Adaptive Noise Reduction for Engineering Drawings Based on Primitives and Noise Assessment

In this paper, a novel, adaptive noise reduction method for engineering drawings is proposed based on assessment of both primitives and noise. Unlike the current approaches, our method takes into account the special features of engineering drawings and assesses the characteristics of primitives and noise such that adaptive procedures and parameters are applied for noise reduction. For this purpose, we first analyze and categorize various types of noise in engineering drawings. Algorithms for linewidth assessment, noise distribution assessment and noise level assessment are then proposed. These three assessments are combined to describe the features of noise of each individual engineering drawing. Finally, median filters and morphological filters, which can adjust their template size and structural element adaptively according to different noise level and type, are used for adaptive noise reduction. Experimental results show that our approach is effective for reducing most noise in engineering drawings.