Vital Signal Estimation
Heart rate estimation belongs in the field called “Vital Signal Estimation” (VSE). In computer vision, VSE has been around for a while. One of the more famous attempts at this comes from 2012 from a paper entitled “Eulerian Video Magnification for Revealing Subtle Changes in the World” that was published at SIGGRAPH by MIT.
Basically, the way that VSE was implemented by MIT was that they analyzed images captured from a camera for small illumination changes on a person’s face produced by varying amounts of blood flow to it. These changes were then magnified to make it easier to scrutinize. See, for example, this image from their paper:
Uses of Heart Rate Estimation
What could heart rate estimation by computer vision be used for? Well, medical scenarios automatically come to mind because of the non-invasive (i.e. non-contact) feature of this technique. Stress detection is also another use case. And what follows from this is lie detection.
What could heart rate estimation by computer vision be used for? Well, medical scenarios automatically come to mind because of the non-invasive (i.e. non-contact) feature of this technique. The video above (from 3:30) suggests using this technology for SIDS detection. Stress detection is also another use case. And what follows from this is lie detection. I’ve already written about lie detection using thermal imaging – here is one more way for us to be monitored unknowingly.
On the topic of being monitored, this paper suggests (using a slightly different technique of magnifying minute changes in blood flow to the face) detecting emotional reactions to TV programs and advertisements.
This blog post talked about another lesser known use case of computer vision: heart rate estimation. MIT’s famous research from 2012 was briefly presented. This research used a technique of magnifying small changes in an input video for subsequent analysis. Magnifying small changes like this is how most VSE technologies in computer vision work today.
After this, a discussion of what heart rate estimation by computer vision could be used for followed. Finally, it was mentioned that VSE is still predominantly something in the research domain, although one company has recently appeared on the scene that sells baby monitoring systems to detect abnormal breathing in sleeping infants. The product being sold by this company uses computer vision techniques presented in this post.