A Deformable Triangle-Based Approach for the Interframe Coding of of MRI Sequences

Motion estimation using deformable triangle patches has been successfully used for low bit rate coding of videophone sequences. There were also shown to be particularly efficient for interframe coding of MRI sequences, for which the difference between image slices can be well modelled by affine deformations. Regular triangular meshes were used in previous work. In this paper, we present a quadtree decomposition algorithm to generate a triangle mesh for which smaller triangles are used in image areas where the motion or deformation is more complex. The decomposition algorithm uses a strategy based on rate-distortion theory. The cost of using a new grid point, i.e., the bit rate, is compared to the reduction in prediction error energy that would result if that grid point is used. Grid points are recursively added to areas where the reduction in prediction error is more significant. Results show that using variable size triangular patches increases the SNR of the motion-compensated image while reducing the number of grid points when compared to a regular triangular mesh.

کلیدواژه ها:

Interframe Coding ، Magnetic Resonance Image ، Motion Estimation ، Quadtree Decomposition