The Most Efficient Spectrum for 3D Scanning of Human Skin : Retrofitting a Standard RGB Projector with Three Wavelength-Shifted Red LEDs

Reflection-based 3D scanning techniques are widely used in medical applications today. In these techniques, encoded light patterns are projected onto the skin, reflected, and captured by 2D cameras. Conventional RGB white-light projectors emit wavelengths that are suboptimal for darker skin types. This results in weakly reflected patterns, prolonged exposures, and increased artefacts in the 3D image. The aim of this project is to optimise an RGB projector for reflectionbased 3D scanning of human skin. The methods included evaluating the intensity of reflected patterns and the LED power consumption. A novel concept employing three red LEDs with slightly shifted wavelength peaks was devised and simulated. It exploits the ideal spectrum, while keeping costs and power consumption low.