1. A method of identifying operational mode shapes of an object in a video stream, the method comprising: extracting pixel-wise Eulerian motion signals of an object from an undercomplete representation of frames within a video stream; downselecting signals from the pixel-wise Eulerian motion signals to produce a representative set of Eulerian motion signals of the object; and identifying operational mode shapes of the object based on the representative set of Eulerian motion signals from the undercomplete representation of the frames within the video stream.