This narrow-band simple reflectance colorimeter
analyses an area of 20 mm2, i.e. a disk of 5 mm
in diameter. The device contains 16 diodes positioned at the periphery of the photodetector.
Diodes emit at 568, 660 and 880 nm, which
respectively correspond to green, red and infrared light. Photodetection of the reflected light
after emissions in the green and red allows computing cutaneous hemoglobin content (i.e. erythema value with arbitrary units) while analysis
of reflected light from wavelengths in the red
and near-infrared provides values of skin melanin co2