High-precision distance measurement system, method, device, processor and storage medium based on dynamic gimbal compensation and intrinsic calibration

Abstract

The application relates to a high-precision distance measurement system based on dynamic gimbal compensation and intrinsic feature calibration, wherein the system comprises a mobile chassis used for carrying and moving the whole system, a positioning module used for acquiring self-position information is arranged on the mobile chassis, a gimbal is installed on the mobile chassis and can be horizontally and vertically rotated, an image acquisition unit is installed on the gimbal and is used for acquiring images of a target region, and a control and processing unit is electrically connected with the positioning module, the gimbal and the image acquisition unit. The application also relates to a corresponding method, device, processor and computer readable storage medium. The high-precision distance measurement system based on dynamic gimbal compensation and intrinsic feature calibration, the method, the device, the processor and the computer readable storage medium adopt the application, dynamic angle compensation of the gimbal is adopted, positioning error of the chassis is effectively isolated from the influence on a measurement line of sight, and the measurement precision is improved.

Description

Technical Field

[0001] This invention relates to the field of machine vision and automated measurement technology, and is particularly applicable to distance measurement of industrial equipment by mobile robots. Specifically, it refers to a high-precision distance measurement system, method, device, processor, and computer-readable storage medium based on dynamic gimbal compensation and inherent feature calibration. Background Technology

[0002] Mobile robots (such as Automated Guided Vehicles, AGVs) are widely used in industrial environments for tasks such as material handling, inspection, and measurement. Their positioning typically relies on technologies like laser SLAM (Simultaneous Localization and Mapping), but these technologies have inherent absolute positioning errors, typically around ±5cm. On such mobile platforms, the cameras or sensors used for measurement are usually fixedly mounted on a gimbal. When there are positioning errors in the chassis, the fixed gimbal cannot adjust the viewing angle, causing the measurement line of sight to deviate from the target, introducing additional measurement errors. This is unacceptable in scenarios requiring sub-millimeter or millimeter-level high-precision measurements (such as the detection of spacing between components in large industrial equipment).

[0003] Existing solutions such as high-precision lidar, while offering high ranging accuracy, are susceptible to interference in dynamic environments and are costly; manual adjustment is inefficient and lacks real-time performance, failing to meet the demands of automated high-precision measurement.

[0004] 1) LiDAR Positioning: While lidar positioning technology offers high ranging accuracy and is widely used in various measurement scenarios, it exhibits significant limitations in dynamic environments. Its performance is affected by multiple factors, including changes in ambient lighting, obstacle interference, and limitations imposed by the sensor's installation location, leading to significant measurement errors in fast-moving or complex terrain. Furthermore, lidar systems are costly and perform poorly in foggy environments, often failing to provide accurate real-time data. These factors severely restrict the adaptability and real-time performance of lidar in dynamic applications.

[0005] 2) Manual Adjustment Technique: Manual adjustment can improve measurement accuracy in some cases because operators can make fine adjustments based on the actual situation. However, this method relies on human operation, is inefficient, and is easily affected by human factors. When the chassis moves in unstable or dynamic environments, the real-time nature and accuracy of manual adjustments cannot be guaranteed, which may lead to inconsistencies in measurement results and increased errors.

[0006] Therefore, there is an urgent need for a high-precision measurement solution that can dynamically compensate for chassis motion errors and integrate multiple error sources for real-time correction. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-precision distance measurement system, method, device, processor, and computer-readable storage medium based on dynamic gimbal compensation and inherent feature calibration.

[0008] To achieve the above objectives, the present invention provides a high-precision distance measurement system, method, apparatus, processor, and computer-readable storage medium based on dynamic gimbal compensation and inherent feature calibration as follows: This high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration is characterized by the following: A mobile chassis is used to support and move the entire system, and it is equipped with a positioning module for acquiring its own pose information. The gimbal is mounted on the mobile chassis and can rotate horizontally and in pitch. An image acquisition unit, mounted on the pan-tilt unit, is used to acquire images of the target area; The control and processing unit is electrically connected to the positioning module, the pan-tilt unit, and the image acquisition unit, respectively; wherein, the control and processing unit is configured to perform the following operations: a. The chassis pose acquired in real time by the positioning module. By transforming the coordinate system, the gimbal target control angle used to compensate for chassis pose error is calculated. ; b. Drive the gimbal to rotate to the target control angle. And align the image acquisition unit with the target; c. Based on the inherent characteristics of the known physical dimensions in the image acquired by the image acquisition unit, calculate the initial scaling factor between the image pixels and the actual physical dimensions. ; d. Combine with perspective correction factor and / or temperature drift compensation for the initial scaling factor After correction, the compensated scaling factor is obtained. ; e. Using the compensated scaling factor described above Calculate the actual physical distance between the targets to be measured.

[0009] Preferably, the process of calculating the gimbal target control angle in step a includes: Using the chassis pose transformation matrix Install offset matrix with gimbal Transform the target point coordinates from the world coordinate system to the gimbal coordinate system to obtain the target point coordinates in the gimbal coordinate system. ; According to coordinates Calculate the target control angle of the gimbal based on its installation height H. : ; in, For chassis The heading angle of the axis of rotation; , These represent the positions of the chassis in the world coordinate system. , These represent the offsets of the gimbal center in the chassis coordinate system. This refers to the horizontal rotation angle of the gimbal. The tilt angle of the gimbal.

[0010] Preferably, the process of driving the gimbal to rotate is implemented using a PID closed-loop control algorithm: ; in, This represents the error between the current angle of the gimbal and the target control angle. These are the proportional gain, integral gain, and differential gain coefficient, respectively. This refers to the output of the gimbal motor control. Preferably, step c calculates the initial scaling factor in the following manner. : , ; in, These are the coordinates of the two corner points of the fastener. The physical width of the device fixing component is defined as follows: the fixing component is a structurally stable and visually identifiable inherent geometric feature of the device under test or the measurement environment with known precise physical dimensions, thus providing a reliable physical dimension reference.

[0011] Preferably, the perspective correction factor Calculate as follows: ; Where H is the installation height of the gimbal. The height difference between the target point and the reference plane. The angle between the camera's optical axis and the normal to the target plane.

[0012] Preferably, the temperature drift compensation is calculated as follows: ; in, Let be the coefficient of thermal expansion of the system. This refers to the change in temperature. The actual physical distance between the targets to be measured is calculated as follows: ; Where d is the actual physical distance between the targets to be measured. These are the image coordinates of the target to be measured.

[0013] Preferably, the control and processing unit is further configured to perform perspective distortion correction on the image acquired by the image acquisition unit before performing distance measurement, the correction being achieved by calculating the homography matrix. And applied to image coordinate implementation: ; in, The coordinates of the corner points detected in the image ( , For the corresponding physical plane coordinates , The original image coordinates, These are the corrected image coordinates.

[0014] This method, which employs the aforementioned system to implement a high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration, is characterized by the following steps: (1) System initialization: preset the actual physical width of the target fastener Camera focal length f and gimbal mounting height H; (2) Dynamic PTZ compensation: (2.1) Real-time acquisition of the pose of the mobile chassis ; (2.2) Based on the aforementioned pose The target control angle of the gimbal is calculated by inverse kinematics of the coordinate system. , ); (2.3) Control the gimbal to rotate to the target angle to compensate for the chassis pose error; (3) High-precision distance measurement: (3.1) Acquire images containing inherent features, and determine the image pixel width and its actual physical width based on the inherent features. Calculate the initial scaling factor ; (3.2) Introduce perspective correction factor And / or temperature drift compensation, for the initial scaling factor After correction, the compensation ratio factor is obtained. ; (3.3) Based on the pixel distance of the target in the image and the compensation scaling factor mentioned above. Calculate the actual physical distance d of the target to be measured.

[0015] Preferably, before step (3.1), the acquired image is further processed by a homography matrix. Perform perspective distortion correction.

[0016] This high-precision distance measurement device based on dynamic gimbal compensation and inherent feature calibration is characterized in that the device comprises: A processor is configured to execute computer-executable instructions; The memory stores one or more computer-executable instructions, which, when executed by the processor, implement the steps of the high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration described above.

[0017] The high-precision distance measurement processor based on dynamic gimbal compensation and inherent feature calibration is characterized in that the processor is configured to execute computer-executable instructions, which, when executed by the processor, implement the steps of the high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration described above.

[0018] The main feature of this computer-readable storage medium is that it stores a computer program thereon, which can be executed by a processor to implement the steps of the high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration described above.

[0019] The high-precision distance measurement system, method, apparatus, processor, and computer-readable storage medium based on dynamic gimbal compensation and inherent feature calibration of the present invention have the following advantages compared with the prior art: High precision and dynamic adaptability: Through the dynamic angle compensation of the gimbal, the influence of chassis positioning error on the measurement line of sight is effectively isolated, so that the system can still achieve a measurement accuracy of ±10mm or even higher when the chassis has a large pose error (±50mm), which is more than 40% higher than the traditional static measurement method.

[0020] Strong robustness: The innovative combination of temperature drift compensation and perspective correction forms a multi-source error fusion compensation mechanism, which significantly improves the measurement stability and accuracy of the system under different ambient temperatures and non-ideal observation angles.

[0021] Low cost and automation: Without relying on extremely high-precision chassis positioning systems or expensive measurement sensors, it utilizes machine vision and intelligent control algorithms to achieve fully automated high-precision measurement, reducing system costs and operational complexity. Attached Figure Description

[0022] Figure 1This is a schematic diagram of the overall detection process of the high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration of the present invention.

[0023] Figure 2 This is a schematic diagram illustrating the process of high-precision distance measurement using the high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration of the present invention. Detailed Implementation

[0024] To more clearly describe the technical content of the present invention, the following description is provided in conjunction with specific embodiments.

[0025] Before describing the embodiments of the present invention in detail, it should be noted that, in the following, the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0026] Please see Figure 1 As shown, the core idea of ​​this high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration is to establish a model of chassis pose error and gimbal compensation angle through coordinate system transformation, and to achieve image scale calibration by combining the physical reference of the fixed parts, thus forming a complete dynamic compensation-calibration-measurement technology chain to meet the ±10mm accuracy requirement.

[0027] Coordinate system definition: World coordinate system: ; Chassis coordinate system: ; Gimbal coordinate system: ; Camera coordinate system: ; The implementation process of this technical solution will be further explained below with reference to specific technical details: 1. System Initialization 1) Parameter presets: Actual width of the target fastener: (Unit: mm) Camera focal length: f (unit: pixels) Pan-tilt unit installation height: H (unit: mm) 2) Establishing coordinate system transformation relationships: Chassis pose transformation matrix: ; in, Chassis heading angle (around) (Axis rotation) Unit: radians; , The position of the chassis in the world coordinate system, in mm.

[0028] Gimbal mounting offset matrix: ; in, , This represents the offset of the gimbal center in the chassis coordinate system, in mm.

[0029] 2. Real-time dynamic compensation 1) Obtain chassis position and orientation Real-time data from odometer + IMU.

[0030] 2) Inverse kinematics calculation of the gimbal, transforming the target position to the gimbal coordinate system: Target point coordinate transformation: ; in, The physical width of the equipment fastener, in mm; The coordinates of the target point in the gimbal coordinate system are in mm.

[0031] Gimbal angle calculation converts coordinates into gimbal control commands: ; in, This refers to the horizontal rotation angle (azimuth angle) of the gimbal, in radians. The pitch angle (elevation angle) of the gimbal is expressed in radians.

[0032] 3) PID closed-loop control drives the gimbal to precisely reach the target angle: ; in, This is for angular error; These are the proportional, integral, and differential gain coefficients; This refers to the output of the gimbal motor control.

[0033] 3. High-precision distance measurement 1) Reference width calibration: , ; Where s is the height difference between the target point and the reference plane, and represents the actual physical size represented by each pixel, i.e., the scaling factor, with the unit being: millimeters / pixel; These are the coordinates of the two corner points of the fastener. In this step, the coordinates of the two corner points of the fastener are detected. This is used to locate the measurement reference area, which also involves the ROI extraction process. The initial scaling factor s is also used for sub-pixel edge detection.

[0034] 2) Perspective correction factor: ; Where H represents the installation height, in mm; The height difference between the target point and the reference plane, in mm; The angle between the camera's optical axis and the normal to the target plane, in radians; 3) Equipment spacing calculation: ; in, is the image coordinates of the component to be measured, in mm; d is the calculated actual physical distance.

[0035] 4. Error Compensation 1) Temperature drift compensation: ; in, The coefficient of thermal expansion ( ), This represents the change in temperature.

[0036] It should be noted that, in the aforementioned scaling factor It is the basis for converting pixel coordinates to physical dimensions. If temperature changes cause the material to expand or contract, the uncompensated scaling factor... This will lead to measurement errors. Therefore, using the temperature drift compensation formula can more accurately calculate the actual physical distance d.

[0037] 2) Perspective distortion correction: ; in, It is a homography matrix. The coordinates (x, y) of the corner points detected in the image. These are the corresponding physical plane coordinates x and y; The coordinates are those of the original image. These are the corrected image coordinates.

[0038] When calculating the target point coordinates, the inverse kinematics calculation involves converting the target point in the device coordinate system to a point in the gimbal coordinate system. If perspective distortion or angle issues exist during image acquisition, the homography matrix... It can be used to correct image coordinates, thereby improving computation. The accuracy of this directly affects the accuracy of the gimbal angle calculation and the final distance.

[0039] Based on the above processing, this technical solution uses the corrected coordinates to calculate the distance (improving accuracy by more than 40%), and the final measurement accuracy reaches ±10mm.

[0040] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

[0041] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution device.

[0042] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0043] The storage media mentioned above can be read-only memory, disk, or optical disk, etc.

[0044] In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0046] The high-precision distance measurement system, method, apparatus, processor, and computer-readable storage medium based on dynamic gimbal compensation and inherent feature calibration of the present invention have the following advantages compared with the prior art: High precision and dynamic adaptability: Through the dynamic angle compensation of the gimbal, the influence of chassis positioning error on the measurement line of sight is effectively isolated, so that the system can still achieve a measurement accuracy of ±10mm or even higher when the chassis has a large pose error (±50mm), which is more than 40% higher than the traditional static measurement method.

[0047] Strong robustness: The innovative combination of temperature drift compensation and perspective correction forms a multi-source error fusion compensation mechanism, which significantly improves the measurement stability and accuracy of the system under different ambient temperatures and non-ideal observation angles.

[0048] Low cost and automation: Without relying on extremely high-precision chassis positioning systems or expensive measurement sensors, it utilizes machine vision and intelligent control algorithms to achieve fully automated high-precision measurement, reducing system costs and operational complexity.

[0049] In this specification, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations can be made without departing from the spirit and scope of the invention. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. A high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration, characterized in that, The system includes: A mobile chassis is used to support and move the entire system, and it is equipped with a positioning module for acquiring its own pose information. The gimbal is mounted on the mobile chassis and can rotate horizontally and in pitch. An image acquisition unit, mounted on the pan-tilt unit, is used to acquire images of the target area; The control and processing unit is electrically connected to the positioning module, the pan-tilt unit, and the image acquisition unit, respectively; wherein, the control and processing unit is configured to perform the following operations: a. The chassis pose acquired in real time by the positioning module. Through coordinate system transformation, the gimbal target control angle used to compensate for chassis pose error is calculated. , ); b. Drive the gimbal to rotate to the target control angle. , And align the image acquisition unit with the target; c. Based on the inherent characteristics of the known physical dimensions in the image acquired by the image acquisition unit, calculate the initial scaling factor between the image pixels and the actual physical dimensions. ; d. Combine with perspective correction factor and temperature drift compensation for the initial scaling factor After correction, the compensated scaling factor is obtained. ; e. Using the compensated scaling factor described above Calculate the actual physical distance between the targets to be measured; The aforementioned perspective correction factor Calculate as follows: Where H is the installation height of the gimbal. The height difference between the target point and the reference plane. The angle between the camera's optical axis and the normal to the target plane; The temperature drift compensation is calculated as follows: in, Let be the coefficient of thermal expansion of the system. This refers to the change in temperature. The actual physical distance between the targets to be measured is calculated as follows: Where d is the actual physical distance between the targets to be measured. These are the image coordinates of the target to be measured.

2. The high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration according to claim 1, characterized in that, The process of calculating the gimbal target control angle in step a includes: Using the chassis pose transformation matrix Install offset matrix with gimbal Transform the target point coordinates from the world coordinate system to the gimbal coordinate system to obtain the target point coordinates in the gimbal coordinate system. ; According to coordinates Given the installation height H of the gimbal, calculate the target control angle of the gimbal. , ): in, For chassis The heading angle of the axis of rotation; , These represent the positions of the chassis in the world coordinate system. , These represent the offsets of the gimbal center in the chassis coordinate system. This refers to the horizontal rotation angle of the gimbal. The tilt angle of the gimbal.

3. The high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration according to claim 1 or 2, characterized in that, The process of driving the gimbal to rotate is achieved using a PID closed-loop control algorithm: in, This represents the error between the current angle of the gimbal and the target control angle. These are the proportional gain, integral gain, and differential gain coefficient, respectively. This refers to the output of the gimbal motor control.

4. The high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration according to claim 1, characterized in that, Step c is performed by calculating the initial scaling factor in the following manner. : ， in, These are the coordinates of the two corner points of the fastener. The physical width of the equipment fixing component.

5. The high-precision distance measurement system based on dynamic gimbal compensation and inherent feature calibration according to claim 1, characterized in that, The control and processing unit is further configured to perform perspective distortion correction on the image acquired by the image acquisition unit before performing distance measurement, the correction being performed by calculating the homography matrix. And applied to image coordinate implementation: in, The coordinates of the corner points detected in the image ( , For the corresponding physical plane coordinates , The original image coordinates, These are the corrected image coordinates.

6. A high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration using the system described in any one of claims 1 to 5, characterized in that, The method includes the following steps: (1) System initialization: preset the actual physical width of the target fastener Camera focal length f and gimbal mounting height H; (2) Dynamic PTZ compensation: (2.1) Real-time acquisition of the pose of the mobile chassis ; (2.2) Based on the aforementioned pose The target control angle of the gimbal is calculated by inverse kinematics of the coordinate system. , ); (2.3) Control the gimbal to rotate to the target angle to compensate for the chassis pose error; (3) High-precision distance measurement: (3.1) Acquire images containing inherent features, and determine the image pixel width and its actual physical width based on the inherent features. Calculate the initial scaling factor ; (3.2) Introduce perspective correction factor And / or temperature drift compensation, for the initial scaling factor After correction, the compensation ratio factor is obtained. ; (3.3) Based on the pixel distance of the target in the image and the compensation scaling factor mentioned above. Calculate the actual physical distance d of the target to be measured.

7. The high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration according to claim 6, characterized in that, The step (3.1) described above also includes processing the acquired image through a homography matrix. Perform perspective distortion correction.

8. A high-precision distance measurement device based on dynamic gimbal compensation and inherent feature calibration, characterized in that, The device includes: A processor is configured to execute computer-executable instructions; The memory stores one or more computer-executable instructions, which, when executed by the processor, implement the steps of the high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration as described in claim 7.

9. A high-precision distance measurement processor based on dynamic gimbal compensation and inherent feature calibration, characterized in that, The processor is configured to execute computer-executable instructions, which, when executed by the processor, implement the steps of the high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration as described in claim 7.

10. A computer-readable storage medium, characterized in that, It stores a computer program that can be executed by a processor to implement the steps of the high-precision distance measurement method based on dynamic gimbal compensation and inherent feature calibration as described in claim 7.

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