A real-time measurement system and method for the pointing of an artillery barrel

Abstract

The present invention discloses a real-time measurement system and method for the pointing of a gun barrel. After zero-position adjustment of the gun barrel, a camera captures an image of the gun barrel at the zero position. The position of the camera is adjusted. When the marked figure in the gun barrel image received by the computer is a circle, the position of the camera is fixed. The computer continuously receives the gun barrel pointing images captured by the camera in real time and caches the images. The computer preprocesses the images and binarizes the images. The edges and contours of the figures are extracted in the binary images, and circular marks or elliptical marks formed after the barrel rotates are detected in the edge and contour images, and the centers of the circular mark areas or elliptical mark areas are determined. A vertical line segment L3 passing through the center of the circle is added within the circular or elliptical boundary of the current image mark area, and the included angle between the two line segments L1 and L3 is calculated to output the azimuth angle. The length ratio of the line segments L1 and L2 in the current image is calculated to output the elevation angle.

Description

Technical Field

[0001] The present invention relates to the technical field of gun barrel pointing measurement, and particularly to a real-time measurement system and method for gun barrel pointing. Background Art

[0002] The statements in this section only mention the background art related to the present invention and do not necessarily constitute the prior art.

[0003] Accurate measurement of the gun barrel pointing (pitch angle, azimuth angle) is a difficult point in realizing the accuracy closed-loop test of the gun fire control system, and it is of great help to improve the accurate strike, accurate correction and rapid response capabilities of artillery under informationized conditions.

[0004] Most of the existing gun barrel pointing measurements adopt contact measurement methods, that is, sensors are installed on the trunnions of the gun cradle for measurement. Although the contact measurement method can obtain the gun barrel angle information, there are the following problems:

[0005] (1) The installation and maintenance of the sensors are difficult.

[0006] (2) The installation of the sensors changes the gun structure and may affect the shooting accuracy and stability of the gun.

[0007] (3) Sensors such as gyroscopes and electronic compasses are vulnerable to external environmental interference and have large measurement errors.

[0008] The double-theodolite space intersection method is a non-contact barrel pointing measurement method commonly used in weapon equipment test bases. The pitch angle and azimuth angle of the gun barrel are calculated by measuring the three-dimensional coordinates of 2 specific points on the barrel. Its static test accuracy reaches 0.05°, but the operation process is complex, time-consuming, mainly static measurement, and the measurement efficiency is low. Therefore, there is an urgent need for a real-time measurement method for gun barrel pointing that can avoid direct contact and has a high measurement efficiency. Summary of the Invention

[0009] To solve the deficiencies of the existing technology, the present invention provides a real-time measurement system and method for gun barrel pointing; the target on the gun barrel is image-collected by a visual acquisition device to realize non-contact and real-time measurement of the pitch angle and azimuth angle of the gun barrel.

[0010] In the first aspect, the present invention provides a real-time measurement system for gun barrel pointing;

[0011] A real-time measurement system for gun barrel pointing includes:

[0012] A base, on which a gun barrel is installed, and a marked pattern is fixedly installed on the upper surface of the gun barrel;

[0013] An elevating frame is also installed on the base. The elevating frame includes a vertical slide bar and a horizontal slide bar. One end of the vertical slide bar is fixed on the base, and the other end of the vertical slide bar is connected to one end of the horizontal slide bar. An industrial camera is installed at the other end of the horizontal slide bar, and the lens of the industrial camera faces the base. The lens of the industrial camera is used to capture the image of the gun barrel containing circular marks. The industrial camera sends the captured sequence of marked graphic images to a computer by wireless communication. The computer receives and processes the image data collected by the industrial camera, and calculates the elevation angle and azimuth angle of the gun barrel based on the image data.

[0014] The circular mark includes a vertical diameter L1 and a horizontal diameter L2. The vertical diameter L1 is parallel to the axis of the gun barrel, and the horizontal diameter L2 is perpendicular to the vertical diameter L1.

[0015] After zero position adjustment of the gun barrel, the industrial camera captures the image of the gun barrel at the zero position of the gun barrel, and adjusts the position of the camera. When the marked graphic in the gun barrel image received by the computer is circular, the position of the camera is fixed.

[0016] The computer continuously receives the pointing images of the gun barrel captured by the industrial camera in real time and caches the images. The computer preprocesses the images, removes noise and interference, and binarizes the images.

[0017] Extract the edges and contours of the graphics in the binary image, and then detect the circular mark or the elliptical mark formed after the gun barrel rotates in the edge and contour image, and determine the center of the circular mark area or the elliptical mark area.

[0018] Add a vertical line segment L3 passing through the center of the circle within the circular or elliptical boundary of the current image mark area, calculate the included angle between the two line segments of the vertical diameter L1 and L3, and output the azimuth angle; calculate the length ratio of the vertical diameter L1 and the horizontal diameter L2 in the current image, and output the elevation angle; display the azimuth angle and elevation angle of the gun barrel.

[0019] In a second aspect, the present invention provides a method for real-time measurement of the pointing of a gun barrel.

[0020] A method for real-time measurement of the pointing of a gun barrel includes:

[0021] After zero position adjustment of the gun barrel, the industrial camera captures the image of the gun barrel at the zero position of the gun barrel, and adjusts the position of the camera. When the marked graphic in the gun barrel image received by the computer is circular, the position of the camera is fixed.

[0022] The computer continuously receives the pointing images of the gun barrel captured by the industrial camera in real time and caches the images.

[0023] The computer preprocesses the image, removes noise and interference, and binarizes the image;

[0024] In the binary image, the edges and contours of the figure are extracted, and then circular marks or elliptical marks formed after the barrel rotates are detected in the edge and contour image, and the center of the circular mark area or the elliptical mark area is determined;

[0025] A vertical line segment L3 passing through the center of the circle is added within the circular or elliptical boundary of the current image marking area, the included angle between the vertical diameter L1 and the line segment L3 is calculated, and the azimuth angle is output;

[0026] Calculate the length ratio of the vertical diameter L1 and the horizontal diameter L2 in the current image, and output the pitch angle;

[0027] Display the azimuth angle and pitch angle of the gun barrel;

[0028] Repeat the above steps until the measurement is completed.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] (1) The present invention does not modify the gun structure, does not affect the shooting accuracy and stability of the gun, is simple and portable to operate, has a high test efficiency, and at the same time reduces the measurement cost.

[0031] (2) The present invention proposes a method for measuring the barrel pointing and algorithms for calculating the pitch angle and azimuth angle. By extracting feature points or lines through a vision algorithm, it avoids the influence of environmental interference that may occur in the sensor detection method, has a high measurement accuracy, is applicable to various types of guns, and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0033] Figure 1 It is a schematic structural diagram of a real-time gun barrel pointing measurement system of the present invention;

[0034] Figure 2 It is a flowchart of a real-time gun barrel pointing measurement method of the present invention;

[0035] Figure 3 It is a flowchart of adding auxiliary lines to the marked figure in the image of the present invention;

[0036] Figure 4(a) is the original image of the simulated gun barrel pointing of the present invention;

[0037] Figure 4(b) is the image obtained after binarizing the original image of the gun barrel and performing image segmentation according to the present invention;

[0038] Figure 4(c) is the image obtained after extracting the edges and contours of the image according to the present invention;

[0039] Figure 4(d) is the image obtained after adding auxiliary lines to the marked figure according to the present invention;

[0040] Figure 5 It is the schematic diagram of the method for calculating the elevation angle of the gun barrel provided by the present invention.

[0041] Among them, 1. Marked figure, 2. Gun barrel, 3. Industrial camera, 4. Elevating bracket, 5. Computer, 6. Gun base. Detailed implementation manners

[0042] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0043] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices.

[0044] Embodiment 1

[0045] This embodiment provides a real-time measurement system for the pointing of a gun barrel;

[0046] As Figure 1 shown, a real-time measurement system for the pointing of a gun barrel includes:

[0047] A gun base 6, on which a gun barrel 2 is installed, and a marked figure 1 is fixedly installed on the upper surface of the gun barrel;

[0048] A lifting frame 4 is also installed on the base. The lifting frame includes a vertical slide bar and a horizontal slide bar. One end of the vertical slide bar is fixed on the base, the other end of the vertical slide bar is connected to one end of the horizontal slide bar, and an industrial camera 3 is installed at the other end of the horizontal slide bar. The lens of the industrial camera faces the base, and the lens of the industrial camera is used to capture the image of the gun barrel containing circular marks. The industrial camera sends the captured sequence of marked graphic images to a computer 5 through wireless communication. The computer receives and processes the image data collected by the industrial camera, and calculates the elevation angle and azimuth angle of the gun barrel based on the image data.

[0049] The circular mark includes a vertical diameter L1 and a horizontal diameter L2. The vertical diameter L1 is parallel to the axis of the gun barrel, and the horizontal diameter L2 is perpendicular to the vertical diameter L1.

[0050] After zero position adjustment of the gun barrel, the industrial camera captures the image of the gun barrel at the zero position of the gun barrel, and adjusts the position of the camera. When the marked graphic in the image of the gun barrel received by the computer is circular, the position of the camera is fixed.

[0051] The computer continuously receives the pointing images of the gun barrel captured by the industrial camera in real time and caches the images. The computer preprocesses the images, removes noise and interference, and binarizes the images.

[0052] Extract the edges and contours of the graphics in the binary image, and then detect the circular mark or the elliptical mark formed after the gun barrel rotates in the edge and contour image, and determine the center of the circular mark area or the elliptical mark area.

[0053] Add a vertical line segment L3 passing through the center of the circle within the circular or elliptical boundary of the current image mark area, calculate the included angle between the two line segments of the vertical diameter L1 and L3, and output the azimuth angle.

[0054] Calculate the length ratio of the vertical diameter L1 to the horizontal diameter L2 in the current image, and output the elevation angle.

[0055] Display the azimuth angle and elevation angle of the gun barrel.

[0056] The lifting frame adjusts the up and down position of the camera through a locking block with end teeth, and adjusts the left and right position of the camera by adjusting the connection position of the horizontal slide bar and the vertical slide bar through a fixing nut.

[0057] Embodiment 2

[0058] This embodiment provides a real-time measurement method for the pointing of a gun barrel.

[0059] As Figure 2 shown, a real-time measurement method for the pointing of a gun barrel includes:

[0060] S200: After zero adjustment of the gun barrel, the industrial camera captures an image of the gun barrel when it is at zero position. Adjust the position of the camera. When the marked figure in the captured gun barrel image received by the computer is a circle, fix the position of the camera.

[0061] S201: The computer continuously receives the images of the gun barrel pointing captured in real time by the industrial camera and caches the images.

[0062] S202: The computer preprocesses the images, removes noise and interference, and binarizes the images.

[0063] S203: Extract the edges and contours of the figures in the binary images, and then detect circular marks or elliptical marks formed after the barrel rotates in the edge and contour images, and determine the centers of the circular mark areas or elliptical mark areas.

[0064] S204: Add a vertical line segment L3 passing through the center of the circle within the circular or elliptical boundary of the current image marking area, calculate the angle between the two line segments of the vertical diameter L1 and L3, and output the azimuth angle.

[0065] S205: Calculate the length ratio of the vertical diameter L1 and the horizontal diameter L2 in the current image, and output the elevation angle.

[0066] S206: Display the azimuth angle and elevation angle of the gun barrel.

[0067] S207: Repeat S201 to S206 until the measurement is completed.

[0068] Further, before the step S200: After zero adjustment of the gun barrel, it further includes:

[0069] S200-1: Take pictures of Zhang Zhengyou chessboard pictures through the industrial camera, calculate various distortion parameters, and perform distortion correction on the camera.

[0070] Further, the step S200-1: Take pictures of Zhang Zhengyou chessboard pictures through the industrial camera, calculate various distortion parameters, and perform distortion correction on the camera, specifically including:

[0071] Collect multiple chessboard pictures, use the Camera Calibrator tool in the MATLAB toolbox to calculate the internal and external parameters and distortion parameters of the camera, construct an undistortion mapping table, map the distorted coordinates to the coordinates before distortion, and then perform interpolation on the images to avoid pixel loss.

[0072] Such as Figure 3As shown in Figure 4(a), further, in step S203: extract the edges and contours of the figure in the binary image, and then detect the circular marks or the elliptical marks formed after the barrel is rotated in the edge and contour image, and determine the center of the circular mark area or the elliptical mark area. The specific steps are as follows:

[0073] S203-1: Perform erosion and dilation operations on the binarized image, and use the Canny edge detection algorithm to detect the edges and contours in the image;

[0074] S203-2: Use the contour search method to segment the circular marks from the image, perform contour analysis on the detected contours, find the target shape, and separate the target shape from the background, as shown in Figure 4(b);

[0075] S203-3: Detect the center of the marked circle based on the Hough transform, and mark the center coordinates (x0, y0), as shown in Figure 4(c).

[0076] Further, in step S204: add a vertical line segment L3 passing through the center of the circle within the circular or elliptical boundary of the current image marking area, calculate the included angle between the two line segments L1 and L3, and output the azimuth angle. The specific steps are as follows:

[0077] S204-1: In the current image circular marking area, make a vertical line segment L3 of x = x0, and the two endpoints of the line segment L3 fit the boundary of the marked circle or ellipse, where x0 is the abscissa in the center coordinates (x0, y0), as shown in Figure 4(d);

[0078] S204-2: Detect the line segments L1 and L3 in the current image marking area based on the Hough transform, and extract the endpoint coordinates of the line segments L1 and L3. The upper endpoint coordinates of L1 are (x1, y1), the lower endpoint coordinates of L1 are (x2, y2), the upper endpoint coordinates of L3 are (x3, y3), and the lower endpoint coordinates of L3 are (x4, y4);

[0079] S204-3: Calculate the included angle between the line segments L1 and L3, that is, the azimuth angle θ. The calculation formula is:

[0080]

[0081] As Figure 5 shown, further, in step S205: calculate the length ratio of the line segments L1 and L2 in the current image, and output the pitch angle. The specific steps are as follows:

[0082] S205-1: Extract the endpoint coordinates of line segments L1 and L2 within the marked area based on the Hough transform. The upper endpoint coordinates of L1 are (x1, y1), the lower endpoint coordinates of L1 are (x2, y2), the upper endpoint coordinates of L2 are (x5, y5), and the lower endpoint coordinates of L2 are (x6, y6). Then, the length S1 of L1 in the image is:

[0083]

[0084] The length S of L2 in the image is:

[0085]

[0086] S205-2: Since the line segment L1 captured by the industrial camera is the result of the real vertical diameter line L1 mapped to the image coordinates, and the length of the line segment detected in the image changes linearly, the ratio of the length of the line segment L1 in the image to the length of the real vertical diameter line L1 is the cosine of the pitch angle. And the length of the real vertical diameter line L1 is equal to the length of L2 in the image. Then, the calculation formula for the pitch angle α is:

[0087]

[0088] The present invention provides a real-time measurement system and method for the pointing of a gun barrel. The industrial camera is used to collect the target image on the gun barrel, and the computer processes the acquired image data, and finally displays the pitch angle and azimuth angle of the gun barrel, so as to realize the real-time monitoring of the attitude of the gun barrel. During the monitoring process, no sensors need to be installed on the gun barrel, which is applicable to various types of guns and has wide applicability.

[0089] In summary, the present invention provides a novel and practical solution, which has broad application prospects and economic benefits. By effectively solving the problems and limitations existing in the prior art, the present invention provides a feasible technical means and solution for professionals in related fields.

[0090] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A real-time measurement system for the pointing of an artillery barrel, characterized in that, Comprising: A base on which a gun barrel is mounted, and a marking pattern is fixedly mounted on the upper surface of the gun barrel; A lifting frame is also mounted on the base. The lifting frame includes a vertical rod and a horizontal rod. One end of the vertical rod is fixed on the base, the other end of the vertical rod is connected to one end of the horizontal rod, and an industrial camera is mounted at the other end of the horizontal rod. The lens of the industrial camera faces the base, and the lens of the industrial camera is used to capture the barrel image containing the circular mark. The industrial camera sends the acquired sequence of marking pattern images to a computer via wireless communication. The computer receives and processes the image data collected by the industrial camera, and calculates the elevation angle and azimuth angle of the gun barrel based on the image data; The circular mark includes a vertical diameter L1 and a horizontal diameter L2. L1 is parallel to the axis of the gun barrel, and L2 is perpendicular to L1; After zero position adjustment of the gun barrel, the industrial camera captures the gun barrel image at the zero position of the gun barrel, and adjusts the position of the camera. When the marking pattern in the gun barrel image received by the computer is circular, fix the position of the camera; The computer continuously receives the gun barrel pointing images real-time collected by the industrial camera and caches the images. The computer preprocesses the images, removes noise and interference, and binarizes the images; Extract the edges and contours of the pattern in the binary image, and then detect the circular mark in the edge and contour image to determine the center of the circular mark area; Add a vertical line segment L3 passing through the center of the circle within the circular boundary of the current image marking area, calculate the included angle between the two line segments L1 and L3, and output the azimuth angle; Calculate the length ratio of L1 to L2 in the current image and output the elevation angle; Display the azimuth angle and elevation angle of the gun barrel; The specific steps for determining the center of the circular mark area include: Perform erosion and dilation operations on the binarized image, and use the Canny edge detection algorithm to detect the edges and contours in the image; Use the contour search method to segment the circular mark from the image, perform contour analysis on the detected contours, find the target shape, and separate the target shape from the background; Detect the center of the marked circle based on the Hough transform and mark the center coordinates (x0, y0); The specific steps for outputting the azimuth angle include: Within the circular marking area of the current image, make an L3 with x = x0. The two endpoints of L3 fit the boundary of the marked circle, where x0 is the abscissa in the center coordinates (x0, y0); Based on the Hough transform, detect L1 and L3 within the current image marking area, and extract the endpoint coordinates of L1 and L3. The upper endpoint coordinates of L1 are (x1, y1), the lower endpoint coordinates of L1 are (x2, y2), the upper endpoint coordinates of L3 are (x3, y3), and the lower endpoint coordinates of L3 are (x4, y4); Calculate the included angle between L1 and L3, that is, the azimuth angle θ. The calculation formula is:

2. An in-real-time measuring system for the pointing of a gun barrel as described in claim 1, characterized in that, Calculate the length ratio of L1 and L2 in the current image and output the pitch angle. The specific steps include: Extract the endpoint coordinates of L1 and L2 within the marked area based on the Hough transform. The upper endpoint coordinates of L1 are (x1, y1), the lower endpoint coordinates of L1 are (x2, y2), the upper endpoint coordinates of L2 are (x5, y5), and the lower endpoint coordinates of L2 are (x6, y6). Then the length S1 of L1 in the image is: The length S2 of L2 in the image is: The calculation formula for the pitch angle α is:

3. A measurement method for a real-time measurement system of the pointing of a gun barrel according to any one of claims 1-2, After zero-position adjustment of the gun barrel, an industrial camera collects an image of the gun barrel at the zero position of the gun barrel. Adjust the position of the camera. When the marked pattern in the image of the gun barrel received by the computer is a circle, fix the position of the camera; The computer continuously receives the images of the pointing of the gun barrel collected in real time by the industrial camera and caches the images; The computer preprocesses the images, removes noise and interference, and binarizes the images; Extract the edges and contours of the patterns in the binary images, and then detect the circular marks in the edge and contour images to determine the center of the circular marked area; Add a line L3 passing through the center of the circle within the circular boundary of the marked area in the current image, calculate the included angle between the two line segments L1 and L3, and output the azimuth angle; Calculate the length ratio of L1 and L2 in the current image and output the pitch angle; Display the azimuth angle and pitch angle of the gun barrel; Repeat the above steps until the measurement is completed; The specific steps for determining the center of the circular marked area include: Perform erosion and dilation operations on the binarized images, and use the Canny edge detection algorithm to detect the edges and contours in the images; Use the method of contour search to segment the circular marks from the images, perform contour analysis on the detected contours, find the target shape, and separate the target shape from the background; Detect the center of the marked circle based on the Hough transform and mark the center coordinates (x0, y0); The specific steps for outputting the azimuth angle include: In the circular marked area of the current image, make a line L3 with x = x0, and the two endpoints of L3 fit the boundary of the marked circle, where x0 is the abscissa in the center coordinates (x0, y0); Detect L1 and L3 within the marked area of the current image based on the Hough transform, and extract the endpoint coordinates of L1 and L3. The upper endpoint coordinates of L1 are (x1, y1), the lower endpoint coordinates of L1 are (x2, y2), the upper endpoint coordinates of L3 are (x3, y3), and the lower endpoint coordinates of L3 are (x4, y4); Calculate the included angle between L1 and L3, that is, the azimuth angle θ. The calculation formula is:

4. The measurement method according to claim 3, characterized in that, Before the computer continuously receives the images of the pointing of the gun barrel collected in real time by the industrial camera and caches the images, it also includes: Take pictures of the checkerboard with the industrial camera, calculate various distortion parameters, and perform distortion correction on the camera.

5. Using the measurement method according to claim 4, characterized in that, Take pictures of the checkerboard with the industrial camera, calculate various distortion parameters, and perform distortion correction on the camera. The specific steps include: Collect multiple checkerboard images, calculate the internal and external parameters and distortion parameters of the camera, construct a distortion correction mapping table, map the distorted coordinates to the coordinates before distortion, and then interpolate the image to avoid pixel loss.

6. Using the measurement method according to claim 3, characterized in that, Calculate the length ratio of L1 and L2 in the current image and output the pitch angle. The specific steps include: Based on the Hough transform, extract the endpoint coordinates of L1 and L2 within the marked area. The upper endpoint coordinates of L1 are (x1, y1), the lower endpoint coordinates of L1 are (x2, y2), the upper endpoint coordinates of L2 are (x5, y5), and the lower endpoint coordinates of L2 are (x6, y6). Then the length S1 of L1 in the image is: The length S2 of L2 in the image is: The calculation formula for the pitch angle α is:

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