Method for detecting misformed clips in packaging

A technique is described for detecting misformed clips in hermetically scal ed packages. The technique involves use of a machine vision system incorpor ating an image processing algorithm, that calculates the directions of cont ours of intensity in grey-scale images of clips. The algorithm approximatel y locates the clip by scanning a box over the contour direction transformed image, and finding the position of the box such that the standard deviatio n of the directions in the box is a minimum. The clip is accurately located by scanning a rectangular template over the contour direction transformed image in the vicinity of the approximate location of the clip, and determin ing, the best-fit position of the template. Accurate location of the clip e nables the critical clip dimensions to be calculated and used for assessmen t of clip integrity. The clip integrity is considered acceptable if all of the critical dimensions lie within an acceptable range, as defined by prede termined upper and lower thresholds.