PVC floor buckle type measuring method based on multi-angle line laser
Through multi-angle line laser measurement method and direct calibration method, the problems of floor damage and low accuracy in PVC floor buckle measurement are solved, and high-precision, non-contact buckle profile measurement is achieved, which improves measurement efficiency and digital processing effect .
Patent Information
- Application Number
- CN202411563115.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-05
- Publication Date
- 2025-02-14
AI Technical Summary
The prior art requires slices when measuring PVC floor buckles, resulting in floor damage and time-consuming measurement process, with low accuracy and digitization.
Using a multi-angle line laser measurement method, high-precision non-contact measurement of PVC floor buckle profile is achieved by selecting an appropriate number and attitude position line laser sensor, combined with direct calibration method and simple calibration block.
It realizes high-precision measurement of the buckle profile without destroying the floor, avoids damage and time-consuming problems of traditional methods, and improves measurement accuracy and digital processing efficiency.
Smart Images
Figure CN119437079A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of line laser measurement technology and industrial detection, and in particular to a PVC floor buckle type measurement method based on multi-angle line laser. Background Art
[0002] In the production process of PVC flooring, the accuracy of the buckle pattern has a direct impact on the final quality and fit of the floor. The tools used in the production process cut buckles of specific geometric shapes according to the design drawings. However, as the tool is used for a longer time, its cutting effect will change, thus affecting the accuracy of the buckle pattern. Therefore, accurately measuring the buckle pattern and comparing it with the original design drawings is important for evaluating the degree of tool wear and optimizing maintenance cycles.
[0003] Currently, the main method used to measure the buckle type of PVC floor is the slice projection method. After slicing the PVC floor, the surface contour is photographed with a CCD camera and a light source to obtain the buckle type contour of the floor. This method can provide the contour information of the buckle type, but because the floor needs to be sliced, the original floor is damaged and the measurement process is time-consuming, and the degree of digitization is also low. Optical measurement has great research value and significance in the field of quality inspection due to its non-contact, fast, and accurate advantages. Among them, line laser measurement technology has achieved good results in the manufacturing field and industrial inspection field. When measuring contours, line laser sensors are easily affected by the environment, field of view, and posture. Summary of the invention
[0004] In order to solve the above technical problems and shortcomings: how to maintain high-precision button shape measurement without damaging or contacting the base plate, the present invention provides a PVC floor button shape measurement method based on multi-angle line laser.
[0005] In order to achieve the above-mentioned purpose and other related purposes, the present invention adopts the following technical solutions: A method for measuring the buckle type of PVC floor based on multi-angle line laser includes the following steps: Step 1: Select the number n and posture position of the line laser sensor according to the buckle type of the PVC base plate to be measured. The posture position determines the measurement range. The world coordinate system is established according to the posture of the measurement range of the line laser sensor with vertical downward incidence. The origin of the world coordinate system is made to coincide with the origin of the measurement coordinate system to establish a new world coordinate system. Step 2: Based on the direct calibration method, an n-gon calibration block is set and processed to calibrate the multi-angle line laser sensor.
[0006] Preferably, an XY-axis precision displacement slide is installed on each line laser sensor, and the XY-axis precision displacement slide is adjusted to make each line laser sensor in the same straight line.
[0007] Preferably, line laser sensors in different directions scan the n-gonal calibration block, first extract the contour curves scanned by the first n-1 line laser sensors, find the common field of view of the n-1 curves, and use the two end points of the hypotenuse AB of the n-gonal calibration block as marking points. The hypotenuse AB can be regarded as the common field of view scanned by the n-1 line laser sensors, and calculate the rotation matrix and translation matrix of the second to n-1th line laser sensors relative to the first line laser sensor.
[0008] Preferably, for the calibration of the nth line laser sensor, the common area CD of the n-1th line laser sensor and the nth line laser sensor is found, and the scanning profile of the nth line laser sensor is converted to the coordinate system of the n-1th line laser sensor using a formula model, and then converted to the coordinate system where the first line laser sensor is located.
[0009] Preferably, the line laser sensor is an SR8060 line laser measuring instrument, whose working distance is 60 mm and the light source wavelength is 405 nm blue light.
[0010] Preferably, the method further includes step three, scanning the button pattern of the PVC floor with multiple line laser sensors, mapping each scanned contour to a reference coordinate system based on calibration information, using a kd tree to accelerate neighborhood query, and then calculating the mean of each point in its neighborhood, thereby merging repeated or close points into one point to complete the splicing.
[0011] Preferably, the method further includes step 4, analyzing the contour accuracy after multi-angle scanning and stitching, photographing the contour using CCD, extracting the contour using canny edge extraction operator to implement slice projection method, and aligning the scanned contour, CCD contour and CAD standard contour.
[0012] In summary, the invention has at least one of the following beneficial technical effects: In order to solve the problems existing in the traditional methods in the background technology, a method for measuring the contour of the PVC floor buckle type based on non-contact, multi-angle line laser is proposed. This method uses line laser scanning technology to perform real-time contour scanning of the PVC floor without cutting or damaging the floor. In view of the fact that a single line laser cannot perform a comprehensive scan, multiple high-precision line laser measuring instruments are designed to scan the floor buckle type contour from multiple angles. Since different line lasers are installed in different positions, the scanned data is not in the same coordinate system. Therefore, a simple calibration block is designed for calibration to achieve precise splicing of multi-sensor contours, obtain detailed contour information of the floor buckle type, and analyze and compare through digital processing. Compared with traditional methods, this method has higher accuracy and efficiency, and avoids damage to the original floor, providing an efficient tool for quality control in the production process. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 (a) is a diagram of a female buckle type of a PVC floor according to an embodiment of the present invention; Figure 1 (b) is a male button diagram of a PVC floor according to an embodiment of the present invention; Figure 2 This is an example diagram of a detection reference system according to an embodiment of the present invention; Figure 3 It is a world coordinate system pose diagram of an embodiment of the present invention; Figure 4 (a) is a schematic diagram of trapezoidal calibration block acquisition; Figure 4 (b) Dimensional drawing of the trapezoidal calibration block; Figure 5 (a) is the profile before calibration; Figure 5(b) is the contour after calibration; Figure 6 The invalid points are deleted and then the buckle type contour is created. DETAILED DESCRIPTION
[0014] The following is an explanation of the embodiments of the present invention by specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.
[0015] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The illustrations only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.
[0016] The following is combined with Figure 1-6 The specific implementation methods of the present invention are further described. Example
[0017] The present invention discloses a method for measuring the buckle type of a PVC floor based on a multi-angle line laser, comprising the following steps: Step 1: Select the number n and posture position of the line laser sensor according to the buckle type of the PVC base plate to be measured. The posture position determines the measurement range. The world coordinate system is established according to the posture of the measurement range of the line laser sensor with vertical downward incidence. The origin of the world coordinate system is made to coincide with the origin of the measurement coordinate system to establish a new world coordinate system. Step 2: Based on the direct calibration method, an n-gon calibration block is set and processed to calibrate the multi-angle line laser sensor.
[0018] The PVC floor buckle type to be measured in this embodiment is as follows Figure 1 As shown in the figure, at least four line laser sensors are required to fully measure the entire button profile. Figure 2 shown.
[0019] like Figure 3 As shown, let the sensor's measurement coordinate system be O-UV, and let the origin of the world coordinate system be O w Coincident with the origin O of the measurement coordinate system, let X w and Y w Establish the world coordinate system by measuring the U direction and V direction of the coordinate system respectively .
[0020] Calibration principle: In practical application, the mathematical model of geometric imaging will ignore some nonlinear distortion factors such as cameras and lenses, resulting in low calibration accuracy. The direct calibration method does not require the establishment of a geometric imaging model. The intersection of the laser line and the edges of the calibration block is used as the calibration point, and direct calibration is achieved using a calibration model based on binary quintic polynomial fitting. Using a high-precision combined gauge block and a three-dimensional precision displacement platform, direct calibration is achieved by establishing a corresponding relationship between known three-dimensional spatial coordinate points and corresponding image coordinates.
[0021] In this embodiment, a trapezoidal calibration block is designed and processed based on a direct calibration method to calibrate a multi-angle line laser sensor.
[0022] As shown in Figure 4, two standard inclined surfaces are processed so that different line laser scanners can capture the common field of view, and the coordinate system where the contour scanned by laser 1 is located is used as the reference to calibrate other line laser scanners. The measurement accuracy of the line laser scanner is ±0.012mm in the X-axis and ±0.0036mm in the Z-axis direction. Therefore, the processing accuracy of the inclined surface of the calibration block we designed is ±0.002mm, which can meet the calibration accuracy requirements.
[0023] Preferably, an XY-axis precision displacement slide is installed on each line laser sensor, and the XY-axis precision displacement slide is adjusted to make each line laser sensor in the same straight line.
[0024] Preferably, line laser sensors in different directions scan the n-gonal calibration block, first extract the contour curves scanned by the first n-1 line laser sensors, find the common field of view of the n-1 curves, and use the two end points of the hypotenuse AB of the n-gonal calibration block as marking points. The hypotenuse AB can be regarded as the common field of view scanned by the n-1 line laser sensors, and calculate the rotation matrix and translation matrix of the second to n-1th line laser sensors relative to the first line laser sensor.
[0025] Preferably, for the calibration of the nth line laser sensor, the common area CD of the n-1th line laser sensor and the nth line laser sensor is found, and the scanning profile of the nth line laser sensor is converted to the coordinate system of the n-1th line laser sensor using a formula model, and then converted to the coordinate system where the first line laser sensor is located.
[0026] Preferably, the line laser sensor is an SR8060 line laser measuring instrument (scanner, laser), whose working distance is 60 mm and the light source wavelength is 405 nm blue light.
[0027] Calibration process: (1) For the measurement of the button type of PVC floor, we only need the coordinate data in the X and Z directions, so we need to ensure that each line laser hits the same line. We installed an XY axis precision displacement slide on each line laser scanner and adjusted the slide to make the line laser of each scanner on the same straight line.
[0028] (2) The laser measuring instruments in different directions scan the trapezoidal calibration block. Taking Figure 4 as an example, first extract the contour curves scanned by laser 1, laser 2, and laser 3, find the common field of view of the three curves, and use the two end points of the hypotenuse AB of the trapezoidal calibration block as the Mark points. The hypotenuse AB can be regarded as the common field of view scanned by the three groups of sensors. The coordinate system where the laser 1 scans the contour is taken as the reference coordinate system. The transformation of laser 2 and laser 3 to the laser 1 coordinate system includes two processes: rotation and translation. The following transformation relationship can be obtained:
[0029] is the public field of view coordinate of laser 1, is the common field of view coordinate of laser 2, R is the rotation matrix, T is the translation matrix. θ is the rotation angle. Thus, the rotation matrix and translation matrix of laser 2 and laser 3 relative to laser 1 can be obtained respectively.
[0030] (3) For the calibration of laser 4, the common area CD of laser 3 and laser 4 is found, and the laser scanning profile is converted to the coordinate system of laser 3 according to formula (1), and then converted to the coordinate system of laser 1.
[0031] At this point, the calibration of multiple laser scanners can be realized, and the splicing of multi-angle button profiles can be achieved.
[0032] A fourth step may be added to analyze the contour accuracy after multi-angle scanning and stitching, photograph the contour using CCD, extract the contour using the canny edge extraction operator to implement the slice projection method, and align the scanned contour, CCD contour and CAD standard contour.
[0033] The PVC floor buckle type is scanned by multiple line laser measuring instruments, and each scanned contour is mapped to the reference coordinate system based on the calibration information. The contour information before and after calibration is shown in Figure 5. In step three, the PVC floor buckle type is scanned by multiple line laser sensors, and each scanned contour is mapped to the reference coordinate system based on the calibration information. After calibration, the spliced contours have overlapping coordinate data. In order to delete invalid points and overlapping points, the kd tree is used to accelerate the neighborhood query, and then the mean of each point in its neighborhood is calculated, so that repeated or close points are merged into one point to complete the splicing.
[0034]
[0035] t is the distance threshold of adjacent points, idx is the index set of points within the distance threshold t, n is the number of points in the neighborhood, X m and Y m are the means of the X and Y coordinates respectively. After deleting invalid points, the fitted contour is as follows Figure 6 shown.
[0036] The contour accuracy after multi-angle scanning and stitching is analyzed. The button shape photographed by the scanner is sliced at the scanning position, its contour is photographed by CCD, and the canny edge extraction operator is used to extract the contour to implement the slice projection method (existing method, used to compare the accuracy and effect of this solution). The contours of different regions are selected to verify the reconstruction accuracy, and the three contours of the region are resampled respectively so that the sampling points of different curves can correspond one to one. The overall evaluation index is calculated for the scanned contour and the CCD photographed contour respectively, and the evaluation index is shown in the following table.
[0037] Table 1: Evaluation index table.
[0038]
[0039] From the evaluation indexes in the table, it can be seen that the scanning contour accuracy is higher than the CCD contour reconstruction accuracy of the traditional slice projection method.
[0040] In summary, the present invention solves the problems existing in the traditional methods in the background technology and proposes a method for measuring the contour of the PVC floor buckle type based on non-contact, multi-angle line laser. This method uses line laser scanning technology to perform real-time contour scanning of the PVC floor without cutting or damaging the floor. In view of the fact that a single line laser cannot perform a comprehensive scan, multiple high-precision line laser measuring instruments are designed to scan the floor buckle type contour from multiple angles. Since different line lasers are installed in different positions, the scanned data is not in the same coordinate system. Therefore, a simple calibration block is designed for calibration to achieve precise splicing of multi-sensor contours, obtain detailed contour information of the floor buckle type, and analyze and compare through digital processing. Compared with traditional methods, this method has higher accuracy and efficiency, and avoids damage to the original floor, providing an efficient tool for quality control in the production process.
[0041] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, any equivalent changes made to the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for measuring the buckle type of PVC floor based on multi-angle line laser, characterized in that: The steps include: Step 1: Select the number n and posture position of the line laser sensor according to the buckle type of the PVC base plate to be measured. The posture position determines the measurement range. The world coordinate system is established according to the posture of the measurement range of the line laser sensor with vertical downward incidence. The origin of the world coordinate system is made to coincide with the origin of the measurement coordinate system to establish a new world coordinate system. Step 2: Based on the direct calibration method, an n-gon calibration block is set and processed to calibrate the multi-angle line laser sensor.
2. The method for measuring the buckle type of PVC floor based on multi-angle line laser according to claim 1 is characterized in that: An XY-axis precision displacement slide is installed on each line laser sensor, and the XY-axis precision displacement slide is adjusted to make each line laser sensor in the same straight line.
3. The method for measuring the buckle type of PVC floor based on multi-angle line laser according to claim 2 is characterized in that: Line laser sensors in different directions scan the n-gon calibration block. First, extract the contour curves scanned by the first n-1 line laser sensors, find the common field of view of the n-1 curves, and use the two end points of the hypotenuse AB of the n-gon calibration block as marking points. The hypotenuse AB can be regarded as the common field of view scanned by the n-1 line laser sensors. Calculate the rotation matrix and translation matrix of the second to n-1th line laser sensors relative to the first line laser sensor.
4. The method for measuring the buckle type of PVC floor based on multi-angle line laser according to claim 3 is characterized in that: For the calibration of the nth line laser sensor, the common area CD of the n-1th line laser sensor and the nth line laser sensor is found, and the scanning profile of the nth line laser sensor is converted to the coordinate system of the n-1th line laser sensor using a formula model, and then converted to the coordinate system where the first line laser sensor is located.
5. The method for measuring the buckle type of PVC floor based on multi-angle line laser according to claim 1 is characterized in that: The line laser sensor is an SR8060 line laser measuring instrument, whose working distance is 60 mm and the light source wavelength is 405 nm blue light.
6. The method for measuring the buckle type of PVC floor based on multi-angle line laser according to claim 1 is characterized in that: The method also includes step three, using multiple line laser sensors to scan the PVC floor buckle pattern, mapping each scanned contour to the reference coordinate system based on the calibration information, using the kd tree to accelerate the neighborhood query, and then calculating the mean of each point in its neighborhood, so as to merge repeated or close points into one point to complete the splicing.
7. The method for measuring the buckle type of PVC floor based on multi-angle line laser according to claim 6 is characterized in that: The method also includes step 4, analyzing the contour accuracy after multi-angle scanning and stitching, photographing the contour with CCD, extracting the contour with canny edge extraction operator to implement slice projection method, and registering the scanned contour, CCD contour and CAD standard contour.