Theoretical And Applied Study Of Double-exposure Digital Holographic Interferometry

With the development of modern computer technique and higher- resolution image grabber, the digital processing technique for automatic optical fringe patterns analysis, especially phase analysis technique has become one of the most important methods in the optical interferometry and computer-aided optical metrology. In this paper, we apply the Fourier transform method (FTM) of the phase analysis method to double-exposure holographic interferometry and propose double-exposure digital holographic interferometry.In this paper, aimed at the problems existed in theoretical analysis and application of FTM, the discrete Fourier transform method is applied to analyze the traditional FTM (TFTM).and computer simulation is applied. The main propose is to solve the problem, such as frequency shifting, selection of carrier frequency big or small and selection of filter window size. Considering the feature of double-exposure holographic interferometry, we propose a modified FTM (MFTM).In addition, from the point of view of practicality, we make a study of experiment and application for double-exposure digital holographic interferometry, namely measuring Gradn and Grad/i of plane optical flat and measuring phase modulation characteristic of a kind of liquid crystal spatial light modulator (LC-SLM) -liquid crystal television (LCTV). In this paper, we design an optical system for double-exposure digital holographic interferometry. The comparison of the other measured result and experimental result proves the feasibility and validity of double-exposure digital holographic interferometry.