Research On The Refractive Index Measurement Technology Of Germanium Materials Based On Sub-pixel Analysis

Germanium is a kind of important material of infrared optical system,its optical index is the basic input parameters for design For high quality infrared imaging optical system,the precise parameters of refractive index must be controlled,so the refractive index of germanium materials research possess practical significance.Currently testing germanium material that most of people use lock signal amplification processing method,the measurement process more cumbersome,not intuitive to the human eye,affecting the measurement accuracy and efficiency.In this paper,arbitrary deflection angle of the basic measurement methods,we propose a visualization,a quick test of the program,combined with the image processing method of sub-pixel analysis to improve the system of positioning accuracy,and on the basis of analysis of the environmental conditions of the test results influences.Firstly,the refractive index of the principles of germanium in the classic test measurements were analyzed to compare the advantage and disadvantage among various methods,based on the design of the overall program measurement system scheme,and according to the project specifications are given for each composition the working principle and indicators,specially analyzes the key indicators and measurement accuracy precision angle measuring system;Then use the VC++6.0 complete data acquisition system software development work,making the whole system measurements convenient and fast.In precision index measurement system based on the requirements with the use of sub-pixel analysis algorithms to improve the accuracy of the measurement system.Robert detection,Sobel detection edge analyzed and improved detection Sobel-edge analyzed,improving image location accuracy.Then the polynomial interpolation algorithm is improved to improve the algorithm of the systemimage adaptive capacity,resulting in an image detection accuracy of 0.1 pixels.Analysis of the environmental conditions for test results.Finally,using the developed measurement system to measure the refractive index of germanium in three spectral wave period,according to the test report of 205 research institution,the use of standard deviation of experimental data,obtained that the whole system reaches 2×10^-4with the refractive index measurement accuracy.