Abstract: To enhance the image quality of the measuring system based on visual imaging,by analyzing the imaging devices and lighting of the light source spectral imaging system,and matching characteristics of the aberration characteristics,this paper studies the influence on image quality of the spectrum of the lighting system.No-reference image quality evaluation methods,such as constrast signal noise ratio(CSNR) and Tenengrad function,are introduced to analyze the ability of image contrast and clarity under different spectrum lightings.Based on this condition,spectrum optimization principle for imaging,measurement and lighting system is obtained.According to this theory,a spectrum lighting comparison experiment including the monochromatic and the polychromatic light in the same illumination was carried out.The index of quality evaluation of digital image contrast and definition from different spectrum conditions was made by the suggested evaluation function.Result shows that the image quality index of contrast and definition under polychromatic light are inferior to that by using pure spectrum lighting,which is near to the peak wavelength of CCD spectral response function in the experiment.Therefore,it give us an optimization guide for the spectral characteristics when we choose the lighting source system in designing a system based on vision.