1. A method to count people, comprising: determining, by executing an instruction with a processor, an orientation of a head detected in a first frame, the first frame corresponding to a first time, the first time occurring after a second time corresponding to a second frame; selecting, by executing an instruction with the processor, a body region based on the orientation of the detected head; obtaining, with the processor, first image data of the first frame at a location in the first frame corresponding to the selected body region; comparing, with the processor, the first image data of the first frame to second image data of the second frame corresponding to the location via an image data comparison operation; and incrementing, with the processor, a first count of persons when the first image data corresponds to the second image data.