The Structural SIMilarity Measure (SSIM) combined with the
sequential Monte Carlo approach has been shown  to achieve more reliable video object tracking performance, compared with similar methods based on colour and edge histograms and Bhattacharyya distance. However, the combined use of the structural similarity and a particle filter results in increased computational complexity of the algorithm. In this paper, a novel fast approach for video tracking based on the structural similarity measure is presented. The tracking algorithm proposed determines the state of the target (location, size) based on the gradient ascent procedure applied to the structural similarity surface of the video frame, thus avoiding computationally expensive sampling of the state space. The new method, while being computationally less expensive, has shown
higher accuracy compared with the standard mean shift algorithm and the SSIM Particle Filter (SSIM-PF)  and its performance is illustrated over real video sequences.