Research On The Measurement Of 3D Surface Microcosmic Topography Based On White Light Phase Shift Technology

The 3D microcosmic surface topography analysis is an important method of getting the characteristic information on the object surface. In this thesis, the author comprehensively described the research results on the theory and algorithms of phase-stepping interference. Phase-shifting interference has been considered as a type of optic-electrical measuring interference and it has many advantages, such as simple structure, easily modulated, fast and real time, high accuracy and whole field automatic measurement. The measure process include phase-stepping, sample taking, extracting of phase, data handling.This dissertation, first and foremost, gave the significance of 3D surface topography analysis in a nutshell, then explain the principle of 3D surface topography measurement and the process of the measurement. And then build the base level to separate harshness, waviness, form error and the characteristic of surface topography deciding for other parametric, using the theory model of wavelet. Divided the parameter into four kinds, basing on diversity's characteristic property, they are extent parameter, composite parameter, space parameter and function parameter. Thinking to the cause of"parameter explosion", gave out the parameters for assessment. Experiment adopted PZT as driving apparatus and chosen the area that it's characteristic of linearity is better. Based on this area, we designed power supply that drives the PZT and completed the precision phase stepping system, and realized a continuation's Phase. The system required automatic continuous preserve the interference image, established rational software to collect the image. This article analyzed the processing of method of interference image,an improved algorithm is proposed, improved the accuracy of interference. The study is concentrated on the key problem of phase-shifting interference. Based on the interference image and phase extracting formula, we can calculate the height of all points, restore the 3D profile. Then set up the datum of 3D morphology using the fast algorithm of gauss filtering through simulation.The entire measurement system used the white light as the light resource, CCD as the sensor and PZT to provide microscopic translating, the computer sampled image and processed data with high speed. Adopted the theory, the 3D surface topography of standard specimen was carried out. Based on the base level, separated the information of harshness, and then make the rational software to calculate the 3D parameter, using the formula of parameters for valuation. Finally, gave out some results and analysis of the experiment, then the further experiment was conceived.