Abstract: A method for illumination-independent change detection in a pair of original registered gray images based on blob extraction. Blobs are extracted from the two original images and their negatives, using an enhanced blob extraction algorithm based on connectivity analysis along gray-levels. Blobs extracted from the first original and negative images are compared with blobs extracted from the second original and negative images to determine whether each blob has a corresponding blob, i.e. whether it is a matched or unmatched blob. All unmatched blobs are tested for significance as “blobs of change” using a fitness measure based on either a ratio of saliency gradients, or a product of this ratio and a gradient distribution measure.

Abstract: A method for fast motion estimation determines the relative motion between a first and a second image by using either a bi-directional gradient method (BDGM) or a symmetric gradient method (SGM) approach. The global motion, defined by a plurality of parameters in which each parameter has an interval, is estimated by providing an initial estimate of two translation parameters each having an interval of values, dividing each interval into two non-equal (BDGM) or equal (SGM) sub-intervals, and using an iterative process starting with the initial estimate of the two equal sub-intervals. The iterative process calculates the optimal value (BDGM) or a center value (SGM) of the value interval of each parameter and yields a final parameters vector defining the global motion. The bi-directional and the symmetric gradient methods provide faster convergence and smaller linearization error, or convergence in cases where regular gradient methods do not converge.

Abstract: A method for automatic, stable and robust object extraction of moving objects in color video frames, achieved without any prior knowledge of the video content. For high rate video, the method includes providing at least a first and a second high frame rate video frames, performing a reciprocal illumination correction of the first and second video frames to yield respective first and second smoothed frames, performing a change detection operation between the first and second smoothed frames to obtain a difference image, and performing a local adaptive thresholding operation on the difference image to generate a binary image containing extracted objects, the local thresholding operation using a weight test to determine a boundary of each of the extracted objects. For an extracted object with a fragmented boundary, the method further comprises re-unifying the boundary.