A dual-wedge scanner calibration system and method based on the principle of directional decoupling

Abstract

This invention relates to a dual-wedge scanner calibration system and method based on the principle of directional decoupling. The system comprises a dual-wedge scanner, an imaging detector, a target, and a reference screen. The implementation method includes assembling the calibration system, adjusting the imaging line of sight pitch, adjusting the imaging line of sight azimuth, and calibrating the dual-wedge rotation angle error. Compared with existing technologies, this invention detects the optical pointing error of the dual-wedge scanner by combining the imaging detector and the target. Simultaneously, it utilizes the optical scanning characteristics of the dual-wedge scanner to establish a decoupled adjustment strategy for pitch and azimuth, transforming the dual-wedge calibration problem into an imaging line of sight pointing adjustment problem. This allows for large-scale, high-precision calibration of the dual-wedge main cross-section position using a simple and compact system composition and flexible and efficient implementation methods, providing technical support for the application of dual-wedge scanners.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic testing, and in particular to a dual-wedge scanner calibration system and method based on the principle of directional decoupling. Background Technology

[0002] Dual-wedge scanners possess advantages such as compact structure, low moment of inertia, high pointing accuracy, strong environmental adaptability, and high cost-effectiveness, making them widely used in optoelectronic reconnaissance, infrared countermeasures, laser communication, target tracking, and 3D imaging. However, the beam pointing and aiming performance of dual-wedge scanners largely depends on the accurate calibration of the principal section position of each prism, as calibration errors in the principal section position can introduce significant systematic errors to the pointing accuracy of the dual-wedge scanner. Existing dual-wedge scanner calibration techniques rely on mechanical scribing to ensure the prism principal section positions are correctly installed, or on numerical optimization methods to obtain least-squares estimates of the prism principal section position errors. However, these methods cannot fully guarantee the accuracy and reliability of the dual-wedge principal section calibration.

[0003] The following prior art provides several typical dual-wedge scanner calibration schemes:

[0004] For example, Chinese patent application CN202210097369.3 discloses a method for correcting the pointing deviation of a rotating double-wedge based on the Levenberg-Marquardt algorithm. It uses a non-paraxial ray tracing method to establish a double-wedge beam pointing model, constructs an error evaluation function by measuring the theoretical and actual beam pointing at multiple positions across the entire field of view, and finally uses numerical optimization methods to obtain the optimal solutions for parameters such as the double-wedge zero-position calibration error, wedge angle error, and refractive index error. This type of method requires controlling the double-wedge to rotate to dozens or even hundreds of different rotation angles to measure the actual beam pointing at each angle, making the implementation process quite complex. Furthermore, this method is affected by the coupling of several types of errors, and can only provide optimal estimates of multiple error parameters, making it difficult to accurately identify the actual value of the double-wedge main cross-section position error.

[0005] Prior art (Qiu Sai et al., A method for correcting the deviation of rotation angle compensation in a rotating double-wedge pointing system, Optical Communication Technology, 2021, 45(2): 41-45) established a system of total differential equations to address the relationship between beam pointing error and double-wedge rotation angle error. By solving the system of total differential equations, the rotation angle error compensation equation was obtained. Then, the fitting coefficients of the compensation equation were obtained by combining the actual measured pointing error, and these coefficients were substituted into the beam pointing model to achieve error correction. This type of method also requires measuring the actual beam pointing error under multiple sets of double-wedge rotation angles to obtain a reasonable fitting coefficient. Moreover, simply introducing the double-wedge rotation angle error parameter cannot completely compensate for the coupling effect of multiple error sources, which means that the corrected beam pointing model still inevitably has the influence of systematic errors. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art and provide a dual-wedge scanner calibration system and method based on the principle of directional decoupling.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A dual-wedge scanner calibration system based on the principle of directional decoupling includes a dual-wedge scanner, a target, an imaging detector, and a reference screen;

[0009] The dual-wedge scanner includes two wedge-shaped prisms with unknown main cross-section positions, and the dual-wedge scanner is the object to be calibrated;

[0010] The target is used to indicate the direction of the optical axis, providing a reference for the calibration process of the dual-wedge scanner;

[0011] The imaging detector is used to capture the target position through the wedge prism, and the imaging position of the target reflects the current position of the main cross section of the wedge prism.

[0012] The reference screen is used to provide a reference scale for the calibration process of the dual-wedge scanner, while eliminating the influence of cluttered backgrounds.

[0013] Furthermore, the dual-wedge scanner is connected to a drive unit and an encoder. The drive unit drives the two wedge prisms to rotate independently and coaxially. The encoder is installed on the outside of the barrel of each wedge prism to measure and provide feedback on the actual rotation angle of the prism. Specifically, the two wedge prisms can be driven to achieve independent coaxial rotation by means of direct motor drive, gear drive, synchronous belt drive, worm gear drive, etc.

[0014] Furthermore, the arrangement of the two prisms in the dual-wedge scanner can be any one of four forms: flat-wedge-flat, wedge-flat-wedge-flat, flat-wedge-flat-wedge, or wedge-flat-flat-wedge. The wedge angle and refractive index of the two wedge prisms are determined according to the specific application scenario and can be made of materials such as glass, fused silica, or single-crystal silicon.

[0015] Furthermore, the target can be an easily distinguishable geometric target such as a circle, ring, square, or star, so that it can be observed and captured by the imaging detector. Alternatively, an LED dot matrix can be used to construct a more unique active target, thereby improving the accuracy and robustness of the imaging detector in identifying and locating the target.

[0016] Furthermore, the imaging detector is selected according to the target type. Generally, it can be an image detector such as CMOS or CCD. For active targets, it can also be a four-quadrant detector, infrared detector, etc.

[0017] Furthermore, the visual axis of the imaging detector is aligned with the optical axis of the dual-wedge scanner, and the center of the target falls on the axis of the calibration system.

[0018] Furthermore, the reference screen is parallel to the sensing surface of the imaging detector, and the center of the reference screen is aligned with the visual axis of the imaging detector and the optical axis of the dual-wedge scanner.

[0019] A calibration method for a dual-wedge scanner based on the principle of directional decoupling includes the following steps:

[0020] S1. System Construction: Based on the relative positional relationship between the dual-wedge scanner, imaging detector, target, and reference screen, establish the calibration system and reference system of the dual-wedge scanner;

[0021] S2, Pitch Adjustment: Control the two wedge prisms to rotate in opposite directions at the same speed. Gradually adjust the orientation of the imaging detector's line of sight in the pitch direction of the two wedge prisms, while detecting the changing trend of the target's imaging position on the detector, until the deviation of the target's imaging position from the center of the field of view is minimized.

[0022] S3, Orientation Adjustment: Control the two wedge prisms to rotate in the same direction at the same speed, and gradually scan the orientation of the imaging detector's line of sight in the orientation direction of the two wedge prisms, while detecting the scanning trajectory of the target's imaging position on the detector, until the target's imaging position reaches the bottom of its circular scanning trajectory.

[0023] S4. Angle calibration: Following steps S2 and S3, iteratively adjust the pitch and azimuth angles of the imaging detector's imaging axis with smaller rotation steps until the change in the pointing angle of the imaging axis between two iterations is lower than a given threshold, thus determining that the current main section positions of the two wedge prisms are 0° and 180° respectively.

[0024] Furthermore, in step S1, the dual-wedge scanner, imaging detector, target, and reference screen are aligned axially, and the working coordinate system of the dual-wedge scanner calibration system is established according to the right-hand rule. O-XYZ ,origin O Fixed at the optical center position of the camera, Z The axis coincides with the optical axis of the camera. X shaft and Y The shafts are all with Z The axes are orthogonal; the zero position of the dual-wedge scanner is set to the position when the thin end of its main section faces upward.

[0025] Further, step S2 includes the following sub-steps:

[0026] S21. In the initial state of the dual-wedge scanner, extract the imaging position of the target from the imaging detector and calculate its initial deviation relative to the center of the field of view. d 0;

[0027] S22. Control the two prisms to rotate in opposite directions by a certain angle according to a given step size, change the orientation of the imaging detector's line of sight, and calculate the deviation of the current target imaging position from the center of the field of view. d 1. The change in the rotation angle of the two wedge prisms at this time can be represented as follows:

[0028]

[0029] in i 1 and i 2 represents the corner positions of the two wedge prisms, respectively. l Given a rotation step size, the superscript 0 indicates the initial state of the wedge prism, and the superscript 1 indicates the current state of the wedge prism;

[0030] S23. If the current target imaging position deviates from the center of the field of view... d 1 is less than the initial deviation. d If the value is 0, then the two wedge prisms are rotated by a certain angle in their respective directions; otherwise, the two prisms are rotated by a certain angle in opposite directions. The deviation of the target imaging position from the center of the field of view is calculated. The rotation angle change law of the two wedge prisms is expressed as follows:

[0031]

[0032] in k It is an integer greater than 1;

[0033] S24. Repeat step S23 until the deviation of the current target imaging position is simultaneously less than the deviations of the previous and next steps, i.e. d k-1 > d k < d k+1 At that time, the process of adjusting the imaging axis in the pitch direction is completed.

[0034] Furthermore, step S3 includes the following sub-steps:

[0035] S31. Adjust the deviation at completion according to the imaging line of sight pitch direction. d K The target imaging position relative to the center of the field of view is obtained by decomposition, which corresponds to the deviation amount. Y Directional deviation y K ;

[0036] S32. Control the two wedge prisms to rotate in the same direction by a certain angle according to a given step size, and extract the current target imaging position relative to the center of the field of view. YDirectional deviation y K+1 The change in the rotation angle of the two wedge prisms at this time can be represented as follows:

[0037]

[0038] in K This represents the total number of rotation angle changes of the two wedge prisms in step S2;

[0039] S33, if the current target imaging position is... Y Towards the deviation component y K+1 Greater than the previous step Y Towards the deviation component y K If the target image position is not directly in the current direction, the two wedge prisms will continue to rotate by a certain angle in the current direction; otherwise, the two wedge prisms will be rotated by a certain angle in the opposite direction to the current direction. The target image position relative to the center of the field of view will be calculated. Y Towards the deviation component, the variation law of the double-wedge rotation angle is expressed as follows:

[0040]

[0041] in m greater than K Integers;

[0042] S34. Repeat step S33 until the current target imaging position is reached. Y The deviation component is simultaneously greater than the deviations of the previous and next steps, i.e. y m-1 < y m > y m+1 At that time, the imaging axis adjustment process in the azimuth direction is completed.

[0043] Furthermore, in step S4, the rotation step size used in each iteration is taken as 1 / 2 of the rotation step size used in the previous iteration, until the limit resolution is reached when the drive device adjusts the rotation angle of the prism or the encoder provides feedback on the rotation angle of the prism.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. This invention utilizes the combination of an imaging detector and a target to establish a dual-wedge scanner calibration system. The target position is extracted using a simple image processing algorithm as a reference benchmark for the calibration process. It eliminates the need to introduce a precision angle measuring device to measure the actual beam pointing error multiple times, and has advantages such as simple structure, low cost, and high flexibility.

[0046] 2. This invention utilizes feedback information from imaging detection to establish a new calibration principle for dual-wedge scanners, transforming the complex dual-wedge main cross-section calibration problem into a general imaging line-of-sight adjustment problem. This avoids error coupling and local optima problems caused by numerical optimization methods, ensuring the feasibility and adaptability of dual-wedge system calibration.

[0047] 3. This invention proposes a dual-wedge scanner calibration method based on the principle of directional decoupling. It utilizes the scanning characteristics of the dual-wedge beam to achieve separation of the imaging line-of-sight pointing adjustment in the pitch and azimuth directions, which can effectively overcome the difficulties caused by the nonlinear coupling problem of the dual-wedge and improve the accuracy and robustness of the dual-wedge main section position calibration.

[0048] 4. This invention proposes a novel, simple, and flexible dual-wedge scanner calibration system and method, which can overcome the shortcomings of existing calibration methods and provide key technical support for the application of dual-wedge scanners in fields such as optoelectronic reconnaissance, laser communication, infrared countermeasures, target tracking, and three-dimensional imaging. Attached Figure Description

[0049] Figure 1 A schematic diagram of the composition principle of a dual-wedge scanner calibration system;

[0050] Figure 2 The diagram shows four arrangement configurations of the dual-wedge scanner, where (a) is a "flat wedge-flat wedge" arrangement, (b) is a "flat wedge-flat wedge" arrangement, (c) is a "flat wedge-flat wedge" arrangement, and (d) is a "flat wedge-flat wedge" arrangement.

[0051] Figure 3 The strategy for decoupling the scanning beam of the dual-wedge in the pitch and azimuth directions is as follows: (e) is to achieve azimuth adjustment by rotating the dual wedges in the same direction at the same speed, and (f) is to achieve pitch adjustment by rotating the dual wedges in opposite directions at the same speed.

[0052] Figure 4 The flowchart shows the calibration method for a dual-wedge scanner based on the principle of directional decoupling.

[0053] Figure 5 This is a schematic diagram of the target imaging position change during the calibration process of the dual-wedge scanner, where A represents the change process during pitch adjustment and B represents the change process during azimuth adjustment.

[0054] Figure reference numerals: 1-Dual optical wedge scanner; 101-First prism; 102-Second prism; 2-Imaging detector; 3-Target; 4-Reference screen. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0056] Example 1

[0057] like Figure 1 As shown, this embodiment proposes a dual-wedge scanner calibration system based on the principle of directional decoupling, including a dual-wedge scanner 1, an imaging detector 2, a target 3, and a reference screen 4.

[0058] The dual-light wedge scanner 1 includes a first prism 101 and a second prism 102. The dual-light wedge scanner 1 is also connected to a drive unit, an encoder, and a support structure. The support structure is used to fix the drive unit and the encoder, maintaining the arrangement relationship between each prism and its drive unit and encoder. The first prism 101 and the second prism 102 are two wedge-shaped prisms with unknown main cross-sectional positions. The first prism 101 and the second prism 102 are coaxially mounted. The two wedge prisms employ... Figure 2 The two optical wedges are placed in one of the four arrangement forms shown: (a) "flat wedge-flat wedge" arrangement, (b) "flat wedge-flat wedge" arrangement, (c) "flat wedge-flat wedge" arrangement, and (d) "flat wedge-flat wedge" arrangement. In the ideal zero-position state, the thin end of the main cross-section faces upwards, but a fixed angular error may exist in the initial state. The material used to manufacture the two optical wedges is determined by the specific application scenario, and can be in the visible light or infrared band. The wedge angle of the two optical wedges is determined by the requirements of the imaging field of view and pointing resolution. The two optical wedges rotate independently under the drive of a driving device, which can be a direct-drive motor, gear drive, synchronous belt drive, worm gear drive, etc. This embodiment uses a torque motor direct-drive scheme, and the arrangement of the two optical wedges is "flat wedge-flat wedge".

[0059] The visual axis of the imaging detector 2 is strictly aligned with the optical axis of the dual-wedge scanner 1. The type of imaging detector 2 is selected based on the imaging characteristics of the target 3, employing a CMOS camera, a CCD camera, or a four-quadrant detector. In this embodiment, a CCD camera is selected, including an image sensor and an optical lens. The sensor target surface size, pixel resolution, and parameters such as the focal length and field of view of the optical lens are determined by the aperture and pointing range of the dual-wedge scanner 1, as well as the size and distance of the target 3.

[0060] The plane of target 3 is parallel to the sensor target surface of imaging detector 2, and the center of target 3 falls on the optical axis direction of dual-wedge scanner 1 and the visual axis direction of imaging detector 2. Target 3 is designed as a geometric pattern that is easy to recognize, such as a circle, ring, square, or star. It can also be constructed using an LED dot matrix to create a target that can actively emit light. In this embodiment, a target containing a circular pattern is selected. By combining edge detection algorithm and ellipse fitting algorithm, the imaging position of target 3 on imaging detector 2 can be accurately extracted.

[0061] The reference screen 4 is parallel to the sensor target surface of the imaging detector 2, and the center of the reference screen 4 is aligned with the dual-wedge scanner 1 and the imaging detector 2 in an axial alignment relationship. The reference screen 4 contains uniformly distributed coordinate scales, which can provide a reference for the change of the line of sight during the calibration of the dual-wedge scanner 1.

[0062] This embodiment utilizes a combination of an imaging detector and a target to establish a calibration system for a dual-wedge scanner. By combining the beam scanning characteristics of the dual-wedge with imaging detection feedback information, it guides the adjustment of the dual-wedge principal section position to an ideal state, transforming the complex dual-wedge principal section position calibration problem into a general imaging axis pointing adjustment problem. Compared to existing dual-wedge scanner calibration systems, this embodiment does not require the introduction of a precision angle measuring device to repeatedly measure the actual beam pointing error, nor does it impose excessively high precision requirements on the design and manufacturing of the cooperative target. It can improve the flexibility and adaptability of the dual-wedge principal section position calibration while ensuring the system's compact structure.

[0063] Example 2

[0064] like Figure 3-5 As shown, this embodiment proposes a dual-wedge scanner calibration method based on the principle of directional decoupling, which specifically includes the following steps:

[0065] S1. Establish the dual-wedge scanner calibration system and its working coordinate system.

[0066] Based on the requirements of the optical scanning range and pointing resolution of the dual-wedge scanner 1, the field of view, resolution and imaging band of the imaging detector 2 are determined. The positions of the imaging detector 2, reference screen 4, target 3 and dual-wedge scanner 1 are fixed in sequence according to the coaxial arrangement. The relative distance between each component is based on the principle of avoiding field of view occlusion of the imaging detector 1 and ensuring the observability of the target 3.

[0067] Setting the working coordinate system of the dual-wedge scanner calibration system O-XYZ Consistent with the local coordinate system of imaging detector 2, its origin... O Fixed at the optical center position of the camera, Z The axis coincides with the optical axis of the camera. X shaft and Y The shafts are all withZ The axes are orthogonal, corresponding to the row and column scanning directions of the image sensor, respectively;

[0068] S2. Reverse constant-speed rotation of the double-beam wedge to adjust the line-of-sight pointing pitch angle.

[0069] S21. When the dual-wedge scanner 1 is at the initial angle position At the same time, the image of target 3 is recorded using imaging detector 2, and the target imaging position is extracted by combining edge detection algorithm and ellipse fitting algorithm. At the same time, its initial deviation relative to the center of the field of view is calculated. d 0;

[0070] S22, Set the rotation step size to... l =5°, controlling the double optical wedges to rotate in the opposite direction by this step size, expressed as:

[0071]

[0072] in These represent the current rotational positions of the two prisms; after the dual optical wedges are rotated into position and the line of sight of imaging detector 2 is changed, the current target imaging position is extracted from the target image acquired by the detector, and its deviation relative to the center of the field of view is calculated. d 1;

[0073] S23. Determine whether the current rotation direction of the dual-wedge can bring the target imaging position close to the center of the field of view. If the current deviation is... d 1 is less than the initial deviation. d If the value is 0, the two optical wedges continue to rotate in their respective directions; otherwise, they rotate in opposite directions. This is represented as:

[0074]

[0075] in k It is an integer greater than 1; after each rotation of the dual optical wedge into position, the target imaging position is extracted from the target image and its deviation relative to the center of the field of view is calculated;

[0076] S24. Repeat step S23 until the deviation of the target imaging position from the center of the field of view is minimized. d k-1 > d k < d k+1 At that time, the process of adjusting the imaging axis in the pitch direction is completed.

[0077] S3. Rotate the double-optical wedges in the same direction and at the same speed to adjust the azimuth angle of the line of sight.

[0078] S31. Target deviation after the imaging axis pitch adjustment is completed. d K The rotation angle of the double-wedge beam is obtained through directional decomposition. At that time, the target imaging position is relative to the center of the field of view. Y Towards the deviation component y K ;

[0079] S32. Control the dual optical wedges to move according to the given step size. l Rotation in the same direction is represented as:

[0080]

[0081] in K This represents the total number of times the dual-wedge rotation angle changes in step S2; once the dual-wedge has rotated to its correct position, the current target imaging position relative to the center of the field of view is extracted from the target image. Y Towards the deviation component y K+1 ;

[0082] S33. Determine whether the current rotation direction of the dual-light wedge can bring the target imaging position close to the target. Y Positive half axis, if the current Y Towards the deviation component y K+1 Greater than the previous step Y Towards the deviation component y K If the current direction is selected, the dual optical wedges will continue to rotate; otherwise, they will rotate in the opposite direction. This is represented as:

[0083]

[0084] in m greater than K The integer; after the dual-wedge rotates into position, the target imaging position relative to the center of the field of view is extracted from the target image. Y Towards the deviation component;

[0085] S34. Repeat step S33 until the current target imaging position is reached. Y The deviation component reaches its maximum value, that is... y m-1 < y m > y m+1 At that time, the imaging axis adjustment process in the azimuth direction is completed.

[0086] S4. Iteratively perform pitch and azimuth adjustments to complete the dual-wedge angle calibration.

[0087] The line-of-sight pointing angle error is calculated based on the target imaging position. If the line-of-sight pointing error is higher than a given threshold...e 1. Set the rotation step size to half of the current value, and then iteratively adjust the pitch and azimuth angles of the line of sight according to steps S2 and S3 until the change in the line of sight angle between two iterations is lower than a given threshold. e 2; When the iteration condition terminates, the current double-wedge rotation angles can be determined. i 1=0° and i 2 = 180°, thus achieving accurate calibration of the main cross-section position of the double-wedge.

[0088] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A calibration method for a dual-wedge scanner based on the principle of directional decoupling, characterized in that, Includes the following steps: S1. System Construction: Based on the relative positional relationship between the dual-wedge scanner, imaging detector, target, and reference screen, establish the calibration system and reference system of the dual-wedge scanner; The calibration system includes a dual-wedge scanner, a target, an imaging detector, and a reference screen; The dual-wedge scanner includes two wedge-shaped prisms with unknown main cross-section positions, and the dual-wedge scanner is the object to be calibrated; The target is used to indicate the direction of the optical axis, providing a reference for the calibration process of the dual-wedge scanner; The imaging detector is used to capture the target position through the wedge prism, and the imaging position of the target reflects the current position of the main cross section of the wedge prism. The reference screen is used to provide a reference scale for the calibration process of the dual-wedge scanner, while eliminating the influence of cluttered backgrounds; S2, Pitch Adjustment: Control the two wedge prisms to rotate in opposite directions at the same speed. Gradually adjust the orientation of the imaging detector's line of sight in the pitch direction of the two wedge prisms, while detecting the changing trend of the target's imaging position on the detector, until the deviation of the target's imaging position from the center of the field of view is minimized. S3, Orientation Adjustment: Control the two wedge prisms to rotate in the same direction at the same speed, and gradually scan the orientation of the imaging detector's line of sight in the orientation direction of the two wedge prisms, while detecting the scanning trajectory of the target's imaging position on the detector, until the target's imaging position reaches the bottom of its circular scanning trajectory. S4. Angle calibration: Following steps S2 and S3, iteratively adjust the pitch and azimuth angles of the imaging detector's imaging axis with smaller rotation steps until the change in the pointing angle of the imaging axis between two iterations is lower than a given threshold, thus determining that the current main section positions of the two wedge prisms are 0° and 180° respectively.

2. The dual-wedge scanner calibration method based on the principle of directional decoupling according to claim 1, characterized in that, In step S1, the dual-wedge scanner, imaging detector, target, and reference screen are aligned axially, and the working coordinate system of the dual-wedge scanner calibration system is established according to the right-hand rule. O-XYZ ,origin O Fixed at the optical center position of the camera, Z The axis coincides with the optical axis of the camera. X shaft and Y The shafts are all with Z The axes are orthogonal; the zero position of the dual-wedge scanner is set to the position when the thin end of its main section faces upward.

3. The dual-wedge scanner calibration method based on the principle of directional decoupling according to claim 1, characterized in that, Step S2 includes the following sub-steps: S21. In the initial state of the dual-wedge scanner, extract the imaging position of the target from the imaging detector and calculate its initial deviation relative to the center of the field of view. δ 0; S22. Control the two prisms to rotate in opposite directions by a certain angle according to a given step size, change the orientation of the imaging detector's line of sight, and calculate the deviation of the current target imaging position from the center of the field of view. δ 1. The change in the rotation angle of the two wedge prisms at this time can be represented as follows: in θ 1 and θ 2 represents the corner positions of the two wedge prisms, respectively. λ Given a rotation step size, the superscript 0 indicates the initial state of the wedge prism, and the superscript 1 indicates the current state of the wedge prism; S23. If the current target imaging position deviates from the center of the field of view... δ 1 is less than the initial deviation. δ If the value is 0, then the two wedge prisms are rotated by a certain angle in their respective directions; otherwise, the two prisms are rotated by a certain angle in opposite directions. The deviation of the target imaging position from the center of the field of view is calculated. The rotation angle change law of the two wedge prisms is expressed as follows: in k It is an integer greater than 1; S24. Repeat step S23 until the deviation of the current target imaging position is simultaneously less than the deviations of the previous and next steps, i.e. δ k-1 > δ k < δ k+1 At that time, the process of adjusting the imaging axis in the pitch direction is completed.

4. The dual-wedge scanner calibration method based on the principle of directional decoupling according to claim 3, characterized in that, Step S3 includes the following sub-steps: S31. Adjust the deviation at completion according to the imaging line of sight pitch direction. δ K The target imaging position relative to the center of the field of view is obtained by decomposition, which corresponds to the deviation amount. Y Directional deviation y K ; S32. Control the two wedge prisms to rotate in the same direction by a certain angle according to a given step size, and extract the current target imaging position relative to the center of the field of view. Y Directional deviation y K+1 The change in the rotation angle of the two wedge prisms at this time can be represented as follows: in K This represents the total number of rotation angle changes of the two wedge prisms in step S2; S33, if the current target imaging position is... Y Towards the deviation component y K+1 Greater than the previous step Y Towards the deviation component y K If the target image position is not directly in the current direction, the two wedge prisms will continue to rotate by a certain angle in the current direction; otherwise, the two wedge prisms will be rotated by a certain angle in the opposite direction to the current direction. The target image position relative to the center of the field of view will be calculated. Y Towards the deviation component, the variation law of the double-wedge rotation angle is expressed as follows: in m greater than K Integers; S34. Repeat step S33 until the current target imaging position is reached. Y The deviation component is simultaneously greater than the deviations of the previous and next steps, i.e. y m-1 < y m > y m+1 At that time, the imaging axis adjustment process in the azimuth direction is completed.

5. The dual-wedge scanner calibration method based on the principle of directional decoupling according to claim 1, characterized in that, In step S4, the rotation step size used in each iteration is 1 / 2 of the rotation step size used in the previous iteration, until the limit resolution is reached when the drive device adjusts the prism rotation angle or the encoder provides feedback on the prism rotation angle.

Images