Table 1. MPE of estimating hemoglobin parameters and RMSE% of quantifying µ_a(λ) and µ_s'(λ) of the bottom layer with known optical properties of the top layer. The numbers are expressed as mean ± standard deviation among 10 independent runs.

	MPE (%)			RMSE%
	fHb	StO2	d	µa	µs'
(a) d was known
SDS = 0.2 mm	−3 ± 13	−10 ± 10	NA	14.1 ± 7.4	2.0 ± 1.1
SDS = 1.0 mm	−8 ± 3	−5 ± 5	NA	8.3 ± 3.0	1.8 ± 0.7
SDS = 2.0 mm	−2 ± 15	−10 ± 6	NA	14.5 ± 9.1	18.0 ± 10.4
Multiple SDSs = 0.4-2.0 mm	−2 ± 7	−6 ± 5	NA	6.6 ± 4.4	0.9 ± 0.5
(b) d was unknown
SDS = 1.0 mm	0 ± 8	−4 ± 4	6 ± 11	7.9 ± 4.3	1.7 ± 0.9
Multiple SDSs = 0.4-2.0 mm	5 ± 4	−1 ± 3	4 ± 3	6.2 ± 4.2	1.8 ± 1.0