A system for inspecting the edges of rolled metal strip, which edges have been trimmed by passing the strip between upper and lower rotary blades, comprises video cameras arranged to image the trimmed edges to provide video signals to an image processing unit which derives from the video information the ratio between the depth of the strip separated by slitting and the depth of the strip separated by shearing. The quality of the edge can be maintained at an acceptable level by maintaining this ratio within predetermined limits.