We have all read the Sunday newspaper where we were challenged with finding the difference between one image and an almost identical image positioned right next to it. Sounds easy but some are more difficult than others.
Many machine vision systems are faced with a similar challenge but the stakes are much higher. They must find the difference between one image, a “golden template,” and another image, usually a currently captured image. Any differences might indicate a failed and rejected product. The “golden template,” as it is affectionately known, is considered the standard. It is the perfect image that is defect free. From a manufacturer’s point of view, it is the ideal product. That might be a stretch since there is usually more to a product than what meets the eye, but aesthetics can play an important role in determining the quality of a product. The difference between the golden template and a new image might point out a defect like a missing washer, a missing electronic component or a botched printed page.