RESUMO
A new interferometry procedure (Holon View measuring system) permits non-invasive and objective measurement of the surface, height/depth and volume of ulcerous lesions. The method, which uses a combination of the so-called phase-shift and gray-code technique, is new in dermatology. The measuring system consists of a diffraction grating projection system, a video camera and a computer-aided, digital image processing and analysis system. A diffraction grating consisting of 320 lines is projected onto the skin surface or a silicone impression of the ulcerous lesion. The course of the light-intersection lines is recorded by a video camera and read into an image computer. The special feature of the method is the combination of grey-code projection and a phase-shift procedure. For evaluation of the method in dermatology, 2,000 interferometric measurements of volume were carried out on objects of known volume, on silicone impressions and on leg ulcers. The accuracy of the method has been proven by means of the evaluation of objects of known volume. The results of interferometric measurements were compared with the values of the volume determined by water capacity and those of the surface determined by image analysis. The healing of a leg ulcer was followed over an 8-week period. The Holon View measuring system permits no-touch measurement of the volume and surface of ulcerous skin lesions with a high degree of accuracy and precision, in a short time.
