Methods and systems for measuring pose changes between objects

Abstract

This invention relates to a method and system for measuring pose changes between objects. By setting up a measuring device to accurately reflect the pose changes of a first object and a second object, and because: 1) the image acquisition module is mounted on the first object, identical to the first target, the image acquisition module remains relatively stationary when the first object moves, only exhibiting relative displacement with respect to the second target. This allows for the consideration of the second object's displacement without considering the first object's own displacement, greatly simplifying the calculation steps; 2) the image acquisition module captures images of the opposite target, and the camera's intrinsic parameters, the target's pose relative to the camera, and the relative pose between the targets are solved using the real image. Therefore, the deformation solution is independent of the camera's installation, and the initial parameters of the image acquisition module can be arbitrarily set, with no requirements on camera installation. In summary, this method significantly simplifies the algorithm's complexity, while exhibiting good stability and robustness, avoiding interference from changes in camera extrinsic parameters.

Description

Technical Field

[0001] This invention relates to the field of optical measurement, and in particular to an optical measurement technique for measuring changes in pose between objects. Background Technology

[0002] In real-world scenarios, it is often necessary to measure pose changes between objects (such as relative displacement or minute deformation between two objects). Sometimes, these pose changes are so small that they are difficult to observe with the naked eye or measure directly with metrological tools. Taking an inertial navigation system as an example, during use, rapid attitude changes or large-angle movements may cause pose changes (minor deformations) between its internal main mount (the first object) and the external box base (the second object) due to shock absorber deformation. This directly affects the accuracy of the internal main mount's measurement values, such as acceleration, velocity, deflection angle, and position, leading to deviations and severely impacting the operation of the autonomous navigation system. Therefore, it is necessary to accurately understand the magnitude of the pose changes between the internal main mount (the first object) and the external box base (the second object) to adaptively adjust the internal main mount's measurement values.

[0003] In existing technologies, the measurement of pose changes between objects can be done in two ways: first, by directly measuring with metrological tools, which is a traditional method with low accuracy and difficulty in measuring minute deformations; second, by using optical principles to determine pose changes through photography, which is a method with high accuracy. However, existing optical measurement methods require effective calibration of the image acquisition module, and the calculation results depend on camera parameters, leading to high measurement difficulty and complex calculations.

[0004] Therefore, how to provide a simple, convenient and highly accurate optical measurement method is a technical problem that urgently needs to be solved in measuring the pose changes between objects. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a method for measuring pose changes between objects, comprising:

[0006] S1: Set up a measuring device, the measuring device including: an image acquisition module and a first target set on a first object, and a second target set on a second object;

[0007] S2: At the first moment, acquire a first image of the coexistence of the first target and the second target; at the second moment, acquire a second image of the coexistence of the first target and the second target.

[0008] S3: Determine the first pose of the first target and the second target based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the first image, and the pixel coordinates of the second target on the first image;

[0009] S4: Determine the second pose of the first target and the second target based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the second image, and the pixel coordinates of the second target on the second image;

[0010] S5: Determine the pose changes of the first and second objects based on the first and second poses.

[0011] Further, step S3 includes:

[0012] S31: Based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the first image, and the pixel coordinates of the second target on the first image, iteratively update the initial parameters of the image acquisition module and the pixel coordinates of the first target on the first image and the pixel coordinates of the second target on the first image until the updated initial parameters of the image acquisition module and the pixel coordinates of the first target on the first image and the pixel coordinates of the second target on the first image minimize the global objective function;

[0013] S32: Determine the first pose of the first target and the second target on the first image based on the pixel coordinates of the first target and the second target on the first image corresponding to the minimum of the global objective function.

[0014] Furthermore, the measuring device is a single device to form a single-channel measuring device; or the measuring device is multiple devices to form a multi-channel optical device.

[0015] When constructing a single-channel measurement device, according to steps S2-S5, the single pose change results of the first object and the second object are obtained, and the single pose change result is taken as the final pose change result.

[0016] When constructing a multi-channel measurement device, according to steps S2-S5, multiple pose change results of the first object and the second object are obtained. Then, the multiple pose change results are coupled and calculated to obtain the final pose change result.

[0017] Furthermore, the first target and the second target are planar structures, and when the first target and the second target are stacked, at least one area is cut out to allow visibility of the second target.

[0018] Furthermore, the first target is elongated and the second target is square. When the first and second targets are stacked, two triangular areas are cut out to allow a view of the second target.

[0019] Furthermore, the first target and the second target are three-dimensional structures, and the first target and the second target are nested together.

[0020] Furthermore, the first target includes a strip-shaped bottom edge and a central protrusion disposed on the strip-shaped bottom edge; the second target includes a square bottom surface and a left protrusion, a central recess, and a right protrusion disposed on the square bottom surface; when the first target and the second target are stacked, the central protrusion of the first target is embedded in the central recess of the second target.

[0021] Furthermore, the first target is installed at a 45° angle on the first object; the second target, the outer target, is installed on the second object at a 90° angle perpendicular to the first target.

[0022] Furthermore, the image acquisition module, the first target, and the second target are coaxially aligned.

[0023] On the other hand, the present invention also provides a system for measuring pose changes between objects, for performing any of the above methods; the system includes: a measuring device and a control device;

[0024] The measuring device includes an image acquisition module and a first target disposed on a first object, and a second target disposed on a second object; the image acquisition module is used to acquire a first image of the first target and the second target coexisting at a first moment; and to acquire a second image of the first target and the second target coexisting at a second moment.

[0025] A control device is used to execute any of the above steps S3-S5.

[0026] The key feature of the method and system for measuring pose changes between objects provided by this invention lies in its ability to utilize optical measurement principles. An image acquisition module is set up to acquire images of a first target and a second target, accurately reflecting the pose changes of the first and second objects. Compared to traditional measurement methods, this invention is superior in the following ways: 1. The image acquisition module is positioned on the first object, just like the first target. When the first object moves, the image acquisition module and the first target are relatively stationary; the module only has relative displacement with respect to the second target, thus fully considering the displacement changes of the second object while disregarding the displacement of the first object itself; 2. The image acquisition module captures images of the first and second targets on opposite sides. For example, the method solves for the camera's intrinsic parameters, the relative pose parameters of the first target (or second target) to the camera (pixel coordinates on the first image, pixel coordinates on the second image), and the relative pose parameters between the first and second targets (first pose, second pose) using real images. Therefore, the deformation solution is independent of the camera's mounting parameters. As mentioned in step S3, the initial parameters of the image acquisition module can be arbitrarily set without calibration. Thus, the method of this invention has no requirements regarding camera mounting stability or changes in mounting parameters. Even if the camera's intrinsic parameters change, it has no impact on the measurement results. Therefore, it greatly improves the scalability and adaptability of the image acquisition module and reduces its installation and stability requirements. In summary, this method greatly simplifies the algorithm's complexity, while maintaining good stability and robustness, and can avoid interference from temperature and camera parameter changes to a certain extent. Attached Figure Description

[0027] Figure 1 A flowchart of an embodiment of the method for measuring pose changes between objects according to the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of a single-channel measuring device for the method of measuring pose changes between objects according to the present invention.

[0029] Figure 3 This is a schematic diagram of the light source used in the method for measuring pose changes between objects according to the present invention.

[0030] Figure 4 This is a schematic diagram of the planar structure of the first target and the second target in the method for measuring pose changes between objects according to the present invention;

[0031] Figure 5 This is a schematic diagram of the stacking of the first target and the second target in the method for measuring pose changes between objects according to the present invention;

[0032] Figure 6 This is a three-dimensional structural diagram of the first target in the method for measuring pose changes between objects according to the present invention.

[0033] Figure 7This is a three-dimensional structural diagram of the second target in the method for measuring pose changes between objects according to the present invention;

[0034] Figure 8 This is a schematic diagram of the stacking of the first target and the second target in the method for measuring pose changes between objects according to the present invention;

[0035] Figure 9 This is a schematic diagram of the coordinate system relationship for the method of measuring pose changes between objects according to the present invention;

[0036] Figure 10 This is a schematic diagram of the dual-channel measurement device for the method of measuring pose changes between objects according to the present invention. Detailed Implementation

[0037] like Figure 1 As shown, a method for measuring pose changes between objects is presented. To explain the inventive concept in detail, an example is given: an inertial navigation system experiences pose changes due to rapid attitude changes or large-angle attitude movements, causing deformation of the internal main body mount (first object) and the external box base (second object) caused by shock absorber deformation. The method addresses the need to accurately understand the magnitude of these pose changes and addresses the technical problem of adaptively adjusting the measurement values ​​of the internal main body mount. It is important to note that this example is merely an application example of the invention; the method for measuring pose changes between objects can be applied to measuring pose changes between any objects and is not limited to this example. Specifically, the method includes:

[0038] S1: Set up a measuring device, such as Figure 2 As shown, the measuring device includes an image acquisition module and a first target mounted on a first object, and a second target mounted on a second object. Specifically, the specific structure, size, and placement and relative positions of the image acquisition module, the first target, and the second target can be arbitrarily set by those skilled in the art according to the actual situation.

[0039] Preferred, such as Figure 2 As shown, the image acquisition module, the first target, and the second target are coaxially arranged so that they are on a straight line and within the same line of sight. This ensures that both the first and second targets are centered in the field of view of the image acquisition module, improving image acquisition accuracy. Furthermore, it increases the overlap area of ​​the first and second targets to more accurately reflect the relative displacement of pose changes. Of course, it is also possible for the three targets to be arranged non-axially (even if the first and second targets are not on a straight line, they can be separated in the image acquired by the image acquisition module, such as one in the upper left corner and the other in the upper right corner), as long as the image acquisition module can simultaneously acquire both the first and second targets, meaning both are within the field of view of the image acquisition module.

[0040] More preferably, such as Figure 2 As shown, the image acquisition module, optionally including but not limited to a camera and lens, is preferably mounted on the first object via a mounting bracket. More preferably, the image acquisition module may also optionally include, but is not limited to, a light source, such as an illuminator. Specifically, the camera is preferably an industrial camera. Depending on the internal space of the structure and accuracy requirements, any model and size of camera can be selected. The preferred camera size is as small as possible, ideally meeting requirements of a cross-sectional area of ​​less than 30mm*30mm, a thickness of less than 20mm, a pixel resolution of 2k*2k or higher, and a frame rate of 90fps or higher. This satisfies the requirements of small size for easy installation, high resolution and precision, high refresh rate, and fast response. Optional models include the German Ximea MQ042MG-CM: 2k*2k*90fps, 26mm*26mm*21mm. Ximea also offers cameras with similar form factor and performance: 2K*1K*170fps, 2.4K*2K*165fps, 4K*2K*95fps, 4K*3K*133fps, 2K*2K*180fps, etc. Specific selection requires consideration of accuracy analysis and simulation, embedded system conditions, data volume and computational load, interface requirements, and synchronization with gyroscopes. The camera's internal structure and parameters should be as stable as possible, or their variations should be continuous and modelable. More specifically, the light source can be selected based on the camera's spectral response characteristics to reduce the effects of refraction and astigmatism. Options include, but are not limited to, monochromatic light sources. Figure 3 As shown, it includes two light-emitting surfaces and one back surface. In addition, since the structure is a closed space with no interference from other light sources, the camera side does not need to be filtered. The illumination intensity can be determined based on the analysis and experimental results. The illumination path is specially designed to be used on the camera side or the target side, which is compatible with the camera's imaging of the target, so as to achieve uniform illumination, no obstruction, and no shadows.

[0041] More specifically, the specific shape and size of the first and second targets can be arbitrarily set by those skilled in the art according to actual requirements such as space size and expected accuracy, as long as the image acquisition module can acquire the first and second targets simultaneously. The targets can be, but are not limited to, planar or three-dimensional structures.

[0042] In a preferred embodiment, the first target and the second target are planar structures, and the first target has a partial shape of the second target, with feature units marked on it. That is, when the first target and the second target are stacked, at least one area is cut out to allow visibility of the second target. Figure 4 As shown (the left side is the first target, and the right side is the second target), a planar structural example of the first and second targets is given. The first target is elongated, and the second target is square. When the first and second targets are stacked, two triangular areas are cut out to allow visibility of the second target. In this embodiment, the image acquisition module can image the diagonal areas of the first and second targets, obtaining the following: Figure 5The superimposed image shown reflects the pose changes of the first and second objects by calculating the pose changes of the first and second targets in the superimposed image. Specifically, in another preferred embodiment, the first and second targets are three-dimensional structures, and the first and second targets are nested, with feature units marked on them. Figure 6 The diagram shows a three-dimensional structural schematic of the first target (left is a 45° side view, right is a front view), including a strip-shaped bottom edge and a central protrusion disposed on the bottom edge; as shown Figure 7 The diagram shows a three-dimensional structural schematic of the second target (left is a 45° side view, right is a front view), including a square base and a left protrusion, a central recess, and a right protrusion disposed on the square base; the central protrusion of the first target is embedded in the central recess of the second target. In this embodiment, similar to the planar structure, the first target has two triangular regions cut out to allow visibility of the second target. In this embodiment, the image acquisition module can image the diagonal regions of the first and second targets, obtaining... Figure 8 The superimposed image shown (left is the image before superposition, right is the image after superposition) reflects the pose changes of the first and second targets by calculating the pose changes of the first and second targets in the superimposed image. More specifically, the specific structure of the first and second targets, their feature units, and specific parameters (feature unit form, number, processing accuracy requirements, the proportion of the first and second targets in the image, the height and area of ​​the protruding part of the three-dimensional target, etc.) can be arbitrarily determined based on the image acquisition module, accuracy analysis, simulation, experiments, etc. More preferably, the target structure parameters can be designed and processed in conjunction with the imaging optical path, illumination optical path, and structural components to ensure compatibility with the structure, illumination, and imaging, and to design an effective imaging area with no obstruction, no waste, and uniform illumination. More preferably, the target material has high stability requirements, requiring no deformation under mechanical vibration, impact, temperature changes, and long-term use; 7075 aluminum alloy is preferred. Even more preferably, the target is manufactured as a single piece to increase its stability. More preferably, when installing the image acquisition module, the first target, and the second target, they must be securely installed, and the installation baseline direction should be as accurate as possible to be consistent with the reference direction or calibrated, requiring no deformation under mechanical vibration, impact, temperature changes, or long-term use. Preferably, the first target is installed at a 45° angle on the first object; the second target is installed on the second object at a 90° angle perpendicular to the first target; the mounting bracket is installed on the first object, the light source is installed on the mounting bracket, the camera is installed on the mounting bracket via the upper and lower sides, and the lens is installed on the camera, passing through the central hole of the light source and coinciding with the central axis of the central hole of the light source, so that the central axes of the image acquisition module, the first target, and the second target are coincidentally aligned (coaxial).

[0043] S2: At the first moment, acquire a first image of the first target and the second target coexisting; at the second moment, acquire a second image of the first target and the second target coexisting. Specifically, you can optionally, but are not limited to, adjusting various parameters of the image acquisition module, such as adjusting the aperture or focal length. At the first moment (initial moment), trigger the image acquisition module to acquire the first image (including the first and second targets), and after an interval of time T, trigger the image acquisition module to acquire the second image at the second moment (current moment). Specifically, the first and second moments are conceptual historical moments and the current moment, which can be any moment in the world attributes. The interval time T can also be arbitrarily set according to the sampling time, the performance of the image acquisition module, the requirements for pose change measurement, etc.

[0044] S3: Based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the first image, and the pixel coordinates of the second target on the first image, determine the first pose of the first and second targets. Specifically, the initial parameters of the image acquisition module can be arbitrarily set without calibration; the world coordinates of the first and second targets are known and are set by those skilled in the art based on the feature units on the targets, and their coordinate systems remain unchanged once determined. The pixel coordinates of the first and second targets on the first image can be determined based on the coordinate system of the first image.

[0045] Preferably, step S3 may include, but is not limited to:

[0046] S31: Based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the first image, and the pixel coordinates of the second target on the first image, iteratively update the initial parameters of the image acquisition module and the pixel coordinates of the first target on the first image and the pixel coordinates of the second target on the first image until the updated initial parameters of the image acquisition module and the pixel coordinates of the first target on the first image and the pixel coordinates of the second target on the first image minimize the global objective function; specifically, the global objective function may be, but is not limited to, a combination function of pixel reprojection error, and the global objective function is continuously iteratively updated and reduced until the global objective function is minimized.

[0047] S32: Based on the pixel coordinates of the first target and the second target on the first image corresponding to the minimum global objective function, determine the first pose of the first and second targets. Specifically, the relationship between the coordinate systems is as follows: Figure 9As shown. The image acquisition module (camera) coordinate system is C, and the camera intrinsic parameter is A; the first target coordinate system is S (world coordinates of the first target); the second target coordinate system is L (world coordinates of the second target); rotation between S and C is R:SC, translation is T:SC (pixel coordinates of the first target in the first image); rotation between L and C is R:LC, translation is T:LC (pixel coordinates of the second target in the first image); rotation between S and L is R:LS, translation is T:LS (first pose of the first and second targets, and their relative positional relationship). By optimizing the calculation parameters A, R:SC, T:SC, R:LC, and T:LC, and then calculating R:LS and T:LS according to the coordinate transformation relationship, the first poses of the first and second targets are obtained.

[0048] S4: Determine the second pose of the first target and the second target based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the second image, and the pixel coordinates of the second target on the second image; specifically, it is optional, but not limited to, using the same principle as step S3 to calculate the second pose of the first target and the second target.

[0049] S5: Based on the first pose and the second pose, determine the pose changes of the first object and the second object. Specifically, based on camera parameters, scaling ratio, etc., convert the pose changes (minor deformations) between the first and second targets reflected by the first pose and the second pose into the pose changes of the actual objects—the first object and the second object—reflecting the specific magnitude of their minor deformations.

[0050] This embodiment provides several preferred embodiments of the method for measuring pose changes between objects according to the present invention. The key is the ability to utilize optical measurement principles to set up a measuring device—an image acquisition module—to acquire images of the first and second targets, accurately reflecting the pose changes of the first and second objects, such as minute deformations and displacements. Taking the problem of pose changes between the internal main body mount (first object) and the external box base (second object) of an inertial navigation system due to shock absorber deformation as an example, the method proposed in this invention can accurately measure the minute displacements occurring between the internal main body mount and the external box base, adaptively adjusting the measurement results of the inertial navigation system to avoid errors caused by the displacement of the objects themselves, further improving the control accuracy of the inertial navigation system. Furthermore, compared to traditional measurement methods, the advantages of this invention are as follows: 1. The image acquisition module is mounted on the first object in the same manner as the first target. When the first object moves, the image acquisition module and the first target are relatively stationary, and the module only moves relative to the second target. This allows for the consideration of the displacement of the second object without considering the displacement of the first object itself, simplifying the pose calculation steps. 2. The image acquisition module captures images of the first and second targets on the opposite side and solves for the camera's intrinsic parameters, the pose parameters of the first target (or the second target) relative to the camera (pixel coordinates on the first image and pixel coordinates on the second image), and the relative pose parameters between the first and second targets (first pose and second pose). Therefore, the deformation solution is independent of the camera installation parameters. As mentioned in step S3, the initial parameters of the image acquisition module can be arbitrarily set without calibration. Therefore, the method of this invention has no requirements for camera installation stability or changes in installation parameters. Even if the camera's intrinsic parameters change, it has no impact on the measurement results. This greatly improves the expandability and adaptability of the image acquisition module and reduces its installation and stability requirements. In summary, this method can greatly simplify the algorithm's complexity, while also exhibiting good stability and robustness, and can to some extent avoid interference caused by changes in temperature and camera parameters.

[0051] More preferably, the measuring device may be, but is not limited to, one or more, to constitute a single-channel measuring device. Figure 2 (Schematic diagram of single-channel optical measurement) or multi-channel optical device ( Figure 10 (This is a schematic diagram of dual-channel optical measurement). When constructing a single-channel measurement device, according to steps S2-S5, a single pose change result of the first object and the second object is obtained, and this single pose change result is taken as the final pose change result; when constructing a multi-channel measurement device, according to steps S2-S5, multiple pose change results of the first object and the second object are obtained, and then multiple pose change results are coupled and calculated to obtain the final pose change result.

[0052] In this embodiment, if a single-channel optical measurement device is used, a pose change result for the first and second objects can be obtained, which can then be used as the final result. This method is simple, computationally efficient, and allows for rapid and low-cost acquisition of pose change results. However, some applications require high accuracy in pose change measurement. To reduce the error of single-channel measurement and further improve accuracy, a multi-channel optical measurement device can be used to obtain multiple change results for the first and second objects (multiple pose changes for the first and second objects). Coupling processing (such as averaging or weighted calculation) is required for these multiple results to obtain the final result, further improving measurement accuracy. More specifically, the multi-channel optical measurement devices do not need to be installed in a central position to avoid mutual obstruction and interference.

[0053] To verify the accuracy of the pose change measurement device formed by combining a single-channel measurement device, a dual-channel measurement device, and two planar and three-dimensional targets, the inventors conducted repeated experiments and simulations, drawing the following conclusions: 1) Single-channel measurement device + dual-planar targets: roll angle 2.8 arcseconds, pitch angle unmeasurable, yaw angle unmeasurable (X-axis single channel); or roll angle unmeasurable, pitch angle 2.8 arcseconds, yaw angle unmeasurable. 2) Single-channel measurement device + dual-three-dimensional targets: roll angle 2.8 arcseconds, pitch angle 4.9 arcseconds, yaw angle 4.9 arcseconds (X-axis single channel); or roll angle 4.9 arcseconds, pitch angle 2.8 arcseconds, yaw angle 4.9 arcseconds (Y-axis single channel). 3) Dual-channel measurement device + dual-planar targets: roll angle 2.8 arcseconds, pitch angle 2.8 arcseconds, yaw angle unmeasurable. 4) Dual-channel measurement device + dual stereo targets: roll angle 2.5 arcseconds, pitch angle 2.5 arcseconds, yaw angle 3.5 arcseconds.

[0054] Based on the above experiments, those skilled in the art can select the number of measuring devices (single or multiple channels) and the target shape (planar or three-dimensional) according to the accuracy requirements of the roll angle, pitch angle, yaw angle and other hard indicators, as well as the cost considerations of the device.

[0055] More preferably, the present invention also provides a system for measuring pose changes between objects, for performing any of the above methods; the system includes: a measuring device and a control device;

[0056] The measuring device includes an image acquisition module and a first target mounted on a first object, and a second target mounted on a second object. The image acquisition module is used to acquire a first image of the first target and the second target coexisting at a first moment, and to acquire a second image of the first target and the second target coexisting at a second moment. Specifically, the specific structure of the measuring device can be set with reference to the above method.

[0057] A control device is used to execute steps S3-S5 above. Specifically, the control device may be, but is not limited to, a microcontroller or other processor, and may be a terminal device or a handheld mobile device to monitor the measurement results in real time. Preferably, the control device may also be, but is not limited to, connected to a host computer to send the measurement results to a remote terminal for real-time monitoring of the measurement results and adaptive adjustments to the current data.

[0058] The system for measuring pose changes between objects described above is based on the method for measuring pose changes between objects described above. Its technical function and beneficial effects will not be elaborated here. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for measuring pose changes between objects, characterized in that, include: S1: Set up a measuring device, the measuring device including: an image acquisition module and a first target set on a first object, and a second target set on a second object; S2: At the first moment, acquire a first image of the coexistence of the first target and the second target; at the second moment, acquire a second image of the coexistence of the first target and the second target. S3: Determine the first pose of the first target and the second target based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the first image, and the pixel coordinates of the second target on the first image; S4: Determine the second pose of the first target and the second target based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the second image, and the pixel coordinates of the second target on the second image; S5: Determine the pose changes of the first object and the second object based on the first pose and the second pose. Step S3 includes: S31: Based on the initial parameters of the image acquisition module, the world coordinates of the first target, the world coordinates of the second target, the pixel coordinates of the first target on the first image, and the pixel coordinates of the second target on the first image, iteratively update the initial parameters of the image acquisition module and the pixel coordinates of the first target on the first image and the pixel coordinates of the second target on the first image until the updated initial parameters of the image acquisition module and the pixel coordinates of the first target on the first image and the pixel coordinates of the second target on the first image minimize the global objective function; S32: Determine the first pose of the first target and the second target on the first image based on the pixel coordinates of the first target and the second target on the first image corresponding to the minimum of the global objective function.

2. The method for measuring pose changes between objects according to claim 1, characterized in that, The measuring device is one, forming a single-channel measuring device; or the measuring device is multiple, forming a multi-channel optical device. When constructing a single-channel measurement device, according to steps S2-S5, the single pose change results of the first object and the second object are obtained, and the single pose change result is taken as the final pose change result. When constructing a multi-channel measurement device, according to steps S2-S5, multiple pose change results of the first object and the second object are obtained. Then, the multiple pose change results are coupled and calculated to obtain the final pose change result.

3. The method for measuring pose changes between objects according to claim 2, characterized in that, The first and second targets are planar structures. When the first and second targets are stacked, at least one area is cut out to allow a view of the second target.

4. The method for measuring pose changes between objects according to claim 3, characterized in that, The first target is rectangular, and the second target is square. When the first and second targets are stacked, two triangular areas are cut out to allow a view of the second target.

5. The method for measuring pose changes between objects according to any one of claims 1-4, characterized in that, The first and second targets are three-dimensional structures, and the first and second targets are nested together.

6. The method for measuring pose changes between objects according to claim 5, characterized in that, The first target includes a strip-shaped bottom edge and a central protrusion on the strip-shaped bottom edge; the second target includes a square bottom surface and a left protrusion, a central recess, and a right protrusion on the square bottom surface; when the first target and the second target are stacked, the central protrusion of the first target is embedded in the central recess of the second target.

7. The method for measuring pose changes between objects according to claim 5, characterized in that, The first target is installed at a 45° angle on the first object; the second target, the outer target, is installed on the second object at a 90° angle perpendicular to the first target.

8. The method for measuring pose changes between objects according to claim 5, characterized in that, The image acquisition module, the first target, and the second target are set coaxially.

9. A system for measuring pose changes between objects, characterized in that, The system is used to perform the method according to any one of claims 1-8; the system includes: a measuring device and a control device; The measuring device includes an image acquisition module and a first target disposed on a first object, and a second target disposed on a second object; the image acquisition module is used to acquire a first image of the first target and the second target coexisting at a first moment; and to acquire a second image of the first target and the second target coexisting at a second moment. A control device for performing steps S3-S5 as described in any one of claims 1-8.

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