Dear all,

I am interested in processing PPG signals with the least possible delay. The high-frequency noise should be removed. Then, the local maxima, local minima and DC component should be computed in order to extract the ratio of ratios (mentioned in "Design of pulse oximeters", section 9.3):

R = ln ( Rmin / Rmax ) / ln ( IRmin / IRmax ),

where Rmin ,  Rmax,  IRmin, IRmax  are the minima and maxima of the red and infrared light intensities.

Which FAST method do you recommend me for this procedure, please? Standard tools in the temporal domain are affected by noise, and spectral domain tools introduce 1 cycle (about 1 s) delay.

Thank you very much in advance.

Best regards,

Fernando

https://www.amazon.es/Oximeters-Medical-Physics-Biomedical-Engineering/dp/0750304677