Design & Implementation On The System Of Geometric Measurement And Defect Detections For Monocrystalline Silicon Cell

In the production process of solar modules, wielding the solar cells in a string andlaminating the solar modules are the two key steps. Before and after the welding process,the geometric measurements and automatic defect detections of the solar cells has becomean important research topic as a key element. In this paper, based on the analysis of theplacement and the typical defect characteristics of the monocrystalline silicon cells beforewelding, comprehensive application of machine vision and image processing knowledge,have launched a study to the geometric measurements and defect detections of the cells.Firstly, imaging processing techniques have been studied, focuses on the classicimage smoothing and sharpening preprocessing, edge detection and morphologicalalgorithms.Secondly, in order to achieve the online automatically detect the cells before welding,a set of image processing system has been designed. In accordance with the requirementsof the specific content and accuracy of the detection, Selection and combination of variouscomponents are introduced, and the structure of the software system and image processingsteps are briefly described. The function and requirements of the component parts of thesystem hardware structure have been analyzed, and specifically analysis the selection ofthe various components and the composition of the system.Thirdly, to the requirements of the solar cell before welding needs to be reformed thedirection and determined the positions of the two bus-burs, measured the geometricparameters of the cells, including the deflection and geometric distance. Using an edgedetection method extracted for the target edges. According to the tilt angle of the targetedge line to determine the deflection of the cells, and then rotate the image of the cells to apositive position. By using a fixed column of a progressive scan way on the rotated imageof cells to measure the geometric distance. Verify the design method for detecting theimage of cells with different deflection, and the experimental results were analyzed.Finally, in order to achieve the online automatically detect defections of the cells,analyze the common and typical defects of the solar cells. For the analysis of the defect characteristics, detection methods are designed for different characteristics of four defects.Verified by experiments with the corresponding defective cells, and experimental resultsare analyzed.