Comment Re:It does measure Oxygen saturation to deduce pul (Score 1) 156
At a glance the patent seems to be for a very specific approach to measuring pulse oximetry. The approach seems near identical to US patent 5737439 Anti-fraud biometric scanner that accurately detects blood flow. In any event the basic technique for using pulse oximetry for liveness testing is described in Sandstrom, "Liveness Detection in Fingerprint Recognition Systems", 2004 and Hill & Stoneham, "Practical applications of pulse oximetry", 2000. The use of two IR absorption measurements is not novel (see patent 5737439).