Accuracy improvement of 3D measurement using digital fringe projection

Because of the increased social interest on 3D graphics, a 3D acquisition system based on Digital Fringe Pattern Profilometry (DFPP) technique is increasingly popular. This technique is widely applied in various areas, such as archaeology, mechanical engineering, and social security. This thesis describes the research project on 3D surface reconstruction based on DFPP technique. The prime objective of the project is to develop a DFPP system and improve the system accuracy performance. We start the project from a comprehensive literature review of DFPP technique. Based on the review, three tasks are planned and completed in this project. The first task is to establish a DFPP system. The system establishmentis based on Phase Shifting Profilometry (PSP) algorithm. This system is able to reconstruct 3D profiles of complex targets with details, but the accuracy is not high. To improve the system accuracy, the other two task is conducted. In task 2, we calibrate the 3D acquisition system. We design a self-calibration procedure for the DFPP system based on a specific analysis of the optical geometry. System parameters are precisely determined by this method. In task 3, gamma correction of the system are conducted. Because of the non-linear response of the digital projector, the DFPP system suffers from gamma distortions. To correct the nonlinear errors in the DFPP system, we propose a gamma correction method, which is referred as Inverse Function Gamma Alleviation (IFGA). The 3D surfaces reconstructed by IFGA is free of gamma distortion. During the project, experiments are conducted, and results show significant accuracy improvement of our work. Finally, we conclude the thesis and the future works.