Research on Smooth Surface Defect Identification Method Based on Multispectral Scattering Illumination

ZHU Chengxiang; CHEN Zeqing; GE Aiming

doi:10.3969∕j.issn.1004-440X.2025.03.017

Abstract：With the continuous development of optical technology,the modern optical industry has increasingly high requirements for the surface quality of optical components.The presence of defects such as bubbles,scratches,and broken edges on the surface can cause varying degrees of scattering,seriously affecting imaging quality.At present,the detection of surface defects in precision optical components both domestically and internationally is mostly based on the different scattering characteristics of the defects under different light conditions,such as visual inspection,low-pass filtering imaging,and so on.However,due to the fact that some defects on smooth surfaces exhibit different manifestations under different light irradiation,especially some defects with light intensity and spectral selectivity,in-depth research on different light intensities and spectra irradiated on the tested surface has significant practical significance for precise detection of smooth surfaces.This paper adopts an optical microscopy scattering imaging system,which generates four types of monochromatic scattering light and their combinations through a fiber optic light source,and irradiates the smooth surface of optical components at a specific angle for detection.It illuminates and images opaque,semi transparent,and fully transparent smooth surfaces,adjusts the illumination angle,intensity,monochromatic and multi-color light combination lighting method,enters the optical imaging system,fuses the images collected from multiple spectra,and processes them with a computer to obtain defect information on the surface of optical components.This method can greatly improve the accuracy of defect detection and detection on smooth surfaces,and the feasibility of this detection method has been theoretically and experimentally verified.