Three-dimensional measurement method for microstructure based on optical microscope and variable illumination

Abstract

The invention discloses a three-dimensional measurement method for a microstructure based on an optical microscope and variable illumination. According to the method, a three-dimensional morphology of the surface of the microstructure is re-established according to multiple microscopic images shot by the optical microscope in different illumination directions of a fixed viewpoint. The process comprises the following steps: firstly, obtaining a surface albedo and a normal direction with GBR (guaranteed bit rate) ambiguity by adopting a UPS (ultraviolet photoelectron spectroscopy) method and surface integrable restrain; then obtaining the surface albedo or the normal direction without ambiguity based on a GBR disambiguity method with minimum entropy; in order to reduce the influence of noise, further optimizing the normal direction of the surface by utilizing a graph cutting method in a model of a Markov random field; and finally, re-establishing the three-dimensional morphology of the surface of the microstructure by adopting an integration method according to the normal direction of the surface.

Description

technical field [0001] The invention belongs to the field of precision measurement, and in particular relates to a three-dimensional measurement method for microscopic appearance based on an optical microscope and changing illumination. The present invention refers to the proposed method as the MPS method. Background technique [0002] Three-dimensional measurement of microscopic shape is a very important research field. At present, research institutions and enterprises at home and abroad have developed three-dimensional shape measurement equipment with various principles, such as confocal microscopy, white light interference, etc., which are widely used. instrument (white-light interferometry), microscopic grating projection (microscopic fringe projection) and microscopic stereo vision (light microscope stereo vision), etc. Among them, focusing microscopes and white light interferometers can measure three-dimensional data at the nanometer scale; while microscopic grating p...

AI Technical Summary

Problems solved by technology

[0005] Existing methods cannot be directly applied to MPS, because in MPS, when the light source moves arbitrarily, the light intensity of multiple microscopic images captured by the microscope changes significantly, and the image noise is very serious

The former phenomenon makes the assumption of uniform light source intensity unusable; the latter phenomenon makes complex non-Lambertian reflection models introduce serious numerical errors

Therefore, existing GBR disambiguation methods relying on light source intensity constraints or non-Lambertian models are not suitable for MPS

Images