A fast and accurate multi-level B-spline approximation with adaptive lattice partitioning and independent subregions transformation

Image warping is an important visual effect tool in entertainment industry and other research field. To date many warping algorithms have been proposed and used such as mesh transformation, radial basis functions, thin plate splines and B-splines (free-form deformations). In particular, the free-form deformation based on B-spline approximation is a powerful and useful morphing algorithm and is proven to have the one-to-one property which can prevent the transformed image from folding back upon itself. In order to minimize the transformation error, a multi-level B-spline approximation has been proposed. Though a natural and smooth morphed image can be obtained by using the multi-level B-spline approximation, it takes a large computation cost. In this paper, we proposed an adaptive lattice partitioning method to reduce the large computation cost and a partial transformation method for enhancement of transformation accuracy. The experimental results show that the proposed methods are more efficient and accurate than conventional multi-level B-spline method.