Question

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Detecting heart rate using the camera

I am working on detecting pulse rate in iOS. I have done some search and now I am able to read heart beats using external bluetooth device which is capable of reading heart beats. But now I am ver curious about detecting pulse using iPhone camera. I am trying to understand How it can be done? What is actual theory behind that? Can any one have an idea behind this?

According to my search I found that I need to use camera in video mode. And I need to compare each frames from that video for colour changes. When our heart pumps blood into our body, colours are changed with every pump. So how will I get that colour change using camera or is there any other way to do this?

Answer 1

Someone at MIT Media Labs beat you to it 😛

http://www.cardiio.com/

Click on “How it works”.

I believe the gist of it was that the app measures the amount of light reflected off your face due to increase/decrease in blood. Based on this, they can determine your heart rate.

Don’t know about the underlying algorithm. If I know, I wouldn’t be sitting here, I’d be writing MIT apps 😀

Apparently there is a threshold that is considered a “standard” heart rate.

Studies have shown that our heart rate measurements are within 3 bpm
of a clinical pulse oximeter when performed at rest in a well-lit
environment (Poh et al., Opt. Express 2010; Poh et al., IEEE Trans
Biomed Eng 2011).

You’ll probably need some sophisticated equipment to record your results like a real heart rate measure machine so you can compare the RGB (in 255,255,255 triplets values) between different frames at different heart rate and also you have to make sure you’re sitting in about the same exact environment with controlled lighting.

If you try to do it at home, you’ll get no where. If the sky dims for example, you’re going to get different RGBA value.