Automated Visual Inspection (AVI) capability has become an important key component in the automated manufacturing system. In such a visual inspection system an intensity image of a scene is quickly affected by optical property of objects, condition and roughness of surface, lens and filters, image sensor property and lighting system. In particular, the lighting system design is the most important factor ,since it affects overall performance of the visual system. In this paper, the lighting subsystem of AVI system is analyzed for the inspection of PCB patterns. The reflection property is theoretically obtained by a reflection model and also obtained by experiments which measure intensity with varying the viewing direction of image sensor and the lighting direction of illuminator. The illumination uniformity of a ring-type illuminator is measured with varying the diameter of illuminator and the distance between object and illuminator. The lighting systems designed based upon the experimental results and theoretical analysis.
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