How to assess the performance of part location tools
John Stamos, 01-22-2013
Part location tools find the part within the vision system’s field of view. This is typically the first step in any vision application, from the simplest robot pick-and-place operation to the most complex assembly verification task. It’s also the most critical step, because it often determines whether an application succeeds or fails, since you can’t inspect, measure or identify the part if you can’t find it.
While it sounds simple enough, locating parts in an actual production environment can be extremely challenging. Vision systems are trained to recognize parts based on a pattern, but even the most tightly controlled manufacturing processes allow some variability in the way a part appears to the vision system. Your vision system’s part location tools must be intelligent enough to quickly, and accurately compare trained patterns to the actual objects moving down a production line, and tolerate variations in part appearance. It’s important for pattern matching tools to be able to tolerate large variations in contrast and ignore lighting changes, while being reliable enough to always find the right part.