An Active Inspection System for the Assessment of Steel Quality

A prototype of an active inspection system for the evaluation of the carbide distribution of High Speed Steel is presented. By actively controlling the magniication, the position of the specimen stage, the illumination, and the focus of the microscope, the classiication of steel specimens showing the carbide distribution is made feasible regarding classiication robustness and performance. The system determines a focus of attention at a lower magniication and tracks this area up to a magniication of 1:100, at which the region is classiied according to a standard chart. This active vision process yields the classiication for a large surface area in a more robust and faster way than a passive process could achieve. 1 Motivation In the process of quality control of high speed steel, one important task is to estimate its carbide distribution. Currently, metallographers visually classify specially prepared surfaces of metallographic specimens at a magniication of 1:100 using a light microscope. At rst the area of most salient (i.e. largest, most net-shaped, lowest steel quality) carbide distribution on the surface of a few cm 2 is determined visually by scanning over certain areas and over the whole surface. Afterwards this carbide distribution is classiied by reference to a standard chart of 28 images, arranged in 4 rows (type) of 7 columns (degree) (see Fig. 1). The metallographers are capable of classifying the specimens rapidly but rather subjectively based on their visual