Search

CN-122015706-A - Data acquisition method and system for three-dimensional laser scanner

CN122015706ACN 122015706 ACN122015706 ACN 122015706ACN-122015706-A

Abstract

The invention provides a data acquisition method and system of a three-dimensional laser scanner, wherein the method comprises the steps of carrying out N p times of contour pre-scanning on a region to be detected (N p is more than or equal to 1, and is set by a user according to the complex condition of the region to be detected), obtaining 2*N p contour lines of the region to be detected according to the pre-scanning result, selecting the longest contour line from 2*N p contour lines as a reference contour line, uniformly dividing the reference contour line according to an expected scanning interval Tol (Tol >0, and is set by the user according to the requirement), calculating an angle theta i of each radial swing of a scanning head, obtaining an angle alpha i,j of each axial rotation of the scanning head through iterative transition interpolation between each contour line and the next contour line under a radial angle theta i , and carrying out laser scanning sequentially according to each radial swing angle theta i and an axial rotation angle alpha i,j under the radial angle. The data acquisition method and system of the three-dimensional laser scanner can obtain uniform and fine data acquisition points which meet the expected scanning interval as much as possible.

Inventors

  • XIAO HOUZAO

Assignees

  • 肖厚藻

Dates

Publication Date
20260512
Application Date
20260414

Claims (5)

  1. 1. A three-dimensional laser scanner data acquisition method-equidistant acquisition method is characterized by comprising the following steps: Performing N p contour pre-scans on the region to be detected (N p is more than or equal to 1, and setting by a user according to the complex condition of the region to be detected); Obtaining contour lines of 2*N p areas to be detected according to a pre-scanning result, and selecting the longest contour line from 2*N p contour lines as a reference contour line; Uniformly dividing the reference contour line according to the expected scanning interval Tol (Tol >0, which is set by a user according to the requirement), thereby calculating the angle theta i of each radial swing of the scanning head; Under the radial angle theta i , the angle alpha i,j of each rotation of the axial direction of the scanning head is obtained through iterative transition interpolation between each contour line and the next contour line; And sequentially carrying out laser scanning according to each radial swing angle theta i and the axial rotation angle alpha i,j under the radial angle to obtain three-dimensional space data points of the region to be detected.
  2. 2. The method according to claim 1, wherein the contour lines of 2*N p regions to be measured are obtained by N p pre-scan results, and the longest contour line is selected from 2*N p contour lines as the reference contour line. The method comprises the steps of intersecting N p pre-scanning results with an initial azimuth line at the same point, dividing each scanning result into two parts through the intersection point, obtaining 2*N p contour lines of an area to be detected, calculating the length of 2*N p contour lines, selecting the longest contour line from the calculated length of 2*N p contour lines as a reference contour line, numbering the reference contour line as 1, numbering the rest contour lines as 2,3 according to the anticlockwise direction, and defining the next contour line of the 2*N p th contour line as the reference contour line, wherein the N p pre-scanning results are intersected with the initial azimuth line at the same point, and dividing each scanning result into two parts through the intersection point.
  3. 3. A method according to claim 1, characterized in that the reference contour line is equally divided (Tol >0, set by the user according to the need) at the desired scanning interval Tol, whereby the angle θ i of each radial swing of the scanning head is calculated. Wherein, the angle theta i of each radial swing of the scanning head is calculated as follows: θ i =Θ i -Θ i-1 =arcsin(R n,i /S n,i )-arcsin(R n,i-1 /S n,i-1 ) Wherein Θ i is the included angle between the ray emitted after the ith radial swing of the scanning head and the initial azimuth line (i is not less than 1, Θ 0 =0）;R n,i is the vertical distance from the intersection point of the ray emitted after the ith radial swing of the scanning head and the reference contour line to the initial azimuth line (n=1, indicating that the ray emitted by the scanning head intersects the reference contour line), and S n,i is the distance from the intersection point of the ray emitted after the ith radial swing of the scanning head and the reference contour line to the laser scanning head (n=1, indicating that the ray emitted by the scanning head intersects the reference contour line).
  4. 4. The method of claim 1, wherein the angle α i,j for each axial rotation of the scanner head is obtained by iterative transitional interpolation between each contour and the next contour at a radial angle θ i . Wherein the angle α i,j of each rotation of the scanning head in the axial direction is calculated as follows: α i,j =Tol×360/(2π×r n,i,m ) Wherein Tol is the expected scanning interval, R n,i is the vertical distance from the intersection point of the ray emitted by the ith radial swing of the scanning head and the reference contour line to the initial azimuth line (n is more than or equal to 1, which indicates that the ray emitted by the scanning head intersects with the nth contour line), and R n,i,m is the distance value (n is more than or equal to 1, which indicates that the ray emitted by the scanning head intersects with the nth contour line) obtained by the m-th iterative transition interpolation between R n,i and R n+1,i .
  5. 5. A three-dimensional laser scanner data acquisition system, comprising: an information setting unit for setting spatial orientation information of the scanning head, including an azimuth angle and an inclination angle at the time of the spatial coordinates and the initial position of the scanning head, and a radial range of the scanning head; the pre-scanning unit is used for facilitating a user to set a pre-scanning scheme according to the complex condition of the area to be detected; A selecting unit, configured to obtain 2*N p contour lines of the area to be measured according to the pre-scanning result, and select the longest contour line from 2*N p contour lines as a reference contour line; The calculating unit is used for calculating each radial swing angle theta i and the axial rotation angle alpha i,j under the radial angle; and the equidistant scanning unit is used for sequentially carrying out laser scanning according to each radial swing angle theta i and the axial rotation angle alpha i,j under the radial angle to obtain three-dimensional space data points of the region to be detected.

Description

Data acquisition method and system for three-dimensional laser scanner Technical Field The invention relates to the field of laser scanning, in particular to a data acquisition method and system of a three-dimensional laser scanner. Background The three-dimensional laser scanner is a novel three-dimensional coordinate measuring instrument integrating various high and new technologies, adopts a non-contact high-speed laser measuring mode, acquires three-dimensional data of an array geometric figure on the surface of a measured object in a point cloud mode, has developed and matured the basic principle of laser ranging, ensures the accuracy and the effectiveness of data acquisition, is worth discussing, the traditional data acquisition method, namely an equiangular acquisition method, is characterized in that the radial swing and the axial rotation of a scanning head are respectively controlled through two stepping motors, the scanning head uniformly and axially rotates under a preset radial angle, one point data is acquired every time the scanning head rotates (usually is a fixed value between 0.5 and 3 degrees), the scanning head automatically swings (usually is a fixed value between 1 and 5 degrees) after one circle of scanning is completed, and the scanning of the next circle is continued until the scanning process is completely ended. The result of this data acquisition method, in which the angle per radial swing and the angle per axial rotation are fixed values, is that the near data acquisition is too dense and the far data acquisition is too sparse. The principle of the method is shown in fig. 3, and the method plays a certain role in the refinement and uniformity of data acquisition, but the method requires continuous back and forth operation of a stepping motor for controlling radial swing and a stepping motor for controlling axial rotation, and meanwhile, the contour shown in the figure does not exist in practice, so that the method has great blindness. The method not only greatly reduces the data acquisition efficiency, but also has serious damage to instruments, and cannot meet the actual requirements. No research on a data acquisition method of a three-dimensional laser scanner is available abroad, so that a high-efficiency and practical data acquisition method of the three-dimensional laser scanner is urgently needed. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a data acquisition method and a system of a three-dimensional laser scanner, which can obtain uniform and fine data acquisition points meeting the expected scanning interval as much as possible. In order to achieve the above purpose, the present invention is realized by the following technical scheme: in a first aspect, the present invention provides a data acquisition method of a three-dimensional laser scanner, i.e. an equidistant acquisition method, comprising: Performing N p contour pre-scans on the region to be detected (N p is more than or equal to 1, and setting by a user according to the complex condition of the region to be detected); Obtaining contour lines of 2*N p areas to be detected according to a pre-scanning result, and selecting the longest contour line from 2*N p contour lines as a reference contour line; Uniformly dividing the reference contour line according to the expected scanning interval Tol (Tol >0, which is set by a user according to the requirement), thereby calculating the angle theta i of each radial swing of the scanning head; Under the radial angle theta i, the angle alpha i,j of each rotation of the axial direction of the scanning head is obtained through iterative transition interpolation between each contour line and the next contour line; And sequentially carrying out laser scanning according to each radial swing angle theta i and the axial rotation angle alpha i,j under the radial angle to obtain three-dimensional space data points of the region to be detected. The reference contour line is uniformly divided according to the expected scanning interval Tol (Tol >0, set by a user according to the requirement), so that the angle theta i of each radial swing of the scanning head is calculated. The angle θ i of each radial swing of the scanning head is calculated as follows: θi=Θi-Θi-1=arcsin(Rn,i/Sn,i)-arcsin(Rn,i-1/Sn,i-1) Wherein Θ i is the included angle between the ray emitted after the ith radial swing of the scanning head and the initial azimuth line (i is not less than 1, Θ 0=0）;Rn,i is the vertical distance from the intersection point of the ray emitted after the ith radial swing of the scanning head and the reference contour line to the initial azimuth line (n=1, indicating that the ray emitted by the scanning head intersects the reference contour line), and S n,i is the distance from the intersection point of the ray emitted after the ith radial swing of the scanning head and the reference contour line to the laser scanning head (n=1, indicating that th