Method of defect edge reconstruction based on region growing algorithm and the Hausdorff distance

Abstract

Aiming to edge deformation in extracting the de- fects of X-ray weld images, a method of defect edge recon- struction based on region growing and the Hausdorff distance is proposed. Firstly, the complement of the image is computed and the size of structure is chosen by watershed algorithm. Then, the image is filtered by improved adaptive morphology filter and its two valued image comprised of the defects is obtained. On this basis, the seeds are obtained by shrinking the objects to points. The original gray value of seeds serve as the beginning value and the object region grows by combining these selected pixels whose gray values are greater than or equal to the begin- ning value which is renewed by 2 subtracted from the previous. Then, the object region grows iteratively and the Hausdorff distance of the Canny edge image of objects and the original objects are calculated each time. The region growing stop when the minimum Hausdorff distance is achieved. When all objectsregion growing are completed, the defect edge is reconstructed by region growing. The method is verified by experiments and the results prove that the method is avail to renew the original shape of defect and obtain good results in defect edge recon- struction.