SURFACE DEFECT INSPECTION INSTRUMENT

摘要

PURPOSE:To provide a surface defect inspection instrument applicable on line which enables highly accurate decision of the type and grade of a surface defect of a long-sized plate material. CONSTITUTION:The surface of a steel plate 1 is scanned optically across the width thereof with a projector 2a and the reflected light from the surface is received with a photodetector 2b. A detection signal of the device is binary coded by the level to discriminate a defect part and a sound part of a texture with a discrimination circuit 3 and binary coding signals indicating the defect part are added up at a specified length and at each width of the steel plate 1 with a histogram generation circuit 4 to generate separate histograms. A feature value is extracted from the respective histograms with a feature value extraction circuit 5 to judge the feature values comprehensively with a judging circuit 6 thereby deciding the type and the grade of a surface defect of the steel plate 1.