Research On Measurement And Parametric Assessment Of The 3D Surface Microcosmic Topography

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-shifting interferometry. Phase-shifting interferometry has been considered as a type of opto-electrical measuring interferometry 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-shifting, sample taking, extracting of phase, data handling.This dissertation, first and foremost, gave the significance of 3D surface topography analysis in a nutshell, when next enunciated the principle of 3D surface topography measurement and the process of the measurement. 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 interferograms, established rational software to collect the image. This article analyzed the processing of method of interferograms,an improved algoritlim is proposed, improved the accuracy of interferometry. The study is concentrated on the key problem of phase-shifting interferometry. Based on the interferograms and phase extracting formula, we can calculate the height of all points, restore the 3D profile. 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, synthetical parameter, space parameter and function parameter. Thinking to the cause of"parameter explosion", gave out 15 parameters for assessment. The entire measurement system used the laser 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.