Patent ID: 8820647

Claim:
A method for authorizing use of a biometric card, comprising: sensing a fingerprint of a card user; authenticating the sensed fingerprint information; generating a first photocurrent signal based on reflective scattering of a first laser light generated by a red laser, generating a second photocurrent signal based on reflective scattering of a second laser light emitted by an infrared laser, converting the first photocurrent signal to a first waveform and converting the second photocurrent signal to a second waveform; estimating an SpO2 level of the card user based on the ratio of the first waveform and the second waveform; determine whether the estimate is at least 90 percent; evaluating whether the sensed fingerprint is from live human skin based on the determination; and authorizing the use of the card based on the fingerprint authentication and the evaluation.