Study On Improving The Precision Of FTP Based On DLP Projector

With the development of science & technology and the need of industrial production, people hopes to get the 3-D shape information of some objects in many fields, such as machine vision, industry monitoring, real object visualization, biomedicine etc. Therefore, developing rapid, higher-precision and non-contact 3-D shape measurement methods becomes one of the most popular research fields. FTP based on fringe projection is a fundamental 3-D sensing method, including following merits: only one fringe needed, full field analysis, and high resolution. Meanwhile, the rapid development of computer hardware & software technique, the advent of Digital Light Processor(DLP) and the high resolution Charge Coupled Device(CCD), and the extensive application of the technique of digital image processing make FTP became one of the most important and popular methods and take more and more researchers' attention. Because Fourier transform profilometry involved the operation of Fourier transformation and filtering, the problems about frequency aliasing, phase unwrapping and measurement precision are needed study further.In this paper, we extensively research FTP based on digital light projecting. The main work is listed as follows:Digital Light Processor(DLP) is used as projecting device in FTP, which brings great flexibility. However, the gamma nonlinearity of DLP introduces specific higher-order harmonics, which perhaps leads to appearance of spectrum aliasing and decrease the accuracy of measurement. A gamma-correction method is proposed based on statistical analysis of fringe pattern's intensity to calculate the gamma...