Fig. 4.

(a)–(c) Comparison between analytical (solid purple) and measured (dotted green) $⟨L⟩$ ratio at ${\mathrm{SpO}}_2=20\%$, 60%, and 100%, respectively. (d) RSS between analytical and measured $⟨L⟩$ ratio at ${\mathrm{SpO}}_2=0\%$ to 100%. (e) Comparison between ${\mathrm{SpO}}_2$ calculated by the self-calibrated algorithm (red square) and the conventional method with constant $⟨L⟩$ ratio = 0.61 (yellow triangle) and 0.87 (blue circle).