This vision system for BlueScope Steel finds holes in rolling mill products that are up to 1.6m wide, with holes down to 0.5mm at rolling speeds of 200m/min. It reports the size and position of holes and virtually eliminates the shipment of bad products who require a contiguous sheet, such as canned food producers. The system includes a high-speed line-scan camera capturing over 6000 pixels across. Due to the speed of the sheet and the required hole sizes, high-output, high-frequency fluorescent lighting was required. The image to the right shows a list of holes, where they were detected and their size. Also shown is a live update of part of the line-scan camera'a image with the edge of the continuous sheet in grey, the sheet itself in black and the hole in white.
Digital Image Processing