Study Of Laser Interference Surface Texture Measuring System And 3D-MOTIF Evaluatin Method

Engineering surface texture Measurement and evaluation is a hot researching area in metrology today. After summarize the development history of surface texture measurement and evaluation methods, this thesis narrates some achievements in the measurement and evaluation of engineering surface texture systematically.Based on remarkable improvements on the traditional Form Talysurf optical profiler, a long range, high precision measuring instrument needed for measurements of engineering surface texture is developed. Its main improvements and innovations are as follows:(1) By changing the moving tip measurement style into the moving work-table measurement style, this thesis solves the problem of unstable in measuring stage consist in the original system;(2) By using the absolute zero position combined with a look-up table method, this thesis eliminates the systematic nonlinear error in the original system; make the HST optical profiler developed by this thesis having the characteristic of long range and high precision;(3) By using the common base level two dimensional work-table, this thesis solves the problem of less of a two dimensional measuring datum plane in the original system;(4) This thesis develops a grading subdivision interference pattern receiver based on CCD, and proposes a method using the Fourier power spectrum to determine the initial phase of the interference pattern received by the CCD.This thesis designs and implements the HST optical profiler used in engineering surface texture measurements, realizes the high precision measurements of engineering surface texture. Its vertical measuring range is 10mm, and its vertical resolution is 0.01μm. The working range of the two dimensional work-table is 40mm×40mm, the minimum moving step is 0.5μm. This profiler can satisfy most of the measuring requirements of the engineering surfaces today, the structure is simple, and its cost is low.This thesis also studies two of the key problems of two dimensional MOTIF evaluation algorithm. (1) Based on the structure of single link list, a full and high performance MOTIF combination algorithm is implemented; (2) Based on the traditional MOTIF evaluation method, a MOTIF filter is proposed. According to the common M-system filter, MOTIF filter is a non-phase shift, robust, adaptive and optimal filter.This thesis proposes a completed three dimensional MOTIF evaluation system, presents the definitions of three dimensional MOTIF and its associated parameters, describes the three dimensional MOTIF combination method in detail, and demonstrates the results with some examples. The three dimensional MOTIF evaluation system proposed by this thesis solves some problems existed in current three dimensional MOTIF evolution systems, provides a new method to evaluate three dimensional surface.