Synthetic aperture photoplethysmography sensor
A synthetic aperture photoplethysmography (PPG) sensor is disclosed. A group or matrix of contiguous PPG sensors located on a toilet seat are conditionally combined based on sensor measurements. Conditional combinations may be based on timing data and signal-to-noise ratio data of each of the PPG measurements. Measurements associated with the conditional combinations are then used to determine a cardiac function of a toilet user.
1. A method of conditionally combining photoplethysmography (PPG) measurements comprising:
providing a toilet, the toilet comprising a toilet seat, the toilet seat comprising a group of contiguous PPG sensors and at least one weight sensor, wherein the at least one weight sensor is in communication with the group of contiguous PPG sensors;
obtaining a weight detection from the at least one weight sensor when a user is seated on the toilet seat;
transmitting a signal from the weight sensor to the group of contiguous PPG sensors;
actuating the group of contiguous PPG sensors;
obtaining PPG measurements from the group of contiguous PPG sensors;
combining the PPG measurements into one or more conditional combinations based on timing data and signal-to-noise ratio data corresponding to each of the PPG measurements;
wherein the timing data is collected by a PPG sensor with low or high intensity values which change relative to a user's heart beating; and
using the one or more conditional combinations to determine a cardiac function of a toilet user.
2. The method of claim 1 , further comprising averaging the one or more conditional combinations to determine the cardiac function of the toilet user.
3. The method of claim 1 , wherein one or more of the one or more conditional combinations are determined at least partially based on an intensity level of received light at the PPG sensors.
4. The method of claim 1 , further comprising obtaining ballistocardiography (BCG) measurements from a BCG sensor located in the toilet seat.
5. The method of claim 1 , wherein the group of contiguous PPG sensors is arranged in a two-dimensional array.
6. The method of claim 1 , wherein the contiguous PPG sensors comprise photodiode devices, charge-coupled devices (CCDs), active-pixel sensors, or complementary metal-oxide-semiconductor (CMOS) sensors.
7. The method of claim 1 , wherein the contiguous PPG sensors comprise light emitting diodes or laser diodes.
8. The method of claim 1 , wherein the contiguous PPG sensors comprise both light transmitters and light receivers.
9. The method of claim 1 , wherein combining the PPG measurements comprises selectively averaging two or more of the PPG measurements.
10. The method of claim 1 , wherein the one or more conditional combinations is determined by choosing a conditional combination of the one or more conditional combinations which has a first arrival in time.
11. The method of claim 1 , wherein the cardiac function comprises blood oxygen level, heart rate, blood pressure, blood flow rate, pulse transit time, or a combination thereof.
12. The method of claim 1 , wherein the toilet seat further comprises optical fibers.
13. The method of claim 12 , wherein the optical fibers connect to a plurality of light emitting diodes and at least one optical detector.