1. A method comprising: receiving a first frame captured by an imaging device; designating the first frame as a key; generating at least one feature map to identify features in the key frame; receiving a second frame captured by the imaging device; designating the second frame as a current frame; applying a flow estimation algorithm to the key frame and current frame to generate a flow field representing a flow from the key frame to the current frame; and propagating each of the at least one feature maps based on the flow field to approximate current locations of features identified within each of the at least one feature maps; and wherein frames are received from the imaging device at a rate of a plurality of frames per second and a time or frame count interval is set for when to re-designate the key frame to restart the method.