Digital Simulation Study On Shadow Moiré Profilometry And Phase-stepping Interferometric Holo-Photoelasticity

Photo-optical measurement methods for digital profile reconstruction (digital photo-optical measurement profilometry) belong to a new developing subject domain. Combining contemporary digital image processing techniques with photo-optical measurement methods, many scientists make great efforts to develop a new field which includes profile reconstruction of macro- and micro-objects, optical interferometric fringes reconstruction, stress and strain reconstruction. In this paper, there are only two prosperous and focus methods in the field to be involved, the one is the digital shadow moire profilometry for profile reconstruction of objects, and the other' is the digital phase-stepping interferometric holo-photoelasticity for isopachic phase acquisition. Their simulation principals, techniques and auto-measuring and processing systems are discussed in detail.Point-illumination and point-receiving arrangements with different optical parameters are common adopted optical arrangements in the application of shadow moire profilometry for profile reconstruction. However, phase-shifting values in the arrangements are approximate and different from optical arrangements. Accordingly, an uncertain initial system error appears in the measuring system of shadow moire profilometry and makes it difficult to get reliable results in error analysis procedures. Therefore, in order to have the ability of comparisons of different reconstructive results and applications, it is important to have an accuracy and economic method, which is able to analyze, examine and appraise the rule of the initial system error for providing reliable references and control guides to design engineers and researchers. By general consensus, using digital simulation is a feasible method for achieving those prospective targets.Due to the above reasons, in the paper, a digital simulation method based on the shadow virtual moire principle is introduced to shadow moire profilometry, about which we have not found any reports yet. An auto-measuring and processing experimental system and digital simulated profile shadow moire profilometry are proposed. Relative software is developed with Matlab? program. High quality moire fringe patterns in different arrangements are obtained by the simulation software, including parallel-illumination and parallel-receiving standard arrangement, under which accuracy values can be provided, and point-illumination and point-receiving nonstandard arrangements with different optical parameters. Experimental results reveal that the proposed method and its experimental system are correct and feasible.