This work refers to the development of equipment for Computer Assisted Digital Dermatology (CADD) as a basis for the creation of Active Support Systems (ASS) for early diagnosis of melanotic disease. It is based on a Digital Epiluminescence (DELM) tecnique, taking advantage of polarized light guided by optical fibers. In the purpose to dicriminate between malignant and benign melanocytic lesions, several dermatoscopical features have been proposed by different research groups. Nevertheless many are the attempts to reach a reliable and objective classification procedure. We adopt, as reference, the approach used by Stanganelli and Kenet. Through a bioengineering analyisis we can organize reference grids that offer the possibility to extract the maximum information content from dermatological data. The classification takes into account the Spread (local, point size, global) and Intrinsic Descriptors (morphological, geometric, chromatic, others) and corresponds to the best operative description. Therefore these grids are the more suitable tools for applications which require ASS for diagnosis. Infact it is possible to obtain quantitative evaluations too. We propose a method based on Geometrical Syntetical Descriptors. All that permits a reliable early diagnosis of melanotic disease and to follow its evolution in time.