Visualization of Hidden Skin Spots by Cross-Polarized Imaging Using Liquid Crystal Displays as Light Source

This study proposes a method for visualizing hidden spots on the skin by photographing the face using light from a computer display as the light source. Blue light, a component of white light, penetrates deeper into the skin than ultraviolet light, making it effective for illuminating hidden spots. Since the surface of a liquid crystal display includes a polarizing filter, the light emitted from the display is polarized. Cross-polarized imaging is achieved by equipping the camera lens with polarizing filters in a crossed configuration. This method eliminates direct reflections from the skin’s surface, revealing spots beneath the skin. While ultraviolet imaging has traditionally been the primary method for visualizing hidden spots, the proposed approach presents a low-cost alternative. This novel method is expected to be implementable using only a laptop computer, effectively addressing the challenges of high costs and limited accessibility.