1. A computer-implemented method for background modeling, the method comprising executing on a processor the steps of: determining dimensional gradients for pixel image data extracted from input video data; defining average image pixel gradient models for each pixel of the pixel image data by averaging the determined dimensional gradients with at least one of previous dimensional gradients of the each pixel, and dimensional gradients of neighboring pixels as a function of their distance to the pixel; and constructing and updating background pixel models for a static image scene of the input video data by using data of the averaged pixel dimensional gradient data that has similar orientation and magnitude for each of a plurality of pixel model sets.