An optical inspection system has been developed to study laser speckle technology which analyzes the solar wafer roughness. It can, accurately measure the surface roughness, without contacting with the surface of the solar cells and increase the speed of measurement. The incident laser light on the surface of a solar wafer generates a reflected light, then, the variations in roughness of the speckle pattern can be observed for further analysis and judgement. According to the

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... bright spots, statistical methods are adopted to analyze the diffraction efficiency of computer-simulated surface relief gratings and calculate the surface roughness of solar wafers. The surface roughness of a solar wafer is determined by a CCD camera and the conveyor while using independently-developed software for rapid and continuous imaging as well as analysis through the image processing toolkit. In the future, this inspection technology can be utilized in industries related to solar wafer manufacturing.