1. A computer-implemented method for detecting a sudden illumination change (SIC) in a sequence of video frames, comprising: receiving a current video frame, of the sequence of video frames; identifying one or more sets of pixels in the current video frame, wherein each set of pixels is classified as depicting a foreground object; for each pixel in at least a first one of the sets of pixels: identifying a radiance value for the pixel and for each pixel within a spatial neighborhood of the pixel, and determining, for the pixel, whether the radiance values for the pixel and the pixels in the spatial neighborhood indicate that a sudden illumination change has occurred in a scene depicted by the sequence of video frames; and upon determining that a majority of pixels in the first set of pixels indicate that a sudden illumination change has occurred, reclassifying one or more pixels in the first set of pixels as depicting a background of the scene in the current frame, wherein the reclassified pixels were classified as depicting scene background in one or more frames prior to the current frame.