A Quick Method for Matching Object Subspaces Based on Visual Inspection

In visual inspection, the object image subspace should be segmented and matched, then the affine relationship is built between the template image and the sample image. But sometime the illumination is uneven on the surface of object image, it is difficult to obtain accurate position of the object subspace quickly. In this paper, a novel strategy is proposed to adopt discrete radial search paths instead of searching all points in the image. Therefore, the searching time can be reduced. In order to reduce the influence coming from the industrial environment, the paper proposes another method that is local energy level set segmentation, which can locate the object subspace quickly and accurately. The detection upon crown caps is as an example in the paper, then the detection effects and computing time are compared between several detection methods, and the mechanism of inspecting has been analyzed. The industrial applications are also given in the paper.