Reconstruction of trace map of a circuit card assembly based on fuzzy pattern recognition

In this paper, a methodology of adaptive pattern recognition based on adaptive hierarchical fuzzy rules is used to reconstruct the trace map of a printed circuit board. In order to implement this concept, hierarchical structures are discussed. Based on this, a frame-work of adaptive hierarchical fuzzy rule based pattern recognition is presented, where the different features of a pattern are delineated and sorted by different subsets of fuzzy rules, and subsets are arranged into different levels in the hierarchy. In the lower levels of the hierarchy, the fuzzy rules are formulated to delineate and sort the local features of a pattern, and in the higher levels of the hierarchy, the subsets of fuzzy rules are formulated to delineate and sort the global features of a pattern. The fuzzy rules in the lower level are fired first, to locate the sets of pixels hosting the local features, and then, these pixels are evaluated to see whether they exhibit global features. The parameters of fuzzy rules are adaptively changed in order to be more precise in delineating and sorting the features as more quantitative characteristics are being recovered from raw data. The hierarchy greatly reduces the number of the rules necessary for describing a pattern and also facilitates adding rules for new features or removing rules for faulty features of a pattern. As an example, the proposed approach is applied to extract the trace map from the X-ray image of a populated printed circuit board