This paper presents an interframe coding method for volumetric medical images by treating interslice variation as a motion. Instead of a block matching algorithm (BMA), which is the most common motion estimation (ME) algorithm in video coding, image warping with affine transformation or bilinear transformation is used to predict complex motions in medical images. When an object disappears between slices, warping prediction has poor performance. In order to overcome this drawback, an overlapped block motion compensation (OBMC) technique is combined with warping prediction. Motion compensated residual error images are then encoded by using an embedded zerotree wavelet (EZW) coder with small modification for consistent quality of reconstructed images.
In the proposed method, interframe coding provides better performance compared with intraframe coding, and the MC scheme based on warping and OBMC improves the PSNR compared with the conventional BMA.