Contact-less, multi-spectral imaging of dermal perfusion

Photoplethysmography (PPG) has come to be accepted as a common, non-invasive methodfor measuring the level ofoxygen saturation in arterial blood. This paper describes a variation of the accepted PPG technique, to provide a contact-less and non-invasive method of characterizing dermal perfusion. It employs a 3-CCD, multi-spectral camera, to image the selected area. The acquired images are analysed by making use of the fact that the absorption co-efficient of oxygenated blood is more in the Infra-Red (IR) region of the spectrum, when compared to the red region. This fact is utilised to characterize the extent of dermal perfusion in the selected area of the skin. ©2008 IEEE.