I dont believe so. Since the heart rate could be much higher, it would alias, and the camera wouldn't be able to tell the difference between normal heart rate and low heart rate.
This is what I suspect could happen, with two possible heart rates matching the same set of samples:
If your heart rate is higher than 3bps, you won't be sitting patiently in front of a webcam waiting for lock-on.
Sedentary (calm, sitting) heartrates go from ~40bpm for extremely fit people to ~90-100 for particularly unfit people. Higher than 100 is unusual for sedentary people, and works out to ~ 1.5bps. The waveforms in the pulse itself (note pulse, not ECG, which has much faster elements) speed up with the pulse, but I would estimate (could be wrong) that your highest frequency significant elements would be around 5hz for a 1.5bps heartrate.
Your example from wikimedia has a signal that is ten times faster than the sample rate - and the nyquist limit says this would be aliased. My back-of-the-envelope calcs above suggest a 5Hz signal at the high end against a 15Hz sampling at the low end, which is a ratio of 3:1, which is enough to satisfy nyquist.
Disclaimer: I am an ex-neuro tech and ex-sleep tech. I am used to sticking electrodes onto people and studying them. The exact form of the pulse wasn't big in my area, so maybe a cardio tech can chime in and correct me.
