<title>Detection of enclosed shape boundaries for automatic inspection</title>

Abstract

The inspection and evaluation of surface mount assemblies and solder joints is a complex problem in computer vision which is as yet not satisfactorily solved. In this paper we outline an approach to a fast, low-cost inspection system, using a simple optical platform as opposed to more complex alternatives such as x-ray techniques or laser range finding. This paper describes the software modules required to perform feature extraction and shape analysis for inspection. In particular, we give detailed attention to the process of creating fully enclosed shape boundaries avoiding gaps in the outline of an object where the contrast is weak or noisy. A novel multi-stage generic linking and dropout correction algorithm is presented which preemptively overcomes problems difficult to rectify at later stages within the vision software. The algorithm is illustrated using examples from the surface-mount inspection system.