Research On Data Capture And Processing Method Of Optics Interferogram

The paper focuses on optical components detection based on interference pattern. It summarizes the detection technology of modern optics in detail. The commonly used methods can be divided into two types of probe measurement and optical measurement. Optical measurement method generally includes the phase-shifting method and the method based on carrier. Based on the theory of phase-shifting interferometry, the principle of measurement and the structure of phase-shifting system are introduced in this paper. The system called phase-shifting digital wavefront interferometer, Interferometer, phase shift system, image acquisition system, data processing and control system make up of the whole measurement system. Phase-shifting methods and equipments, such as diffraction grating, polarizer and piezoelectric transducer, are present concisely. Image acquisition system is built with DSP hardware as the core to capture several fringe patterns with different phases. In order to ensure the continuity of the phase field, it requires effective regional template to select effective area of interferogram, and image denosing is essential to improve the measurement accuracy. The paper analysis the theory of different phase-shifting algorithm, and proves the insensitivity of five-step phase-shifting algorithm to system error. It studies the mathematic model of phase unwrapping and expounds the unwrapping principle of Branch-cut method, Quality-guide method and the Least Squares Method. At last, a new phase unwrapping method based on edge extraction is proposed to promote the development of phase-shifting digital wavefront interferometer.