Study On Error Analysis And Calibration Technology Of Three-Dimensional Laser Scanner System

The Three-Dimensional Laser Scanning Technique owned effective method of obtaining space data, and has a more and more important effect on a number of fields due to its quickness, precision and measure without contact. With the three-dimensional laser scanning technique widely used in scientific research field, industrial production field and other fields, people put forward higher request about the measuring accuracy. In view of this situation, this paper took the laboratory's SEREIN three-dimensional laser scanner as the research object, studied on a number of key issues, such as error model, obtaining and processing point-cloud data, and calibration technology.(1) The factors of measuring accuracy which influence the three-dimensional laser scanning system has been discussed deeply in the thesis. According to establish the three-dimensional laser scanner's coordinate systems and based on the homogeneous coordinate transformation theory, the relational matrix and all of the erroneous expression about the work table and the CCD measurement's pose are deduced. At last, the error model of the three dimensional laser scanner was established.(2) The point cloud data which obtained by the three-dimensional laser scanner includes massive mixed spots and the noise will bring a lot of trouble for our later processing and application. The paper has completed the spot cloud data's pretreatment by using IMAGEWARE (reverse-engineering software) and MATLAB (programming simulation software). For the first, the ASC documents which contained the message of cloud data were inducted in the environment of IMAGEWARE, and then we uses the semiautomatic processing method to reject the obvious mixed spots. Considering the density portion, the spot cloud data was reduced by the MATLAB procedure. In order to filter noise in the point cloud data, this paper chooses wavelet which is good at filtering to filter the noise.(3) Presently, through research on calibration technique to better the measurement precision of the three-dimensional laser scanner is one of the main research direction. Through reference massive literature material which related the calibration technique, we designed 11*11 dimensions calibration plate which is composed of standard steel balls arid standard orifice plate to calibration. At same time, in order to improve the precision of calibration, the paper use the ultra precision instrument to measure the center distance of round holes of the calibration orifice plate. And in the later calibration process we take this as the standard. According to computation mentality, the paper use genetic algorithm to optimize the point cloud data which has been pretreated. As a result, we obtained the most superior center coordinate of the standard steel balls. Finally, through compare with the standard distances and the optimal distances between the neighboring balls, we obtained the error of the three-dimensional laser scanner. The paper has completed the calibration of the SEREIN three- dimensional laser scanner's 11 positions, and has given the scope of measuring error. It has certain reference functions to study the measuring error and the calibration technique of three-dimensional scanner system.