1. A computer-implemented surveillance method for tracking a target in a featureless background, the method comprising the steps of: providing a real imaging means forming a pair of first and second images of a real space in a field of view of the imaging means, the field of view having a center; storing the pair of first and second images in non-transitory memory; performing, with a processor, a correlation operation on the pair of first and second images for forming a resultant image including blobs corresponding to elements in the real space and then storing the resultant image in the non-transitory memory; detecting and discarding portions of the blobs which correspond to shadows by: defining a bounding box around one of the blobs; defining a first half of the bounding box, an opposed second half of the bounding box, a first part of the bounding box in the first half, and a separate second part of the bounding box in the second half; computing a first column-sum ratio for the first part; computing a second column-sum ratio for the second part; and either discarding a portion of the one of the blobs in the second half of the bounding box if the first column-sum ratio is greater than a user-defined threshold, or discarding another portion of the one of the blobs in the first half of the bounding box if the second column-sum ratio is greater than the user-defined threshold; selecting a target from the blobs, the target having a centroid; tracking the target by moving the imaging means toward the centroid by an amount corresponding to the distance between the centroid and the center of the field of view; and continually repeating the tracking step as the target moves in the real space.