An image's pixels are initially segmented into pixels of the image foreground
and background by comparing the pixels of the image to updated models of background
reference pixels. Pixel structures are identified in the image. The probability
that a pixel is in the background or foreground is refined by considering the initial
segmentation of the pixel's neighbors and the pixel's membership in a pixel structure.
If a pixel is identified as a background pixel it is replaced by a pixel of a new background.
