1. A system for processing a raw video stream, comprising: a target presence stage comprising integrated circuitry configured to determine if a current frame of the video stream includes skintone colored pixels by evaluating only pixels included in a thresholding-event region within a markered region that is a subset of a given imaging field of view, and in response to the current frame not including skintone colored pixels, the target presence stage is further configured to stop further processing of the current frame by a subsequent stage; and a gesture processing stage configured to perform at least one of spatial and temporal interpretation of image data within the markered region for frames indicated by the target presence stage as including skintone; wherein pixels outside the markered region are not processed by the target presence or gesture processing stages.