<title>Comparison of different quantization strategies for subband coding of medical images</title>

Abstract

In this paper di erent methods for the quantization of wavelet transform coe cients are compared in view of medical imaging applications. The goal is to provide users with a comprehensive and application oriented review of these techniques.Coding methods based on subband transforms are commonly used for image compression in a wide range of applications. In recent y ears, wavelet based methods have also been applied to medical images, and the rst commercial implementations of such techniques have appeared. 1 The issues related to clinical reliability o f processed images, together with additional features which will be o ered by future coding schemes render the conventional evaluation criteria e.g. PSNR insu cient. In this paper, the performance of four quantization methods namely standard Scalar Quantization , Embedded Zerotree, Variable Dimension Vector Quantization and Pyramid Vector Quantization are compared with regard to their application in the eld of medical imaging. In addition to the standard rate distortion criterion, we t o o k i n to account the possibility of bitrate control, the feasibility of real-time implementation, the genericity for use in non-dedicated multimedia environments of each approach. In addition, the diagnostical reliability of the decompressed images has been assessed during a viewing session and the help of a specialist.