[Cyborg] medical mirror
mrericboyd at yahoo.com
Mon Oct 11 13:03:16 PDT 2010
My guess would be that they can't really get HRV. It looks to me like
their analysis system requires multiple beats just to get the heart-rate
accurately (they do the equivalent of an FFT to get it). But given that
they can get HR at all, I'm sure getting HRV is just a matter of time.
Might be hard with only 15Hz webcam though - if my calculations are
right that limits intra-beat timings to +/-4BPM, yes? Or could you
calculate HRV over a big data set?!?
I am looking forward to having my new pulse-choker stuff (using polar
heart rate receiver and a heart-shaped circuit I have designed), I'm
totally gonna hack a logger into one of them and when I do so I'll share
the data here :-).
On 10/9/10 6:03 PM, Tomm wrote:
> A tray app that monitors your heart rate is a great idea. I wonder if
> the time resolution is good enough to measure heart rate variation
> (HRV)? Variations in heartrate is also pretty interesting:
> "[...] asked 52 adults to report how often they experienced positive
> emotions like happiness, awe, and gratitude and how socially connected
> they felt in their social interactions every day for a period of nine
> weeks. The researchers also measured the HRV of each individual at the
> beginning and end of the study by measuring heart rate during a
> two-minute session of normal breathing. HRV at the beginning of the
> study predicted how quickly people developed positive feelings and
> experiences of social connectedness throughout the nine-week period. In
> addition, experiences of social connectedness predicted increases in HRV
> at the end of the study, demonstrating a reciprocal relationship between
> heart rate and having satisfying social experiences."
> On Sat, Oct 9, 2010 at 8:21 AM, Eric Boyd <mrericboyd at yahoo.com
> <mailto:mrericboyd at yahoo.com>> wrote:
> Basically, using nothing other than a webcam (1.3MP, 15 Hz!), they can
> read your heart rate. Then they built that into a "medical mirror", so
> you can see your heart beat in the morning when you brush your teeth :-)
> I found one of his papers about it online, full text:
> Non-contact, automated cardiac pulse measurements using video imaging
> and blind source separation
> Looks to me like the big breakthrough here is the motion independence,
> which they got through a combination of face recognition and cropping
> and separating the video into it's three component colors. They claim
> an average error from the reference pulseox reading of less than 1 BPM
> even with movement, that's pretty impressive.
> Anyone want to write a laptop app which would just keep the webcam on
> all the time and log your heartbeat?
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