Displacement vision measurement device and method based on angle mirror imaging

Abstract

The invention relates to a displacement vision measurement device based on angle mirror imaging. The displacement vision measurement device comprises an angle mirror, an area-array camera and a computer, the angle mirror is arranged below a measured object and is used for imaging the measured object; according to the angle mirror imaging principle, the measured object is imaged in the angle mirror to obtain a corresponding virtual image; the area-array camera is used for carrying out image acquisition on a virtual image position of a measured object in the angle mirror and sending an image to the computer for analysis and calculation; and the computer processes the acquired image to obtain the relative displacement information of the measured object. According to the measuring device and method, the measured object does not need to be marked, measurement is convenient and efficient, the device is simple, and the implementation cost is low.

Description

Technical Field

[0001] The present invention relates to the field of displacement measurement technology, and in particular to a displacement visual measurement device and method based on angular mirror imaging. Background Art

[0002] In modern manufacturing, displacement measurement technology, as a key technology in precision machining, has become a vital pillar driving innovation and development in the manufacturing industry. These technologies are widely used in high-end manufacturing fields such as aerospace, automotive manufacturing, and mold processing, and their importance is becoming increasingly prominent.

[0003] In recent years, in the study of displacement measurement, many scholars have proposed vision-based measurement methods, including point tracking, digital image correlation, and template matching. In these methods, a high-contrast black and white pattern or a special spatial arrangement pattern is appropriately designed and pasted on the surface of the object to be measured, making it easy to identify. Compared with previous traditional measurement methods, vision-based displacement measurement methods have the advantages of non-contact and high precision. This type of method manually pastes the target on the object to be measured, then uses a camera to capture the movement of the object to be measured, and then uses image processing technology to extract the dynamic information of the object to be measured through the changes in the target. These methods require manual placement of markers on the object to be measured. This step is not only cumbersome to operate, but also limits the widespread application of these methods. If monocular vision is used to measure the displacement of an unmarked object, it can only achieve the displacement measurement of the structure in the direction perpendicular to the camera imaging optical axis, and cannot achieve the displacement measurement of the structure in the direction of the camera imaging optical axis. Summary of the Invention

[0004] The object of the present invention is to provide a displacement visual measurement device and method based on angular mirror imaging, which does not require marking of the object to be measured, is convenient and efficient, and has a simple device and low implementation cost.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a displacement visual measurement device based on corner mirror imaging, including a corner mirror, an area array camera and a computer; the corner mirror is arranged under the object to be measured, and is used to image the object to be measured; according to the corner mirror imaging principle, the object to be measured is imaged in the corner mirror to obtain a corresponding virtual image; the area array camera is used to capture the virtual image position of the object to be measured in the corner mirror, and send the image to the computer for analysis and calculation; the computer processes the captured image to obtain the relative displacement information of the object to be measured.

[0006] Furthermore, the corner mirror is composed of two mutually perpendicular plane mirrors, forming a 90° angle.

[0007] Furthermore, the area array camera is arranged directly above the corner mirror and the object to be measured.

[0008] The present invention also provides a displacement visual measurement method based on the above device, comprising the following steps:

[0009] Step S1: Place the corner mirror below the object to be measured; at the same time, place the area array camera directly above the corner mirror and the object to be measured; adjust the relevant parameters of the area array camera to the optimal state to ensure that the captured image is clear;

[0010] Step S2: When the object being measured moves, the position of the virtual image formed in the corner mirror changes accordingly; during this process, the position of the area array camera is kept fixed, and the area array camera continuously collects virtual images with position information and transmits them to the computer;

[0011] Step S3: The computer processes each received frame image in sequence and extracts the position information of the virtual image of the object under test in each frame image; then, based on the extracted position information of the virtual image of the object under test, the computer obtains the two-dimensional displacement information of the object under test along the camera imaging optical axis and perpendicular to the axial direction of the object under test and the camera imaging optical axis, that is, in the X and Y directions.

[0012] Furthermore, step S3 includes the following steps:

[0013] Step S31: determining a region of interest in the image;

[0014] Step S32: performing a series of processing on the image within the determined area, including denoising, sharpening, and contrast enhancement;

[0015] Step S33: analyzing and processing the pixel position coordinates of the virtual image of the object to be measured in each frame image to extract the position information of the virtual image of the object to be measured;

[0016] Step S34: Calculate the two-dimensional displacement information of the object to be measured along the camera imaging optical axis and perpendicular to the axial direction of the object to be measured and the camera imaging optical axis, that is, in the X and Y directions, based on the imaging ratio relationship of the corner mirror.

[0017] Furthermore, the displacement calculation formula of the measured object along the X and Y directions is:

[0018] Establish a rectangular coordinate system with the vertex of the angle of the corner mirror as the origin, the camera imaging optical axis direction as the X direction, and the direction perpendicular to both the axis of the object being measured and the camera imaging optical axis direction as the Y direction;

[0019] When the object P is located at any position in the corner mirror, two virtual images P1' and P2' are formed through the corner mirror;

[0020] The object P and its two virtual images P1' and P2' are imaged by the area array camera to obtain three images I, I1, and I2. Since I, I1, and I2 are all located on the same plane, the x-coordinates of I, I1, and I2 satisfy the relationship: I x =D+U,I 1x =D+U,I 2x =D+U; among them, I x , I 1x , I 2x are the x-coordinates of I, I1, and I2, respectively; D is the object distance between the vertex of the angle of the corner mirror and the camera imaging lens; and U is the image distance between the camera imaging lens and the image sensor;

[0021] According to the perspective principle of camera imaging, the y coordinates of I, I1, and I2 are:

[0022]

[0023]

[0024] Where x and y are the coordinates of the object P. Expanding formulas (2) and (3) yields formulas (4) and (5):

[0025] U·x=I 1y ·(Dy) (4)

[0026] U·x=I 2y ·(D+y) (5)

[0027] Combining formulas (4) and (5), we can get the y coordinate of object P as follows:

[0028]

[0029] Expanding formula (1) yields formula (7):

[0030]

[0031] Combining formula (6) and formula (7), we can get the x-coordinate of object P as follows:

[0032]

[0033] By using formula (8) and formula (6), the coordinates of object P at any position in the corner mirror are calculated;

[0034] When object P is displaced, the coordinates of object P at different positions are calculated in sequence; by calculating the difference in x coordinates between different positions, the movement distance ΔX of object P in the x direction is obtained; by calculating the difference in y coordinates between different positions, the movement distance ΔY of object P in the y direction is obtained.

[0035] Compared with the existing technology, the present invention has the following beneficial effects: The present invention provides a displacement visual measurement device and method based on angular mirror imaging. The device and method utilize an area array camera to continuously image the virtual image of the object being measured in the angular mirror, and process the acquired images, thereby efficiently achieving the measurement of the object's two-dimensional displacement. Compared with existing measurement methods, the present invention cleverly combines the principle of angular mirror imaging with monocular vision technology to achieve the effect of binocular vision without relying on markers. This innovation not only significantly reduces hardware costs, but also greatly simplifies the operating process, making the displacement signal extraction process faster and more efficient. Therefore, the present invention has strong practicality and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1 is a schematic structural diagram of a displacement visual measurement device according to an embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of an image processing process according to an embodiment of the present invention;

[0038] Figure 3 1 is a diagram showing the principle of imaging for displacement measurement in the X and Y directions in an embodiment of the present invention.

[0039] In the figure: 1-area array camera; 2-data cable; 3-computer; 4-object to be measured; 5-angle mirror; 6-bearing; 7-coupling; 8-motor. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0042] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0043] like Figure 1As shown, this embodiment provides a displacement visual measurement device based on angular mirror imaging, including an angular mirror 5, an array camera 1 and a computer 3. The angular mirror 5 is set below the object to be measured 4 through an angular mirror bracket, and is used to image the object to be measured. According to the principle of angular mirror imaging, the object to be measured 4 is imaged in the angular mirror 5 to obtain a corresponding virtual image. The array camera 1 is used to capture the image of the virtual image position of the object to be measured in the angular mirror 5, and send the image to the computer 3 through the data line 2 for analysis and calculation. The computer 3 processes the captured image to obtain the relative displacement information of the object to be measured. While measuring the displacement of the object, the measuring device can also track and record its motion trajectory, showing excellent comprehensive measurement performance.

[0044] In this embodiment, if Figure 1 As shown, the direction parallel to the camera's imaging optical axis is defined as the X direction, and the direction perpendicular to the camera's imaging optical axis is defined as the Y direction. The corner mirror 5 is composed of two mutually perpendicular plane mirrors, forming a 90° angle. The area array camera 1 is positioned directly above the corner mirror 5 and the object under test 4.

[0045] In this embodiment, image processing is achieved by a computer, and the computer is pre-installed with an image processing program. The image processing process is as follows: Figure 2 As shown, the captured image sequence is subjected to region of interest selection and image preprocessing, and then edge detection is performed according to the morphology of the object to be measured, thereby obtaining the pixel coordinates of the object to be measured in the image.

[0046] This embodiment also provides a displacement visual measurement method based on the above device, comprising the following steps:

[0047] Step S1: Place the corner mirror below the object being measured. Simultaneously, place the area array camera directly above the corner mirror and the object being measured. Adjust the area array camera's focal length, aperture, and other parameters to the optimal setting to ensure the captured image is clear and high-resolution.

[0048] Step S2: When the object being measured moves, the position of the virtual image formed in the corner mirror changes accordingly; during this process, the position of the area array camera is kept fixed, and the area array camera continuously collects virtual images with position information and transmits them to the computer.

[0049] Step S3: The computer processes each frame of images received in sequence and extracts the position information of the virtual image of the object being measured in each frame of images. Then, based on the extracted position information of the virtual image of the object being measured, Figure 3 The imaging principle shown is to obtain the two-dimensional displacement information of the object being measured along the camera imaging optical axis and perpendicular to the axial direction of the object being measured and the camera imaging optical axis, that is, the X and Y directions.

[0050] The step S3 specifically includes the following steps:

[0051] Step S31: Determine a region of interest in the image, which will serve as the focus of subsequent analysis.

[0052] Step S32: Perform a series of processing on the image within the determined area, including but not limited to denoising, sharpening, and contrast enhancement, etc. These processing steps are intended to improve the overall quality of the image and ensure that subsequent analysis and processing can be performed more accurately and efficiently.

[0053] Step S33: Analyze and process the pixel position coordinates of the virtual image of the object to be measured in each frame image to extract the position information of the virtual image of the object to be measured.

[0054] Step S34: Calculate the two-dimensional displacement information of the object to be measured along the camera imaging optical axis and perpendicular to the axial direction of the object to be measured and the camera imaging optical axis, that is, in the X and Y directions, based on the imaging ratio relationship of the corner mirror.

[0055] Based on Figure 3 According to the imaging principle shown in the figure, the displacement calculation formula of the measured object along the X and Y directions is:

[0056] A rectangular coordinate system is established with the vertex of the angle of the corner mirror as the origin, the camera imaging optical axis direction as the X direction, and the direction perpendicular to both the axial direction of the measured object and the camera imaging optical axis direction as the Y direction.

[0057] When the object P is located at any position in the corner mirror, two virtual images P1' and P2' are formed through the corner mirror.

[0058] The object P and its two virtual images P1' and P2' are imaged by the area array camera to obtain three images I, I1, and I2. Since I, I1, and I2 are all located on the same plane, the x-coordinates of I, I1, and I2 satisfy the relationship: I x =D+U,I 1x =D+U,I 2x =D+U; among them, I x , I 1x , I 2x are the x-coordinates of I, I1, and I2 respectively, D is the object distance between the angle vertex of the corner mirror and the camera imaging lens, and U is the image distance between the camera imaging lens and the image sensor.

[0059] According to the perspective principle of camera imaging, the y coordinates of I, I1, and I2 are:

[0060]

[0061] Where x and y are the coordinates of the object P. Expanding formulas (2) and (3) yields formulas (4) and (5):

[0062] U·x=I 1y ·(Dy) (4)

[0063] U·x=I 2y ·(D+y) (5)

[0064] Combining formulas (4) and (5), we can get the y coordinate of object P as follows:

[0065]

[0066] Expanding formula (1) yields formula (7):

[0067]

[0068] Combining formula (6) and formula (7), we can get the x-coordinate of object P as follows:

[0069]

[0070] By using formula (8) and formula (6), the coordinates of the object P at any position in the corner mirror are calculated.

[0071] When object P is displaced, the coordinates of object P at different positions are calculated in sequence; by calculating the difference in x coordinates between different positions, the movement distance ΔX of object P in the x direction is obtained; by calculating the difference in y coordinates between different positions, the movement distance ΔY of object P in the y direction is obtained.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A displacement visual measurement device based on angular mirror imaging, characterized in that: It includes a corner mirror, an area array camera and a computer; the corner mirror is set below the object to be measured and is used to image the object to be measured; according to the corner mirror imaging principle, the object to be measured is imaged in the corner mirror to obtain a corresponding virtual image; the area array camera is used to collect images of the virtual image position of the object to be measured in the corner mirror and send the images to the computer for analysis and calculation; the computer processes the collected images to obtain relative displacement information of the object to be measured.

2. The displacement visual measurement device based on angular mirror imaging according to claim 1 is characterized in that: The corner mirror is composed of two mutually perpendicular plane mirrors, forming a 90° angle.

3. The displacement visual measurement device based on angular mirror imaging according to claim 1 is characterized in that: The area array camera is arranged directly above the corner mirror and the object to be measured.

4. A method for visually measuring displacement based on angular mirror imaging according to the device of any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1: Place the corner mirror below the object to be measured; at the same time, place the area array camera directly above the corner mirror and the object to be measured; adjust the relevant parameters of the area array camera to the optimal state to ensure that the captured image is clear; Step S2: When the object being measured moves, the position of the virtual image formed in the corner mirror changes accordingly; during this process, the position of the area array camera is kept fixed, and the area array camera continuously collects virtual images with position information and transmits them to the computer; Step S3: The computer processes each received frame image in sequence and extracts the position information of the virtual image of the object under test in each frame image; then, based on the extracted position information of the virtual image of the object under test, the computer obtains the two-dimensional displacement information of the object under test along the camera imaging optical axis and perpendicular to the axial direction of the object under test and the camera imaging optical axis, that is, in the X and Y directions.

5. The displacement visual measurement method based on angular mirror imaging according to claim 4 is characterized in that: The step S3 comprises the following steps: Step S31: determining a region of interest in the image; Step S32: performing a series of processing on the image within the determined area, including denoising, sharpening, and contrast enhancement; Step S33: analyzing and processing the pixel position coordinates of the virtual image of the object to be measured in each frame image to extract the position information of the virtual image of the object to be measured; Step S34: Calculate the two-dimensional displacement information of the object to be measured along the camera imaging optical axis and perpendicular to the axial direction of the object to be measured and the camera imaging optical axis, that is, in the X and Y directions, based on the imaging ratio relationship of the corner mirror.

6. The displacement visual measurement method based on angular mirror imaging according to claim 5 is characterized in that: The displacement calculation formula of the measured object along the X and Y directions is: Establish a rectangular coordinate system with the vertex of the angle of the corner mirror as the origin, the camera imaging optical axis direction as the X direction, and the direction perpendicular to both the axis of the object being measured and the camera imaging optical axis direction as the Y direction; When the object P is located at any position in the corner mirror, two virtual images P1' and P2' are formed through the corner mirror; The object P and its two virtual images P1' and P2' are imaged by the area array camera to obtain three images I, I1, and I2. Since I, I1, and I2 are all located on the same plane, the x-coordinates of I, I1, and I2 satisfy the relationship: I x =D+U,I 1x =D+U,I 2x =D+U; among them, I x , I 1x , I 2x are the x-coordinates of I, I1, and I2, respectively; D is the object distance between the vertex of the angle of the corner mirror and the camera imaging lens; and U is the image distance between the camera imaging lens and the image sensor; According to the perspective principle of camera imaging, the y coordinates of I, I1, and I2 are: Where x and y are the coordinates of the object P. Expanding formulas (2) and (3) yields formulas (4) and (5): U·x=I 1y ·(D-y) (4) U·x=I 2y ·(D+y) (5) Combining formulas (4) and (5), we can get the y coordinate of object P as follows: Expanding formula (1) yields formula (7): Combining formula (6) and formula (7), we can get the x-coordinate of object P as follows: By using formula (8) and formula (6), the coordinates of object P at any position in the corner mirror are calculated; When object P is displaced, the coordinates of object P at different positions are calculated in sequence; by calculating the difference in x coordinates between different positions, the movement distance ΔX of object P in the x direction is obtained; by calculating the difference in y coordinates between different positions, the movement distance ΔY of object P in the y direction is obtained.

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