Table 1.

Five skin parameters used in the retrieval algorithm. The range of each parameter is selected from the literature. The retrieval parameters are bounded to these limits.

Skin parameter	Symbol	Range
Melanin concentration	f mel	1.3 to 45%
Epidermis thickness	D epi⁡	0.01–0.15 mm
Volume fraction of haemoglobin	f blood	0.2–7%
Oxygenated haemoglobin	C oxy	25–90%
Dermis thickness	D dermis	0.6–3 mm