Reflectance measurement using digital camera and a protecting dome with built in light source

The reflectance of the skin reveals the chemical and physical changes of the skin as well as many metabolic changes. The reflectance measurement is an important method for medical diagnosis, follow-up and screening. This article concentrates on designing and validating an imaging system, based on a digital camera. The proposed system can measure the reflectance of the skin with high spatial and currently four channel spectral resolution, in the range of 450 nm to 980 nm. The accuracy of the system is determined by imaging a colour checker board and comparing the obtained values with both given values and spectrometer measurements. The diffuse interreflections of both, the integrating sphere and the lighting dome of the imaging system, is compensated with a correction factor. The accuracy of the proposed system is only slightly weaker than the spectrometer. The imaging system characteristics are independent of the camera characteristics.