Fig. 3. Comparison of spectroscopic normalization methods.

Spectroscopic normalizations in the human retina. A vis-OCT B-scan of a healthy human retina; vessels labeled V1-V4 were identified as vein, artery, vein, and vein, respectively; B Measured spectra in V1 with no normalization (yellow), normalization by NFL (green), normalization by the anterior vessel wall (blue), and normalization by the start of signal decay in the blood ($z_d$) (purple), respectively; predicted spectrum for sO₂ = 56.5% (gray dashed line); C Bias for each normalization with respect to predicted spectrum at five wavelengths; D, E Same analysis for V2 and sO₂ = 99.6%; F, G Same analysis for V3 and sO₂ = 61.3%; H, I Same analysis for V4 and sO₂ = 62.5%.