Resumen
First, the surface defect inspection characteristics of continuous casting slab is that the slab moves slowly on the production line, so the feature extraction method does not need too fast a calculation speed. Second, the inspection difficulties of continuous casting slabs are the defect with complex backgrounds, so some common feature extraction methods cannot meet these needs. DNST (discrete non-separable shearlet transform) is a new multiresolution analysis method with moderate computing speed. It can extract images information from multiple scales and directions. Therefore, this paper proposed a DNST-GLCM-KSR (discrete non-separable shearlet transform-gray-level co-occurrence matrix-kernel spectral regression) feature extraction method. The method is suitable for surface defects inspection with complex background and moderate running speed of production line.