[HN Gopher] Eulerian Video Magnification
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       Eulerian Video Magnification
        
       Author : smusamashah
       Score  : 21 points
       Date   : 2020-09-03 10:12 UTC (12 hours ago)
        
 (HTM) web link (people.csail.mit.edu)
 (TXT) w3m dump (people.csail.mit.edu)
        
       | CretinDesAlpes wrote:
       | For those interested in the pulse rate extraction, there is
       | actually a branch of biomedical engineering/computer science
       | called "remote photoplethysmography" (rPPG).
       | 
       | I worked on it a bit at some point, it does work pretty well
       | assuming you don't move that much and the light isn't too bad. As
       | you can imagine, it's more difficult to estimate on non-white
       | faces, particularly very dark skin tones. All the algorithms (at
       | least until 2016) differ in the way of combining the RGB signals
       | into a pulse signal by making different assumptions.
       | 
       | If you are interested more, Philips in the Netherlands are
       | particularly active in this research domain, one of the main
       | application being non-contact pulse estimation in hospitals for
       | example.
        
       | scg wrote:
       | Related: "Learning-based Video Motion Magnification" in PyTorch.
       | (https://people.csail.mit.edu/tiam/deepmag/)
       | 
       | Motion magnification" means you pick up and amplify small motions
       | so they're easier to see. It's like a microscope for motion.
       | 
       | Example videos reproducing these results:
       | 
       | https://twitter.com/cgst/status/1210691577078636544
        
       | gmfawcett wrote:
       | That Euler guy really did think of everything, didn't he.
        
       | darkstarsys wrote:
       | This is from 2012.
        
         | yorwba wrote:
         | Discussed at the time:
         | https://news.ycombinator.com/item?id=4062216
        
       | jphoward wrote:
       | So I've actually tried to implement Eulerian video magnification
       | myself, albeit using Python, because I believe when I first
       | looked into this, ~5 year ago, the code was MatLab only.
       | 
       | I was really excited about it, because, as a cardiologist, I
       | immediately thought we could use this to identify irregular heart
       | beats in the patient waiting room, for example. This was pre
       | Apple watch etc. I was thinking people could briefly sit in the
       | chair in front of the camera if they are willing to be recorded,
       | as a quick screening whilst they wait for the doc.
       | 
       | Unfortunately, I found it incredibly difficult to reproduce their
       | results, even using similar data. I remember videoing my foot as
       | I have a relatively prominent posterior tibial pulse, which in
       | good light I can actually make out visually (but not in the video
       | I took, as intended). The Eulerian magnification didn't seem to
       | do anything.
       | 
       | Has anyone else had better luck? I did wonder if maybe I had to
       | use specific video capture equipment, certain frame rates or
       | filters, but if so that wasn't clear from the documentation?
       | 
       | It's been 8 years since this paper came out, and yet I still
       | haven't seen it being used in the 'real world', so I am slightly
       | suspicious that I am not alone in my experiences.
        
         | 46Bit wrote:
         | I did a Masters project on this sort of technology and yes, I
         | think it makes fantastic demos but hasn't found a killer
         | usecase in the real-world (publicly, anyway.)
         | 
         | Their techniques are at least patent-pending if not fully
         | patented by now, which may limit how much it gets used.
        
         | oh_sigh wrote:
         | This or similar tech would definitely be integrated into high
         | end baby monitors if it worked. State of the art is putting a
         | wrist or ankle band onto your baby though AFAICT.
        
         | MByte wrote:
         | I played with it 7 years ago for a hackathon -- not to
         | transform the video, but just to extract pulse data from a face
         | cam. For that purpose, even without optimization, it did work
         | fairly well, though when we went to demo it live, the frequency
         | of the projector lamp interfered with detection.
         | https://github.com/MegaByte/web-webcam-pulse-detector/tree/r...
         | I did run across this company recently, which seems to be doing
         | something similar: https://www.binah.ai/
        
         | mkl wrote:
         | I haven't played with any myself, but there seem to be quite a
         | few implementations on GitHub now:
         | https://duckduckgo.com/?q=eulerian+video+magnification+site%...
        
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