Image Processing And Software Developing Of Grating Projection

Three-dimensional shape measurement of object surface is now widely applied in different areas, such as reverse engineering, computer vision, online product inspection and medical diagnosis. A new method was proposed to detect the grating fringe center. After obtaining the displacement of the fringe centerline, three dimensional shape of object is reconstructed with interpolation. The accuracy and error of Fourier Transform Profilometry(FTP) is analyzed by simulation. The spreading technology is applied to improve the accuracy of the FTP. Finally, The system of three-dimensional shape is developed based on the library which the Matrox Graphics Company provide on the VC++ 6.0 platform. The main contributions of this dissertation as follows:This paper presents a new method of acquiring the centerline of grating to measure the three-dimensional shape of object. A sinusoidal grating is projected onto reference surface and object surface. The depth information of the object is encoded into a deformed fringe pattern recorded by an image acquisition sensor. After obtaining the displacement of the fringe centerline, the height of the object can be calculated, and the shape of object can be reconstructed with the interpolation. The experimental results indicate that shape measuring method based on acquiring the fringe centerline is simplicity, effectiveness, and reliability. The accuracy can be effectively improved with interpolation.The method of simulating three-dimensional shape measurement with computer was proposed, and the shape of object can be reconstructed by FTP technique. Comparing with the theoretical simulation and experimental results, the accuracy and error are analyzed. It is found that the FTP technique can be used to detect the deformation for highway from analysis of the simulation results.Separating the zero component and basic component frequency is a key to the FTP technique. Studies on different kinds of spreading techniques affect the accuracy of FTP by simulation .These results indicate that background spreading technique effectively improve the accuracy of FTP.A system was designed to measuring the three-dimensional shape of object. On the aspect of hardware design, simply introduce the constitution of the system. On the other hand, Programming the procedure about regular image processing algorithm, PSM and FTP technique with the library which the Matrox Graphics company provide on the VC++ 6.0 platform.