Non-contact high-precision defect detection and 3D reconstruction of object surface
Aimed at the requirement of non-contact and high-precision detection on the surface of optical devices, a set of geometric precision measurement system was constructed by using the principle of spectral confocal to realize flaw detection and 3D reconstruction on the surface of optical devices such as microscope lens and so on.A set of 3D scanning system of object surface was constructed combined with high-precision displacement platform to analyze structure and principle of system after introducing the measurement principle of spectral confocal displacement sensor. A self-adaptive method based on dichotomy was adopted to control sampling rate of system for the problem of inaccurate reading of spectral confocal displacement sensor caused by sampling rate, and overall measurement error of system was analyzed by repeated measurement of the same standard measured mass. Finally, high-precision measurement on the surface of microscope lens was realized. Experimental result shows that the method realizes micro-grade measurement of transparent surfaces, and still has better measurement result in the edges with larger surface gradient change. Maximum error of measurement is 0.624 μm, average error is 0.167 μm and uncertainty of measurement is 0.633 μm.Analysis of morphology and size can be realized for micro defects existing on the surface of lens and accurate 3D model on the surface of lens to be detected can be obtained.