Research On Differential Profilometry Technology

3D shape measurement has an excellent prospect in the areas of industrial production, live entertainment, medical research, defense security and so on, such as the dynamic measurement on-line of product quality, film and television animation, medical repair surgery, face recognition etc. Due to the advantages of one pattern needed and full field analysis, Fourier Transform Profilometry (FTP) is becoming one of the key technology in the field of 3D shape measurement.Based on FTP, the differential algorithm can reconstruct the continuous phase without an unwrapping step. It offers broad application prospects for 3D shape measurement. While in practice, the differential algorithm still has some problems to solve, such as:while the deformation fringes and the axes are in different directions, errors are easily introduced; the spatial domain algorithm to computer the phase partial differentiation is very complex and the elapsed time is very long. To enlarge the applicable area, improve accuracy and accelerate speed, further theory and experiment study is carried out on the differential algorithm.The main research contents are as follows:1> The background and basic theories of 3D shape measurement are introduced. The orthogonal fringes differential algorithm and the single fringe differential algorithm are analyzed and verified. Some weaknesses are found by experiments. This part is the premises and theory basis for the research.2> The rotation property of Discrete Fourier Transform is used to expand the applied range of differential algorithms. When the fringes and the coordinate axes are in different directions, the errors and the way to calculate the angle deviation are analyzed. It is studied and verified to eliminate the errors by the rotation property of Discrete Fourier Transform.3> The Fourier differentiation property is used to improve the orthogonal fringes differential algorithm and the single fringe differential algorithm. It is studied and verified to simplify the differential processes and decrease the computing complexities in differential algorithms by the Fourier differentiation property.4> 3D shape measurement software is developed to realize the module functions.