CN204730814U - A kind of parts passer based on line laser three-dimensional measurement - Google Patents

Abstract

The utility model discloses a component quality inspection device based on line laser three-dimensional measurement, which comprises a mobile platform installed on a guide rail and capable of sliding along the guide rail at a constant speed. There are cameras and several laser emitters for projecting equidistant linear stripes to the parts to be tested; the cameras collect the images that the laser emitters project onto the surface of the parts to be tested and are deformed after being modulated by the surface, and the cameras will collect The image data is transmitted to the computer for analysis and processing. The utility model projects the linear stripes emitted by the laser transmitter onto the surface of the parts to be tested for linear scanning, and uses the camera to continuously collect the image information on the parts to be tested, so that the measured 3D point cloud data is consistent with the initially designed 3D point cloud data. Graphics are compared and analyzed in the same coordinate system, so that qualified parts can be screened out, the detection accuracy is high, and automation and assembly line production can be realized.

Description

A component quality inspection device based on line laser three-dimensional measurement

technical field

The utility model belongs to the field of three-dimensional optical measurement and parts quality inspection, in particular to a part quality inspection device based on line laser three-dimensional measurement.

Background technique

With the rapid development of the machinery manufacturing industry, many manufacturing industries have put forward higher and higher requirements for the quality control of their processed parts. However, at present, most enterprises are not doing well enough in component quality inspection due to technical and cost issues. In the inspection of parts, one is to use the method of sensory inspection, that is, the inspection personnel only rely on visual, auditory, tactile and other intuitive senses and basically do not use inspection equipment to inspect the technical condition of parts. This method is simple and low in cost, but this method cannot be used for quantitative inspection, and cannot be used to inspect parts with high precision requirements, and requires inspectors to have rich experience. The other is the instrument and tool inspection method, which uses some measuring tools, mechanical instruments, etc. to inspect parts. In short, the quality inspection is usually carried out by the master worker who selects appropriate measuring tools and determines a reasonable measurement method based on experience, so that not only the measurement speed is slow, but also the measurement accuracy cannot be guaranteed. In addition, for a large number of parts, it is impossible to measure all of them. Only some parts are randomly selected for measurement, and then the quality of the parts in the sample is used to estimate the overall quality. The quality detection effect is poor. Summarizing the existing methods for detecting auto parts, there are the following deficiencies: 1) The quality inspection of parts requires human intervention, the degree of automation is not high, and the efficiency is low. 2) Relying on the measuring tools and experience of the master worker for testing, the uncertain factors are large and the testing accuracy is low. 3) The anti-interference is weak and the measurement is unstable.

Utility model content

The purpose of this utility model is to solve the above-mentioned problems in the prior art, to provide a component quality inspection device based on line laser three-dimensional measurement, in the process of auto parts quality inspection, under the premise of ensuring detection accuracy and efficiency No human intervention is required to realize automation and assembly line production, improve production efficiency and reduce production costs.

In order to achieve the above object, the technical solution adopted by the utility model is:

It includes a mobile platform installed on a guide rail that can slide at a constant speed along the guide rail, the parts to be tested are fixed on the mobile platform, a camera and several lasers for projecting equidistant linear stripes to the parts to be tested are installed above the guide rail through brackets Transmitter; the camera collects the image that is projected by the laser transmitter onto the surface of the component to be tested and deformed after being modulated by the surface, and the camera transmits the collected image data to a computer for analysis and processing.

The laser emitter adopts six laser emitters arranged at equal intervals along a straight line.

The line connecting the optical center of the camera and the laser transmitter is parallel to the upper surface of the mobile platform where no parts to be tested are placed.

Adjust the laser emitter and camera through the calibration plate placed in the center of the mobile platform, so that the light can be completely projected to the calibration plate and ensure that the camera can capture the complete light.

The calibration board adopts a black and white grid board of 500mm×500mm, the size of each black and white grid is 10mm×10mm, and an origin for calibration is provided as an azimuth point on a corner of the black and white grid board.

The camera is a CCD camera.

Compared with the prior art, the utility model has the beneficial effects as follows:

1) The utility model is designed for the parts production line, which can realize automatic quality inspection during the production process of parts, and can quickly screen out qualified parts, improving the detection efficiency of parts;

2) The laser emitter and camera of the utility model are fixed, and the parts to be tested move with the mobile platform. Only one optical plane needs to be calibrated, which is relatively simple to calibrate, with less data redundancy and higher work efficiency;

3) The utility model uses a laser transmitter to project light, a camera collects images, and the quality inspection accuracy is high;

4) The utility model does not need to keep the probe and the parts to be tested relatively static during the measurement process, is not sensitive to vibration, and has good anti-interference and stability.

Description of drawings

Fig. 1 structural diagram of the quality inspection platform for parts and components of the utility model;

Fig. 2 is a structural schematic diagram of the utility model laser three-dimensional fast measuring device;

Fig. 3 is the linear diagram of the modulation and deformation of the surface of the object collected by the camera of the utility model;

The schematic diagram of Fig. 4 triangulation of the utility model;

Figure 5 is a schematic diagram of the black and white grid calibration version of the utility model;

The work flowchart of Fig. 6 utility model measuring method;

In the drawings: 1- guide rail; 2- mobile platform; 3- bracket; 4- camera; 5- laser transmitter; 6- calibration board.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Referring to Fig. 1, the utility model is based on the component quality inspection device of line laser three-dimensional measurement, comprises laser emitter 5, video camera 4, guide rail 1, mobile platform 2, support 3, calibration board 6 and computer;

The laser emitter 5 adopts six laser emitters 5 arranged in a straight line, and the distance between two adjacent ones is H, which is used to project six linear stripes at equal intervals H to the parts to be tested; the camera 4 is a high-speed CCD camera, and the six The laser emitter 5 is collinearly arranged, and is used to collect the image that the laser emitter 5 is projected onto the surface of the auto part to be tested and deformed after surface modulation; the computer image signal input end is connected with the image signal output end of the CCD camera, and is used It is used to analyze and process the graphic information obtained by the camera; the guide rail 1 is used to install the mobile platform 2, and the mobile platform 2 on the guide rail is controlled to move at a specific speed at a constant speed, which is convenient for the line laser to scan the parts to be tested; the mobile platform 2 is used for The parts to be tested are placed, and the moving speed is controlled by the computer; the bracket 3 is used to install the laser emitter 5 and the camera 4, and the height of the laser emitter 5 and the camera 4 can be adjusted; the calibration plate 6 is used to calibrate the measurement system Parameters of camera 4 and light source.

The working principle of the component quality inspection device based on the line laser three-dimensional measurement of the utility model is as follows:

In the utility model, the linear stripes emitted by the laser emitter 5 are projected onto the surface of the parts to be tested, and a three-dimensional light strip image modulated by the surface shape of the parts to be tested is formed on the surface, and then the mobile platform carrying the parts to be tested is controlled. 3 Move at a set speed at a constant speed, linearly scan the surface of the part to be tested, use the CCD camera to continuously collect image information on the part to be tested, and send it to the computer for analysis and processing, and obtain the part to be tested in the world coordinate system 3D point cloud data. Use non-uniform rational B-splines to construct a smooth surface from the 3D point cloud data, and compare and analyze the measured 3D point cloud data with the initially designed 3D graphics in the same coordinate system to determine whether the maximum error is within the maximum allowable error Within the range, if it is within the allowable range of its settings, the qualified parts will be screened out through the screening mechanism.

Referring to Fig. 6, the utility model is based on the three-dimensional line laser three-dimensional measurement method for parts quality detection, the specific implementation steps are as follows:

(1) The measurement system is calibrated with a black and white grid plate of 500mm*500mm, as shown in Figure 5, where the size of the black and white grid is 10mm*10mm, and the position of the calibration plate 6 is adjusted so that the light emitted by the six laser emitters 5 can be projected Go to the calibration plate 6, and adjust the camera 4 to shoot the calibration plate 6 at different positions, and ensure that the laser line is projected on the central area of the calibration plate 6 when shooting. Then, through the black-and-white grid with a size of 10mm*10mm on the calibration board 6 and the pictures collected by the camera 4, it is determined that 10mm in the X and Y directions in the world coordinate system corresponds to the N _xi and N _yi pixels collected on the corresponding direction coordinates on the image, and finally The linear stripes projected by the six laser emitters 5 onto the calibration plate 6 determine the conversion coefficients K _xi and K _yi from the pixel coordinate system to the world coordinate system in the X and Y directions, i=1, 2, 3, 4, 5, 6 ; Conversion coefficients K _xi , K _yi from the pixel coordinate system to the world coordinate system, i=1, 2, 3, 4, 5, 6, obtained through the following three calculation formulas:

[x _c y _c z _c ] ^T ＝T+R[x y z] ^T (1)

$\begin{array}{cc}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; d</span>}\frac{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; c</span>}}{\mathrm{<span\; class="notranslate">\; z</span>}\mathrm{<span\; class="notranslate">\; c</span>}}& \stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; d</span>}\frac{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; c</span>}}{\mathrm{<span\; class="notranslate">\; z</span>}\mathrm{<span\; class="notranslate">\; c</span>}}\end{array}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

$\begin{array}{cc}\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&times;</span>\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}& \mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&times;</span>\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span>\end{array}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them: (x, y, z) are the coordinates in the world coordinate system, (x _c , y _c , z _c ) are the coordinates in the camera coordinate system, the rotation matrix is R, the translation matrix is T, and the coordinates of the corresponding point in the image coordinate system for The focal length of the camera is d, (u, v) are the corresponding row and column coordinate values in the image coordinate system, and (U ₀ , V ₀ ) are the coordinates of the origin of the image coordinate system in the pixel coordinate system. n _xi , n _yi is the number of pixels within a unit distance in the horizontal and vertical directions in the image coordinate system, namely: n _xi =N _xi /10, n _yi =N _yi /10, i=1, 2, 3, 4, 5 6. The specific representation of the rotation matrix R and the translation matrix T is:

$\begin{array}{cc}\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 13</span>}}\\ {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; one</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; two</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}\\ {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 31</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 32</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 33</span>}}\end{array}\right]& \mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}\\ {\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}\\ {\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}\end{array}\right]\end{array}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Therefore, the conversion formula from the world coordinate system to the camera coordinate system, that is, formula (1), can be specifically expressed as:

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 13</span>}}\\ {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; one</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; two</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; three</span>}}\\ {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 31</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 32</span>}}& {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 33</span>}}\end{array}\right]\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; x</span>}\\ \mathrm{<span\; class="notranslate">\; the\; y</span>}\\ \mathrm{<span\; class="notranslate">\; z</span>}\end{array}\right]<span\; class="notranslate">\; +</span>\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

(2) project the linear stripes that the laser emitter 5 sends onto the surface of the component to be measured, as shown in Figure 2;

(3) By controlling the mobile platform 2 to move at a constant speed, the linear stripes emitted by the laser generator 5 are linearly scanned on the surface of the component to be measured on the mobile platform 2;

(4) Use a CCD camera to collect image information on the surface of the component to be tested, and obtain the fringes L ₁ -L ₆ after surface modulation, as shown in FIG. 3 . The image information collected by the CCD camera is input into the computer for processing and analysis.

(5) Obtain the height value of the component to be measured from the collected image information according to the principle of triangulation. Combined with the system calibration parameters to obtain the corresponding relationship between the pixel coordinates on the picture and the world coordinates of the parts to be tested. When the light emitted by the laser emitter 5 is projected onto the reference plane, part of the light will be reflected, and the reflected light will be imaged and displayed on the photosensitive surface through the lens. When the component under test is placed on the reference plane, the displayed pixel position will change, and this change reflects the height change of the component. As shown in Figure 4, the height value h of the measured component, that is, the calculation formula of the Z coordinate of the measured component in the world coordinate system is:

$\frac{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; D.</span>}}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; B</span>}\mathrm{<span\; class="notranslate">\; E.</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{{\mathrm{<span\; class="notranslate">\; DA</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}}{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; E.</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

in $\stackrel{\&OverBar;}{B_1\mathrm{D.}}=x\mathrm{the\; s}i\mathrm{no}\mathrm{\&beta;},\stackrel{\&OverBar;}{B\mathrm{E.}}=\stackrel{\&OverBar;}{BA}\mathrm{the\; s}i\mathrm{no}(\mathrm{\&alpha;}+\mathrm{\&theta;}),\stackrel{\&OverBar;}{{\mathrm{DA}}_1}=xco\mathrm{the\; s}\mathrm{\&beta;},\stackrel{\&OverBar;}{A\mathrm{E.}}=\stackrel{\&OverBar;}{BA}co\mathrm{the\; s}(\mathrm{\&alpha;}+\mathrm{\&theta;}),\stackrel{\&OverBar;}{BA}=\frac{h}{co\mathrm{the\; s}\mathrm{\&theta;}}.$

The calculation formula of lens imaging is:

$\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Among them, the object distance is u, the image distance is v, and the focal length is f. When the incident light spot is on the component to be tested, u=l ₁ , v=l ₂ , Therefore, the calculation formula for the height h of the measured component is:

Among them, after the optical path is determined, the parameters l ₁ , l ₂ , α, β, θ, and f are all known, and the height h of the component to be measured can be determined by knowing the displacement x on the photosensitive unit. Take "-" when the actual plane is below the reference plane, and take "+" when it is above the reference plane.

(6) Perform flying point elimination, point cloud splicing and fusion processing on the obtained 3D point cloud data to obtain complete 3D point cloud data of the parts to be tested. According to the comparison of the distance deviation E(p _i ) and the given threshold E, the flying spots are eliminated, and the algorithm formula is:

$\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\sqrt{\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; k</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}{<span\; class="notranslate">\; (</span><span\; class="notranslate">\; ||</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; ||</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; k</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; ||</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; ||</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

Among them, p _i is any point in the point cloud data, k is the number of adjacent points, c _j is a point in the neighborhood of p _i point k ( _j =1,...,k), if the distance deviation E( p _i ) is greater than a given threshold E, the point is regarded as a flying point and removed, otherwise it is kept.

The two surfaces P(u,v) and Q(u,v) obtained by fitting the overlapping areas of the point clouds P and Q to be spliced by using the moving least squares surface, and determine the initial corresponding point set, and then according to the curvature Constraint removes the wrong corresponding point set, and determines the final corresponding point set. Calculate the normal vector N _pi of the point p _i in the point cloud P, which intersects the point cloud Q at point q _i in the direction of the normal vector, and then averages the overlapping points p _i and q _i points to obtain a new point cloud d _i , and finally spliced and fused into a complete model.

(7) Using non-uniform rational B-splines (NURBS) in the computer to process the measured 3D point cloud data to construct a smooth surface. The formula for constructing a smooth surface from 3D point cloud data is:

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; )</span>}{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

Among them: p _i,j (i=0,1,...,m; j=0,1,...,n) is a control vertex, which is in the form of a topological matrix and forms a control grid; w _{i, j} is the weight corresponding to the vertex p _i,j ; N _i,p (x) and N _j,p (y) are the normalized B-spline basis functions of parameter x to p times and parameter y to q times respectively, they It is the node vector U=(x ₀ ,x ₁ ,...,x _m-p+1 ) and V=(y ₀ ,y ₁ ,...,y _n-q+ 1 ) in x direction and y direction ) is determined by the deBoor-Cox recursive formula.

The recursive formula of N _i,p (x) is:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right.\\ {\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; x</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

However, it is stipulated that 0/0=0. The recursive formula of N _j,p (y) is similar to the above formula.

(8) Compare and analyze the 3D model of the part to be measured obtained by measurement and the 3D model of the initial design in the same coordinate system to obtain the maximum error E _max , whose calculation formula is:

E _max ＝|M ₂ −M ₁ | (12)

Among them, M ₁ is the design value, and M ₂ is the measured value.

(9) According to the maximum error of each point, display the error cloud map of the parts to be tested in the computer, and judge whether the maximum error is within the maximum allowable error range. If it is within the allowable range set, pass the screening mechanism Screen out, if the error is too large, mark the location of the largest error on the unqualified parts.

Claims (6)

1. the parts passer based on line laser three-dimensional measurement, it is characterized in that: comprise the mobile platform (2) being arranged on and guide rail (1) at the uniform velocity can slide along guide rail (1), the upper fixing parts to be measured of mobile platform (2), described guide rail (1) top is provided with video camera (4) by support (3) and several are for projecting the generating laser (5) of equidistantly linear striped to parts to be measured; Described video camera (4) gathers generating laser and projects to component surface to be measured and the image be out of shape after surface modulation, and the image data transmission collected is carried out analyzing and processing to computing machine by video camera (4).

2. the parts passer based on line laser three-dimensional measurement according to claim 1, is characterized in that: described generating laser (5) adopts six generating lasers linearly equidistantly arranged.

3. the parts passer based on line laser three-dimensional measurement according to claim 1, is characterized in that: video camera (4) is parallel with mobile platform (2) upper surface not placing parts to be measured with the photocentre line of generating laser (5).

4. the parts passer based on line laser three-dimensional measurement according to claim 1, it is characterized in that: regulate generating laser (5) and video camera (4) by the scaling board (6) being placed in mobile platform (2) central authorities, make that light is complete projects scaling board (6) and function of guaranteeing to make a video recording photographs complete light.

5. the parts passer based on line laser three-dimensional measurement according to claim 4, it is characterized in that: described scaling board (6) adopts the black and white grate of 500mm × 500mm, each black and white grid is of a size of 10mm × 10mm, and a drift angle of black and white grate is provided with initial point for demarcating as bearing point.

6. the parts passer based on line laser three-dimensional measurement according to claim 1 or 4, is characterized in that: described video camera (4) is CCD camera.