System for non-contact colored label identification and inspection and

Abstract

An optical inspection system which inspects for the presence of defects in colored labels placed, for example, on the side walls of cylindrical beverage cans. The optical inspection system utilizes a conveyor for conveying the beverage cans in a production line where such beverage cans typically are randomly oriented. The optical inspection system positions an optical head near the beverage cans as they move in the production line without physically interferring or interacting with the movement. The optical head senses a preselected number of different colors which appear in a predetermined field of view of each moving can. The cans being randomly oriented have different portions of the label visible in the predetermined field of view which is fixed in position. The optical head produces analog electrical signals corresponding to the intensity of each sensed color. A computer is utilized to process these analog electrical signals from the optical head. The computer first generates a number of two color signatures based upon the selected number of colors. After sufficient cans have passed the optical head wherein all two color signatures are fully developed, the computer senses the colors from each successive subsequent can and compares it to the generated color signature. if the sensed color pattern falls outside the generated color signatures, then the can fails and an air signal is generated.