Structured light micro-nano three-dimensional shape measurement method based on focused evaluation algorithm

Abstract

The invention relates to a structured light micro-nano three-dimensional shape measurement method based on a focused evaluation algorithm. The traditional three-dimensional measurement method based ona focusing evaluation function has the characteristics of simple measurement system and no damage but hardly can measure an object having a smooth surface structure and insufficient textures due to the essence of judging a focus level according to texture information of the object. The invention provides a three-dimensional shape profilometry combining structured light illumination and the focusing evaluation function, and measurement on an object with a smooth surface and a rough surface coexisting can be realized. In a measurement system, a pattern produced by a DMD is projected to the surface of an object, the object is longitudinally scanned and a to-be-processed picture is obtained, for one pixel point, a fuzzy-to-clear and clear-to-fuzzy process is shown in an image sequence, wherein the focused evaluation algorithm is used for determining a picture position where imaging of the pixel point is the clearest, then a curve fitting algorithm is combined for extracting a precise focusing position, and all the pixel points are traversed, so that a three-dimensional shape of the object can be obtained.

Description

technical field [0001] The invention belongs to the technical field of optical measurement engineering, and in particular relates to a structured light micro-nano three-dimensional shape measurement method based on a focus evaluation algorithm. Background technique [0002] In recent years, under the rapid development and strong promotion of emerging technologies, the technology in the field of micro-nano structure has been continuously developed and improved, such as the manufacture of micro-structures such as micro-electro-mechanical systems and micro-optical components, and research directions such as cell observation in the biological field. The requirements for high precision and high reliability of shape measurement are increasing day by day. The surface topography of an object not only affects the mechanical and physical properties of contact parts, but also affects the properties of non-contact surfaces, such as the reflection of optical devices and so on. The measu...

AI Technical Summary

Problems solved by technology

Among them, the laser confocal method uses point detectors to measure objects point by point, which has high precision but low efficiency.

White light interferometry uses the principle of short coherence length of white light to measure objects. It has high precision and fast speed, but it cannot measure objects that slow down and change drastically.

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