توسعه يك سيستم تصويربرداري اپتيكي بر مبناي نور قطبيده و پلاريزاسيون جهت ارزيابي ضايعات پوستي

An optical imaging system development based on polarized light and polarization for evaluating skin lesions

Background and Objectives: Part of linear polarized light that illuminates skin is backscattered by the superficial layers and rapidly depolarized by collagen fibers and Particles of light scatterer in skin. It is possible to distinguish such superficially backscattered light from the total reflected light. Method and Material: For this purpose, two images are obtained by a system that includes a linear polarizer in front of the camera (analyzer) and a linear polarizer in front of the light source. Results: First image is Ipar that acquire when the passing axis of analyzer is parallel to the passing axis of polarizer. Second image is Iper that acquire when the passing axis of analyzer is perpendicular to the passing axis of polarizer. Image Pol= (Ipar- Iper)/ ( Ipar+ Iper) that is based on the polarization ratio is created. Conclusion: It is shown that we can achieve a lower border error percentage in extracting lesion from dermoscopy images using Pol image. Also qualitative Interpretation of Pol image is useful for assessment of skin lesions and review of treatment process.