Show HN: A weird thing that detects your pulse from the browser video

_Microft 19 minutes ago | parent | next [-]

You as reader might also be interested in this: https://hbenbel.github.io/blog/evm/

functionmouse 6 hours ago | parent | prev | next [-]

I feel like the primary use case for such a technology is manipulating and profiling people over video chat, maybe even autonomously. Hiring managers, HR, landlords, and police are obvious customers.

The response I anticipate will be "But this will help doctors over telehealth and stuff!" - Please see https://calebhearth.com/dont-get-distracted

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nearbuy 4 hours ago | parent | next [-]

This tech (detecting pulse from regular video) has been around almost 20 years now, and this doesn't seemed to have happened yet.

You see this type of thing in spy movies, but I'm not sure it's that useful in real life. You're basically taking one piece of data a polygraph uses, but without the most important component (skin conductance). Polygraph accuracy isn't that great to begin with. You can profile and manipulate people more effectively based on their reactions and behaviour, and their pulse will be much harder to interpret.

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ranger_danger 4 hours ago | parent [-]

I don't think this tech has actually been used in practice for that long, if at all. It was only first demonstrated in 2012 at SIGGRAPH.

Can you cite any commercially available uses of such tech?

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swiftcoder a few seconds ago | parent | next [-]

I don't it's ever been practical to ship in a product? You need ~20 seconds of data to stabilise the reading, and any large motion ruins it - even though Microsoft Research demonstrated a Kinect could detect heartrate in a lab setting, it wasn't viable to ship in a fitness game.

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nearbuy 2 hours ago | parent | prev | next [-]

I don't know any commercial uses of such tech today. I'm not saying they don't exist. I just don't know of them.

I had said I don't think it's very useful for "manipulating and profiling people over video chat", so I wouldn't really expect there to be a commercial product for that. Probably it's used in fitness or heart rate monitoring apps for people that don't have a fitness tracker device and prefer not to manually count their pulse.

Here is the tech demonstrated in 2007: https://pubmed.ncbi.nlm.nih.gov/17074525/

The core algorithm is really simple. You find a patch of skin. Take the average color of the pixels in that patch. The color will become more reddish each pulse. Do an FFT and take the strongest peak in the plausible heart rate range. You could prototype this in a few hundred lines of python.

If this were useful for police or hiring managers, someone could have use the tech to make an app for them within the past 19 years.

Of course, companies have a history of trying to market a lot of BS metrics (e.g. graphology, MBTI) to hiring managers, so I wouldn't be that surprised to see a company claim they can predict employee success using pulse. Whether it works is another story.

	▲	ddalex 2 hours ago \| parent [-]
		> You could prototype this in a few hundred lines of python. You mean Claude can one-shot this.

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numpad0 3 hours ago | parent | prev [-]

(2008)

1: https://pmc.ncbi.nlm.nih.gov/articles/PMC2717852/

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metalcrow 5 hours ago | parent | prev [-]

Can you explain how https://calebhearth.com/dont-get-distracted applies to the potential response you described? I don't get it.

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croes 5 hours ago | parent | next [-]

They will weaponize it.

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godelski 4 hours ago | parent | prev [-]

Don't get distracted, sit down and read it in full.

Don't get distracted, think about what he wrote.

If you still don't get it, take a step back. Think. Process. Then take a break and read it again tomorrow.

Slow down. Don't get distracted. You don't need to respond so fast. Take your time. There is no rush. There is no shortcut. Read it in full and you'll understand this comment says much more.

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_Microft 24 minutes ago | parent | next [-]

Here‘s also an advice: if you want someone to listen, try not to come across like you just did.

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peyton 20 minutes ago | parent [-]

We’re just BSing on the internet. No need to tone police.

	▲	_Microft 13 minutes ago \| parent [-]
		That internet is elsewhere.

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collingreen 4 hours ago | parent | prev [-]

This feels overly patronizing

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godelski 4 hours ago | parent [-]

Probably because I repeated "don't get distracted". But if you read the article then I think it'll take on a different context, as I'm mimicking the author, including their short paragraph style.

	▲	user2722 21 minutes ago \| parent [-]
		I get really annoyed at those articles which advocate the developer to sacrifice themselves towards a better future. Companies externalize costs. I refuse to be the one, as an individual, with the burden of fixing society ills to my own detriment. Tell me to get into politics, join an association, whatever. Now, as an individual, lose money for morals? No thank you. I may, and probably will, do it -- but don't expect I do it. I have no business, in a society with less and less public services, to harm myself and my family for refusing to do well paying jobs. I will externalise those costs as much as possible. I will bring awareness. I will write letters. But don't ask me to leave a well paying job -- that's someone else job to fix.

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twodave 5 hours ago | parent | prev | next [-]

It’s not very accurate. Maybe because of the camera fidelity. It was about 10bpm lower than actual for me. Seems to operate off of subtle motions caused by pulse. It was even worse at detecting breathing.

	▲	brynnbee 3 hours ago \| parent [-]
		It showed my BPM at nearly half of what it really was

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jmusall 5 hours ago | parent | prev | next [-]

May be related: Explanation of motion and color amplification in video by Steve Mould https://youtube.com/watch?v=rEoc0YoALt0

He even shows pulse detection (around 8:30).

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smusamashah 3 hours ago | parent | prev | next [-]

I made my own heart rate app (using gemini at first and then Claude for lots of further edits). https://xosh.org/heart-rate/ https://github.com/SMUsamaShah/heart-rate it's all offline. UI needs more work but me and my wife are the only users therefore it doesn't matter that much.

At one point I added the same EVM based heart rate detection but that requires sitting very still. I use it on my phone mainly therefore the common finger method is easiest one to use.

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sxp 4 hours ago | parent | prev | next [-]

How does it work? Is it https://people.csail.mit.edu/mrub/evm/? I see the FAQ about VitalLens, but I couldn't find technical details.

It's super cool. Thanks for sharing. I want to build a biofeedback app for meditation and this looks like a good platform to use.

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serious_angel 4 hours ago | parent [-]

Please consider checking out comments: https://news.ycombinator.com/item?id=47293662

	▲	whilenot-dev 33 minutes ago \| parent [-]
		What do you mean? Eulerian-Video-Magnification could be (and probably is) the underlying algorithm in the VitalLens API.

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amagasaki 6 hours ago | parent | prev | next [-]

Could be interesting, but allowing the webcam crashes my browser.Repeatedly

macOS 15.7.1 (24G231) Brave 1.87.186 (Official Build) (arm64) Chromium: 145.0.7632.45

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serious_angel 6 hours ago | parent [-]

In the minified source code, we may see, it uses:

``` try { const l=await navigator.mediaDevices.getUserMedia({audio:!1,video:{facingMode:"user"}}); /* ... */ } catch { this.showError("Could not access webcam. Please check permissions.") } ```

There are alternatives to verify mediaDevices support as https://addpipe.com/getusermedia-examples/

	▲	echoangle 4 hours ago \| parent [-]
		But even a missing check shouldn’t be able to crash the browser.

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hluska 6 hours ago | parent | prev | next [-]

I would prefer some kind of privacy statement or even some kind of explanation about what is going on before I just randomly turn my webcam on. This might be great and I’m proud of you for launching but I don’t do things like that. Heck, videos can make a person’s heart race - I had my first attack at 39 and that’s a hell of a lot of risk.

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serious_angel 6 hours ago | parent [-]

I haven't dug deeper due to time availability, but for the same sake of privacy, I've found:

1. `/api/event` endpoint mentioned in the `/stats/script.js` file;

2. There's `/parties/lobby/main/telemetry` in a minified JavaScript chunk asset;

3. There's VitalLens mentioned, and there's an error string in the same asset: "A valid API key or proxy URL is required to use VitalLens. If you signed up recently, please try again in a minute to allow your API key to become active. Otherwise, head to https://www.rouast.com/api to get a free API key."

	▲	hluska 6 hours ago \| parent [-]
		This is really kind of you - I appreciate this. Thank you for taking that time!

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trothamel 4 hours ago | parent | prev | next [-]

There's a version of this built into the Google Fit application for Android.

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gumboshoes 6 hours ago | parent | prev | next [-]

Worked for me on Android. Love the simplicity.

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abakker 5 hours ago | parent | prev [-]

It registered in the low 40s for me, while my watch was saying 72-75. I guess YMMV