Polarized light imaging with a hand-held camera

Polarized light imaging can. facilitate clinical mapping of skin cancer margins and can potentially guide clinical excision. A real-time hand-held polarized-light system was built to image skin lesions in the clinic. The system consisted of two 8-bit CCD cameras (Camera 1 and Camera 2) mounted on two sides of a polarizing beam-splitter. A polarized light source was mounted on the camera assembly and illuminated the patient's skin. Light was polarized parallel to the source-patient-camera plane. The light, reflected from the patient, was collected with an objective lens mounted on the beam splitter and divided into a horizontal (H) and vertical (V) component. The H component was collected by Camera 1, and the V component was collected by Camera 2. A new image was generated based on the polarization ratio (H - V)/(H + V) and displayed. This image was sensitive to the superficial skin layer and some early clinical examples are presented.