Raster to vector conversion of construction engineering drawings

A novel method for vectorizing construction engineering drawing images is presented. The method consists of two algorithms: a seed-segment based line-network vectorization algorithm and a knowledge-supported vectorization algorithm designed specially for construction engineering drawings. The seed-segment based algorithm converts a line wholly and a line network globally so that both the quality and speed are satisfied. The knowledge supported vectorization algorithm takes full use of the features and rules of construction engineering drawings to solve the difficulties of vectorization caused by noises and degradations. The performance of this method is discussed at the end of this paper.