Image processing system for comparing a test article with a master article to determine that an object is correctly located on the test article

摘要

An image processing system for inspecting an article under test to determine whether a selected object is correctly located on the article comprises a television-type camera for line-by-line scanning the article to generate a video signal corresponding to an image of the article, and threshold logic for converting the video signal into a first binary video signal in which the selected object is represented by a first logic level and non-selected objects and background are represented by a second logic level. A first image store stores a second binary video signal corresponding to a master image of the article in which the selected object is not represented but instead in which the region of the article within which the selected object should lie is represented. Also, a second image store stores information defining the correct area of the selected object on the article. The lines of the second binary video signal are read from the first store in synchronism with the lines of the first binary video signal, and logic circuitry responsive to the first and second binary video signals measures the degree of overlap of the selected object with the respective region within which such object should lie. Finally, the measured degree of overlap of the selected object with the correct area of such object is determined.