A Study on the Recognition and Understanding Expert System of Mechanical Drawings. A Thinning Algorithm and a Rule Interpreter for Understanding of Mechanical Drawings.

Abstract

The authors are developing an intelligent recognizing and understanding system for mechanical drawings. This system is designed to extract the meanings of drawings and translate them into CAD data. Some of the characteristic features of the system are a module specialized in the image processing of horizontal and vertical lines and an image understanding module based on interpretation rules. To achieve a higher performance, a new parallel thinning algorithm and a rule interpreter are introduced. The thinning algorithm uses protective patterns, and it is expected to preserve corners and diverging points consisting of horizontal and verticallines. The rule interpreter is newly designed by analyzing the interpretation process for mechanical drawings. The thinning algorithm gives results with less distortion than a previous sequential thinning algorithm, and it is also applicable to the image data containing oblique lines and curves. The rule interpreter enhances the ability and the flexibility of image understanding, and it improves the interpretation result.