Abstract: Several feature parametres of the microstructures in welded joints is extracted, a Minimum-distance-classifier is designed a microstructure recognition system for welded joints is set up, thus the automatically quantitative recognition of the microstructures is well realised in the welded joints made of the mild steels and the low-alloy steels. The practical evaluation shoves that the accuracy and reappearance of this system satisfies the requirements of the quantitative metallography for the recognition of microstructures in the welded joints. This system is of great importance to theory and practice for the establishment of quantitative relationship between the microstructures of welding and the mechanical properties of welded joints and for selecting the reasonable technological parametres, as well as for creating CAD system for welding.

Key words: Feature extraction, Image recognition, Microstructure, Welded joints