A high-precision calibration method for dual-camera galvanometer gimbal

Abstract

The invention discloses a high-precision calibration method for a dual-camera galvanometer pan-tilt. For a dual-camera galvanometer pan-tilt consisting of a high-magnification camera, a galvanometer and a wide-angle camera, a rough modeling of the galvanometer angle mapping relationship is first performed to construct a simplified model; then geometric optical modeling simulation is performed in a computer to visualize the optical path of the galvanometer pan-tilt and obtain the deviation of the galvanometer; the deviation of the galvanometer is used to perform error compensation on the simplified model to obtain a higher-precision galvanometer angle mapping relationship, and then actual application processing is performed to obtain the galvanometer angle in the dual-camera galvanometer pan-tilt. The invention realizes high-precision calibration of a dual-camera galvanometer pan-tilt system, realizes high-precision positioning of a target, and can accurately estimate the target positioning error under different optical configurations.

Description

Technical Field

[0001] The invention belongs to the technical field of optical calculation and simulation, and relates to a high-precision calibration method for a dual-camera galvanometer type pan / tilt platform. Background Art

[0002] With the improvement of the sensitivity and detection range of modern optical detection technology and the rapid improvement of computer's ability to process digital signals, the target detection and recognition technology based on image processing and pattern recognition has made rapid progress, and various visual systems have been derived from it. The visual pan-tilt is an indispensable core component for intelligent robots to simulate the eyes of humans or other animals to perceive the external environment. Intelligent robots equipped with visual pan-tilt have many potential application scenarios, such as automatic inspection, smart cities, etc.

[0003] Faced with complex application environments such as large field of view, long distance, and multiple targets, the effective implementation of existing visual gimbals also faces many challenges, such as the inability to achieve both large field of view and high resolution, slow dynamic response speed, and difficulty in taking into account multiple targets at the same time. In response to the above problems, the dual-camera galvanometer gimbal came into being. By decoupling the target detection and detail information collection tasks, and utilizing the collaborative working mode of specially designed wide-angle and high-magnification variable-angle camera modules and the fast dynamic response characteristics of the scanning galvanometer, the dual-camera galvanometer gimbal can achieve high-precision positioning, real-time tracking, and identification of multiple targets within a large field of view, and obtain more comprehensive, richer, and more detailed dynamic target information.

[0004] Different from the traditional mechanical gimbal, the core of the dual-camera galvanometer gimbal is the optical path control technology based on multiple reflections. It can quickly change the imaging optical path of the camera through one or more sets of high-speed rotating reflective lenses, and can achieve rapid switching of the camera's perspective in dynamic scanning tasks, so that it can be applied to the detection and tracking tasks of multiple dynamic targets. On this basis, combined with the collaborative working mode of wide-angle and high-magnification variable-angle camera modules, it can overcome the defects of the traditional mechanical gimbal that the wide field of view observation and target detail information cannot be achieved at the same time, and achieve the stable collection of high-fidelity detail information of multiple dynamic targets.

[0005] A high-magnification camera under the action of a two-dimensional galvanometer can be regarded as a dynamic camera that constantly changes its viewing angle in space. Each set of galvanometer rotation angles corresponds to a specific viewing angle direction of the high-magnification camera in space. Therefore, as long as the coordinate angle mapping function between the wide-angle camera image coordinate system and the galvanometer rotation angle can be established, the high-magnification camera can point to the target detected in the high-magnification camera under the action of the galvanometer and obtain its detailed information in real time. In order to establish the coordinate angle mapping function between the wide-angle image coordinate system and the galvanometer rotation angle, the existing system assumes that the distance between the target and the system is significantly greater than the distance between the wide-angle camera and the high-magnification camera. This assumption can regard the optical centers of the two cameras as approximately coincident, so as to facilitate coordinate-angle conversion through similarity relations. However, due to the physical size of optical components, it is unrealistic to regard the wide-angle camera and the high-magnification camera as completely coincident. Therefore, the standard angle mapping function established using this assumption will produce serious positioning errors, resulting in serious system failures, such as target drift in the high-magnification image, or even complete loss of tracking of important targets. It is necessary to study the parametric characterization method and spatial layout strategy of key optical components in the pan-tilt system, and analyze the influence of key parameters of optical components such as focal length, field of view, galvanometer shape, and deflection angle of the variable-angle camera lens on the accuracy of the pan-tilt system. By parametrically characterizing key optical components such as lenses and mirrors in the pan-tilt system, the relative spatial positions of optical components in the system are determined, the mapping relationship between the spatial layout of optical components and the optical model is analyzed, the coordinate angle mapping function between the wide-angle image coordinate system and the galvanometer rotation angle is corrected, and the positioning error is compensated to complete the high-precision calibration of the dual-camera galvanometer pan-tilt system. Summary of the invention

[0006] In order to solve the problems existing in the background technology, the present invention provides a high-precision calibration method for a dual-camera galvanometer pan / tilt.

[0007] The purpose of the present invention is to correct the coordinate angle mapping function between the wide-angle image coordinate system and the galvanometer rotation angle in the existing system, compensate for the positioning error, complete the high-precision calibration of the dual-camera galvanometer pan-tilt system, and realize high-precision positioning of the target with an accuracy of within 10 pixel values.

[0008] The technical solution adopted by the present invention is:

[0009] A dual-camera galvanometer gimbal is used, which is mainly composed of a high-magnification camera, a galvanometer and a wide-angle camera. The galvanometer is composed of two lenses. The high-precision calibration method in the present invention mainly consists of the following steps:

[0010] (1) Rough modeling of the galvanometer angle mapping relationship of the dual-camera galvanometer gimbal:

[0011] In actual galvanometer control, a set of galvanometer angles is generated according to the position of the target in the wide-angle camera, so that the target details can be observed through the high-magnification camera. First, a simplified model is constructed to obtain a rough galvanometer angle mapping relationship. The simplified model is used to obtain the angles of the two lenses in the galvanometer;

[0012] (2) The dual-camera galvanometer gimbal was simulated in a computer, the optical path of the galvanometer gimbal was visualized, and the deviation of the galvanometer was obtained;

[0013] (3) The deviation of the galvanometer is used to perform error compensation on the simplified model of step (1) to obtain a higher-precision galvanometer angle mapping relationship. The simplified model after error compensation is used to obtain the accurate galvanometer angle in the dual-camera galvanometer gimbal, thereby achieving high-precision calibration.

[0014] The present invention is directed to camera tracking and positioning of moving targets, such as traffic scenes of cars or moving targets of monitors.

[0015] The simplified model in step (1) is expressed by the following formula:

[0016] ( α , β )=(( x w / X w -1 / 2) i p ,( y w / Y w -1 / 2) i t )

[0017] In the formula, α and β Respectively represent the angles of the two lenses in the galvanometer, i p and i t represents the rotatable angle range of the two lenses in the galvanometer, ( x w ,y w ) represents the coordinates of the moving target in the wide-angle image captured by the wide-angle camera, ( X w ,Y w ) represents the pixel value of the wide-angle camera observation plane in the length and width directions. The plane where the wide-angle camera observes the moving target is the wide-angle camera observation plane.

[0018] The step (2) specifically includes establishing a dual-camera galvanometer pan-tilt system model in a computer simulation software, and then using the dual-camera galvanometer pan-tilt system model to perform galvanometer scanning, and then using the galvanometer scanning to record the different positions of the high-magnification camera to the wide-angle camera observation plane to obtain the galvanometer position. x and y The deviation in direction, x The direction is the optical axis direction of the wide-angle camera. y The direction is vertical to gravity.

[0019] In the simulation process, the models of the high-magnification camera, the galvanometer and the wide-angle camera are established. The dual-camera galvanometer pan-tilt system model includes the high-magnification camera model, the galvanometer model and the wide-angle camera model;

[0020] The high-magnification camera model includes a point light source and a lens, wherein the lens simulates the high-magnification camera itself, and the point light source simulates the light convergence point used as the imaging of the high-magnification camera. The lens is located at the high-magnification camera, and the point light source and the lens are located on the same optical axis and are arranged in sequence along the original optical axis direction of the high-magnification camera, that is, the point light source is on the optical axis of the lens, the optical axis of the lens is the optical axis of the high-magnification camera, and the point light source is located at the focus of the lens;

[0021] The focal length of the lens is consistent with the focal length of the high-magnification camera, and the diameter of the lens is consistent with the diameter of the lens of the high-magnification camera.

[0022] The wide-angle camera model only includes a rectangular detector, which simulates the observation plane of the wide-angle camera, and the rectangular detector is located at the observation plane of the wide-angle camera;

[0023] The galvanometer model includes two mutually orthogonal polygonal objects, each polygonal object is completely consistent with the outer contour of the reflective area of ​​the galvanometer lens, and the polygonal objects are used to simulate the lenses in the galvanometer. The two polygonal objects are respectively located at the two lenses in the galvanometer, and the real-time rotation angle and the limit rotation angle of the two polygonal objects are respectively consistent with the real-time rotation angle and the limit rotation angle of the two lenses.

[0024] In the dual-camera galvanometer gimbal system model, the high-magnification camera model, the wide-angle camera model, and the galvanometer model are established in the optical simulation with the physical constraint relationship consistent with the high-magnification camera, the wide-angle camera, and the galvanometer in reality, wherein:

[0025] The optical axis of the lens is parallel to the rotation axis of the polygonal object corresponding to the pitch rotation lens, and the optical axis of the rectangular detector is parallel to the rotation axis of the polygonal object corresponding to the horizontal rotation lens;

[0026] The distance between the lens and the polygonal object corresponding to the horizontal rotating lens is consistent with the distance between the high-magnification camera and the horizontal rotating lens in the actual physical arrangement, and the point light source is placed at the focus of the lens;

[0027] The center position of the rectangular detector is consistent with the center position of the observation plane of the wide-angle camera in the actual physical arrangement, that is, on the optical axis of the rectangular detector.

[0028] The distance between the rectangular detector and the optical axis of the lens is set according to the target depth. The distance is the target depth. The polygonal object representing the horizontal rotation lens and the polygonal object representing the pitch rotation lens are scanned and rotated within the rotation angle range. The simulation process obtains the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera after it is transmitted through the lens and then passes through the polygonal object representing the galvanometer and records it. According to all the recorded positions, the imaging centers of the high-magnification camera and the wide-angle camera are obtained at different horizontal rotation lens and pitch rotation lens angles. x and y Position deviation in direction:

[0029] e x =( l h max + l h min ) / 2

[0030] e y =( l v max + l v min ) / 2

[0031] in, e x , e y Respectively expressed in x direction, y The position deviation between the imaging centers of the high-magnification camera and the wide-angle camera in the direction, where x Along the optical axis of the wide-angle camera, y Along the vertical direction of gravity, l h max It represents the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the horizontal rotating lens is rotated to the maximum rotation angle. l h minIt represents the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the horizontal rotating lens is rotated to the minimum rotation angle. l v max It represents the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the pitch lens is rotated to the maximum rotation angle. l v min Represents the position of a point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the pitch lens is rotated to the minimum rotation angle.

[0032] The step (3) is to perform error compensation on the simplified model of step (1) according to the following formula to obtain a higher-precision galvanometer angle mapping relationship by using the deviation of the galvanometer:

[0033] Δx s = e x X w / L h

[0034] Δy s =e y Y w / L w

[0035] ( α , β )=((( x w + Δx s ) / X w -1 / 2) i p , (( y w + Δy s ) / Y w -1 / 2) i t )

[0036] In the formula, α and β Respectively represent the angles of the two lenses in the galvanometer, i p and i trepresents the rotatable angle range of the two lenses in the galvanometer, ( x w ,y w ) represents the coordinates of the moving target in the wide-angle image captured by the wide-angle camera, ( X w ,Y w ) represents the pixel value of the wide-angle camera observation plane in the length and width directions, L h and L w are the length and width of the wide-angle camera observation plane in spatial coordinates, e x and e y They are obtained according to the simulation x direction, y The position deviation between the imaging centers of the high-magnification camera and the wide-angle camera in the direction, Δx s and Δy s are the pixel deviations of the position deviation in the wide-angle image respectively;

[0037] Finally, the actual coordinates of the moving target in the wide-angle image captured by the wide-angle camera are substituted into the simplified model after the error compensation to obtain the accurate galvanometer angle in the dual-camera galvanometer gimbal, and the galvanometer rotation is controlled according to the accurate galvanometer angle, thereby calibrating the dual-camera galvanometer gimbal.

[0038] The dual-camera galvanometer gimbal comprises a high-magnification camera, a galvanometer and a wide-angle camera. The high-magnification camera and the galvanometer are arranged close to the wide-angle camera. The high-magnification camera shoots the target plane where the moving target is located through the galvanometer, and the wide-angle camera directly shoots the target plane where the moving target is located. In a specific implementation, the high-magnification camera and the wide-angle camera are both fixed, and the galvanometer can rotate. Then, the rotation angle of the galvanometer is adjusted and compensated by the method of the present invention, so that the shooting angle of the high-magnification camera after the galvanometer is close to the shooting angle of the wide-angle camera, and finally the target in the image captured by the high-magnification camera is at the center of the image.

[0039] The galvanometer includes a pitching lens and a horizontal lens, the rotation axes of which are both located in a horizontal plane and perpendicular to each other, and the high-magnification camera sequentially captures the target plane where the moving target is located through the horizontal lens and the pitching lens;

[0040] The high-magnification camera and the wide-angle camera are both oriented horizontally and perpendicular to each other. The optical axis of the high-magnification camera is parallel to the rotation axis of the pitch rotating lens, and the optical axis of the wide-angle camera is parallel to the rotation axis of the horizontal rotating lens.

[0041] The high magnification in the high magnification camera refers to a camera lens focal length greater than 50 mm.

[0042] The innovation of the present invention lies in setting up a simplified model for dual-camera galvanometer gimbal calibration processing, obtaining error terms through designed simulation processing, optimizing and compensating the simplified model based on the error terms, thereby achieving accurate high-precision calibration.

[0043] The present invention analyzes the deviation of the galvanometer by geometric optical modeling and simulation of the system, and uses these deviations to compensate for the error of the simplified model, thereby obtaining a more accurate galvanometer angle mapping relationship. Specifically, we simulate the system behavior under different optical configurations to obtain accurate optical path information, and optimize the mapping function based on these data to ensure that the positioning error can be effectively reduced in practical applications.

[0044] The beneficial effects of the present invention are:

[0045] In order to solve the problem of low precision of galvanometer pan-tilt heads in target positioning tasks, the present invention performs geometric optical modeling and simulation on a galvanometer pan-tilt head system based on a two-dimensional galvanometer and a multi-camera module, visualizes the optical path of the galvanometer pan-tilt head, and designs a reasonable wide-angle image coordinate and galvanometer angle mapping function calibration method based on the simulation results. The method can accurately estimate the target positioning error under different optical configurations, which is of great significance for constructing a high-precision galvanometer pan-tilt head to capture high-resolution details of the target.

[0046] The present invention has strong practicality and can be widely used in multiple fields such as three-dimensional reconstruction, microscope imaging, monitoring systems, and smart transportation. For the dual-camera galvanometer pan-tilt system, the present invention effectively solves the current problem of inaccurate target positioning, which will greatly improve the reliability and accuracy of the dual-camera galvanometer pan-tilt in practical applications, enabling it to work stably in various complex environments, and providing strong support for technological progress in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the effect diagram of the high-precision calibration method of the dual-camera galvanometer gimbal;

[0048] Figure 2 Construct a schematic diagram for the coordinate angle mapping function between the wide-angle image coordinate system and the galvanometer rotation angle;

[0049] Figure 3 This is a schematic diagram of the optical path simulation results of the dual-camera galvanometer gimbal;

[0050] Figure 4 The error diagram of the galvanometer rotation angle and the roughly simplified model; (a) represents the horizontal position of the point light source on the rectangular detector representing the observation plane of the wide-angle cameral h Distribution diagram with the rotation of the horizontal and pitch lenses. (b) represents the vertical position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera. l v Distribution diagram of lens rotation with horizontal and pitch rotation;

[0051] Figure 5 It is a schematic diagram of the structural arrangement of the dual-camera galvanometer type pan / tilt platform of the present invention;

[0052] Figure 6 Schematic diagram of the scene setting for the comparison experiment before and after error compensation;

[0053] Figure 7 Comparison of target positioning deviation pixels before and after error compensation. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] like Figure 1 and Figure 5 As shown, the dual-camera galvanometer gimbal includes a high-magnification camera, a galvanometer and a wide-angle camera. The high-magnification camera and the galvanometer are arranged close to the wide-angle camera. The high-magnification camera shoots the target plane where the moving target is located through the galvanometer, and the wide-angle camera directly shoots the target plane where the moving target is located. In a specific implementation, the high-magnification camera and the wide-angle camera are both fixed, and the galvanometer can rotate. Then, the rotation angle of the galvanometer is adjusted and compensated by the method of the present invention, so that the shooting angle of the high-magnification camera after the galvanometer is close to the shooting angle of the wide-angle camera, and finally the target in the image captured by the high-magnification camera is at the center of the image.

[0056] The galvanometer includes two lenses, a pitch rotating lens and a horizontal rotating lens. The rotation axes of the pitch rotating lens and the horizontal rotating lens are both located in the horizontal plane and are perpendicular to each other. The high-magnification camera sequentially captures the target plane where the moving target is located through the horizontal rotating lens and the pitch rotating lens, that is, the light of the moving target sequentially passes through the pitch rotating lens and the horizontal rotating lens and is incident on the high-magnification camera.

[0057] In a specific implementation, the high-magnification camera and the wide-angle camera are both oriented horizontally and perpendicular to each other, the optical axis of the high-magnification camera is parallel to the rotation axis of the pitch rotation lens, the optical axis of the wide-angle camera is parallel to the rotation axis of the horizontal rotation lens, and a three-dimensional Cartesian coordinate system is established, with the orientation of the wide-angle camera as U Direction, the direction of the high-magnification camera is W Direction, vertical direction as V direction.

[0058] Embodiments of the present invention are as follows:

[0059] This embodiment is aimed at the traffic scene of cars on the road. The cars on the road are taken as moving targets. The dual-camera galvanometer gimbal is set on the light pole at the intersection to track and locate the cars passing through the intersection.

[0060] (1) Rough modeling of the galvanometer angle mapping relationship of the dual-camera galvanometer gimbal:

[0061] In actual galvanometer control, a set of galvanometer angles is generated according to the position of the target in the wide-angle camera, so that the target details can be observed through the high-magnification camera. First, a simplified model is constructed to obtain a rough galvanometer angle mapping relationship, such as Figure 2 As shown, a simplified model is used to obtain the angles of the two lenses in the galvanometer.

[0062] The simplified model is expressed by the following formula:

[0063] ( α , β )=( i p ( x w / X w -1 / 2), i t ( y w / Y w -1 / 2))

[0064] In the formula, α and β Respectively represent the angles of the two lenses in the galvanometer, i p and i t represents the rotatable angle range of the two lenses in the galvanometer, ( x w , y w ) represents the coordinates of the moving target in the wide-angle image captured by the wide-angle camera, ( X w , Y w ) represents the pixel value of the wide-angle camera observation plane in the length and width directions. The plane where the wide-angle camera observes the moving target is the wide-angle camera observation plane.

[0065] (2) Establishment of high magnification camera model:

[0066] In the simulation software, a lens is used to simulate a high-magnification camera. The lens is located at the high-magnification camera, and a point light source is used to simulate the convergence point of light for imaging the high-magnification camera, that is, the focus of the high-magnification camera. The point light source is on the optical axis of the lens, and the optical axis of the lens is the optical axis of the high-magnification camera, and the point light source is located at the focus of the lens.

[0067] The focal length of the lens is consistent with the focal length of the high-magnification camera, and the diameter of the lens is consistent with the lens diameter of the high-magnification camera.

[0068] (3) Wide-angle camera model establishment:

[0069] According to the field of view of the wide-angle camera, a rectangular detector is used in the simulation software to simulate the wide-angle camera at a specific depth, and the rectangular detector is used to simulate the observation plane of the wide-angle camera. The rectangular detector is located at the observation plane of the wide-angle camera, and the optical axis of the wide-angle camera passes through the center of the rectangular detector when shooting.

[0070] The observation plane of the wide-angle camera is located at the distance from the galvanometer system (the optical axis of the high-magnification camera) D The half length and half width of the rectangular detector are D tan( H / 2 )and D tan( V / 2 ),in D It represents the vertical distance between the observation plane of the wide-angle camera and the optical axis of the high-magnification camera, that is, the vertical distance between the rectangular detector and the optical axis of the lens, which is the target depth. V ° represents the field of view of the wide-angle camera in the horizontal direction, H ° represents the field of view of the wide-angle camera in the vertical direction.

[0071] (4) Galvanometer model establishment:

[0072] In the simulation software, two orthogonal polygonal objects are used to simulate two galvanometers. Each polygonal object is completely consistent with the outer contour of the reflective area of ​​the galvanometer lens. The polygonal object is used to simulate the lens in the galvanometer, and the two polygonal objects are used to simulate the pitch rotation lens and the horizontal rotation lens in the galvanometer. The two polygonal objects are respectively located at the two lenses in the galvanometer, and the real-time rotation angle and the limit rotation angle of the two polygonal objects are respectively consistent with the real-time rotation angle and the limit rotation angle of the two lenses.

[0073] More specifically, the horizontal rotation polygon object corresponds to the horizontal rotation lens in the galvanometer, and the pitch rotation polygon object corresponds to the pitch rotation lens in the galvanometer.

[0074] It should be noted that before the galvanometer scanning begins, the initial positions of the two mirrors in the galvanometer are arranged at 45° to the horizontal plane. The maximum rotation angle of the two mirrors in the galvanometer is ±11°, which matches the actual physical position and angle range of the galvanometer.

[0075] (5) Establishment of the dual-camera galvanometer gimbal system model.

[0076] The models of the high-magnification camera, wide-angle camera, and galvanometer mirror established above are respectively used to establish the same physical constraint relationships in optical simulation according to the actual physical relationships.

[0077] The optical axis of the lens is parallel to the rotation axis of the polygonal object corresponding to the pitch rotation lens, and the optical axis of the rectangular detector is parallel to the rotation axis of the polygonal object corresponding to the horizontal rotation lens; in the simulation process, establish UVW The three-axis orthogonal coordinate system sets the normal vector of the rectangular detector representing the wide-angle camera and the axis of rotation of the horizontal rotating lens to U The normal vector of the lens representing the high-magnification camera and the rotation axis of the pitch lens are parallel to W Axis parallel.

[0078] The distance between the polygonal objects corresponding to the lens and the horizontal rotating lens is consistent with the distance between the high-magnification camera and the horizontal rotating lens in the actual physical arrangement, and the point light source representing the light captured by the high-magnification camera is placed at the focus of the lens;

[0079] The center position of the rectangular detector is consistent with the center position of the wide-angle camera observation plane in the actual physical layout, that is, on the optical axis of the rectangular detector, and U The depth of the axial direction is adjustable, that is, the rectangular detector is U The axis direction is movable and can be adjusted according to the target depth.

[0080] At this point, the simulation model of the galvanometer pan / tilt system has been completed.

[0081] (6) Optical path simulation of dual-camera galvanometer gimbal.

[0082] The target depth in the simulation model and the polygonal object angle of the galvanometer are adjustable.

[0083] Under a specific set of galvanometer angles, the point light source is refracted by the lens and reflected by the polygonal object on both sides of the lens, covering a certain area of ​​the rectangular detector on the observation plane of the wide-angle camera, which means that when the target is at this position, adjusting the galvanometer angle to the current value can observe the target in the center of the image of the high-magnification camera.

[0084] Select the wide-angle camera observation plane corresponding to the target depth, set the distance between the rectangular detector and the optical axis of the lens according to the target depth, and set the distance between the wide-angle camera observation plane and the galvanometer system.

[0085] The polygonal objects representing the horizontal rotating lens and the polygonal objects representing the pitch rotating lens are combined and scanned and rotated within the rotation angle range, and the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera after being transmitted by the lens and then passing through the polygonal object representing the galvanometer is obtained by simulation and recorded. According to all the recorded positions, the imaging centers of the high-magnification camera and the wide-angle camera at different horizontal rotating lens and pitch rotating lens angles are obtained by processing. x and y The amount of position deviation in the direction.

[0086] In a specific implementation, the polygonal object of the horizontally rotating lens is rotated from 30° to 60°, and the polygonal object of the pitching rotating lens is rotated from 30° to 60°, and the position of the point light source on the observation plane of the wide-angle camera after passing through the system is obtained and recorded.

[0087] After the above records are drawn, the imaging center position deviation map of the high-magnification camera and the wide-angle camera is drawn according to all positions, and the data of the center position deviation map are extracted respectively. x and y Position deviation value in direction e x and e y ,according to e x and e y The values ​​are processed according to the following formula to obtain the imaging center of the high-magnification camera and the wide-angle camera. x and y Position deviation in direction:

[0088] e x =( l h max + l h min ) / 2

[0089] e y =( l v max + l v min ) / 2

[0090] like Figure 4 As shown, l h max It represents the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the horizontal rotating lens is rotated to the maximum rotation angle. l h min It represents the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the horizontal rotating lens is rotated to the minimum rotation angle. l v max It represents the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the pitch lens is rotated to the maximum rotation angle. l v min Represents the position of a point light source on the rectangular detector representing the observation plane of the wide-angle camera when the polygonal object representing the pitch lens is rotated to the minimum rotation angle.

[0091] like Figure 4 As shown in (a), the horizontal position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera is l h Distribution of lens rotation with horizontal and pitch rotation.

[0092] like Figure 4 As shown in (b), the vertical position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera is l v Distribution of lens rotation with horizontal and pitch rotation.

[0093] (7) Calibration of the mapping relationship between wide-angle image coordinates and galvanometer rotation angle at a fixed depth.

[0094] According to Figure 3 The simulation results shown in the figure are based on the accurate galvanometer rotation angle and the roughly simplified model to obtain the angle error, and the error compensation of the simplified model is performed to obtain a high-precision mapping relationship.

[0095] The simplified model after error compensation is as follows:

[0096] Δx s = e x X w / L h

[0097] Δy s =e y Y w / L w

[0098] ( α , β )=((( x w + Δx s ) / X w -1 / 2) i p ,(( y w + Δy s ) / Y w -1 / 2) i t )

[0099] In the formula, α and β Respectively represent the angles of the two lenses in the galvanometer, i p and i t represents the rotatable angle range of the two lenses in the galvanometer, ( x w ,y w ) represents the coordinates of the moving target in the wide-angle image captured by the wide-angle camera, ( X w ,Y w ) represents the pixel value of the wide-angle camera observation plane in the length and width directions, L h and L w are the length and width of the wide-angle camera observation plane in spatial coordinates, e x and e y The imaging centers of the high-magnification camera and the wide-angle camera are obtained based on the simulation. x and y Position deviation in direction, Δx s and Δy sare the pixel deviations of the position deviation in the wide-angle image. Finally, the actual coordinates of the moving target in the wide-angle image captured by the wide-angle camera are substituted into the simplified model after the error compensation to obtain the accurate galvanometer angle in the dual-camera galvanometer gimbal, and the galvanometer rotation is controlled according to the accurate galvanometer angle, thereby calibrating the dual-camera galvanometer gimbal.

[0100] So far, the high-precision modeling and calibration of the galvanometer pan-tilt head has been completed, and the wide-angle image coordinates of the galvanometer pan-tilt head are associated with the galvanometer rotation angle, thereby achieving high-precision positioning of the target.

[0101] To prove the practical effect of the present invention, Figure 6 As shown, six identification code targets at known distances are located, the target positions before and after the calibration method of the present invention are recorded, and the offset pixel values ​​are calculated. In this experiment, the resolution of the high-magnification camera is 540×720, so the center coordinates of the high-magnification camera are (270,360). If the coordinates of the target in the high-magnification camera are measured to be ( x z , y z ), the target positioning deviation is (( x z -270) 2 +( y z -360) 2 ) 1 / 2 , the comparison results are shown in Figure 7 .

[0102] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

[0103] The above description is only a preferred embodiment of the present invention, so all equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. A high-precision calibration method for a dual-camera galvanometer gimbal, characterized in that: A dual-camera galvanometer gimbal is used, which is mainly composed of a high-magnification camera, a galvanometer and a wide-angle camera. The galvanometer is composed of two lenses. The high-precision calibration method mainly consists of the following steps: (1) Rough modeling of the galvanometer angle mapping relationship of the dual-camera galvanometer gimbal: First, a simplified model is constructed to obtain the angles of the two lenses in the galvanometer. (2) Perform simulation processing on the dual-camera galvanometer gimbal in a computer to obtain the deviation of the galvanometer; (3) Using the deviation of the galvanometer to perform error compensation on the simplified model of step (1) to obtain a higher-precision galvanometer angle mapping relationship, and using the simplified model after error compensation to obtain the galvanometer angle in the dual-camera galvanometer gimbal, thereby achieving high-precision calibration; The step (3) is to perform error compensation on the simplified model of step (1) according to the following formula to obtain a higher-precision galvanometer angle mapping relationship by using the deviation of the galvanometer: Δx s = ε x X w / L h Δy s =ε y Y w / L w ( α , β )=((( x w + Δx s ) / X w -1 / 2) θ p , (( y w + Δy s ) / Y w -1 / 2) θ t ) In the formula, α and β Respectively represent the angles of the two lenses in the galvanometer, θ p and θ t represents the rotatable angle range of the two lenses in the galvanometer, ( x w ,y w ) represents the coordinates of the moving target in the wide-angle image captured by the wide-angle camera, ( X w ,Y w ) represents the pixel value of the wide-angle camera observation plane in the length and width directions, L h and L w are the length and width of the wide-angle camera observation plane in spatial coordinates, ε x and ε y They are obtained according to the simulation x direction, y The position deviation between the imaging centers of the high-magnification camera and the wide-angle camera in the direction, Δx s and Δy s are the pixel deviations of the position deviation in the wide-angle image respectively; Finally, the actual coordinates of the moving target in the wide-angle image captured by the wide-angle camera are substituted into the simplified model after the error compensation to obtain the accurate galvanometer angle in the dual-camera galvanometer gimbal, and the galvanometer rotation is controlled according to the accurate galvanometer angle, thereby calibrating the dual-camera galvanometer gimbal.

2. A high-precision calibration method for a dual-camera galvanometer pan / tilt according to claim 1, characterized in that: The simplified model in step (1) is expressed by the following formula: ( α , β )=(( x w / X w -1 / 2) θ p ,( y w / Y w -1 / 2) θ t ) In the formula, α and β Respectively represent the angles of the two lenses in the galvanometer, θ p and θ t represents the rotatable angle range of the two lenses in the galvanometer, ( x w ,y w ) represents the coordinates of the moving target in the wide-angle image captured by the wide-angle camera, ( X w ,Y w ) represents the pixel values ​​of the wide-angle camera observation plane in the length and width directions.

3. A high-precision calibration method for a dual-camera galvanometer pan / tilt according to claim 1, characterized in that: The step (2) specifically includes establishing a dual-camera galvanometer pan-tilt system model in a computer simulation software, and then using the dual-camera galvanometer pan-tilt system model to perform galvanometer scanning, and then using the galvanometer scanning to record the different positions of the high-magnification camera to the wide-angle camera observation plane to obtain the galvanometer position. x and y The deviation in direction, x The direction is the optical axis direction of the wide-angle camera. y The direction is vertical.

4. A high-precision calibration method for a dual-camera galvanometer pan / tilt according to claim 3, characterized in that: The dual-camera galvanometer gimbal system model includes a high-magnification camera model, a galvanometer model and a wide-angle camera model; The high-magnification camera model includes a point light source and a lens, wherein the lens simulates the high-magnification camera itself, and the point light source simulates the light convergence point of the high-magnification camera. The lens is located at the high-magnification camera, and the point light source and the lens are arranged in sequence along the optical axis of the high-magnification camera, and the point light source is located at the focus of the lens; The wide-angle camera model includes a rectangular detector, which simulates the observation plane of the wide-angle camera, and the rectangular detector is located at the observation plane of the wide-angle camera; The galvanometer model includes two mutually orthogonal polygonal objects, each polygonal object is completely consistent with the outer contour of the galvanometer lens, and the polygonal objects are used to simulate the lenses in the galvanometer. The two polygonal objects are respectively located at the two lenses in the galvanometer, and the real-time rotation angle and the limit rotation angle of the two polygonal objects are respectively consistent with the real-time rotation angle and the limit rotation angle of the two lenses.

5. The high-precision calibration method for a dual-camera galvanometer pan / tilt according to claim 1, characterized in that: In the dual-camera galvanometer gimbal system model, the high-magnification camera model, the wide-angle camera model, and the galvanometer model are established in the optical simulation with the physical constraint relationship consistent with the high-magnification camera, the wide-angle camera, and the galvanometer in reality, wherein: The optical axis of the lens is parallel to the rotation axis of the polygonal object corresponding to the pitch rotation lens, and the optical axis of the rectangular detector is parallel to the rotation axis of the polygonal object corresponding to the horizontal rotation lens; The distance between the lens and the polygonal object corresponding to the horizontal rotating lens is consistent with the distance between the high-magnification camera and the horizontal rotating lens in the actual physical arrangement, and the point light source is placed at the focus of the lens; The center position of the rectangular detector is consistent with the center position of the observation plane of the wide-angle camera in the actual physical arrangement, that is, on the optical axis of the rectangular detector.

6. The high-precision calibration method for a dual-camera galvanometer pan / tilt according to claim 1, characterized in that: According to the target depth, the distance between the rectangular detector and the optical axis of the lens is set. This distance is the target depth. The polygonal object representing the horizontal rotating lens and the polygonal object representing the pitch rotating lens are scanned and rotated within the rotation angle range. The simulation process obtains the position of the point light source on the rectangular detector representing the observation plane of the wide-angle camera after it is transmitted through the lens and then passes through the polygonal object representing the galvanometer, and records it. According to all the recorded positions, the imaging centers of the high-magnification camera and the wide-angle camera at different angles are obtained by processing. x and y Position deviation in direction: ε x =( l h max + l h min ) / 2 ε y =( l v max + l v min ) / 2 in, ε x , ε y Respectively expressed in x direction, y The position deviation between the imaging centers of the high-magnification camera and the wide-angle camera in the direction, l h max It represents the position of the point light source on the rectangular detector when the polygonal object representing the horizontal rotating lens is rotated to the maximum rotation angle. l h min It represents the position of the point light source on the rectangular detector when the polygonal object representing the horizontal rotating lens is rotated to the minimum rotation angle. l v max It represents the position of the point light source on the rectangular detector when the polygonal object representing the pitch lens is rotated to the maximum rotation angle. l v min Represents the position of the point light source on the rectangular detector when the polygonal object representing the pitch lens is rotated to the minimum rotation angle.

7. The high-precision calibration method for a dual-camera galvanometer pan / tilt according to claim 1, characterized in that: The dual-camera galvanometer gimbal comprises a high-magnification camera, a galvanometer and a wide-angle camera. The high-magnification camera and the galvanometer are arranged close to the wide-angle camera. The high-magnification camera shoots the target plane where the moving target is located through the galvanometer, and the wide-angle camera directly shoots the target plane where the moving target is located.

8. The high-precision calibration method for a dual-camera galvanometer pan / tilt according to claim 7, characterized in that: The galvanometer includes a pitching lens and a horizontal lens, the rotation axes of which are both located in a horizontal plane and perpendicular to each other, and the high-magnification camera sequentially captures the target plane where the moving target is located through the horizontal lens and the pitching lens; The high-magnification camera and the wide-angle camera are both oriented horizontally and perpendicular to each other. The optical axis of the high-magnification camera is parallel to the rotation axis of the pitch rotating lens, and the optical axis of the wide-angle camera is parallel to the rotation axis of the horizontal rotating lens.

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