Describing the structural shape of melanocytic lesions

This paper presents an automatic computer system for analyzing the structural shape of cutaneous melanocytic lesion borders. The computer system consists of two steps: pre-preprocessing the skin lesion images and lesion border shape analysis. In the preprocessing step, the lesion border is extracted from the skin images after the dark thick hairs are removed by a program called DullRazor. The second step analyzes the structural shape of the lesion border using a new measure called sigma-ratio. The new measure is derived from scale- space filtering technique with an extended scale-space image. When comparing the new measure with other common shape descriptors, such as compactness index and fractal dimensional, sigma-ratio is more sensitive to the structural protrusions and indentations. In addition, the extended scale- space image can be used to pinpoint the locations of the structural indentations and protrusions, the potential problem areas of the lesion.