| CPC A61B 5/14552 (2013.01) [A61B 5/681 (2013.01); A61B 5/7203 (2013.01); A61B 5/7221 (2013.01); A61B 5/02433 (2013.01); A61B 5/02438 (2013.01); A61B 2562/0238 (2013.01); A61B 2562/0242 (2013.01); A61B 2562/046 (2013.01)] | 20 Claims | 

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               1. A method comprising: 
            measuring physiological signals including a first physiological signal at a first wavelength, a second physiological signal at a second wavelength and a third physiological signal at a third wavelength; 
                determining whether one or more criteria are met for the physiological signals, the one or more criteria including a criterion based on the third physiological signal at the third wavelength; 
                assigning a confidence value to the first physiological signal and the second physiological signal, wherein: 
                in accordance with the determination that the one or more criteria are met for the physiological signals, assigning a first confidence value to the first physiological signal and the second physiological signal; and 
                  in accordance with the determination that the one or more criteria are not met for the physiological signals, assigning a second confidence value, less than the first confidence value, to the first physiological signal and the second physiological signal; and 
                estimating a physiological characteristic using the first physiological signal, the second physiological signal, and the assigned confidence value. 
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