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 one of the sets of pixels: identifying a radiance value for the pixel and for each pixel within a spatial neighborhood of the pixel, 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 a first one of the sets of pixels indicate that a sudden illumination change has occurred, reclassifying the pixels in the first set of pixels as depicting a background of the scene depicted by the sequence of video frames.