Abstract
Crack detection system is developed to rationalize nondestructive testing of fatigue crack. This system judges possibility of existence of fatigue crack beneath the paint crack without removing the paint. The judgement is based on pattern-matching of paint crack pattern and fatigue crack patterns. Paint crack profile is extracted first from the inspection photograph. Mapping transformation is applied on the profile in order to compare 2 different crack images. The original crack profile images are projected on standardized weld bead 2D expansion plan. The image is compared with pattern image of fatigue cracks in crack DB. Those images are previously obtained by same procedure as paint crack pattern image. Possibility of fatigue crack is judged by coincidence factor of pattern matching of 2 images. The performance of this image diagnosis system is accurate and high enough to apply this for preliminary judgments for ordinary NDT.
