The irregularity of a lesion border has been identified as the most significant factor in the diagnosis of malignant melanoma. The objective of the research was to find objective computable measures of contour irregularity and to apply them to skin lesions. A descriptive definition of irregularity was formulated which defines irregularity in terms of the five attributes: departure from a typical sequence (deviation), lack of obvious description, lack of compressibility, lack of symmetry and lack of a rule for generating a sequence. Methods based on the Hidden Markov Models, the...