3D medical image coding using separable 3D wavelet decomposition and lattice vector quantization

An original 3D subband coding scheme is proposed. A separable 3D wavelet, taking full advantage of the 3D structures correlation, decomposes the original volume into subvolumes which can be separately quantized by a uniform scalar quantizer or by a 3D lattice vector quantizer. Concentric hyper-pyramids lying on the cubic lattice are used for searching codewords. A distortion minimization algorithm both selects the best number of decomposition and the best set of quantizers in order to minimize the overall mean square error. The whole algorithm is applied on a 3D image data base issued from the Morphometer (a new true 3D X-Ray scanner). The results presented include traditional signal-to-noise ratio performances and a subjective evaluation made by radiologists. (C) 1997 Elsevier Science B.V.