Patent ID: 8599261
Filing Date: 2013-12-03
Classification: H04N

Abstract:
1. A method of counting vehicles in a road, the method comprising: producing a video stream of the road; processing the video stream to model a prevailing background model of the road; deriving a smoothed incident image of the road; performing a first detection process comprising: computing a gradient orientation of the prevailing background model and a gradient orientation of the smoothed incident image; constructing, smoothing, and normalizing histograms for the gradient orientations of the prevailing background model and the smoothed incident image to arrive at two density functions; deriving two directional divergences from the density functions; and comparing the directional divergences to determine a greater directional divergence between the smoothed incident image and the prevailing background model; performing a second detection process comprising: computing gradient orientation differentials of the prevailing background model and the smoothed incident image at respective pixel coordinates; constructing a histogram of the gradient orientation differentials, the histogram having numbered bins, each bin having a frequency and corresponding to a successively larger gradient orientation differential; smoothing the histogram; and deriving a ratio of a sum of products of all bin numbers upwards of and including a first bin and respective frequencies to the frequency at a zeroth bin to determine a dissimilarity distance between the smoothed incident image and the prevailing background model; detecting an object in response to the greater directional divergence determined from the first detection process being greater than a first threshold; detecting the object in response to the dissimilarity difference determined by the second detection process being greater than a second threshold; and altering a vehicle count in response to detecting the object.