The use of the gray level SAT to find the salient cavities in echocardiograms

We present a fast method for generating cues to the approximate position of the boundaries of the heart chambers in ultrasound images of the heart (echocardiograms). We have used the gray level symmetric axis transform (SAT) to find the boundaries of the salient cavities in the image. The centers of the maximal discs of the gray level SAT are calculated using mathematical morphology, and these centers are grouped to form symmetry surfaces, These surfaces are described as a graph in which each vertex has associated with it a path from the top to the bottom of a symmetry surface. Two vertices are connected if their paths are adjacent. The subgraphs in this graph which correspond to the salient cavities in the image are found by growing subgraphs from seed vertices. Finally, the boundaries of the cavities are reconstructed from these subgraphs. (C) 1996 Academic Press, Inc.