Positioning device and positioning method of engraving and milling machine

Abstract

The invention discloses a positioning device and a positioning method of an engraving and milling machine, and relates to the technical field of engraving and milling machine positioning, the device comprises a camera system connected with an image acquisition interface of an image processing module and used for capturing a workpiece image; and the image processing module is mounted on the machine head of the engraving and milling machine and is used for receiving the workpiece image data captured by the camera system. The camera system captures the workpiece image, the image processing module is combined to carry out image processing and feature point extraction, high-precision positioning of the workpiece can be achieved, the machining precision and the product quality are improved, the image processing module adopts a high-performance computing chip and a high-speed nonvolatile memory, and the image processing module is simple in structure and convenient to use. Image data can be accurately processed in real time, feature points are extracted, rapid positioning is achieved, the production efficiency is improved, a positioning instruction sent by the image processing module is received through the control system, automatic control and adjustment are achieved, the manual operation difficulty and cost are reduced, and the intelligent degree is improved.

Description

Technical Field

[0001] The invention relates to the technical field of precision engraving machine positioning, in particular to a positioning device and a precision engraving machine positioning method. Background Art

[0002] The precision engraving machine is a type of CNC machine tool. The metal precision engraving machine can perform non-contact cutting and punching on metal or non-metallic plates and pipes. It is particularly suitable for laser cutting of stainless steel plates, iron plates, silicon wafers, ceramic sheets, titanium alloys, epoxy, A3 steel, diamond and other materials. The equipment has stable and reliable operation, good processing quality, high efficiency, simple operation and convenient maintenance. The processing automation and informatization with CNC machine tools as the core are the direction of research and development in the equipment manufacturing field and manufacturing enterprises, and are also the mainstream direction of the development of the future manufacturing industry. Among them, in the automated processing of CNC machine tools, the positioning of the workpiece has always been an important component of the machine tool. In order to achieve high-efficiency operation of the machine tool, the positioning of the workpiece has always been the focus of research by technical personnel in this field.

[0003] Traditional positioning devices and positioning methods usually use mechanical contact positioning, which is difficult to ensure high-precision positioning when used, and is easily affected by human factors or mechanical wear, resulting in reduced workpiece processing accuracy and affecting product quality. Traditional manual positioning and mechanical positioning require a lot of time to align and fix the workpiece, which is inefficient. Especially when processing large quantities of workpieces, this inefficient positioning method will seriously affect production efficiency and cost. Therefore, it is necessary to propose a positioning device and a positioning method for a precision engraving machine to solve the problems in the prior art. Summary of the invention

[0004] The purpose of the present invention is to make up for the shortcomings of the prior art and to provide a positioning device and a positioning method for a precision engraving machine, which can realize visual positioning of the workpiece through image processing technology, improve the positioning accuracy and efficiency, reduce the operating difficulty and cost, and provide strong technical support for the development of modern manufacturing industry.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a positioning device, the device comprising: A camera system connected to an image acquisition interface of the image processing module for capturing an image of a workpiece; The image processing module is installed on the head of the precision engraving machine and is used to receive the workpiece image data captured by the camera system, process the image data, extract the feature points of the workpiece, and calculate the coordinate positions of these feature points; A control system connected to the communication interface of the image processing module, used to receive the positioning instruction sent by the image processing module and control the movement of the engraving machine to complete the workpiece positioning; The positioning angle is installed on the head of the engraving machine and is used to align with a specific position on the workpiece during positioning.

[0006] Furthermore, the camera system includes at least one high-definition camera for capturing images of the workpiece. Multiple cameras can be configured as needed to obtain image data of different angles or different areas of the workpiece. The camera has high-speed transmission capabilities for transmitting image data to the image processing module in real time and accurately. The camera system also includes lighting equipment for providing supplementary light when light is insufficient.

[0007] Furthermore, the image processing module includes: An image acquisition interface, used to receive workpiece image data captured by a camera; An image processor processes the received workpiece image data, including denoising, enhancement, and feature extraction image processing steps; A memory, used to store data required for image processing, intermediate processing results and positioning algorithms, wherein the positioning algorithms stored in the memory are used to process the image data processed by the image processor to extract feature points of the workpiece and calculate the coordinate positions of these feature points; The communication interface is used to communicate with the control system and send the calculated coordinate positions of the workpiece feature points to the control system.

[0008] Furthermore, the image processor in the image processing module adopts a high-performance computing chip to improve the speed and efficiency of image processing, and the memory is a high-speed non-volatile memory to ensure fast reading and storage of data during image processing.

[0009] Furthermore, the specific execution steps of the image processor in the image processing module to process the received workpiece image data include: Image acquisition, capture the image of the workpiece through the camera, and input the image data into the image processing module; Image grayscale, convert the input color image into a grayscale image. The grayscale value (brightness) of each pixel in the grayscale image is calculated by the average value of the three components R, G, and B in the color image or other methods. The formula is: grayscale value Image denoising uses Gaussian filtering algorithm to remove noise in the image. Gaussian filtering: For each pixel in the image, the weighted average of the pixels in its neighborhood is taken as the output value of the point. The weight is determined by the Gaussian function. The formula is: The kernel function of the Gaussian filter is , where (x,y) are the coordinates of the pixels in the neighborhood, is the standard deviation of the Gaussian function; Image enhancement, using the histogram equalization algorithm to enhance the useful information in the image to improve the visual effect of the image, histogram equalization: enhance the contrast of the image by stretching the pixel intensity distribution, formula: Let r be the grayscale of the input image, s is the grayscale of the output image, the histogram equalization conversion function T(r) satisfies , where L is the number of gray levels and p is the gray level probability density function of the input image. Furthermore, the specific execution steps of the positioning algorithm stored in the memory of the image processing module include: Feature extraction, extracting key points and corresponding descriptors from the workpiece image captured by the camera; using the SIFT algorithm, the SIFT algorithm involves multiple steps, including scale space extremum detection, key point location, direction assignment, and key point descriptor generation; Feature matching, matching the extracted feature points between different images, and determining the matching feature point pairs by comparing the similarities between descriptors; Three-dimensional reconstruction uses the matching feature point pairs and the camera calibration results (such as the camera's internal and external parameters) to calculate the three-dimensional coordinates of the object using the triangulation method. The algorithm formula (taking triangulation as an example) is as follows: Assuming that the two cameras are located at positions C1 and C2, and the matching feature points on their corresponding images are p1 and p2, then the point P in the three-dimensional space can be obtained by solving the following set of equations: are the position vectors of points P, C1, and C2 in three-dimensional space, is the normalized coordinate vector corresponding to the feature point on the image, λ1, λ 2 、 a 1、 a2 is the parameter to be solved; the calculated workpiece feature point coordinate position data is sent to the control system through the communication interface.

[0010] Furthermore, the specific execution steps of the control system are as follows: The control system establishes a connection with the image processing module through a specific communication interface (such as an Ethernet interface); After completing image processing and feature matching, the image processing module generates a positioning instruction and sends it to the control system through the communication interface; After receiving the positioning instruction, the control system analyzes the target position information in the instruction. Based on the target position information, the control system calculates the path and parameters that the engraving machine needs to move. The control system controls the engraving machine to move according to the specified path and parameters through the motor drive interface (such as a servo drive); In the process of controlling the movement of the engraving machine, the PID control algorithm may be used to ensure that the engraving machine can move to the target position accurately and smoothly. The PID algorithm formula is: , where u(t) is the output of the controller, i.e., the instruction to control the movement of the engraving machine, e(t) is the error signal (i.e., the difference between the set value and the actual value), k p is the proportionality coefficient, T1 is the integration time constant, T D is the differential time constant. A positioning method for a precision engraving machine, the method comprising: Capturing an image of the workpiece by means of a camera system; The captured image data is transmitted to the image processing module through the image acquisition interface; The image processor in the image processing module pre-processes the received image data to improve the image quality; The image processor processes the preprocessed image data using the positioning algorithm stored in the memory, extracts the feature points of the workpiece, and calculates the coordinate positions of these feature points; The control system receives the coordinate position data of the feature points of the workpiece sent by the image processing module through the communication interface; The control system controls the movement of the engraving machine according to the received coordinate position data, so that the positioning angle on the machine head is aligned with the corresponding position on the workpiece to complete the workpiece positioning; After positioning is completed, the engraving machine performs processing according to the preset processing path.

[0011] Furthermore, the image processor in the image processing module preprocesses the received image data, and the preprocessing steps include grayscale, denoising and enhancement steps to improve image quality.

[0012] Furthermore, the method also includes: after the positioning is completed, capturing the image of the workpiece again through the camera system, and comparing the new image with the image before positioning to verify the accuracy of the positioning.

[0013] Compared with the prior art, the positioning device and the positioning method of the engraving machine have the following beneficial effects: The present invention captures the image of the workpiece through a camera system, and combines the image processing module to perform image processing and feature point extraction, which can achieve high-precision positioning of the workpiece and improve processing accuracy and product quality. The image processing module adopts a high-performance computing chip and a high-speed non-volatile memory, which can process image data and extract feature points in real time and accurately, achieve rapid positioning, and improve production efficiency. The control system receives the positioning instructions sent by the image processing module to achieve automatic control and adjustment, reduce the difficulty and cost of manual operation, and improve the degree of intelligence.

[0014] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a structural schematic diagram of a positioning device; Figure 2 The present invention is a flow chart of a positioning method for a precision engraving machine. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Embodiment 1: A positioning device, the device comprising: a camera system connected to an image acquisition interface of an image processing module, for capturing an image of a workpiece; The camera system includes at least one high-definition camera for capturing images of the workpiece. Multiple cameras can be configured as needed to obtain image data of different angles or different areas of the workpiece. The camera has high-speed transmission capabilities for transmitting image data to the image processing module in real time and accurately. The camera system also includes lighting equipment for providing supplementary light when light is insufficient.

[0019] The camera system is one of the core components of the positioning device and is responsible for capturing the image of the workpiece. This system is usually composed of a high-definition camera that can capture high-definition images of the workpiece to ensure the accuracy of subsequent image processing. In order to meet the needs of different workpieces and positioning, the camera system can be configured as a single camera or a multi-camera system. The multi-camera system can capture workpiece images from different angles or different areas to provide more comprehensive workpiece information. The camera system is also equipped with a high-speed transmission interface to ensure that image data can be transmitted to the image processing module in real time and accurately. In addition, in order to cope with low-light environments, the camera system is also equipped with lighting equipment that can provide supplementary light when needed to ensure the clarity and stability of image capture.

[0020] The image processing module is installed on the head of the precision engraving machine and is used to receive the workpiece image data captured by the camera system, process the image data, extract the feature points of the workpiece, and calculate the coordinate positions of these feature points; The image processing module comprises: An image acquisition interface, used to receive workpiece image data captured by a camera; An image processor processes the received workpiece image data, including denoising, enhancement, and feature extraction image processing steps; A memory, used to store data required for image processing, intermediate processing results and positioning algorithms, wherein the positioning algorithms stored in the memory are used to process the image data processed by the image processor to extract feature points of the workpiece and calculate the coordinate positions of these feature points; The communication interface is used to communicate with the control system and send the calculated coordinate positions of the workpiece feature points to the control system.

[0021] The image processor in the image processing module adopts a high-performance computing chip to improve the speed and efficiency of image processing, and the memory is a high-speed non-volatile memory to ensure the rapid reading and storage of data during the image processing process.

[0022] The image processing module is installed on the head of the engraving machine. It is the core part of the positioning device for processing image data. It receives the workpiece image data from the camera system through the image acquisition interface and performs a series of processing operations on these data. First, the image processor will pre-process the received image data, including grayscale, denoising and enhancement steps to improve image quality, reduce noise interference, and enhance the contrast and clarity of the image. Next, the image processor will use the positioning algorithm stored in the memory to process the pre-processed image data, extract the feature points of the workpiece, and calculate the coordinate positions of these feature points.

[0023] This process relies on the efficient computing power of high-performance computing chips to ensure the speed and efficiency of image processing. The memory uses high-speed non-volatile memory to ensure the fast reading and storage of data during image processing. Finally, the image processing module sends the calculated workpiece feature point coordinate position data to the control system through the communication interface.

[0024] A control system connected to the communication interface of the image processing module, used to receive the positioning instruction sent by the image processing module and control the movement of the engraving machine to complete the workpiece positioning; The control system is the decision-making and execution part of the positioning device. It is connected to the communication interface of the image processing module and receives positioning instructions from the image processing module. The control system calculates the position and path that the precision engraving machine needs to move based on the received coordinate position data of the workpiece feature points, and drives the moving mechanism of the precision engraving machine through the corresponding control signal to align the positioning angle on the machine head with the corresponding position on the workpiece to complete the workpiece positioning. The control system is also responsible for monitoring the operating status of the precision engraving machine to ensure its stability and safety during the positioning process.

[0025] The positioning angle is installed on the head of the engraving machine and is used to align with a specific position on the workpiece during positioning.

[0026] The positioning angle has a high-precision and high-reliability mechanical structure to ensure the alignment accuracy with the workpiece. The positioning angle can be fine-tuned through the control system to adapt to different workpieces and processing requirements. The positioning angle is also equipped with a sensor to monitor the alignment status with the workpiece in real time and feed back the information to the control system for precise control.

[0027] The main function of the positioning angle is to align with a specific position on the workpiece during positioning to ensure the accuracy and precision of the workpiece positioning. The positioning angle usually has the characteristics of high precision and high rigidity, and can provide stable support and positioning reference during the positioning process. By adjusting the position and angle of the positioning angle, it can adapt to the positioning needs of workpieces of different shapes and sizes.

[0028] The entire positioning device captures the workpiece image through the camera system, the image processing module processes the image data and extracts the coordinate position of the feature points, the control system controls the movement of the engraving machine according to the coordinate position data, and the positioning is assisted by the angle positioning method, thereby achieving high-precision workpiece positioning. This positioning device has broad application prospects in the fields of engraving machine processing and automated production.

[0029] Embodiment 2: The specific execution steps of the image processor in the image processing module to process the received workpiece image data include: firstly, capturing the image of the workpiece through a camera, and inputting the image data into the image processing module; then converting the input color image into a grayscale image, and the grayscale value (brightness) of each pixel in the grayscale image is calculated by the average value of the three components R, G, and B in the color image or other methods, and the formula is: grayscale value Then, the Gaussian filter algorithm is used to remove the noise in the image. Gaussian filter: For each pixel in the image, the weighted average of the pixels in its neighborhood is taken as the output value of the point. The weight is determined by the Gaussian function. The formula is: The kernel function of the Gaussian filter is , where (x, y) is the coordinate of the pixel in the neighborhood, σ is the standard deviation of the Gaussian function; Finally, the histogram equalization algorithm is used to enhance the useful information in the image to improve the visual effect of the image. Histogram equalization: Enhance the contrast of the image by stretching the pixel intensity distribution. Formula: Let r be the grayscale of the input image, s is the grayscale of the output image, and the transformation function T(r) of the histogram equalization satisfies , where L is the number of gray levels, and p is the gray level probability density function of the input image. The specific execution steps of the positioning algorithm stored in the memory of the image processing module include: first, extracting key points and corresponding descriptors from the workpiece image captured by the camera; using the SIFT algorithm, the SIFT algorithm involves multiple steps, including scale space extreme value detection, key point positioning, direction assignment, key point descriptor generation, matching the extracted feature points between different images, and determining the matching feature point pairs by comparing the similarity between the descriptors; Then, using the matched feature point pairs and the camera calibration results (such as the camera's internal and external parameters), the three-dimensional coordinates of the object are calculated using the triangulation method. The algorithm formula (taking triangulation as an example) is: Assume that the two cameras are located at positions C1 and C 2, The corresponding matching feature points on the image are p1 and p 2, Then the point P in three-dimensional space can be obtained by solving the following system of equations: are the position vectors of points P, C1, and C2 in three-dimensional space, is the normalized coordinate vector corresponding to the feature point on the image, λ 1、 λ 2、 a 1、 a2 is the parameter to be solved; finally, the calculated workpiece feature point coordinate position data is sent to the control system through the communication interface.

[0030] The specific execution steps of the control system are as follows: First, the control system establishes a connection with the image processing module through a specific communication interface (such as an Ethernet interface); after completing image processing and feature matching, the image processing module generates a positioning instruction and sends it to the control system through the communication interface; when the control system receives the positioning instruction, it parses the target position information in the instruction, and according to the target position information, the control system calculates the path and parameters that the engraving machine needs to move, and the control system controls the engraving machine to move according to the specified path and parameters through the motor drive interface (such as a servo drive); In the process of controlling the movement of the engraving machine, the PID control algorithm may be used to ensure that the engraving machine can move to the target position accurately and smoothly. The PID algorithm formula is: Among them, u(t) is the output of the controller, that is, the instruction to control the movement of the engraving machine, e(t) is the error signal (that is, the difference between the set value and the actual value), k p is the proportionality coefficient, T1 is the integration time constant, T D is the differential time constant.

[0031] Embodiment 3: A positioning method for a precision engraving machine, the method comprising: capturing an image of a workpiece by a camera system; First, the image of the workpiece is captured by a high-precision camera system. The camera system can be configured as a single-camera or multi-camera system. The appropriate configuration is selected according to the shape, size and positioning requirements of the workpiece. The multi-camera system can capture the image of the workpiece from different angles or different areas at the same time, providing a full range of workpiece information.

[0032] The captured image data is transmitted to the image processing module through the image acquisition interface; The image of the workpiece is captured by a high-precision camera system. The camera system can be configured as a single camera or a multi-camera system. The appropriate configuration is selected according to the shape, size and positioning requirements of the workpiece. The multi-camera system can capture the image of the workpiece from different angles or different areas at the same time, providing a full range of workpiece information.

[0033] The image processor in the image processing module pre-processes the received image data to improve the image quality; The image processor in the image processing module preprocesses the received image data. The preprocessing steps include graying, denoising and enhancement steps to improve the image quality. In the image processing module, the image preprocessing work is first performed. The image processor performs a series of processing operations on the received image data. These preprocessing steps can effectively remove noise interference in the image, enhance the contrast and clarity of the image, and provide high-quality image data for subsequent feature extraction and coordinate calculation.

[0034] The image processor processes the preprocessed image data using the positioning algorithm stored in the memory, extracts the feature points of the workpiece, and calculates the coordinate positions of these feature points; The pre-processed image data will be sent to the image processor and processed using the positioning algorithm stored in the memory. The positioning algorithm can accurately extract the feature points of the workpiece and calculate the coordinate positions of these feature points. These feature points are usually specific points or areas on the workpiece that are easy to identify and locate, such as corners, edges, and textures. Through precise feature extraction and coordinate calculation, accurate data support is provided for subsequent positioning operations.

[0035] The control system receives the coordinate position data of the feature points of the workpiece sent by the image processing module through the communication interface; The control system controls the movement of the engraving machine according to the received coordinate position data, so that the positioning angle on the machine head is aligned with the corresponding position on the workpiece to complete the workpiece positioning; The image processing module sends the calculated workpiece feature point coordinate position data to the control system through the communication interface. After receiving the coordinate data, the control system will calculate the position and path that the engraving machine needs to move based on these data, and drive the moving mechanism of the engraving machine through the corresponding control signal to align the positioning angle on the machine head with the corresponding position on the workpiece to complete the positioning of the workpiece.

[0036] After positioning is completed, the camera system captures the image of the workpiece again, and the new image is compared with the image before positioning to verify the accuracy of positioning.

[0037] After the positioning is completed, in order to ensure the accuracy and reliability of the positioning, the image of the workpiece can be captured again through the camera system, and the new image can be compared with the image before positioning. If the difference between the two is within the allowable range, the positioning can be considered successful; otherwise, the positioning operation needs to be re-performed. After the positioning verification is passed, the engraving machine will perform processing according to the preset processing path to ensure processing accuracy and efficiency.

[0038] After positioning is completed, the engraving machine performs processing according to the preset processing path.

[0039] The entire process realizes the complete process from image capture to workpiece positioning through the coordinated work of advanced camera systems, image processing modules, control systems and positioning angles. The entire positioning method realizes the complete process from image capture to workpiece positioning, and has the advantages of high precision, high efficiency and high degree of automation. It is particularly suitable for occasions that require high-precision positioning and processing.

[0040] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the same elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A positioning device, characterized in that: The device includes: A camera system connected to an image acquisition interface of the image processing module for capturing an image of a workpiece; The image processing module is installed on the head of the precision engraving machine and is used to receive the workpiece image data captured by the camera system, process the image data, extract the feature points of the workpiece, and calculate the coordinate positions of these feature points; A control system connected to the communication interface of the image processing module, used to receive the positioning instruction sent by the image processing module and control the movement of the engraving machine to complete the workpiece positioning; The positioning angle is installed on the head of the engraving machine and is used to align with a specific position on the workpiece during positioning.

2. A positioning device according to claim 1, characterized in that: The camera system includes at least one high-definition camera for capturing images of the workpiece. Multiple cameras can be configured as needed to obtain image data of different angles or different areas of the workpiece. The camera has high-speed transmission capabilities for transmitting image data to the image processing module in real time and accurately. The camera system also includes lighting equipment for providing supplementary light when light is insufficient.

3. A positioning device according to claim 1, characterized in that: The image processing module comprises: An image acquisition interface, used to receive workpiece image data captured by a camera; An image processor processes the received workpiece image data, including denoising, enhancement, and feature extraction image processing steps; A memory, used to store data required for image processing, intermediate processing results and positioning algorithms, wherein the positioning algorithms stored in the memory are used to process the image data processed by the image processor to extract feature points of the workpiece and calculate the coordinate positions of these feature points; The communication interface is used to communicate with the control system and send the calculated coordinate positions of the workpiece feature points to the control system.

4. A positioning device according to claim 3, characterized in that: The image processor in the image processing module adopts a high-performance computing chip to improve the speed and efficiency of image processing, and the memory is a high-speed non-volatile memory to ensure the rapid reading and storage of data during the image processing process.

5. A positioning device according to claim 3, characterized in that: The specific execution steps of the image processor in the image processing module processing the received workpiece image data include: Image acquisition, capturing the image of the workpiece through a camera and inputting the image data into the image processing module; Image grayscale conversion converts the input color image into a grayscale image. The grayscale value (brightness) of each pixel in the grayscale image is calculated by the average value of the three components R, G, and B in the color image or other methods. The formula is: Grayscale value = ; Image denoising, using Gaussian filtering algorithm to remove noise in the image, Gaussian filtering: For each pixel in the image, take the weighted average of the pixels in its neighborhood as the output value of the point, the weight is determined by the Gaussian function, formula: The kernel function of the Gaussian filter is G(x,y)= , where (x, y) is the coordinate of the pixel in the neighborhood, σ is the standard deviation of the Gaussian function; Image enhancement, using the histogram equalization algorithm to enhance the useful information in the image to improve the visual effect of the image, histogram equalization: enhance the contrast of the image by stretching the pixel intensity distribution, formula: let r be the grayscale of the input image, s is the grayscale of the output image, the histogram equalization conversion function T(r) satisfies S=T(r)=(L-1) , where L is the number of gray levels and p is the gray level probability density function of the input image.

6. A positioning device according to claim 3, characterized in that: The specific execution steps of the positioning algorithm stored in the memory of the image processing module include: Feature extraction, extracting key points and corresponding descriptors from the workpiece image captured by the camera; using the SIFT algorithm, the SIFT algorithm involves multiple steps, including scale space extremum detection, key point location, direction assignment, and key point descriptor generation; feature matching, matching the extracted feature points between different images, and determining the matching feature point pairs by comparing the similarity between descriptors; Three-dimensional reconstruction uses the matching feature point pairs and the camera calibration results (such as the camera's internal and external parameters) to calculate the three-dimensional coordinates of the object using the triangulation method. The algorithm formula (taking triangulation as an example) is: Assume that the two cameras are located at positions and , and the corresponding matching feature points on the image are and , then the point P in three-dimensional space can be obtained by solving the following system of equations: are the position vectors of points P, C1, and C2 in three-dimensional space, is the normalized coordinate vector corresponding to the feature point on the image, 1.

2. a1 and a2 are the parameters to be solved; the calculated coordinate position data of the workpiece feature point is sent to the control system through the communication interface.

7. A positioning device according to claim 1, characterized in that: The specific execution steps of the control system are as follows: The control system establishes a connection with the image processing module through a specific communication interface (such as an Ethernet interface); After completing image processing and feature matching, the image processing module generates a positioning instruction and sends it to the control system through the communication interface; After receiving the positioning instruction, the control system analyzes the target position information in the instruction. Based on the target position information, the control system calculates the path and parameters that the engraving machine needs to move. The control system controls the engraving machine to move according to the specified path and parameters through the motor drive interface (such as servo drive); in the process of controlling the movement of the engraving machine, the PID control algorithm may be used to ensure that the engraving machine can move to the target position accurately and smoothly. The PID algorithm formula is: , where u(t) is the output of the controller, i.e., the instruction to control the movement of the engraving machine, e(t) is the error signal (i.e., the difference between the set value and the actual value), k p is the proportionality coefficient, T1 is the integration time constant, T D is the differential time constant.

8. A positioning method for a precision engraving machine, characterized in that: The method includes: capturing an image of the workpiece by means of a camera system; The captured image data is transmitted to the image processing module through the image acquisition interface; The image processor in the image processing module pre-processes the received image data to improve the image quality; The image processor processes the preprocessed image data using the positioning algorithm stored in the memory, extracts the feature points of the workpiece, and calculates the coordinate positions of these feature points; The control system receives the coordinate position data of the feature points of the workpiece sent by the image processing module through the communication interface; The control system controls the movement of the engraving machine according to the received coordinate position data, so that the positioning angle on the machine head is aligned with the corresponding position on the workpiece to complete the workpiece positioning; After positioning is completed, the engraving machine performs processing according to the preset processing path.

9. A positioning method for a precision engraving machine according to claim 8, characterized in that: The image processor in the image processing module preprocesses the received image data, and the preprocessing steps include grayscale, denoising and enhancement steps to improve the image quality.

10. A positioning method for a precision engraving machine according to claim 8, characterized in that: The method also includes: after the positioning is completed, capturing the image of the workpiece again through the camera system, and comparing the new image with the image before the positioning to verify the accuracy of the positioning.

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