White light interference micro-profile restoration method based on cross-correlation computation

Abstract

The invention discloses a white light interference micro-profile restoration method based on cross-correlation computation. The method comprises the following steps of reading a group of white light interference fringe images and system parameters, wherein the system parameters include center wavelength, spectrum width and scanning step length; for any one pixel point on the surface of a sample to be tested, the gray scale value change sequence of the pixel point in the group of white light interference images is taken and is recorded as a signal to be tested; then, a reference signal is generated according to system parameters and white light interference principles; a correlation function of the signal to be tested and the reference signal is determined; the obtained correlation function is subjected to peak detection to obtain the delay quantity of the signal to be tested and the reference signal; the delay quantity and the scanning step length are multiplied to obtain the relative height between the signal to be tested and the reference signal; further, the relative height of each pixel point is determined; the micro-profile of the surface of a sample to be tested is obtained through restoration. The white light interference micro-profile restoration method has the characteristics that the principle is single; the detection precision is high; the anti-noising capability is high, and the like.

Description

technical field [0001] The invention belongs to the technical field of microscopic shape detection, in particular to a white light interference microscopic contour restoration method based on cross-correlation calculation. Background technique [0002] In the detection process of the early white light interference microscope, from reading, calculation, measurement to parameter evaluation, all rely heavily on manual operation, and the efficiency is very low. In the 1970s, the combination of white light interferometry and the rapidly developing phase shift technology made it one of the main methods for surface precision inspection. In 1980, based on the measurement principle of phase shift technology and the principle of white light interference, Balasubramanian proposed an automatic microscopic three-dimensional profile detection system. In the white light vertical scanning interferometry technique, the positioning information of the zero optical path difference indicates th...

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Problems solved by technology

However, the above method still has the problems of poor anti-noise ability and high requirements for the detection environment.

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