Systems and methods are disclosed to measure a PPG signal. In some embodiments, a method may include capturing a plurality of frames of a subject; tracking the position of a region of interest of the subject in each of the plurality of frames; creating a first time series signal, a second time series signal, and third time series signal corresponding with respective color channels of the plurality of frames; normalizing the first, second, and third time series signals, combining the normalized first time series signal, the normalized first time series signal, and the normalized first time series signal into a combined signal; creating a spectral signal from the combined signal; and extracting the PPG signal from the spectral signal.