A Measurement System For The 3-Dimensional Object Surface Based On The Fast Calibrating Method

Based on the study of the 3-D FTP(Fourier Transform Profilometry), this thesis presents a new engineering calibration method and a new phase-unwrapping method. And then a practical measurement system of 3-D object surfaces has been developed.The study includes the following contents:1. Comparing with other methods, FTP is much easier in the data processing and easy to make up a system, so this thesis analyzes some problems, which may be met during the measuring course, and then shows how to solve those problems.2. System calibration is a key part of the FTP measurement. In this article, after analyzing the measurement system structure, it designs a new system, which is much easier in adjusting, and then it presents a height-calibrating method, which is practical in the engineering measurement. In the height-calibrating method, after the calibration board is moved twice, the calibration matrix can be got from the relationship between the phase and the height of the calibration board. And this method is proved utilitarian in getting the real shape of the object quickly.3. In the traditional unwrapping methods, unwrapping is often failed when there are noises in the images. In this article, a new unwrapping method is presented, which can get the real phase of the image and overcome the influence of the noises.4. After the measurement system solves the difference of phase through FTP and makes the data multiply with the calibration matrix, the real height of the object surface can be got. Then this thesis realizes how to reconstruct the height data of 3-D object surface.5. This thesis has designed a hardware structure and developed a software system by Visual C++ 6.0.6. This article also analyzes the problems of the FTP applied to the measurement of large area and then gives two examples of the experiment.