| 摘要 |
The present invention provides a machine vision inspection system for inspecting the flanges of metal containers that can reliably detect flange defects as small as 0.010 to 0.012 inches. The inspection device comprises apparatus for producing an enlarged image of selected portions of the flange and apparatus for capturing and processing the image. The apparatus for producing the enlarged image includes an annular lens positioned between the flange and the producing apparatus. The invention also provides a method for inspecting a flange of an article, such as a can, for defects. The method comprises the steps of directing light onto the flange of the article from a light source, forming light rays reflected from the flange into a radially expanded image of the flange by positioning an annular lens to redirect reflected light rays into the radially expanded image, and providing apparatus for capturing and processing the image to inspect the flange for defects. By providing an annular lens positioned between the flange and the camera, the present invention enlarges the image of the flange and any defects relative to a pixel of an inspection system. Increasing the effective size of a defect to extend outside of a single pixel increases the effective resolution of the system permitting the detection of smaller defects in the flange of a metal container. |
