Table 4.

Decrease of signal variance when additional wavelengths are used for the calculation of $[{\mathrm{O}}_2\mathrm{Hb}]$ and [HHb]. For both chromophores, two wavelength-combinations were investigated (left row), showing the variance decrease in the right row.

Wavelength-combination	$\mathrm{\Delta }$ variance (%)
$[{\mathrm{O}}_2\mathrm{Hb}]$: two- versus three-wavelengths	$-6$
$[{\mathrm{O}}_2\mathrm{Hb}]$: two- versus four-wavelengths	$-25$
[HHb]: two- versus three-wavelengths	$-1$
[HHb]: two- versus four-wavelengths	$-8$