1. A method for using structured light in a handheld projection device, the method comprising: projecting a structured light pattern in at least one portion of a frame being projected by the handheld projection device, wherein the at least one portion of the frame is a subset of the frame; capturing an image of the projected frame; computing scene depth information based on the structured light pattern in the captured image; and using the scene depth information in processing of a subsequent frame of the video stream.