VERFAHREN UND ANORDNUNG ZUR KOMPENSATION EINES BILDSIGNALS GEGENUEBER BELEUCHTUNGSAENDERUNGEN

摘要

An image processor analyzes objects such as work pieces passing along an assembly line. The processor stores a reference ratio of exemplary signal levels from the object and its background. As subsequent images are processed, a signal level for the image background is detected and multiplied by the reference ration to derive a theoretical signal level for the object in the image. The theoretical signal level and the actual signal level for the object are compared to detect a predetermined relationship therebetween. When the predetermined relationship exists, the amplification of the image signal is adjusted to achieve a predetermined difference between the background and object signal levels. If the predetermined relationship does not exist, the amplification of the image signal is adjusted to achieve a predetermined difference between the background image signal level and the theoretical signal level for the object.