An Engineering Measurement Method For The 3-Dimensional Object Surface With FTP

The application of 3D object surface measurement is more and more important in the domain of industrial inspection, quality controlling, machine vision, CAD/CAM, and medical science, etc. And because of its high precision, nondestructive feature and also fastness of data acquisition, the method of non-contact optical measurement becomes very popular. Based on the method of engineering measurement of 3D object surface, this dissertation studies the theories and applications of FTP. It consists of the following contents:The mathematical model of each phase measurement method is analyzed. The relationship between the phase and the height is introduced. At the same time, the theory and process of engineering measurement is studied.The problems that should be resolved in the engineering measurement of FTP are presented, such as calibration, phase unwrapping, and image connection etc. And a new calibration method for 3D machine vision, which combines height calibration with position calibration, is expounded.After the algorithms of phase unwrapping is studied, a new phase unwrapping method with flexible marking points is proposed. Thus, the effects of noise, height mutation and also shadow can be avoided. On the basis of the study of edge detection algorithms, a zone binary method is presented.The preprocessing methods of grating image are studied, and the 3D object surface data is reconstructed. Meanwhile, the theory of image connection and the connection method of the front and hind image data are analyzed and probed.A measurement system that consists of LCD, CCD, and image card is designed, it can project and obtain grating image simultaneously. At the same time, a software system that integrates the function of system adjusting, system calibration, image processing and also image analyzing is developed with Visual C++ 6.0. At the end of the dissertation, some experiments are carried out to apply FTP to the measurement of human body's sizes.Theoretical analysis and practical measurement prove the availability of all of the methods and algorithms, and an improvement scheme is proposed.