| CPC A61B 5/7221 (2013.01) [A61B 5/0261 (2013.01); A61B 5/7246 (2013.01); A61B 5/725 (2013.01); A61B 2562/0242 (2013.01)] | 20 Claims |

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1. A live subject tissue detection device, comprising:
a light source configured to emit light onto a tissue of a subject;
a photodetector configured to:
receive light reflected from the tissue of the subject and light reflected from blood flow of the subject, wherein the light reflected from the blood flow of the subject has a Doppler shift relative to the light reflected from the tissue of the subject, and
generate a high frequency Doppler signal based on the Doppler shift; a detection circuitry configured to:
receive the high frequency Doppler signal from the photodetector, and
convert the high frequency Doppler signal into a low frequency signal; and
at least one processor configured to:
compute parameters of the low frequency signal,
compare the parameters of the low frequency signal to respective reference values, and
determine a presence of live subject tissue based on the comparison,
wherein the comparing of the parameters of the low frequency signal to the respective reference values comprises splitting the low frequency signal into a plurality of spectral bands and comparing signal power levels in each of the plurality of spectral bands with the respective reference values.
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