiple vertical drive pulses such that the rising edge of one vertical drive pulse coincides with the falling edge of another vertical drive pulse at the candidate times, and using the candidate times as the vertical drive level transition times.

[0007] In one embodiment of the present invention, the distribution of the plurality of vertical drive level transition times includes: the first vertical drive level transition time is located before the start time of the horizontal drive pulse; and each of the other vertical drive level transition times is located between the start time and the end time of the horizontal drive pulse.

[0008] In one embodiment of the present invention, before controlling the horizontal drive pulse and the reset pulse to be in the horizontal transfer stop state, the method includes: obtaining the initial drive level of each horizontal drive pulse and the initial reset level of the reset pulse based on the first vertical drive level transition time.

[0009] In one embodiment of the present invention, controlling the horizontal drive pulse and the reset pulse to be in a horizontal transfer stop state includes: stopping all horizontal drive pulses from transferring for N pixel cycles at each of the other vertical drive level transition times; maintaining the level of each horizontal drive pulse at its respective initial drive level within N pixel cycles, and maintaining the level of the reset pulse at its corresponding initial reset level, wherein N is a positive integer and N≥4.

[0010] In one embodiment of the present invention, when the preset vertical transfer phase number is four phases, the overlap relationship of the vertical drive pulse edges corresponding to each vertical drive level transition moment is as follows: the first vertical drive level transition moment is the overlap moment of the rising edge of the fourth vertical drive pulse and the falling edge of the second vertical drive pulse; the second vertical drive level transition moment is the overlap moment of the rising edge of the first vertical drive pulse and the falling edge of the third vertical drive pulse; the third vertical drive level transition moment is the overlap moment of the rising edge of the second vertical drive pulse and the falling edge of the fourth vertical drive pulse; and the fourth vertical drive level transition moment is the overlap moment of the rising edge of the third vertical drive pulse and the falling edge of the first vertical drive pulse.

[0011] In one embodiment of the present invention, the continuous transfer timing signal further includes: a vertical merging pulse and a vertical transfer pulse; within the horizontal transfer row period, the waveforms of the vertical merging pulse and the vertical transfer pulse include a first interval, a second interval, a third interval, and a fourth interval that alternate sequentially, wherein the first interval and the third interval are intervals with opposite levels, the second interval and the fourth interval are intervals with the same level, the falling edge of the vertical merging pulse falls in the high-level region of the vertical transfer pulse, and the rising edge of the vertical merging pulse falls in the low-level region of the vertical transfer pulse.

[0012] The beneficial effects of this invention are as follows: This invention proposes a method for reducing crosstalk of vertical drive pulses in a TDI CCD. The method includes: controlling the TDI CCD to be in continuous transfer mode and acquiring continuous transfer timing signals in this mode, the continuous transfer timing signals including vertical drive pulses, horizontal drive pulses, and reset pulses; adjusting the phases of multiple vertical drive pulses based on a preset number of vertical transfer phases within the horizontal transfer row period, thereby generating multiple vertical drive level transition moments; controlling the horizontal drive pulses and reset pulses to be in a horizontal transfer stopped state based on the vertical drive level transition moments, thereby reducing crosstalk generated by the vertical drive pulse transition edges on the currently horizontally readout pixels. The crosstalk reduction method provided in this application clamps the horizontal drive pulses and reset pulses to a stopped horizontal transfer state, thereby suppressing vertical drive crosstalk. This method eliminates the reliance on independent debugging of individual circuits, achieving active suppression of crosstalk at its source; simultaneously, crosstalk optimization can be completed by modifying only the software code, avoiding the impact of hardware parameter dispersion on debugging results, significantly improving debugging efficiency and consistency; it has good reproducibility and portability, and can fully meet the engineering consistency requirements of mass module production. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0014] In the attached diagram: Figure 1 This is a flowchart of a method for reducing crosstalk of TDI CCD vertical drive pulses provided in an embodiment of the present invention; Figure 2 This is a timing diagram of the continuous transfer mode provided in the embodiments of the present invention; Figure 3 This is a timing diagram showing the horizontal drive signal and reset pulse in the horizontal transfer stop state provided in this embodiment of the invention; Figure 4 This is a timing diagram showing the four-phase horizontal drive signal and reset pulse in the horizontal transfer stop state provided in this embodiment of the invention; Figure 5 The graph shows the spectral curves corresponding to the driving timing in the traditional continuous transfer mode of existing technology. Figure 6 This is a spectral curve diagram corresponding to crosstalk optimization in the continuous transfer mode shown in an embodiment of the present invention. Detailed Implementation

[0015] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0016] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0017] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0018] The inventors discovered that TDI CCDs, compared to ordinary linear charge-coupled devices (CCDs), have advantages such as high responsivity, large dynamic range, and high signal-to-noise ratio. Through delay integration technology, they effectively enhance image plane energy and are widely used in aerospace optical remote sensing. In traditional burst transfer mode, image shift is a significant problem, reducing the system's modulation transfer function (MTF). Therefore, in engineering practice, continuous transfer mode is often used to mitigate the impact of image shift on the MTF.

[0019] However, while continuous transfer modes improve the system's modulation transfer function (MTF), they also introduce crosstalk due to vertical drive pulse jumps falling into the horizontal transfer window, resulting in alternating bright and dark stripes on the image. Existing hardware and software methods for addressing this inherent interference have significant drawbacks: hardware filtering networks cannot adapt to individual differences between different circuit boards, and software phase tuning requires individual configuration for each circuit. Both methods lack the ability to actively suppress the root cause of crosstalk, resulting in low tuning efficiency and poor consistency, making it difficult to meet the engineering requirements of reproducibility and portability for mass production of modules.

[0020] To solve the above problems, such as Figure 1 As shown, this embodiment of the invention provides a method for reducing crosstalk of TDI CCD vertical drive pulses, the crosstalk reduction method including at least steps S110 to S130: Step S110: Control the TDI CCD to be in continuous transfer mode and acquire the continuous transfer timing signal, which includes the vertical drive pulse, the horizontal drive pulse and the reset pulse.

[0021] Specifically, the TDI CCD's drive circuit receives a continuous transfer drive signal. Driven by the continuous transfer drive signal, the drive circuit sets the TDI CCD to continuous transfer mode and acquires the continuous transfer drive signal when the TDI CCD is in continuous transfer mode. The continuous transfer drive signal includes a vertical drive pulse CIm, a horizontal drive pulse CRx, and a reset pulse RST. Here, m and x are positive integers greater than or equal to 1. When m is 1, 2, 3, or 4, CI1, CI2, CI3, and CI4 represent four-phase vertical drive pulses; when x is 1, 2, 3, or 4, CR1, CR2, CR3, and CR4 represent four-phase horizontal drive pulses.

[0022] In one embodiment, the continuous transfer drive signal further includes a vertical merging pulse SCK and a vertical transfer pulse TCK; within the horizontal transfer row period, the waveforms of the vertical merging pulse SCK and the vertical transfer pulse TCK include a first interval, a second interval, a third interval, and a fourth interval that alternate sequentially. The falling edge of the vertical merging pulse SCK falls in the high-level region of the vertical transfer pulse TCK, and the rising edge of the vertical merging pulse SCK falls in the low-level region of the vertical transfer pulse TCK. The first interval and the third interval are intervals with opposite levels, and the second interval and the fourth interval are intervals with the same level.

[0023] Specifically, such as Figure 2As shown, the continuous transfer drive signal also includes a vertical merging pulse SCK and a vertical transfer pulse TCK; the waveform of the vertical merging pulse SCK is divided according to the horizontal transfer line period Tn. Within the horizontal transfer line period Tn, the first interval is from the falling edge tf1 of the vertical merging pulse SCK to the falling edge tf2 of the vertical transfer pulse TCK, where the level of the vertical merging pulse SCK is low and the level of the vertical transfer pulse TCK is high; the second interval is from the falling edge tf2 of the vertical transfer pulse TCK to the rising edge tr1 of the vertical merging pulse SCK, where both the level of the vertical merging pulse SCK and the level of the vertical transfer pulse TCK are low; the third interval is from the rising edge tr1 of the vertical merging pulse SCK to the rising edge tr2 of the vertical transfer pulse TCK, where both the level of the vertical merging pulse SCK and the level of the vertical transfer pulse TCK are high; the fourth interval is from the rising edge tr2 of the vertical transfer pulse TCK to the falling edge tf3 of the vertical merging pulse SCK, where both the level of the vertical merging pulse SCK and the level of the vertical transfer pulse TCK are high. The falling edge of the vertical merging pulse SCK falls within the high-level region of the vertical transfer pulse TCK, and the rising edge of the vertical merging pulse SCK falls within the low-level region of the vertical transfer pulse TCK. Through the vertical merging pulse SCK and the vertical transfer pulse TCK, the charge in the vertical region of the TDI CCD is transferred to the pixel register in the horizontal region.

[0024] Step S120: Within the horizontal transfer cycle, adjust the phase of multiple vertical drive pulses according to the preset vertical transfer phase number to generate multiple vertical drive level transition moments.

[0025] In one implementation, adjusting the phases of multiple vertical drive pulses according to a preset vertical transfer phase number to generate multiple vertical drive level transition moments includes: dividing the horizontal transfer line period based on the preset vertical transfer phase number to determine multiple candidate moments; adjusting the phases of the multiple vertical drive pulses such that the rising edge of one vertical drive pulse coincides with the falling edge of another vertical drive pulse at a candidate moment, and using the candidate moment as the vertical drive level transition moment. Specifically, the preset vertical transfer phase number is the number of phases of the vertical drive pulses, and the horizontal transfer line period Tn is divided based on the preset vertical transfer phase number, such as... Figure 3 As shown, the horizontal transfer period Tn can be divided into four parts by using the four-phase transfer phase number, thus determining four candidate moments within the horizontal transfer period Tn. Using these four candidate moments, the phases of the four vertical drive pulses (CI1~CI4) are adjusted so that the rising edge of one vertical drive pulse coincides with the falling edge of another vertical drive pulse at a candidate moment. The corresponding candidate moment is then taken as the vertical drive level transition moment (t1, t2, t3, t4).

[0026] In one implementation, the distribution of multiple vertical drive level transition times includes: the first vertical drive level transition time is located before the start time of the horizontal drive pulse, and all other vertical drive level transition times are located between the start and end times of the horizontal drive pulse. Specifically, as shown... Figure 3 As shown, within the horizontal transfer period Tn, the first vertical drive level transition time t1 is located after the rising edge tr1 of the vertical merging pulse SCK and before the start time of the horizontal drive pulse CRx; the second to the kth vertical drive level transition times are all located within the start to end time of the horizontal drive pulse CRx, where k is an integer greater than or equal to 2, and k is the total number of vertical drive level transition times. Figure 3 As shown, the second vertical drive level transition time t2 to the fourth vertical drive level transition time t4 are all within the effective time of the horizontal transition of the horizontal drive pulse CRx.

[0027] Step S130: Based on the vertical drive level transition time, control the horizontal drive pulse and reset pulse to be in the horizontal transfer stop state to reduce the crosstalk generated by the vertical drive pulse transition edge to the currently horizontally readout pixel.

[0028] Specifically, such as Figure 3 As shown, based on multiple vertical drive level transition times (t1~tk), during the horizontal transfer row period Tn, the horizontal drive pulse CRx and the reset pulse RST are controlled to be in the horizontal transfer stop state, thereby reducing the crosstalk generated by the vertical drive pulse transition edge to the currently horizontally readout pixel.

[0029] In one embodiment, before controlling the horizontal drive pulse and the reset pulse to be in the horizontal transfer stop state, the method includes: at the first vertical drive level transition moment, acquiring the initial drive level of each horizontal drive pulse CRx and the initial reset level of the reset pulse RST.

[0030] Specifically, such as Figure 4 As shown, when there are 4 horizontal drive pulses CRx, the levels of the four horizontal drive pulses (CR1, CR2, CR3, CR4) and the reset pulse RST are obtained at the first vertical drive level transition time t1. The initial drive levels of the first horizontal drive pulse CR1 and the second horizontal drive pulse CR2 are high, the initial drive levels of the third horizontal drive pulse CR3 and the fourth horizontal drive pulse CR4 are low, and the initial reset level of the reset pulse RST is low.

[0031] In one embodiment, controlling the horizontal drive pulse and the reset pulse to be in a horizontal transfer stopped state includes: stopping all horizontal drive pulses from transferring for N pixel cycles at each of the other vertical drive level transition times; and maintaining the level of each horizontal drive pulse at its respective initial drive level and maintaining the level of the reset pulse at its corresponding initial reset level within N pixel cycles, where N is a positive integer and N≥4.

[0032] Specifically, such as Figure 4 As shown, when there are 4 horizontal drive pulses and 4 vertical drive level transition times, at the second vertical drive level transition time t2, the third vertical drive level transition time t3, and the fourth vertical drive level transition time t4, the four horizontal drive pulses (CR1 to CR4) are stopped for 4 pixel cycles. During the 4 pixel cycles, the levels of the first horizontal drive pulse CR1 and the second horizontal drive pulse CR2 are kept at the initial high drive level, the levels of the third horizontal drive pulse CR3 and the fourth horizontal drive pulse CR4 are kept at the initial low drive level, and the level of the reset pulse RST is kept at the initial low reset level, so that the four horizontal drive pulses (CR1, CR2, CR3, CR4) do not perform horizontal transition.

[0033] It should be noted that when the TDI CCD is executing continuous transfer mode, the number of vertical drive pulses, the number of vertical drive level transition moments, and the number of horizontal drive pulses can be set according to the actual situation.

[0034] In one embodiment, when the preset vertical transfer phase number is four phases, the overlap relationship of the vertical drive pulse edges corresponding to each vertical drive level transition time is as follows: the first vertical drive level transition time is the overlap time of the rising edge of the fourth vertical drive pulse and the falling edge of the second vertical drive pulse; the second vertical drive level transition time is the overlap time of the rising edge of the first vertical drive pulse and the falling edge of the third vertical drive pulse; the third vertical drive level transition time is the overlap time of the rising edge of the second vertical drive pulse and the falling edge of the fourth vertical drive pulse; and the fourth vertical drive level transition time is the overlap time of the rising edge of the third vertical drive pulse and the falling edge of the first vertical drive pulse.

[0035] Specifically, such as Figure 3As shown, when the preset vertical transfer phase number is four phases, there are four vertical drive pulses and four vertical drive level transition times, the edge overlap relationship of the vertical drive pulses at each vertical drive level transition time is as follows: the first vertical drive level transition time t1 is the time when the rising edge of the fourth vertical drive pulse CI4 overlaps with the falling edge of the second vertical drive pulse CI2; the second vertical drive level transition time t2 is the time when the rising edge of the first vertical drive pulse CI1 overlaps with the falling edge of the third vertical drive pulse CI3; the third vertical drive level transition time t3 is the time when the rising edge of the second vertical drive pulse CI2 overlaps with the falling edge of the fourth vertical drive pulse CI4; and the fourth vertical drive level transition time t4 is the time when the rising edge of the third vertical drive pulse CI3 overlaps with the falling edge of the first vertical drive pulse CI1.

[0036] It is important to emphasize that the above description of the method for reducing crosstalk in the vertical drive pulse only uses the horizontal transfer line period Tn as an example. The method for reducing crosstalk in other horizontal transfer line periods is exactly the same; simply repeat the above steps without changing any parameters or requiring re-tuning. This makes the method highly versatile and easy to implement.

[0037] like Figure 5 As shown, the horizontal axis represents pixels, and the vertical axis represents grayscale values, with units of DN (Digital Number, dimensionless digital quantization value). In continuous transfer mode, the TDI CCD does not stop the horizontal transfer; the crosstalk generated by the rising and falling edges of the vertical drive pulse on the horizontally transferred pixels can reach up to 230 DN. Figure 6 As shown, the horizontal axis represents pixels and the vertical axis represents grayscale values. The TDI CCD implements a vertical drive pulse crosstalk reduction method. At the transition moment of the vertical drive pulse, horizontal transfer is stopped. The crosstalk generated by the rising and falling edges of the vertical drive pulse on the horizontally transferred pixels is reduced to 30DN; the crosstalk problem is significantly reduced.

[0038] This invention proposes a method for reducing crosstalk from vertical drive pulses in a TDI CCD. The method includes: controlling the TDI CCD to be in continuous transfer mode and acquiring continuous transfer timing signals in this mode, the continuous transfer timing signals including vertical drive pulses, horizontal drive pulses, and a reset pulse; adjusting the phases of multiple vertical drive pulses based on a preset number of vertical transfer phases within the horizontal transfer row period, thereby generating multiple vertical drive level transition moments; controlling the horizontal drive pulses and the reset pulse to be in a horizontal transfer stopped state based on the vertical drive level transition moments, thereby reducing crosstalk generated by the vertical drive pulse transition edges on the currently horizontally readout pixels. The crosstalk reduction method provided in this application clamps the horizontal drive pulses and the reset pulse to a stopped horizontal transfer state, thereby suppressing vertical drive crosstalk. This method eliminates the reliance on independent debugging of individual circuits, achieving active suppression of crosstalk at its source; simultaneously, crosstalk optimization can be completed by modifying only the software code, avoiding the impact of hardware parameter dispersion on debugging results, significantly improving debugging efficiency and consistency; it has good reproducibility and portability, and can fully meet the engineering consistency requirements of mass module production.

[0039] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for reducing crosstalk of vertical drive pulses in a TDI CCD, characterized in that, include: The TDI CCD is controlled to be in continuous transfer mode, and the continuous transfer timing signal is acquired, which includes a vertical drive pulse, a horizontal drive pulse, and a reset pulse; Within the horizontal transfer cycle, the phases of multiple vertical drive pulses are adjusted according to a preset number of vertical transfer phases to generate multiple vertical drive level transition moments; Based on the vertical drive level transition time, the horizontal drive pulse and the reset pulse are controlled to be in a horizontal transfer stop state to reduce the crosstalk generated by the vertical drive pulse transition edge on the currently horizontally readout pixel.

2. The method for reducing crosstalk of vertical drive pulses in a TDI CCD according to claim 1, characterized in that, The phases of multiple vertical drive pulses are adjusted according to a preset vertical shift phase number to generate multiple vertical drive level transition moments, including: Based on the preset vertical transfer phase number, the horizontal transfer row period is divided to determine multiple candidate times; The phases of the plurality of vertical drive pulses are adjusted such that the rising edge of one of the vertical drive pulses coincides with the falling edge of another vertical drive pulse at the candidate time, and the candidate time is used as the vertical drive level transition time.

3. The method for reducing crosstalk of TDI CCD vertical drive pulses according to claim 2, characterized in that, The distribution of the multiple vertical drive level transition times includes: The first vertical drive level transition occurs before the start of the horizontal drive pulse; All other vertical drive level transition times are located between the start and end times of the horizontal drive pulse.

4. The method for reducing crosstalk of TDI CCD vertical drive pulses according to claim 3, characterized in that, Before controlling the horizontal drive pulse and the reset pulse to be in the horizontal transfer stop state, the following steps are included: Based on the first vertical drive level transition moment, the initial drive level of each horizontal drive pulse and the initial reset level of the reset pulse are obtained.

5. The method for reducing vertical drive pulse crosstalk of a TDI CCD according to claim 4, characterized in that, Controlling the horizontal drive pulse and the reset pulse to be in a horizontal transfer stop state includes: At each of the other vertical drive level transition times, all horizontal drive pulses are stopped and transferred for N pixel cycles; Within N pixel periods, the level of each horizontal driving pulse is maintained at its respective initial driving level, and the level of the reset pulse is maintained at its corresponding initial reset level, where N is a positive integer and N≥4.

6. The method for reducing crosstalk of TDI CCD vertical drive pulses according to claim 2, characterized in that, When the preset number of vertical transfer phases is four phases, the overlap relationship of the vertical drive pulse edges corresponding to each vertical drive level transition moment is as follows: The first vertical drive level transition time is the time when the rising edge of the fourth vertical drive pulse overlaps with the falling edge of the second vertical drive pulse. The second vertical drive level transition time is the time when the rising edge of the first vertical drive pulse overlaps with the falling edge of the third vertical drive pulse; The third vertical drive level transition time is the time when the rising edge of the second vertical drive pulse overlaps with the falling edge of the fourth vertical drive pulse. The fourth vertical drive level transition time is the moment when the rising edge of the third vertical drive pulse overlaps with the falling edge of the first vertical drive pulse.

7. The method for reducing crosstalk of TDI CCD vertical drive pulses according to claim 1, characterized in that, The continuous transfer timing signal also includes: a vertical merging pulse and a vertical transfer pulse; Within the horizontal transfer cycle, the waveforms of the vertical merging pulse and the vertical transfer pulse include alternating first, second, third, and fourth intervals, wherein the first and third intervals are intervals with opposite levels, and the second and fourth intervals are intervals with the same level. The falling edge of the vertical merging pulse falls on the high-level region of the vertical transfer pulse, and the rising edge of the vertical merging pulse falls on the low-level region of the vertical transfer pulse.

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