Sensitivity reduction method for space surveying and mapping camera optical axis monitoring device

Abstract

The invention belongs to the technical field of space remote sensing surveying and mapping, and particularly relates to a desensitization method for a space surveying and mapping camera optical axis monitoring device. The invention aims to solve the problems of limited error suppression level, lack of a sensitivity control mechanism from a system design stage and the like in a current visual axis compensation model. By analyzing sensitivity influence factors of a three-axis measurement result of a camera coordinate system, an analytical expression of a three-axis calculation result and centroid extraction precision and an analytical relationship between the sensitivity of the three-axis calculation result and an incident beam direction are established. On the basis, an evaluation function is constructed, parameter constraints of an optical system are combined, the optimal incident light direction of a monitoring light beam is obtained through optimization, a systematic optimization method of the relation of the included angle, the view field and the sensitivity is established, and source suppression of optical axis drift error disturbance is achieved.

Description

Technical Field

[0001] This invention belongs to the field of space remote sensing and mapping technology, and particularly relates to a desensitization method for a line-of-sight monitoring device for a space mapping camera. Background Technology

[0002] High-resolution space mapping cameras have extremely stringent requirements for imaging geometric accuracy and line-of-sight stability. Line-of-sight drift not only disrupts the consistency of the image but also introduces systematic deviations into the ground projection coordinates, directly affecting the accuracy of stereo mapping solutions and the geometric reliability of remote sensing data.

[0003] Studies have shown that camera geometric errors originate from a variety of complex sources. Uncertainties in internal and external orientation elements, assembly errors, and on-orbit thermal-structural coupling effects all contribute to varying degrees of accuracy degradation. Particularly during on-orbit operation, periodic variations in solar irradiance cause thermal deformation of the optomechanical structure, manifesting as line-of-sight (LOS) shifts on the order of arcseconds. This has become a key factor limiting mapping accuracy. To address these challenges, scholars both domestically and internationally have proposed various methods to suppress mapping errors. For example, a joint calculation method based on star sensors is used to correct the installation angle of the star-to-ground camera; an on-orbit geometric calibration method based on image matching, utilizing a ground-based range, eliminates long-term thermal deformation of the camera's LOS; a light sensitivity matrix method is used to identify LOS-sensitive optical elements, and a joint optomechanical optimization method is employed to control LOS thermal drift and reduce mapping errors; and a self-collimation method is used to establish camera LOS pointing monitoring, compensate for camera LOS pointing, and reduce mapping data errors.

[0004] The above methods have played a positive role in compensation and correction, but they still have obvious limitations: on the one hand, they mainly rely on ex-post correction, and the level of error suppression is limited, lacking a mechanism for sensitivity control from the system design stage; on the other hand, existing studies focus on improving the accuracy of monitoring and calculation, but lack systematic consideration of the sensitivity effect of the monitoring geometry itself.

[0005] In fact, the field-of-view configuration of the monitoring beam has a decisive influence on the disturbance sensitivity, but this key factor has long been overlooked.

[0006] As remote sensing missions continue to evolve towards higher resolution, wider coverage, and higher geometric stability, the need for desensitization design in line-of-sight (LOS) monitoring has become increasingly urgent. Especially in high-precision mapping applications, sub-arcsecond LOS drift can cause meter-level ground positioning errors, severely impacting product accuracy and mission reliability. Therefore, there is a pressing need to establish a systematic approach that incorporates the angle-field-sensitivity relationship into the design and optimization process to suppress LOS drift at its source, rather than simply relying on post-compensation. Summary of the Invention

[0007] In view of this, the present invention aims to provide a desensitization method for a line-of-sight monitoring device for a space mapping camera, in order to solve the problems of existing technologies, which mainly rely on post-processing correction, have limited error suppression levels, and lack a mechanism for sensitivity control from the system design stage; on the other hand, existing research focuses on improving the accuracy of monitoring and calculation, but lacks systematic consideration of the sensitivity effect of the monitoring geometry itself. The present invention can solve the problem that the monitoring results are highly sensitive to link transmission errors during the line-of-sight monitoring process of a mapping camera.

[0008] To achieve the above objectives, the technical solution created by this invention is implemented as follows: A method for desensitizing a line-of-sight monitoring device for a space mapping camera specifically includes the following steps: S1: The line-of-sight monitoring device of the space mapping camera always outputs dual measurement beams during operation. A first CMOS and a second CMOS are installed on the imaging target surface of the space mapping camera under test. The first CMOS and the second CMOS receive the dual measurement beams output by the line-of-sight monitoring device of the space mapping camera. S2: Using the time before the calibration of the space mapping camera to be measured as the reference time, obtain the first measurement beam vector of the dual measurement beams at the reference time. Second measurement beam vector The time after the spatial mapping camera under test is calibrated is taken as the measurement time, and the vector of the first measurement beam of the dual measurement beams at the measurement time is obtained. Second measurement beam vector The angle between the two measurement beams at the reference time and the angle between the two measurement beams at the measurement time are always the same. S3: Calculate the three-axis rotation of the camera coordinate system corresponding to the mapping camera in the space under test using the TRIAD algorithm; S4: Based on the TRIAD algorithm, establish the analytical relationship between the three-axis rotation of the camera coordinate system, the angle between the two measurement beams, and the normalized Z-axis value; S5: Based on the analytical relationship established in step S4, construct the sensitivity evaluation function; S6: Based on the global optimization algorithm and combined with the sensitivity evaluation function, the optimized double beam angle and normalized Z-axis value are obtained, and the optimal exit direction of the double measurement beams output by the line-of-sight monitoring device of the space mapping camera is calculated.

[0009] Furthermore, the first CMOS and the second CMOS have the same size. A first CMOS coordinate system is established with the lower left corner of the first CMOS as the origin, the horizontal direction of the first CMOS as the x-axis, and the vertical direction of the first CMOS as the y-axis. A second CMOS coordinate system is established with the lower left corner of the second CMOS as the origin, the horizontal direction of the second CMOS as the x-axis, and the vertical direction of the second CMOS as the y-axis.

[0010] Furthermore, step S3 specifically includes: S31: Calculate the vector of the first measurement beam at the reference time. Second measurement beam vector and the first measurement beam vector at the measurement moment Second measurement beam vector : ; ; ; ; in, Let X be the x-coordinate of the origin of the first CMOS coordinate system in the camera coordinate system. Let Y be the Y-coordinate of the origin of the first CMOS coordinate system in the camera coordinate system. The focal length of the camera used to map the space to be measured. Size of a single pixel The centroid coordinates of the first light spot at the reference time are: The centroid coordinates of the second light spot at the reference time are: To measure the centroid coordinates of the first light spot at the time of measurement, To determine the centroid coordinates of the second light spot at the measurement time, Let X be the x-coordinate of the origin of the second CMOS coordinate system in the camera coordinate system. The Y-coordinate of the origin of the second CMOS coordinate system in the camera coordinate system; S32: Based on the calculation results of step S31, calculate the rotation matrix at the reference time. and measurement time rotation matrix : ; ; S33: Calculate the total rotation matrix R based on the rotation matrix at the reference time and the rotation matrix at the measurement time. ; ; in, , , , , , , , and All are elements of the total rotation matrix; S34: Based on the calculation results of step S33, calculate the three-axis rotation of the camera coordinate system of the spatial mapping camera under test: ; ; ; in, This represents the rotation of the camera coordinate system around its own X-axis. This represents the rotation of the camera coordinate system around its own Y-axis. This represents the rotation of the camera coordinate system around its own Z-axis.

[0011] Furthermore, in step S31, the first measurement beam at the reference time is incident on the first CMOS to form the reference time first spot, the second measurement beam at the reference time is incident on the second CMOS to form the reference time second spot, the first measurement beam at the measurement time is incident on the first CMOS to form the measurement time first spot, and the second measurement beam at the measurement time is incident on the second CMOS to form the measurement time second spot.

[0012] Furthermore, step S4 specifically includes the following steps: S41: The first measurement beam vector at the reference time Second measurement beam vector Normalization is performed to obtain the normalized vector corresponding to the first measurement beam vector at the reference time. Or the normalized vector corresponding to the second measurement beam vector : ; ; in, This is the normalized vector corresponding to the first measured beam vector at the reference time. This is the normalized vector corresponding to the second measurement beam vector at the reference time. The angle between the two measurement beams output by the line-of-sight monitoring device of the space mapping camera. The normalized vector corresponding to the first measurement beam vector Or the normalized vector corresponding to the second measurement beam vector The normalized Z-axis value; S42: After introducing temperature changes, calculate the first measurement beam vector at the measurement moment based on the change in the centroid of the first spot and the change in the centroid of the second spot. normalized vector Second measurement beam vector normalized vector : ; ; in, This refers to the change in the first light spot in the x-direction relative to the first light spot at the reference time. This refers to the change in the first light spot in the y-direction relative to the first light spot at the reference time. This refers to the change in the second light spot in the x-direction relative to the reference time at the measurement moment. The change in the second light spot in the y-direction at the measurement time relative to the reference time; S43: Based on the TRIAD algorithm, the normalized vector corresponding to the three-axis rotation of the camera coordinate system and the first measurement beam vector is obtained by the following formula. Or the normalized vector corresponding to the second measurement beam vector Normalized Z-axis values and the angle between the two measurement beams The parsing relationship: ; ; .

[0013] Furthermore, in step S5, the sensitivity evaluation function F is: ; in, It is the angle between two measuring beams. It is the normalized vector corresponding to the first measured beam vector. Or the normalized vector corresponding to the second measurement beam vector The normalized Z-axis value, It is the amount of rotation of the camera coordinate system about its own X-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own X-axis. Change in the Y direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own Y-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own Y-axis. Change in the Y direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system around its own Z-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system around its own Z-axis. Change in the Y direction of the camera coordinate system Sensitivity.

[0014] Furthermore, the rotation of the camera coordinate system around its own X-axis Change in the X direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own X-axis Change in the Y direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own Y-axis Change in the X direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own Y-axis Change in the Y direction of the camera coordinate system sensitivity :

[0015] Rotation of the camera coordinate system about its own Z-axis Change in the X direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own Z-axis Change in the Y direction of the camera coordinate system sensitivity : .

[0016] Furthermore, in step S6, the imaging field of view of the spatial mapping camera to be measured is set to... The constraint relationship between the included angle of the two measurement beams and the range of values ​​in the solution space of the normalized focal length is as follows: ; Where H is the number of pixels in the first CMOS or the second CMOS in the X direction. F is the pixel size, and F is the focal length of the camera used for mapping the space under test. It is the off-axis angle of the spatial mapping camera under test. It is the angle between two measurement beams. It is the maximum field of view in the Y direction of the spatial mapping camera to be tested.

[0017] Furthermore, in step S6, the global optimization algorithm is either the GA algorithm, particle swarm optimization algorithm, ant colony optimization algorithm, or differential algorithm, and the angle between the two measurement beams corresponding to the optimal value of the evaluation function is solved within the range of values ​​in the solution space. With normalized Z-axis values This corresponds to the final optimization result.

[0018] Furthermore, the optimal exit direction vector of the dual measurement beams output by the line-of-sight monitoring device of the space mapping camera is calculated using the following formula: ; ; in, For the optimized angle between the two measurement beams, For the optimized first measurement beam vector Second measurement beam vector The normalized Z-axis value, This is the first optimal exit direction vector. This is the second optimal exit direction vector.

[0019] Compared with the prior art, the present invention can achieve the following beneficial effects: (1) The desensitization method for a line-of-sight monitoring device for a space mapping camera described in this invention addresses the problems of limited error suppression levels and lack of sensitivity control mechanisms in current line-of-sight compensation models, particularly during the system design phase. This is achieved by analyzing the sensitivity influencing factors of the three-axis measurement results in the camera coordinate system, establishing analytical expressions for the three-axis calculation results and centroid extraction accuracy, and defining the analytical relationship between the sensitivity of the three-axis calculation results and the direction of the incident beam. Based on this, this invention constructs an evaluation function, combines it with the inherent parameter constraints of the optical system, optimizes the incident beam direction of the monitoring beam, and establishes a systematic optimization method for the relationship between the included angle, field of view, and sensitivity. This achieves source suppression of line-of-sight drift error disturbances, rather than simply relying on post-compensation.

[0020] (2) The desensitization method for the line-of-sight monitoring device of the space mapping camera described in this invention is the first to propose a line-of-sight monitoring desensitization mechanism based on a global optimization algorithm. In view of the shortcomings of traditional methods that only reduce errors through compensation models in the later stage, this invention proposes to optimize the direction of the incident beam through a genetic algorithm (GA) and combine it with the constraints of optical system parameters to actively reduce the sensitivity of the line-of-sight monitoring results to error sources (such as centroid extraction accuracy). This invention introduces a sensitivity control mechanism from the system design stage to achieve "source suppression" rather than passive compensation.

[0021] (3) The desensitization method for the line-of-sight monitoring device of the space mapping camera described in this invention systematically derives the analytical relationship between the three-axis calculation results of the camera coordinate system and the centroid extraction accuracy. Based on the TRIAD algorithm framework, it forms for the first time an analytical expression of the sensitivity of the three-axis measurement results to the direction of the incident beam, which effectively reduces the sensitivity of the centroid extraction error to the line-of-sight calculation results and provides a theoretical basis for the evaluation function of the global optimization algorithm.

[0022] (4) The desensitization method for the field-of-view monitoring device of the space mapping camera described in this invention constructs a unified relationship model including the incident angle of the beam, the field of view of the camera and the measurement sensitivity, and proposes a method that can quantitatively select the optimal monitoring beam direction under the constraints of system parameters. This invention effectively solves the problem that the existing methods cannot quantitatively balance the contradiction between "field of view utilization" and "measurement accuracy".

[0023] (5) The desensitization method for the line-of-sight monitoring device of the space mapping camera described in this invention combines the genetic algorithm with the optical system parameter constraints to construct a sensitivity evaluation function and perform a global optimization search, which can automatically obtain the optimal monitoring beam direction and avoid the limitations caused by relying on empirical parameters. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic flowchart illustrating the desensitization method for a line-of-sight monitoring device for a space mapping camera as described in an embodiment of the present invention; Figure 2 A graph showing the range of feasible domain values ​​based on constraints, as described in the embodiments of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] like Figure 1 As shown, a desensitization method for a line-of-sight monitoring device for a space mapping camera specifically includes the following steps: S1: The line-of-sight monitoring device for the space mapping camera continuously outputs dual measurement beams during operation. A first CMOS and a second CMOS are installed on the imaging target surface of the space mapping camera under test. The first CMOS and the second CMOS respectively receive the dual measurement beams output by the line-of-sight monitoring device for the space mapping camera; S2: Taking the time before the calibration of the space mapping camera under test as the reference time, the vector of the first measurement beam of the dual measurement beams at the reference time is obtained. Second measurement beam vector The time after the spatial mapping camera under test is calibrated is taken as the measurement time, and the vector of the first measurement beam of the dual measurement beams at the measurement time is obtained. Second measurement beam vector S3: Calculate the three-axis rotation of the camera coordinate system corresponding to the space mapping camera under test using the TRIAD algorithm; S4: Establish the analytical relationship between the three-axis rotation of the camera coordinate system, the angle between the two measurement beams, and the normalized Z-axis value based on the TRIAD algorithm; S5: Construct a sensitivity evaluation function based on the analytical relationship established in step S4; S6: Obtain the optimized angle between the two beams and the normalized Z-axis value based on the global optimization algorithm and the sensitivity evaluation function, thereby realizing the calculation of the optimal exit direction of the two measurement beams output by the line-of-sight monitoring device of the space mapping camera.

[0031] It should be noted that this invention aims to address the problem that the monitoring results in the line-of-sight monitoring process of surveying cameras are highly sensitive to link transmission errors. To this end, a relationship between incident light angle, field of view, and sensitivity is established, a sensitivity evaluation function is constructed, and by combining a global optimization algorithm with the boundary conditions of the actual optical system structure, the incident light angle and field of view direction of the line-of-sight monitoring device are optimized to achieve a desensitization effect in line-of-sight monitoring.

[0032] In some embodiments, the first CMOS and the second CMOS are the same size. A first CMOS coordinate system is established with the lower left corner of the first CMOS as the origin, the horizontal direction of the first CMOS as the x-axis, and the vertical direction of the first CMOS as the y-axis. A second CMOS coordinate system is established with the lower left corner of the second CMOS as the origin, the horizontal direction of the second CMOS as the x-axis, and the vertical direction of the second CMOS as the y-axis.

[0033] In some embodiments, step S3 specifically includes: S31: Calculate the vector of the first measurement beam at the reference time. Second measurement beam vector and the first measurement beam vector at the measurement moment Second measurement beam vector : ; ; ; ; in, Let X be the x-coordinate of the origin of the first CMOS coordinate system in the camera coordinate system. Let Y be the Y-coordinate of the origin of the first CMOS coordinate system in the camera coordinate system. The focal length of the camera used to map the space to be measured. Size of a single pixel The centroid coordinates of the first light spot at the reference time are: The centroid coordinates of the second light spot at the reference time are: To measure the centroid coordinates of the first light spot at the time of measurement, To determine the centroid coordinates of the second light spot at the measurement time, Let X be the x-coordinate of the origin of the second CMOS coordinate system in the camera coordinate system. The Y-coordinate of the origin of the second CMOS coordinate system in the camera coordinate system; S32: Based on the calculation results of step S31, calculate the rotation matrix at the reference time. and measurement time rotation matrix : ; ; S33: Calculate the total rotation matrix R based on the rotation matrix at the reference time and the rotation matrix at the measurement time. ; ; in, , , , , , , , and All are elements of the total rotation matrix; S34: Based on the calculation results of step S33, calculate the three-axis rotation of the camera coordinate system of the spatial mapping camera under test: ; ; ; in, This represents the rotation of the camera coordinate system around its own X-axis. This represents the rotation of the camera coordinate system around its own Y-axis. This represents the rotation of the camera coordinate system around its own Z-axis.

[0034] It should be noted that the TRIAD algorithm was originally used for aircraft navigation. This paper applies it to line-of-sight monitoring of mapping cameras, and its principle is as follows: Two beams of measurement light incident on the camera of the space under test form a pair of light spots on the imaging plane, based on which the beam measurement vector is established in the camera coordinate system. The centroid extraction algorithm is used to calculate the coordinates of the image spot centroid in the corresponding CMOS coordinate system, where the centroid positions of points A and B at the reference time are... , The centroid positions of the image spots at points A and B at the measurement time are: , Let the size of a single pixel be μ, and the focal length of the camera used for mapping the space to be measured be... Then the beam vector under the initial standard state can be calculated. , : ; ; Measurement time beam vector , : ; , By using the normalized cross product and calculating the two vectors of the measurement time and the standard time, the projection of the three-axis vectors corresponding to the plane onto the measurement coordinate system is determined, forming rotation matrices M0 and M1, as shown below: ; ; The rotation matrix R between the two-vector measurement time and the standard initial state is: ; ; Under the small-angle approximation, the rotation matrix R is calculated according to the "321" rotation sequence to obtain the rotation amounts of the camera coordinate system around the X, Y, and Z axes. , , The results are as follows: ; ; ; In some embodiments, in step S31, a first measurement beam at a reference time is incident on a first CMOS to form a first light spot at the reference time, a second measurement beam at a reference time is incident on a second CMOS to form a second light spot at the reference time, a first measurement beam at a measurement time is incident on a first CMOS to form a first light spot at the measurement time, and a second measurement beam at a measurement time is incident on a second CMOS to form a second light spot at the measurement time.

[0035] In some embodiments, when the monitored dual beams are symmetrical beams, the three-axis rotation of the camera coordinate system can be obtained. , The parsing relationship: The dual-beam vectors are symmetric about the YOZ or XOZ plane. Taking the beam about the XOZ plane as an example, the TRIAD algorithm is simplified to obtain the normalized vector corresponding to the first measured beam vector at the reference time. Or the normalized vector corresponding to the second measurement beam vector : ; ; in, This is the normalized vector corresponding to the first measured beam vector at the reference time. This is the normalized vector corresponding to the second measurement beam vector at the reference time. The angle between the two measurement beams output by the line-of-sight monitoring device of the space mapping camera. The normalized vector corresponding to the first measurement beam vector Or the normalized vector corresponding to the second measurement beam vector The normalized Z-axis value.

[0036] The change in the centroid of the first light spot relative to the reference time at the measurement time is: , And the change in the centroid of the second light spot is , The first measurement beam vector at the measurement moment can be obtained. normalized vector Second measurement beam vector normalized vector : ; ; in, This refers to the change in the first light spot in the x-direction relative to the first light spot at the reference time. This refers to the change in the first light spot in the y-direction relative to the first light spot at the reference time. This refers to the change in the second light spot in the x-direction relative to the reference time at the measurement moment. The change in the second light spot in the y-direction at the measurement time relative to the reference time; Considering that the diagonal elements of the rotation matrix M are essentially 1 when the angle is small, further approximation is performed:

[0037] Based on the TRIAD algorithm principle, the three-axis rotation of the camera coordinate system and the normalized vector corresponding to the first measurement beam vector are obtained. Or the normalized vector corresponding to the second measurement beam vector Normalized Z-axis values and the angle between the two measurement beams The parsing relationship: ; ; .

[0038] In some embodiments, in step S3, in step S5, the sensitivity evaluation function F is: ; in, It is the angle between two measuring beams. It is the normalized vector corresponding to the first measured beam vector. Or the normalized vector corresponding to the second measurement beam vector The normalized Z-axis value, It is the amount of rotation of the camera coordinate system about its own X-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own X-axis. Change in the Y direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own Y-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own Y-axis. Change in the Y direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system around its own Z-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system around its own Z-axis. Change in the Y direction of the camera coordinate system Sensitivity.

[0039] In some embodiments, the rotation of the camera coordinate system about its own X-axis Change in the X direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own X-axis Change in the Y direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own Y-axis Change in the X direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own Y-axis Change in the Y direction of the camera coordinate system sensitivity :

[0040] Rotation of the camera coordinate system about its own Z-axis Change in the X direction of the camera coordinate system sensitivity : ; Rotation of the camera coordinate system about its own Z-axis Change in the Y direction of the camera coordinate system sensitivity : .

[0041] In some embodiments, in step S4, in step S6, the imaging field of view of the spatial mapping camera under test is set to be... The constraint relationship between the included angle of the two measurement beams and the range of values ​​in the solution space of the normalized focal length is as follows: ; Where H is the number of pixels in the first CMOS or the second CMOS in the X direction. F is the pixel size, and F is the focal length of the camera used for mapping the space under test. It is the off-axis angle of the spatial mapping camera under test. It is the angle between two measurement beams. It is the maximum field of view in the Y direction of the spatial mapping camera to be tested.

[0042] It should be noted that, considering the need to control the direction of the monitoring spot beam within the camera's imaging field of view (otherwise the monitoring beam cannot pass through the mapping camera's imaging field of view), this is combined with the imaging field of view of the mapping camera in the space under test. Region and off-axis angle We construct a constraint relationship between the angle between the two measurement beams and the normalized focal length in the solution space.

[0043] In some embodiments, in step S5, the global optimization algorithm is a GA algorithm, particle swarm optimization algorithm, ant colony optimization algorithm, or differential algorithm, and the angle between the two measurement beams corresponding to the optimal value of the evaluation function is solved within the range of values ​​in the solution space. With normalized Z-axis values This corresponds to the final optimization result. Based on this, the optimal exit direction vector of the dual measurement beams output by the spatial mapping camera's line-of-sight monitoring device is calculated using the following formula: ; ; in, For the optimized angle between the two measurement beams, For the optimized first measurement beam vector Second measurement beam vector The normalized Z-axis value, This is the first optimal exit direction vector. This is the second optimal exit direction vector.

[0044] It should be noted that the initial population size of the global optimization algorithm is 50, the maximum number of iterations is 500, and the convergence threshold is 1E-8 (10^6). -8 Global optimization algorithms include, but are not limited to, Particle Swarm Optimization (PSO), Ant Colony Optimization (ACO), and Differential Optimization (DE).

[0045] like Figure 2 As shown, taking the line-of-sight monitoring of an off-axis three-lens reflex mapping camera with a focal length of 260mm as an example, the field of view of the off-axis three-lens reflex mapping camera is: For 12°, The off-axis angle is 22°; the off-axis angle of the off-axis three-lens reflex mapping camera. 6°; CMOS pixel size of off-axis three-lens reflex mapping camera used for line-of-sight monitoring The thickness is 0.01mm; the CMOS size is 1920×1080, where H is 1080; symmetrical dual-beam monitoring is used for line-of-sight monitoring, and the line-of-sight angle range is set to [0°, 44°] based on the focal length and field of view of the off-axis three-way reflex camera; the normalized Z-axis value is... It is minimized when monitoring the edge field of view imaging of the beam orientation camera, at which point... The value is 0.887, and the maximum infinity can approach 1, therefore The value range is set to [0.887, 0.999]. Simultaneously, the position of the light spot formed by the monitoring beam on the focal plane of the mapping camera needs to be within the camera's field of view. and The following formula needs to be satisfied.

[0046] By combining the structural parameters of the space mapping camera, we can obtain and The range of values ​​in the solution space, such as Figure 2 As shown.

[0047] After optimization, when The value is 0.9312. When the value is 41.138°, the lowest evaluation function value is 2.84, corresponding to a monitored beam direction of 6.34° in the X direction and a field of view of ±20.68° in the Y direction. At this point, the triaxial sensitivities are as follows: 0.1565 0.531 0.531 0.1565 1.4 It is 0.06.

[0048] Monitoring beam pointing vector in the mapping camera coordinate system , for:

[0049]

[0050] This method theoretically discusses the relationship between the three-axis sensitivity of the line-of-sight monitoring device of a space mapping camera and the sensitivity of the beam incident direction. Based on this, a desensitization method is established, providing a theoretical reference for the design of the optical system of the line-of-sight monitoring device of a space mapping camera.

[0051] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0052] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A desensitization method for a space mapping camera boresight monitoring apparatus, characterized by: Specifically comprising the following steps: S1: the spatial mapping camera visual axis monitoring device always outputs double measurement light beams in the working process, a first CMOS and a second CMOS are installed on the imaging target surface of the to-be-measured spatial mapping camera, and the first CMOS and the second CMOS correspond to receive the double measurement light beams output by the spatial mapping camera visual axis monitoring device; S2: taking the time before the space mapping camera to be measured is calibrated as a reference time, obtaining a first measurement beam vector and a second measurement beam vector of the double measurement beam at the reference time ; taking the time after the space mapping camera to be measured is calibrated as a measurement time, obtaining a first measurement beam vector and a second measurement beam vector of the double measurement beam at the measurement time , wherein the double measurement beam included angle at the reference time and the double measurement beam included angle at the measurement time are always the same.​​ S3: calculating the three-axis rotation amount of the camera coordinate system corresponding to the to-be-measured spatial mapping camera by using the TRIAD algorithm; S4: establishing an analytical relationship between the three-axis rotation amount of the camera coordinate system and the double measurement light beam included angle and the normalized Z-axis value based on the TRIAD algorithm; S5: based on the analytical relationship established in step S4, a sensitivity evaluation function is constructed; S6: based on the global optimization algorithm, the optimized double beam included angle and the normalized Z-axis value are obtained by combining the sensitivity evaluation function, and the calculation of the optimal exit direction of the double measurement light beams output by the spatial mapping camera visual axis monitoring device is realized.

2. The desensitization method for space mapping camera boresight monitoring apparatus according to claim 1, characterized in that: The sizes of the first CMOS and the second CMOS are the same, the lower left corner of the first CMOS is taken as the origin, the horizontal direction of the first CMOS is taken as the x-axis, and the vertical direction of the first CMOS is taken as the y-axis to establish a first CMOS coordinate system; the lower left corner of the second CMOS is taken as the origin, the horizontal direction of the second CMOS is taken as the x-axis, and the vertical direction of the second CMOS is taken as the y-axis to establish a second CMOS coordinate system.

3. The desensitization method for space mapping camera boresight monitoring apparatus of claim 2, wherein: Step S3 specifically comprises: S31: Calculate the first measurement beam vector at the reference time and the second measurement beam vector at the reference time , and the first measurement beam vector at the measurement time and the second measurement beam vector at the measurement time : ； ； ； ； wherein, is the X coordinate of the origin of the first CMOS coordinate system in the camera coordinate, is the Y coordinate of the origin of the first CMOS coordinate system in the camera coordinate system, is the focal length of the space mapping camera to be measured, is the size of a single pixel, is the centroid coordinate of the first light spot at the reference time, is the centroid coordinate of the second light spot at the reference time, is the centroid coordinate of the first light spot at the measurement time, is the centroid coordinate of the second light spot at the measurement time, is the X coordinate of the origin of the second CMOS coordinate system in the camera coordinate system, is the Y coordinate of the origin of the second CMOS coordinate system in the camera coordinate system; S32: Calculate the reference-time rotation matrix based on the calculation result of step S31 and the measurement-time rotation matrix : ； ； S33: calculating the total rotation matrix R based on the reference time rotation matrix and the measurement time rotation matrix: ； ； wherein , , , , , , , , and are elements of the total rotation matrix; S34: based on the calculation result of step S33, calculating the three-axis rotation amount of the camera coordinate system of the to-be-measured spatial mapping camera: ； ； ； wherein, is a rotation amount of the camera coordinate system around its X axis, is a rotation amount of the camera coordinate system around its Y axis, is a rotation amount of the camera coordinate system around its Z axis.

4. The desensitization method for space mapping camera boresight monitoring apparatus of claim 1, wherein: In step S31, the first measurement light beam at the reference time is incident to the first CMOS to form a reference time first light spot, the second measurement light beam at the reference time is incident to the second CMOS to form a reference time second light spot, the first measurement light beam at the measurement time is incident to the first CMOS to form a measurement time first light spot, and the second measurement light beam at the measurement time is incident to the second CMOS to form a measurement time second light spot.

5. The desensitization method for space mapping camera boresight monitoring apparatus of claim 3, wherein: Step S4 specifically comprises the following steps: S41: normalize the first measurement beam vector at the reference time and the second measurement beam vector to obtain a normalized vector corresponding to the first measurement beam vector at the reference time or a normalized vector corresponding to the second measurement beam vector ​ ； ； wherein, is a normalized vector corresponding to the first measurement beam vector at the reference time instant, is a normalized vector corresponding to the second measurement beam vector at the reference time instant, is an angle between the two measurement beams output by the spatial mapping camera boresight monitoring device, is a normalized vector corresponding to the first measurement beam vector or a normalized vector corresponding to the second measurement beam vector normalized Z-axis value. S42: After the introduction of the temperature change, based on the centroid change amount of the first light spot and the centroid change amount of the second light spot, the normalized vector of the first measurement beam vector at the measurement moment and the normalized vector of the second measurement beam vector at the measurement moment are calculated : ； ； wherein, is a change amount of the first light spot in the x direction at the measurement time with respect to the first light spot at the reference time, is a change amount of the first light spot in the y direction at the measurement time with respect to the first light spot at the reference time, is a change amount of the second light spot in the x direction at the measurement time with respect to the second light spot at the reference time, is a change amount of the second light spot in the y direction at the measurement time with respect to the second light spot at the reference time; S43: based on the TRIAD algorithm, a normalized vector corresponding to the three-axis rotation amount of the camera coordinate system and the first measurement beam vector is obtained by the following formula or the normalized vector corresponding to the second measurement beam vector the normalized Z-axis value , and the analytical relationship of the double measurement beam angle ​ ； ； 。 6. The desensitization method for space mapping camera boresight monitoring apparatus of claim 5, wherein: In step S5, the sensitivity evaluation function F is: ； in, It is the angle between two measuring beams. It is the normalized vector corresponding to the first measured beam vector. Or the normalized vector corresponding to the second measurement beam vector The normalized Z-axis value, It is the amount of rotation of the camera coordinate system about its own X-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own X-axis. Change in the Y direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own Y-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system about its own Y-axis. Change in the Y direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system around its own Z-axis. Change in the X direction of the camera coordinate system sensitivity It is the amount of rotation of the camera coordinate system around its own Z-axis. Change in the Y direction of the camera coordinate system Sensitivity.

7. The desensitization method for space mapping camera boresight monitoring apparatus of claim 5, wherein: Rotation of the camera coordinate system around its X axis Sensitivity to changes in the X direction of the camera coordinate system :​ ； Rotation of the camera coordinate system around its X axis Sensitivity to changes in the Y direction of the camera coordinate system :​ ； Rotation of the camera coordinate system around its Y axis Sensitivity to changes in the X direction of the camera coordinate system :​ ； Rotation of the camera coordinate system around its Y axis Sensitivity to changes in the Y direction of the camera coordinate system :​ Rotation of the camera coordinate system around its Z axis Sensitivity to changes in the X direction of the camera coordinate system :​ ； Rotation amount of camera coordinate system around its Z axis Sensitivity to change in Y direction of camera coordinate system :​ 。 8. The desensitization method for space mapping camera boresight monitoring apparatus of claim 1, wherein: In step S6, let the imaging field of view of the space mapping camera to be measured be , and the constraint relationship between the angle between the two measurement beams and the solution space value range of the normalized focal length is: ； wherein H is the number of pixels of the first CMOS or the second CMOS in the X direction, is the pixel size, F is the focal length of the space mapping camera to be measured, is the off-axis angle of the space mapping camera to be measured, is the angle between the two measurement beams, is the maximum field of view in the Y direction of the space mapping camera to be measured.

9. The desensitization method for space mapping camera boresight monitoring apparatus of claim 8, wherein: In step S6, the global optimization algorithm, which is a GA algorithm, a particle swarm algorithm, an ant colony algorithm or a differential algorithm, solves the double-measurement beam angle corresponding to the optimal value of the evaluation function in the solution space value range and the normalized Z-axis value corresponding to the final optimization result.

10. The desensitization method for a space mapping camera boresight monitoring apparatus according to claim 9, characterized in that: The optimal exit direction vector of the double measurement light beams output by the spatial mapping camera visual axis monitoring device is calculated by the following formula: ； ； wherein, is the optimized angle between the two measurement beams, is the normalized Z value of the first measurement beam vector and the second measurement beam vector after optimization, is the first optimal exit direction vector, is the second optimal exit direction vector.

Images