Residual oxides detection and measurement in stainless steel production lines

In this paper, we present a system to detect and measure the amount of residual oxide stains remaining in the surface of stainless steel coils after the pickling process in a production line. The system is able to acquire clear images of the stainless steel surface with the appropriate illumination and magnification, while it is being produced. These images are processed and analyzed in real time in order to detect and measure the oxide stains which typically are between 50 and 200 microns in size. We present here an outline of the acquisition system and the image processing algorithm which has been designed to detect this sort of defect.