yarPPG

yarPPG is yet another implementation of remote PhotoPlethysmoGraphy. Remote photo­plethysmography (rPPG) refers to the camera-based measurement of a blood volume pulse signal. It works by detecting small changes in skin color, originating from the pulsation of blood¹.

Caution

This is just a hobby project. Intended for demo purposes only, the provided program/code is not suitable to be used in a clinical setup or for any decision making in general.

Important

October 2024 Update - yarPPG has seen a major overhaul. The rPPG processing logic has been completely decoupled from the user interface which now also allows offline processing. Not all features have yet been ported to the new code base.

Please submit an issue if you miss something from the old version!

Documentation

The documentation pages are here: https://samproell.github.io/yarppg/

Installation and usage

In order to run the yarPPG application, clone this repository and navigate to the downloaded folder. You can then install the folder into your Python environment. This will install the run-yarppg command.

git clone https://github.com/SamProell/yarppg.git
cd yarppg
pip install "."
run-yarppg

Core functionality

Different from earlier versions of yarPPG, the core functionality for remote PPG signal extraction has been completely decoupled from the user interface. The Rppg class combines all required steps (roi identification, signal extraction, heart rate estimation) into one (stateful) function.

import yarppg

rppg = yarppg.Rppg()

while running:
    # frame = ...  # get an image array of shape h x w x 3
    result = rppg.process_frame(frame)
    print(f"Current rPPG signal value: {result.value} (HR: {result.hr})")

See this guide if you need more fine-grained control over the individual calculation steps.

The Rppg class also comes with a method to process an entire video file at once. See more details here.

User interfaces

The default user interface launched by the run-yarppg command is a simplistic window based on OpenCV. More elaborate user interfaces are available, but require additional dependencies.

Simple Qt6 window

pip install ".[qt6]"
run-yarppg ui=qt6_simple

More to come, you are welcome to contribute

Footnotes

1. W Verkruysse, L O Svaasand and J S Nelson. Remote plethysmographic imaging using ambient light. Optics Express. 2008;16(26):21434–21445. doi:10.1364/oe.16.021434 ↩