Long linear array load inter-row dislocation test and correction method and system

Abstract

The invention provides a long linear array load inter-row dislocation test and correction method and system, and the method comprises the steps: S1, carrying out the analysis of an inter-row dislocation mechanism when a long linear array load works in orbit, and recognizing the formation of inter-row dislocation; s2, a ground imaging test system is constructed, near-field simulation far-field imaging is carried out through a collimator, and the line-to-line dislocation amount is evaluated according to an imaging result; s3, according to the evaluated inter-row dislocation amount, inter-row dislocation caused by long linear array image rotation is tested and corrected; s4, testing and correcting the inter-row dislocation caused by the deviation of the geometric resolution of the pixel according to the evaluated inter-row dislocation quantity; and S5, testing and correcting the inter-row dislocation caused by the servo control error according to the evaluated inter-row dislocation quantity. According to the method, line-to-line dislocation caused by different reasons can be identified, correction can be conveniently carried out according to different factors, error identification is comprehensive, and the requirement of long linear array load on-orbit application can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite overall design and image positioning and registration, and in particular to a method and system for testing and correcting inter-row misalignment of a long linear array payload. Background Art

[0002] Long linear array payloads have the advantages of large width, fast imaging speed, and stable scanning control, and are important payloads for geostationary meteorological satellites. The working method of long linear array payloads in orbit is to adjust the direction of the optical axis through the east-west and north-south two-dimensional scanning mechanisms to achieve observation coverage of the entire Earth disk. Affected by the payload scanning control error, geometric parameter deviation, etc., the two adjacent scanning lines of the long linear array payload will cause geometric misalignment. This phenomenon is specifically manifested in the misalignment of the geometric dimensions of adjacent scanning lines. With the continuous development of satellite remote sensing technology and the continuous deepening of data application, the requirements for core indicators such as the geometric positioning of remote sensing satellite data products are becoming increasingly higher. The inter-row misalignment phenomenon will lead to inaccurate geometric information of remote sensing images and even affect the continuity of the observed target. This phenomenon is a key issue affecting the on-orbit application of long linear array payloads and needs to be tested and corrected on the ground.

[0003] After literature research, in the paper "Registration Method for Inter-row Misalignment of Multi-channel Scanning Radiometer" (Journal of Infrared and Millimeter Waves, Vol. 39, No. 3, 2020), a method for the inter-row misalignment problem of the multi-channel scanning radiometer of the Fengyun-4A satellite was proposed. According to the payload scanning method combined with the Fourier phase shift characteristics, the phase difference spectrum curve of adjacent pixels in the misaligned row was calculated, and the misaligned position was obtained by fitting the low-frequency part of the phase difference spectrum by the least squares method. The misaligned rows were reconstructed using the weight distribution method to solve the inter-row misalignment problem. The method proposed in this paper is used for short linear arrays, focusing on the analysis of inter-row misalignment during bidirectional reciprocating scanning of short linear array payloads, and does not involve the analysis and testing of inter-row misalignment of long linear array payloads.

[0004] In the dissertation "Research on Inter-row Misalignment Registration of Millimeter-Wave Images and Fusion Algorithms for Optical Images" (Master's thesis, University of Electronic Science and Technology of China, 2013), the theories and methods of passive millimeter-wave imaging technology and image fusion technology were studied and analyzed. The characteristics and influencing factors of millimeter-wave images were analyzed. The continuity of images obtained by sensors when imaging natural scenes was studied, and this continuity was measured using cross-correlation coefficients. The amount of random misalignment was estimated based on the correlation between two rows of vector data and the low-frequency phase difference function. Starting from the frequency domain, the method of compensating for phase difference was studied to achieve sub-pixel displacement correction without interpolation. The analysis method for inter-row misalignment in this paper is similar to that in the paper "Registration Method for Inter-row Misalignment of Multi-channel Scanning Radiometers" and does not involve the analysis and testing of inter-row misalignment of long linear array payloads.

[0005] In the dissertation "Study on Multi-Homography Registration and Misalignment Elimination Algorithms in Image Stitching" (Master's thesis, Huazhong University of Science and Technology, 2015), dynamic programming was used to find the optimal stitching line for fusion. For structural misalignment at the stitching site, pixels on the same stitching line of adjacent images were matched based on local energy. The deformation vectors of the matched points were then calculated, and the offsets of the remaining pixels in the overlapping area were calculated using Poisson fusion. This dissertation primarily used overlapping image regions for registration and mosaicking, focusing on image processing and related fields, and did not involve the analysis and testing of inter-row misalignment in long linear array payloads.

[0006] Chinese patent publication CN105572692B discloses a fully physical test apparatus and method for satellite image navigation and registration. The apparatus includes a three-axis air bearing platform, an optical axis measurement system, an adjustment mechanism, wireless communication equipment, an optoelectronic autocollimator, a camera mounting plate, and onboard test equipment such as an imaging camera, a gyroscope assembly, and a flywheel assembly. The system simulates on-orbit satellite operation, conducting system-level verification and performance testing to ensure that the onboard image navigation and registration technical solution and system specifications meet onboard requirements. While this patent describes a fully physical test system based on a three-axis air bearing platform, it does not address the analysis and testing of inter-row misalignment for long linear array payloads.

[0007] Chinese patent publication CN107727232B discloses a geometric alignment test device and method, particularly suitable for testing push-broom, multi-unit externally spliced ​​imaging spectrometers. The device consists of a collimator, a moving target, a support platform, and a one-dimensional turning assembly. The test device performs geometric alignment tests on push-broom, multi-unit externally spliced ​​imaging spectrometers by controlling the rotation of the one-dimensional turntable and the movement of the moving target at the collimator's focal plane. After data processing, the geometric alignment relationship between the multiple units is obtained. This method is primarily used for geometric alignment testing between spectrometers and does not involve inter-row misalignment analysis and testing of long linear array loads.

[0008] Chinese patent publication CN114723622A discloses a method and system for correcting long-line array payload scanning imaging on geostationary meteorological satellites. The method includes the following steps: Step S1: Modeling the optical path based on the imaging principle of the long-line array scanning imaging payload to describe the error mechanism of the long-line array payload scanning imaging; Step S2: Derivation of a geometric correction model for the long-line array scanning imaging; and Step S3: Implementing pixel-by-pixel scanning imaging correction based on the geometric correction model. This patent only discusses the geometric positioning deviation caused by the coupling of the long-line array detector with the two-dimensional scanning mechanism and does not involve analysis and testing of inter-row misalignment.

[0009] Therefore, a method and system for testing and correcting inter-row misalignment of long linear array loads is needed. Summary of the Invention

[0010] In view of the defects in the prior art, the purpose of the present invention is to provide a method and system for testing and correcting inter-row misalignment of long linear array loads.

[0011] According to the present invention, a method for testing and correcting inter-row misalignment of a long linear array load is provided, comprising:

[0012] Step S1: When the long linear array payload is working on-orbit, the inter-row misalignment mechanism is analyzed to identify the formation mechanism of the inter-row misalignment, including the inter-row misalignment caused by the long linear array image rotation, the inter-row misalignment caused by the pixel geometric resolution deviation, and the inter-row misalignment caused by the servo control error;

[0013] Step S2: construct a ground imaging test system, perform near-field simulation of far-field imaging through a collimator, and evaluate the inter-row misalignment based on the imaging results;

[0014] Step S3: testing and correcting the inter-row misalignment caused by the long-line array image rotation according to the estimated inter-row misalignment amount;

[0015] Step S4: testing and correcting the inter-row misalignment caused by pixel geometric resolution deviation based on the assessed inter-row misalignment amount;

[0016] Step S5: testing and correcting the inter-row misalignment caused by the servo control error according to the estimated inter-row misalignment amount.

[0017] Preferably, the step S1 includes:

[0018] Step S1.1: When the long linear array payload is in orbit, the two-dimensional pointing angle of the remote sensing instrument's optical axis is adjusted to observe the pointing direction of different areas on the surface.

[0019] Step S1.2: If there is a deviation in the geometric splicing of two adjacent scanned rows, an inter-row misalignment occurs, and the process proceeds to step S1.3; if there is no deviation in the geometric splicing of two adjacent scanned rows, no inter-row misalignment occurs;

[0020] Step S1.3: Analyze the generation mechanism of inter-row misalignment and identify the formation mechanism of inter-row misalignment. Specifically, the formation mechanism includes inter-row misalignment caused by long-line array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error.

[0021] When the splicing of two adjacent rows is misaligned in the east-west direction, the linear array load has image rotation, which is the inter-row misalignment caused by the long-line array image rotation. According to the corresponding geometric relationship, the inter-row misalignment caused by image rotation in the east-west direction is obtained as follows:

[0022] Δε1=l·θ

[0023] In the above formula, Δε1 is the east-west inter-row misalignment caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle;

[0024] When the geometric resolution deviation causes width error, resulting in a north-south misalignment at the junction of two rows, it is an inter-row misalignment caused by the pixel geometric resolution deviation. The formula for calculating the north-south misalignment is as follows:

[0025]

[0026] In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array;

[0027] When there is a control residual in the control system, causing inter-row misalignment in the east-west direction, the inter-row misalignment is caused by the servo control error. Since the residual of the control system has a random distribution characteristic, the inter-row misalignment at different positions during single-row scanning has a random distribution characteristic.

[0028] Preferably, the step S3 includes:

[0029] Step S3.1: Select a Y-shaped imaging target and test the inter-row misalignment in the east-west direction. Specifically, the junction of two adjacent rows is selected as the vertical edge of the Y target to remove the influence of the north-south misalignment. Under the effect of the long-line array image rotation, the imaging result has an inter-row misalignment in the east-west direction. Through image processing, the inter-row misalignment is identified as Δε1. Based on the misalignment, the image rotation angle of the long-line array is calculated:

[0030]

[0031] In the above formula, θ is the image rotation angle;

[0032] Step S3.2: Based on the image rotation angle θ calculated above, the image is further resampled element by element to perform image rotation correction. The correction formula is as follows:

[0033]

[0034] In the above formula, ε1 is the east-west inter-row misalignment correction caused by the long-line array image rotation; x is the sequence number of the long-line array pixel.

[0035] Preferably, the step S4 includes:

[0036] Step S4.1: Select a Y-shaped imaging target and test the inter-row misalignment in the north-south direction. Specifically, the junction of two adjacent rows is selected as the inclined edge of the Y target to eliminate the influence of east-west misalignment. Due to the effect of pixel geometric resolution deviation, the imaging results have inter-row misalignment in the north-south direction, and there is information loss or overlap at the junction of two rows. Through image processing, the inter-row misalignment is identified as Δη1, and the true pixel resolution of the long linear array payload is calculated based on the misalignment:

[0037]

[0038] In the above formula, τ is the actual pixel geometric resolution of the long linear array;

[0039] Step S4.2: Calculate the north-south latitude step angles and adjust the north-south latitude step angles to eliminate the pixel resolution deviation of the long linear array payload;

[0040] Specifically,

[0041] β=τ·l

[0042] In the above formula, β is the north-south latitude step angle.

[0043] Preferably, the step S5 includes:

[0044] Step S5.1: Select a vertical stripe imaging target and measure the inter-row misalignment at different locations. Specifically, each individual vertical stripe can measure the inter-row misalignment. By measuring multiple vertical stripes, the inter-row misalignment at different locations can be obtained, and the servo control accuracy can be calculated.

[0045] Step S5.2: Constrain the servo control accuracy of the load according to the test results, and reduce the random error of inter-row misalignment by improving the servo control accuracy.

[0046] According to the present invention, a method for testing and correcting inter-row misalignment of a long linear array load is provided, comprising:

[0047] Module M1: Analyzes the inter-row misalignment mechanism when the long linear array payload is operating on orbit and identifies the formation mechanism of inter-row misalignment, including inter-row misalignment caused by long linear array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error.

[0048] Module M2: Build a ground imaging test system, use a collimator to simulate far-field imaging in the near field, and evaluate the inter-row misalignment based on the imaging results;

[0049] Module M3: Based on the estimated inter-row misalignment, test and correct the inter-row misalignment caused by long-line array image rotation;

[0050] Module M4: Based on the estimated inter-row misalignment, test and correct the inter-row misalignment caused by pixel geometric resolution deviation;

[0051] Module M5: Based on the estimated inter-row misalignment, test and correct the inter-row misalignment caused by the servo control error.

[0052] Preferably, the module M1 includes:

[0053] Module M1.1: When the long linear array payload is in orbit, it adjusts the two-dimensional pointing angle of the remote sensing instrument's optical axis to observe the pointing direction of different areas on the surface;

[0054] Module M1.2: If there is a deviation in the geometric splicing of two adjacent scanned rows, inter-row misalignment occurs, triggering module M1.3; if there is no deviation in the geometric splicing of two adjacent scanned rows, no inter-row misalignment occurs;

[0055] Module M1.3: Analyze the generation mechanism of inter-row misalignment and identify its formation mechanism. Specifically, the formation mechanism includes inter-row misalignment caused by long-line array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error.

[0056] When the splicing of two adjacent rows is misaligned in the east-west direction, the linear array load has image rotation, which is the inter-row misalignment caused by the long-line array image rotation. According to the corresponding geometric relationship, the inter-row misalignment caused by image rotation in the east-west direction is obtained as follows:

[0057] Δε1=l·θ

[0058] In the above formula, Δε1 is the east-west inter-row misalignment caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle;

[0059] When the geometric resolution deviation causes width error, resulting in a north-south misalignment at the junction of two rows, it is an inter-row misalignment caused by the pixel geometric resolution deviation. The formula for calculating the north-south misalignment is as follows:

[0060]

[0061] In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array;

[0062] When there is a control residual in the control system, causing inter-row misalignment in the east-west direction, the inter-row misalignment is caused by the servo control error. Since the residual of the control system has a random distribution characteristic, the inter-row misalignment at different positions during single-row scanning has a random distribution characteristic.

[0063] Preferably, the module M3 includes:

[0064] Module M3.1: Select a Y-shaped imaging target and test the inter-row misalignment in the east-west direction. Specifically, the junction of two adjacent rows is selected as the vertical edge of the Y target to remove the influence of the north-south misalignment. Under the effect of long-line array image rotation, the imaging results have inter-row misalignment in the east-west direction. Through image processing, the inter-row misalignment is identified as Δε1. Based on the misalignment, the long-line array image rotation angle is calculated:

[0065]

[0066] In the above formula, θ is the image rotation angle;

[0067] Module M3.2: Based on the image rotation angle θ calculated above, the image is further resampled element by element to perform image rotation correction. The correction formula is as follows:

[0068]

[0069] In the above formula, ε1 is the east-west inter-row misalignment correction caused by the long-line array image rotation; x is the sequence number of the long-line array pixel.

[0070] Preferably, the module M4 includes:

[0071] Module M4.1: Select a Y-shaped imaging target and test the inter-row misalignment in the north-south direction. Specifically, the junction of two adjacent rows is selected as the inclined edge of the Y target to eliminate the effects of east-west misalignment. Due to the effect of pixel geometric resolution deviation, the imaging results have inter-row misalignment in the north-south direction, and there is information loss or overlap at the junction of two rows. Through image processing, the inter-row misalignment is identified as Δη1, and the true pixel resolution of the long linear array payload is calculated based on the misalignment:

[0072]

[0073] In the above formula, τ is the actual pixel geometric resolution of the long linear array;

[0074] Module M4.2: Calculates the north-south latitude step angle and adjusts the north-south latitude step angle to eliminate the pixel resolution deviation of the long linear array payload;

[0075] Specifically,

[0076] β=τ·l

[0077] In the above formula, β is the north-south latitude step angle.

[0078] Preferably, the module M5 includes:

[0079] Module M5.1: Select a vertical stripe imaging target to test the inter-row misalignment at different locations. Specifically, each individual vertical stripe can measure the inter-row misalignment. By using multiple vertical stripes, the inter-row misalignment at different locations can be obtained, and the servo control accuracy can be calculated.

[0080] Module M5.2: Constrain the servo control accuracy of the load based on the test results, and reduce the random error of inter-row misalignment by improving the servo control accuracy.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] 1. The long linear array payload inter-row misalignment testing method proposed in this invention can identify inter-row misalignment caused by different reasons, facilitating targeted correction based on different factors. The error identification is comprehensive and can meet the requirements of long linear array payload on-orbit applications.

[0083] 2. By analyzing the inter-row misalignment, the present invention can reduce signal distortion and interference, improve signal quality, and at the same time, misalignment correction helps to improve the spatial resolution of the system and make target recognition more accurate;

[0084] 3. The symmetry of the "Y"-shaped target selected in this invention enables it to evenly distribute the test load and reduce systematic errors in the test. Even if the target rotates, the "Y"-shaped structure can still maintain test accuracy.

[0085] 4. When correcting inter-row misalignment caused by servo control errors, the present invention uses a "vertical stripe" imaging target to test the amount of inter-row misalignment at different locations due to its random distribution. This "vertical stripe" target can adapt to misalignment detection at different locations and amplitudes, and can also cover the entire imaging area, ensuring comprehensive testing. By selecting different targets based on different misalignment characteristics and combining multiple targets, comprehensive coverage of different types of misalignment detection can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0087] Figure 1 This is a flow chart of a method for testing and correcting inter-row misalignment of a long linear array load according to the present invention;

[0088] Figure 2 This is a flow chart of a method for testing inter-row misalignment of a long linear array load based on Example 1 of the present invention;

[0089] Figure 3 This is a schematic diagram of a two-dimensional pointing direction of a geostationary remote sensing satellite for Earth observation according to embodiment 1 of the present invention;

[0090] Figure 4 This is a schematic diagram of the rotation effect of the long linear array load in Example 1 of the present invention;

[0091] Figure 5 This is a schematic diagram of inter-row misalignment caused by image rotation of a long linear array load in Example 1 of the present invention;

[0092] Figure 6 This is a schematic diagram of inter-row misalignment caused by pixel geometric resolution deviation in Example 1 of the present invention;

[0093] Figure 7 This is a schematic diagram of a ground imaging test system according to embodiment 1 of the present invention;

[0094] Figure 8 This is a schematic diagram of a vertical edge of a "Y" target selected at the junction of two adjacent rows in Example 1 of the present invention;

[0095] Figure 9 This is a schematic diagram of the correction of inter-row misalignment caused by image rotation of a long linear array load according to Example 1 of the present invention;

[0096] Figure 10 Schematic diagram of the inclined edge of the target "Y" selected at the junction of two adjacent rows in Example 1 of the present invention;

[0097] Figure 11 Schematic diagram of correction of inter-row misalignment caused by pixel geometric resolution deviation in Example 1 of the present invention;

[0098] Figure 12 This is a schematic diagram of selecting a “vertical stripe” type imaging target in Example 1 of the present invention. DETAILED DESCRIPTION

[0099] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0100] The inter-row misalignment phenomenon is a key issue affecting the on-orbit application of long linear array payloads and requires testing and correction on the ground. The present invention proposes a method for testing and correcting the inter-row misalignment of long linear array payloads. The method systematically analyzes various factors that cause inter-row misalignment and designs testing and calibration methods for different factors to eliminate the inter-row misalignment phenomenon. The method mainly includes the following contents: (1) Analyzing the generation mechanism of inter-row misalignment for the on-orbit working mode of the long linear array payload and identifying the formation mechanism of inter-row misalignment; (2) Constructing a ground imaging test system, using a parallel light tube to achieve near-field simulation of far-field imaging, and analyzing the inter-row misalignment phenomenon based on the imaging results; (3) Designing a test method for the inter-row misalignment caused by long linear array image rotation; (4) Designing a test method for the inter-row misalignment caused by pixel geometric resolution deviation; (5) Designing a test method for the inter-row misalignment caused by servo control error. The inter-row misalignment test method for long linear array payloads proposed in the present invention can identify the inter-row misalignment caused by different reasons, facilitate correction for different factors, and comprehensively identify errors, which can meet the needs of on-orbit application of long linear array payloads.

[0101] A method for testing and correcting inter-row misalignment of a long linear array load comprises:

[0102] Step S1: When the long linear array payload is working on-orbit, the inter-row misalignment mechanism is analyzed to identify the formation mechanism of the inter-row misalignment, including the inter-row misalignment caused by the long linear array image rotation, the inter-row misalignment caused by the pixel geometric resolution deviation, and the inter-row misalignment caused by the servo control error;

[0103] Step S2: construct a ground imaging test system, perform near-field simulation of far-field imaging through a collimator, and evaluate the inter-row misalignment based on the imaging results;

[0104] Step S3: testing and correcting the inter-row misalignment caused by the long-line array image rotation according to the estimated inter-row misalignment amount;

[0105] Step S4: testing and correcting the inter-row misalignment caused by pixel geometric resolution deviation based on the assessed inter-row misalignment amount;

[0106] Step S5: testing and correcting the inter-row misalignment caused by the servo control error according to the estimated inter-row misalignment amount.

[0107] Specifically, the step S1 includes:

[0108] Step S1.1: When the long linear array payload is in orbit, the two-dimensional pointing angle of the remote sensing instrument's optical axis is adjusted to observe the pointing direction of different areas on the surface.

[0109] Step S1.2: If there is a deviation in the geometric splicing of two adjacent scanned rows, an inter-row misalignment occurs, and the process proceeds to step S1.3; if there is no deviation in the geometric splicing of two adjacent scanned rows, no inter-row misalignment occurs;

[0110] Step S1.3: Analyze the generation mechanism of inter-row misalignment and identify the formation mechanism of inter-row misalignment. Specifically, the formation mechanism includes inter-row misalignment caused by long-line array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error.

[0111] When the splicing of two adjacent rows is misaligned in the east-west direction, the linear array load has image rotation, which is the inter-row misalignment caused by the long-line array image rotation. According to the corresponding geometric relationship, the inter-row misalignment caused by image rotation in the east-west direction is obtained as follows:

[0112] Δε1=l·θ

[0113] In the above formula, Δε1 is the east-west inter-row misalignment caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle;

[0114] When the geometric resolution deviation causes width error, resulting in a north-south misalignment at the junction of two rows, it is an inter-row misalignment caused by the pixel geometric resolution deviation. The formula for calculating the north-south misalignment is as follows:

[0115]

[0116] In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array;

[0117] When there is a control residual in the control system, causing inter-row misalignment in the east-west direction, the inter-row misalignment is caused by the servo control error. Since the residual of the control system has a random distribution characteristic, the inter-row misalignment at different positions during single-row scanning has a random distribution characteristic.

[0118] Specifically, the step S3 includes:

[0119] Step S3.1: Select a Y-shaped imaging target and test the inter-row misalignment in the east-west direction. Specifically, the junction of two adjacent rows is selected as the vertical edge of the Y target to remove the influence of the north-south misalignment. Under the effect of the long-line array image rotation, the imaging result has an inter-row misalignment in the east-west direction. Through image processing, the inter-row misalignment is identified as Δε1. Based on the misalignment, the image rotation angle of the long-line array is calculated:

[0120]

[0121] In the above formula, θ is the image rotation angle;

[0122] Step S3.2: Based on the image rotation angle θ calculated above, the image is further resampled element by element to perform image rotation correction. The correction formula is as follows:

[0123]

[0124] In the above formula, ε1 is the east-west inter-row misalignment correction caused by the long-line array image rotation; x is the sequence number of the long-line array pixel.

[0125] Specifically, the step S4 includes:

[0126] Step S4.1: Select a Y-shaped imaging target and test the inter-row misalignment in the north-south direction. Specifically, the junction of two adjacent rows is selected as the inclined edge of the Y target to eliminate the influence of east-west misalignment. Due to the effect of pixel geometric resolution deviation, the imaging results have inter-row misalignment in the north-south direction, and there is information loss or overlap at the junction of two rows. Through image processing, the inter-row misalignment is identified as Δη1, and the true pixel resolution of the long linear array payload is calculated based on the misalignment:

[0127]

[0128] In the above formula, τ is the actual pixel geometric resolution of the long linear array;

[0129] Step S4.2: Calculate the north-south latitude step angles and adjust the north-south latitude step angles to eliminate the pixel resolution deviation of the long linear array payload;

[0130] Specifically,

[0131] β=τ·l

[0132] In the above formula, β is the north-south latitude step angle.

[0133] Specifically, the step S5 includes:

[0134] Step S5.1: Select a vertical stripe imaging target and measure the inter-row misalignment at different locations. Specifically, each individual vertical stripe can measure the inter-row misalignment. By measuring multiple vertical stripes, the inter-row misalignment at different locations can be obtained, and the servo control accuracy can be calculated.

[0135] Step S5.2: Constrain the servo control accuracy of the load according to the test results, and reduce the random error of inter-row misalignment by improving the servo control accuracy.

[0136] Example 1

[0137] like Figure 2 As shown, the specific embodiments of the present invention are as follows:

[0138] 1. Analysis of the inter-row load misalignment mechanism in long linear arrays

[0139] During the long-line array payload Earth observation process, by adjusting the two-dimensional pointing angle of the remote sensing instrument's optical axis, it is possible to achieve directional observation of different areas of the Earth's surface. For ease of description, the two-dimensional pointing of the satellite's Earth observation can be defined as the east-west dimension and the north-south dimension. See the attached Figure 3 Typically, the detector arrays of a long linear array payload are arranged in a north-south direction. Single-row scanning is achieved by driving the east-west scanning control. Stepping the north-south control adjusts the single-row scanning area to achieve line-by-line scanning. If there is a deviation in the geometric splicing of two adjacent scanned rows, inter-row misalignment will occur.

[0140] Inter-row misalignment includes east-west inter-row misalignment (scanning direction) and north-south inter-row misalignment (north-south stepping direction). The following analyzes different inter-row misalignment mechanisms.

[0141] 1.1 Inter-row misalignment caused by long-line array image rotation

[0142] Ideally, the long linear array detectors are arranged strictly in the north-south direction. However, due to factors such as optical system distortion and detector processing and installation errors, the long linear array load has a rotation effect. Figure 4 When the long linear array payload is working on orbit, it is required that the tail element of the first row and the head element of the second row can be spliced ​​normally to ensure the integrity and accuracy of the observed image. However, when the long linear array payload has image rotation, the splicing of two adjacent rows will have obvious misalignment in the east-west direction, as shown in the attached figure. Figure 5 According to the corresponding geometric relationship, the inter-row misalignment in the east-west direction caused by image rotation can be obtained as follows:

[0143] Δε1=l·θ

[0144] In the above formula, Δε1 is the inter-row misalignment in the east-west direction caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle.

[0145] Generally speaking, based on the existing optical design and processing accuracy, the image rotation angle θ caused by the optical system error is small, generally not exceeding 0.1°. This magnitude mainly causes inter-row misalignment in the east-west direction, and will not cause inter-row misalignment in the north-south direction.

[0146] 1.2 Inter-row misalignment caused by pixel geometric resolution deviation

[0147] The core indicators of geometric resolution and optical payload will be precisely designed and precision-machined in accordance with the requirements of the indicators. However, due to the influence of processing errors, high-precision optical payloads often have geometric resolution deviations of the order of 0.5% to 1%. When the long linear array payload involved in the present invention is working in orbit, it adjusts the north-south pointing angle to perform line scanning. In order to ensure the accuracy of the geometric relationship between the joints of two adjacent rows, it is required that the north-south pointing angle be equal to the north-south width angle of the long linear array payload each time the line is changed.

[0148] For long linear array loads, due to the large width of the line array, even a geometric resolution deviation of the order of 0.5% to 1% will cause a certain error in the width range, which will cause a misalignment in the north-south direction at the joint of the two rows, as shown in the attached figure. Figure 6 The formula for calculating the north-south misalignment is as follows:

[0149]

[0150] In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; l is the pixel length of the long linear array, τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array.

[0151] According to the inter-row misalignment mechanism caused by pixel geometric resolution deviation, when the actual pixel geometric resolution is too small, the north-south latitude pointing angle will be too large when the row is wrapped, resulting in information loss at the splicing point; when the actual pixel geometric resolution is too large, the north-south latitude pointing angle will be too small when the row is wrapped, resulting in information overlap at the splicing point.

[0152] 1.3 Inter-row misalignment caused by servo control error

[0153] Long linear array payloads achieve single-line scanning and imaging through east-west latitude scanning control. To ensure image quality, strictly uniform motion is required in both directions. However, due to control residuals in the control system, misalignment between lines in the east-west direction can occur. Since the control residuals have a random distribution, the amount of misalignment between lines at different positions during single-line scanning also exhibits a certain random distribution.

[0154] 2. Build a ground imaging test system

[0155] The inter-row misalignment of long linear array payloads needs to be evaluated through imaging. The purpose is to simulate the actual imaging results of the payload, extract the inter-row misalignment error based on the image, and verify the correction method for the inter-row misalignment. Therefore, it is necessary to build a ground imaging test system and use collimators to achieve near-field simulation of far-field imaging, as shown in the attached figure. Figure 7 shown.

[0156] As can be seen from the figure, the ground-based imaging test system mainly consists of a long linear array payload, a turntable, a collimator, a target, an integrating sphere, and an optical system bracket. The turntable is used to secure the long linear array payload and ensure that its optical axis remains horizontal. The collimator is a key component of the ground-based optical imaging system, converting incident light into parallel light. The target simulates the payload's observation target. The integrating sphere serves as a light source, adjusting the target's brightness. The optical system bracket supports the optical system.

[0157] According to the principle of optical imaging, the arrangement relationship of each part of the optical system is shown in the attached Figure 7 , it is required that the optical axis of the long linear array load is approximately parallel to the optical axis of the collimator, and the optical axis passes through the target and integrating sphere in sequence through the collimator.

[0158] The specific implementation steps are described as follows:

[0159] Step 2.1: Complete the construction of the ground imaging test system. The test system mainly includes a long linear array payload, a turntable, a collimator, a target, an integrating sphere, and an optical system bracket.

[0160] Step 2.2: Install the long linear array payload so that the optical axis of the payload is aligned with the optical axis of the collimator.

[0161] Step 2.3: Drive the long linear array payload to perform scanning imaging and obtain the original imaging results.

[0162] Step 2.4: Analyze the original image and extract the amount of misalignment.

[0163] Step 2.5: Correct the inter-row misalignment of the image to obtain a corrected image, and evaluate whether the inter-row misalignment error after correction is significantly reduced.

[0164] 3. Testing and Correction Methods for Inter-row Misalignment Caused by Long Linear Array Image Rotation

[0165] According to the analysis in Section 1.1, the image rotation of the long linear array payload will cause inter-row misalignment in the east-west direction. In order to test the inter-row misalignment in the east-west direction, a "Y"-shaped imaging target is selected. In addition, during imaging, in order to remove the influence of the north-south misalignment, the joint of two adjacent rows is selected as the vertical edge of the "Y" target, as shown in the attached figure. Figure 8 shown.

[0166] Under the effect of long-line array image rotation, the imaging results will have inter-row misalignment in the east-west direction, as shown in the attached figure. Figure 9 As shown in (a), through image processing, the inter-row misalignment Δε1 can be identified, and the image rotation angle of the long linear array can be calculated based on the misalignment:

[0167]

[0168] In the above formula, Δε1 is the east-west inter-row misalignment caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle. Based on the image rotation angle θ calculated above, the image can be further resampled element by element to perform image rotation correction. The correction formula is as follows:

[0169]

[0170] In the above formula, ε1 is the correction amount of the inter-row misalignment caused by the long-line array image rotation in the east-west direction; x is the serial number of the long-line array pixel; l is the pixel length of the long-line array, and θ is the image rotation angle. By correcting each pixel, the inter-row misalignment caused by the long-line array image rotation can be eliminated, as shown in the following figure. Figure 9 (b) shown.

[0171] 4. Testing and correction methods for inter-row misalignment caused by pixel geometric resolution deviation

[0172] According to the analysis in Section 1.2, pixel geometric resolution deviation will cause inter-row misalignment in the north-south direction. In order to test the inter-row misalignment in the north-south direction, a "Y"-shaped imaging target is selected. In addition, during imaging, in order to remove the influence of east-west misalignment, the joint of two adjacent rows is selected as the inclined edge of the "Y" target, as shown in the attached figure. Figure 10 At the same time, in order to facilitate the detection of the north-south misalignment from the image, it is necessary for the two scan lines to have a certain overlap area, that is, the north-south latitude step angle β is smaller than the width angle of the long linear array payload.

[0173] Due to the effect of pixel geometric resolution deviation, the imaging results will have inter-row misalignment in the north-south direction, as shown in the following figure. Figure 11 As shown in (a), there is obvious information loss at the junction of two rows. Through image processing, the inter-row misalignment Δη1 can be identified, and the true pixel resolution of the long linear array payload can be calculated based on the misalignment:

[0174]

[0175] In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; l is the pixel length of the long linear array, τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array.

[0176] In order to eliminate the influence of pixel resolution deviation of long linear array payload, the design of north-south latitude step angle β needs to be calculated based on the actual pixel geometric resolution:

[0177] β=τ·l

[0178] In the above formula, β is the north-south latitude step angle; l is the pixel length of the long linear array; τ is the actual pixel geometric resolution of the long linear array. By adjusting the north-south latitude step angle, the inter-row misalignment caused by the pixel geometric resolution deviation can be eliminated, as shown in the following figure: Figure 11 (b) shown.

[0179] 5. Testing and correction methods for inter-row misalignment caused by servo control errors

[0180] According to the analysis in Section 1.3, the inter-row misalignment caused by servo control errors has a random distribution characteristic. In order to test the inter-row misalignment at different positions, a "vertical stripe" imaging target was selected. Moreover, during imaging, each individual vertical stripe can be used to test the inter-row misalignment. The inter-row misalignment at different positions can be obtained by using multiple vertical stripes, and the servo control accuracy can be calculated.

[0181] It should be pointed out that the inter-row misalignment caused by the servo control error is a random quantity and cannot be corrected. Therefore, it is necessary to constrain the servo control accuracy of the load according to the test results, and reduce the random error of the inter-row misalignment by improving the servo control accuracy.

[0182] The present invention also provides a long linear array load row misalignment testing and correction system. The long linear array load row misalignment testing and correction system can be implemented by executing the process steps of the long linear array load row misalignment testing and correction method. That is, those skilled in the art can understand the long linear array load row misalignment testing and correction method as a preferred implementation of the long linear array load row misalignment testing and correction system.

[0183] According to the present invention, a method for testing and correcting inter-row misalignment of a long linear array payload is provided, comprising: module M1: when the long linear array payload is operating on-orbit, analyzing the inter-row misalignment mechanism, and identifying the formation mechanism of the inter-row misalignment, including inter-row misalignment caused by long linear array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error; module M2: constructing a ground imaging test system, performing near-field simulation of far-field imaging through a parallel light tube, and evaluating the amount of inter-row misalignment based on the imaging results; module M3: testing and correcting the inter-row misalignment caused by long linear array image rotation based on the evaluated amount of inter-row misalignment; module M4: testing and correcting the inter-row misalignment caused by pixel geometric resolution deviation based on the evaluated amount of inter-row misalignment; module M5: testing and correcting the inter-row misalignment caused by servo control error based on the evaluated amount of inter-row misalignment.

[0184] Specifically, the module M1 includes: module M1.1: when the long linear array payload is working in orbit, the pointing angle of different areas of the surface is observed by adjusting the two-dimensional pointing angle of the optical axis of the remote sensing instrument; module M1.2: if there is a deviation in the geometric splicing of two adjacent scanned lines, an inter-row misalignment is generated, triggering module M1.3; if there is no deviation in the geometric splicing of two adjacent scanned lines, no inter-row misalignment is generated; module M1.3: analyzing the generation mechanism of the inter-row misalignment and identifying the formation mechanism of the inter-row misalignment; specifically, the formation mechanism includes the inter-row misalignment caused by the long linear array image rotation, the inter-row misalignment caused by the pixel geometric resolution deviation, and the inter-row misalignment caused by the servo control error; when the splicing of two adjacent rows is misaligned in the east-west direction, the linear array payload has image rotation, which is the inter-row misalignment caused by the long linear array image rotation; according to the corresponding geometric relationship, the east-west direction inter-row misalignment caused by the image rotation is obtained as follows:

[0185] Δε1=l·θ

[0186] In the above formula, Δε1 is the east-west inter-row misalignment caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle;

[0187] When the geometric resolution deviation causes width error, resulting in a north-south misalignment at the junction of two rows, it is an inter-row misalignment caused by the pixel geometric resolution deviation. The formula for calculating the north-south misalignment is as follows:

[0188]

[0189] In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array;

[0190] When there is a control residual in the control system, causing inter-row misalignment in the east-west direction, the inter-row misalignment is caused by the servo control error. Since the residual of the control system has a random distribution characteristic, the inter-row misalignment at different positions during single-row scanning has a random distribution characteristic.

[0191] Specifically, the module M3 includes: Module M3.1: Selecting a Y-shaped imaging target to test the inter-row misalignment in the east-west direction; Specifically, the junction of two adjacent rows is selected as the vertical edge of the Y target to remove the influence of the north-south misalignment; Under the effect of the long-line array image rotation, the imaging result has inter-row misalignment in the east-west direction. Through image processing, the inter-row misalignment is identified as Δε1, and the image rotation angle of the long-line array is inversely calculated based on the misalignment:

[0192]

[0193] In the above formula, θ is the image rotation angle;

[0194] Module M3.2: Based on the image rotation angle θ calculated above, the image is further resampled element by element to perform image rotation correction. The correction formula is as follows:

[0195]

[0196] In the above formula, ε1 is the east-west inter-row misalignment correction caused by the long-line array image rotation; x is the sequence number of the long-line array pixel.

[0197] Specifically, the module M4 includes:

[0198] Module M4.1: Select a Y-shaped imaging target and test the inter-row misalignment in the north-south direction. Specifically, the junction of two adjacent rows is selected as the inclined edge of the Y target to eliminate the effects of east-west misalignment. Due to the effect of pixel geometric resolution deviation, the imaging results have inter-row misalignment in the north-south direction, and there is information loss or overlap at the junction of two rows. Through image processing, the inter-row misalignment is identified as Δη1, and the true pixel resolution of the long linear array payload is calculated based on the misalignment:

[0199]

[0200] In the above formula, τ is the actual pixel geometric resolution of the long linear array;

[0201] Module M4.2: Calculates the north-south latitude step angle and adjusts the north-south latitude step angle to eliminate the pixel resolution deviation of the long linear array payload;

[0202] Specifically,

[0203] β=τ·l

[0204] In the above formula, β is the north-south latitude step angle.

[0205] Specifically, the module M5 includes:

[0206] Module M5.1: Select a vertical stripe imaging target to test the inter-row misalignment at different locations. Specifically, each individual vertical stripe can measure the inter-row misalignment. By using multiple vertical stripes, the inter-row misalignment at different locations can be obtained, and the servo control accuracy can be calculated. Module M5.2: Constrain the servo control accuracy of the payload based on the test results, reducing the random error of inter-row misalignment by improving the servo control accuracy.

[0207] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0208] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for testing and correcting inter-row misalignment of a long linear array load, characterized in that: include: Step S1: When the long linear array payload is working on-orbit, the inter-row misalignment mechanism is analyzed to identify the formation mechanism of the inter-row misalignment, including the inter-row misalignment caused by the long linear array image rotation, the inter-row misalignment caused by the pixel geometric resolution deviation, and the inter-row misalignment caused by the servo control error; Step S2: construct a ground imaging test system, perform near-field simulation of far-field imaging through a collimator, and evaluate the inter-row misalignment based on the imaging results; Step S3: testing and correcting the inter-row misalignment caused by the long-line array image rotation according to the estimated inter-row misalignment amount; Step S4: testing and correcting the inter-row misalignment caused by pixel geometric resolution deviation based on the assessed inter-row misalignment amount; Step S5: testing and correcting the inter-row misalignment caused by the servo control error according to the estimated inter-row misalignment amount.

2. The method for testing and correcting inter-row misalignment of a long linear array load according to claim 1, characterized in that: The step S1 includes: Step S1.1: When the long linear array payload is in orbit, the two-dimensional pointing angle of the remote sensing instrument's optical axis is adjusted to observe the pointing direction of different areas on the surface. Step S1.2: If there is a deviation in the geometric splicing of two adjacent scanned rows, an inter-row misalignment occurs, and the process proceeds to step S1.3; if there is no deviation in the geometric splicing of two adjacent scanned rows, no inter-row misalignment occurs; Step S1.3: Analyze the generation mechanism of inter-row misalignment and identify the formation mechanism of inter-row misalignment. Specifically, the formation mechanism includes inter-row misalignment caused by long-line array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error. When the splicing of two adjacent rows is misaligned in the east-west direction, the linear array load has image rotation, which is the inter-row misalignment caused by the long-line array image rotation. According to the corresponding geometric relationship, the inter-row misalignment caused by image rotation in the east-west direction is obtained as follows: Δε1=l·θ In the above formula, Δε1 is the east-west inter-row misalignment caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle; When the geometric resolution deviation causes width error, resulting in a north-south misalignment at the junction of two rows, it is an inter-row misalignment caused by the pixel geometric resolution deviation. The formula for calculating the north-south misalignment is as follows: In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array; When there is a control residual in the control system, causing inter-row misalignment in the east-west direction, the inter-row misalignment is caused by the servo control error. Since the residual of the control system has a random distribution characteristic, the inter-row misalignment at different positions during single-row scanning has a random distribution characteristic.

3. The method for testing and correcting inter-row misalignment of a long linear array load according to claim 2, characterized in that: The step S3 includes: Step S3.1: Select a Y-shaped imaging target and test the inter-row misalignment in the east-west direction. Specifically, the junction of two adjacent rows is selected as the vertical edge of the Y target to remove the influence of the north-south misalignment. Under the effect of the long-line array image rotation, the imaging result has an inter-row misalignment in the east-west direction. Through image processing, the inter-row misalignment is identified as Δε1. Based on the misalignment, the image rotation angle of the long-line array is calculated: In the above formula, θ is the image rotation angle; Step S3.2: Based on the image rotation angle θ calculated above, the image is further resampled element by element to perform image rotation correction. The correction formula is as follows: In the above formula, ε1 is the correction amount of inter-row misalignment in the east-west direction caused by the long-line array image rotation; x is the sequence number of the long-line array pixel.

4. The method for testing and correcting inter-row misalignment of a long linear array load according to claim 2, characterized in that: The step S4 includes: Step S4.1: Select a Y-shaped imaging target and test the inter-row misalignment in the north-south direction. Specifically, the junction of two adjacent rows is selected as the inclined edge of the Y target to eliminate the influence of east-west misalignment. Due to the effect of pixel geometric resolution deviation, the imaging results have inter-row misalignment in the north-south direction, and there is information loss or overlap at the junction of two rows. Through image processing, the inter-row misalignment is identified as Δη1, and the true pixel resolution of the long linear array payload is calculated based on the misalignment: In the above formula, τ is the actual pixel geometric resolution of the long linear array; Step S4.2: Calculate the north-south latitude step angles and adjust the north-south latitude step angles to eliminate the pixel resolution deviation of the long linear array payload; Specifically, β=τ·l In the above formula, β is the north-south latitude step angle.

5. The method for testing and correcting inter-row misalignment of a long linear array load according to claim 2, characterized in that: The step S5 includes: Step S5.1: Select a vertical stripe imaging target and measure the inter-row misalignment at different locations. Specifically, each individual vertical stripe can measure the inter-row misalignment. By measuring multiple vertical stripes, the inter-row misalignment at different locations can be obtained, and the servo control accuracy can be calculated. Step S5.2: Constrain the servo control accuracy of the load according to the test results, and reduce the random error of inter-row misalignment by improving the servo control accuracy.

6. A method for testing and correcting inter-row misalignment of a long linear array load, characterized in that: include: Module M1: Analyzes the inter-row misalignment mechanism when the long linear array payload is operating on orbit and identifies the formation mechanism of inter-row misalignment, including inter-row misalignment caused by long linear array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error. Module M2: Build a ground imaging test system, use a collimator to simulate far-field imaging in the near field, and evaluate the inter-row misalignment based on the imaging results; Module M3: Based on the estimated inter-row misalignment, test and correct the inter-row misalignment caused by long-line array image rotation; Module M4: Based on the estimated inter-row misalignment, test and correct the inter-row misalignment caused by pixel geometric resolution deviation; Module M5: Based on the estimated inter-row misalignment, test and correct the inter-row misalignment caused by the servo control error.

7. The long linear array load inter-row misalignment testing and correction system according to claim 6, characterized in that: The module M1 includes: Module M1.1: When the long linear array payload is in orbit, it adjusts the two-dimensional pointing angle of the remote sensing instrument's optical axis to observe the pointing direction of different areas on the surface; Module M1.2: If there is a deviation in the geometric splicing of two adjacent scan lines, an inter-row misalignment occurs, triggering module M1.3; if there is no deviation in the geometric splicing of two adjacent scan lines; Module M1.3: Analyze the generation mechanism of inter-row misalignment and identify its formation mechanism. Specifically, the formation mechanism includes inter-row misalignment caused by long-line array image rotation, inter-row misalignment caused by pixel geometric resolution deviation, and inter-row misalignment caused by servo control error. When the splicing of two adjacent rows is misaligned in the east-west direction, the linear array load has image rotation, which is the inter-row misalignment caused by the long-line array image rotation. According to the corresponding geometric relationship, the inter-row misalignment caused by image rotation in the east-west direction is obtained as follows: Δε1=l·θ In the above formula, Δε1 is the east-west inter-row misalignment caused by the long-line array image rotation; l is the pixel length of the long-line array, and θ is the image rotation angle; When the geometric resolution deviation causes width error, resulting in a north-south misalignment at the junction of two rows, it is an inter-row misalignment caused by the pixel geometric resolution deviation. The formula for calculating the north-south misalignment is as follows: In the above formula, Δη1 is the inter-row misalignment in the north-south direction caused by the pixel geometric resolution deviation; τ0 is the theoretical pixel geometric resolution of the long linear array, and τ is the actual pixel geometric resolution of the long linear array; When there is a control residual in the control system, causing inter-row misalignment in the east-west direction, the inter-row misalignment is caused by the servo control error. Since the residual of the control system has a random distribution characteristic, the inter-row misalignment at different positions during single-row scanning has a random distribution characteristic.

8. The long linear array load inter-row misalignment testing and correction system according to claim 7, characterized in that: The module M3 includes: Module M3.1: Select a Y-shaped imaging target and test the inter-row misalignment in the east-west direction. Specifically, the junction of two adjacent rows is selected as the vertical edge of the Y target to remove the influence of the north-south misalignment. Under the effect of long-line array image rotation, the imaging results have inter-row misalignment in the east-west direction. Through image processing, the inter-row misalignment is identified as Δε1. Based on the misalignment, the long-line array image rotation angle is calculated: In the above formula, θ is the image rotation angle; Module M3.2: Based on the image rotation angle θ calculated above, the image is further resampled element by element to perform image rotation correction. The correction formula is as follows: In the above formula, ε1 is the correction amount of inter-row misalignment in the east-west direction caused by the long-line array image rotation; x is the sequence number of the long-line array pixel.

9. The long linear array load inter-row misalignment testing and correction system according to claim 7, characterized in that: The module M4 includes: Module M4.1: Select a Y-shaped imaging target and test the inter-row misalignment in the north-south direction. Specifically, the junction of two adjacent rows is selected as the inclined edge of the Y target to eliminate the effects of east-west misalignment. Due to the effect of pixel geometric resolution deviation, the imaging results have inter-row misalignment in the north-south direction, and there is information loss or overlap at the junction of two rows. Through image processing, the inter-row misalignment is identified as Δη1, and the true pixel resolution of the long linear array payload is calculated based on the misalignment: In the above formula, τ is the actual pixel geometric resolution of the long linear array; Module M4.2: Calculates the north-south latitude step angle and adjusts the north-south latitude step angle to eliminate the pixel resolution deviation of the long linear array payload; Specifically, β=τ·l In the above formula, β is the north-south latitude step angle.

10. The long linear array load inter-row misalignment testing and correction system according to claim 7, characterized in that: The module M5 includes: Module M5.1: Select a vertical stripe imaging target to test the inter-row misalignment at different locations. Specifically, each individual vertical stripe can measure the inter-row misalignment. By using multiple vertical stripes, the inter-row misalignment at different locations can be obtained, and the servo control accuracy can be calculated. Module M5.2: Constrain the servo control accuracy of the load based on the test results, and reduce the random error of inter-row misalignment by improving the servo control accuracy.

Images