The Research Based On Projected Fringes For Precisely Measurement Of 3-D Shape

Optical 3-D profilometry has been widely used for machine vision, intelligent robots control, industry monitoring, biomedicine, etc. Several methods of those, such as moire technique, Phase Measuring Profilometry (PMP), Fourier Transformation Profilometry (FTP) have been exhaustively studied these years. Beacause of its higher accuracy, Phase Measuring Profilometry is one of the most important methods. There are several hot issues in the PMP research: unwrapping the phase reliably and calibrating the system accurately. My dissertation focuses on these two issues, and the major work done can be summarized as follows:1. A method that use double spacial frequency fringes to unwrap the phase full automaticlly has been deduced. This method, by using the moire characters of the two fringes, can easily acquire the actual phase from the main-value phase which is obtained by phase-shifting method.2. A method that employs the orders of projected fringes as axises to establish fringe-order-coordinate is presented. It makes the description of the fringe orders very direct and simple. In the fringe-order-coordinate, Bayes estimation method is used to amend the phase(or fringe orders), and a good result is obtained.3. A method that is used to amend the phase of reference plane (or calibration plane) has been put forward. With the phase worked out by phase-shifting method and unwrapping method, it is very easy to get the relationship between the position and phase of a point, which can be used to amend the phase of reference plane (or calibration plane). After the amending, the phase error can be largely reduced.4. A new calibration method has been used to get higher accuracy. This method is different from general calibration methods which always get the actual physical parameters of system. Howener, the combination of these parameters is calibrated in our method, which is convenient and has better accuracy.5. A method that is used to creat simulational images has been developed. In this method, a good many of factors which may influence the image, such as reflectivity and projection angle, have been discussed.