Abstract: In this paper the available approaches of the automatic inspection of the weldingdefects using a developed microcomputer image processing system are discussed.A "group-difference method" has been presented to obtain better result for theimage sharpening of the blurred welding defect x-ray picture.A useful concept of the "Weighted-Freeman's chain code" is used for simplifyingthe boundary tracking and feature extraction of some geometrical configurations.A multi-level recognition system-tree classifier is designed.It simplifys the process of recognition and makes it more effective.