Research Of Three Dimensional Measurement Of Object Based On Laser Holography

The traditional method of deformation measurement of object has short precision because of the measuring instrument itself, and can’t realize measurement of full-field. Laser holography has been used in measuring deformation based on its advantage of non-contact, nondestructive, high-precision, full-field and so on.This paper researched laser holography principle and characteristics deeply. A holographic interference measure system based on EALCD(electrically addressed liquid crystal display) and CCD has been designed in order to realize the measurement of three dimensional deformation of object. And Light path design and adjusting, the key technology, experimental condition analysis and the experimental results demonstration has been studied in this paper.In the experiment, the Fresnel hologram of a metal plate has been recorded by CCD taking the place of traditional holographic recording material. The technology also uses EALCD to realize the reconstruction of hologram in time and get the holographic interferogram caused by deformation. According to the principle of four step phase shifting method and phase unwrapping method, using MATLAB software to compile the program, the three dimensional phase difference map of object deformation can be successfully obtained. Finally, the measurement of three dimensional deformation is realized. The innovation of the paper is showed as follow, because digital phase shifting has been realized, so this method can not only save traditional piezoelectric translator and phase shifting control device, but save the the experiment time. Moreover, the phase shifting error produced by phase shifting control device can be avoided and the precision can be easily reached up to1/10wavelength.