Pre-processing Techniques for On-Line Capsule Inspection Based on Machine Vision

Machine vision has provided great convenience for manufacturing quality inspection. To facilitate on-line capsule inspection base on machine vision, in this paper, a capsule image acquisition system and pre-processing techniques are proposed. Capsule has a cylindrical surface, let it pure rolling on a flat surface, then image it several times during its rolling can make its surface fully visible. As the defect contrasting with capsule is various in different parts, it is needed to segment the capsule image into parts in which the gray values are homogeneous. A method synthesized both local threshold and projection can perform this segmentation quite well. Experiments bear out that this algorithm has good compatibility and the processing time can satisfy on-line inspection.