Non-invasive blood pressure estimation and blood vessel monitoring based on photoacoustic plethysmography

A biometric method, comprising:

• controlling, via a control system, a light source system to emit a plurality of light pulses into biological tissue at a pulse repetition frequency, the biological tissue including blood and blood vessels at depths within the biological tissue;
• receiving, by the control system, signals from a piezoelectric receiver corresponding to acoustic waves emitted from portions of the biological tissue, the acoustic waves corresponding to photoacoustic emissions from the blood and the blood vessels caused by the plurality of light pulses;
• detecting, by the control system, heart rate waveforms in the signals;
• determining, by the control system, a first subset of detected heart rate waveforms corresponding to vein heart rate waveforms;
• and
• determining, by the control system, a second subset of detected heart rate waveforms corresponding to artery heart rate waveforms.

One or more non-transitory media having software stored thereon, the software including instructions for controlling one or more devices to perform a biometric method, the biometric method comprising:

• controlling, via a control system, a light source system to emit a plurality of light pulses into biological tissue at a pulse repetition frequency, the biological tissue including blood and blood vessels at depths within the biological tissue;
• receiving, by the control system, signals from a piezoelectric receiver corresponding to acoustic waves emitted from portions of the biological tissue, the acoustic waves corresponding to photoacoustic emissions from the blood and the blood vessels caused by the plurality of light pulses;
• detecting, by the control system, heart rate waveforms in the signals;
• determining, by the control system, a first subset of detected heart rate waveforms corresponding to vein heart rate waveforms;
• and
• determining, by the control system, a second subset of detected heart rate waveforms corresponding to artery heart rate waveforms.

A biometric system, comprising:

• a piezoelectric receiver;
• a light source system configured for emitting a plurality of light pulses at a pulse repetition frequency between 10 Hz and 1 MHz;
• and
• control means for:
• controlling the light source system to emit a plurality of light pulses into biological tissue at the pulse repetition frequency, the biological tissue including blood and blood vessels at depths within the biological tissue;
• receiving signals from the piezoelectric receiver corresponding to acoustic waves emitted from portions of the biological tissue, the acoustic waves corresponding to photoacoustic emissions from the blood and the blood vessels caused by the plurality of light pulses;
• detecting heart rate waveforms in the signals;
• determining a first subset of detected heart rate waveforms corresponding to vein heart rate waveforms;
• and
• determining a second subset of detected heart rate waveforms corresponding to artery heart rate waveforms.