Analysis of displacement compensation methods for wavelet lifting of medical 3-D thorax CT volume data

TL;DR

This paper analyzes displacement compensation methods for wavelet lifting in medical 3-D thorax CT data, demonstrating significant improvements in coding gain and image quality over traditional methods.

Contribution

It introduces and compares two displacement compensation techniques for wavelet transforms in medical CT, showing substantial enhancements in compression efficiency and image quality.

Findings

Transform coding gain doubled with compensation.

Lowpass band PSNR increased by 8 dB.

Displacement compensation improves wavelet coding for CT data.

Abstract

A huge advantage of the wavelet transform in image and video compression is its scalability. Wavelet-based coding of medical computed tomography (CT) data becomes more and more popular. While much effort has been spent on encoding of the wavelet coefficients, the extension of the transform by a compensation method as in video coding has not gained much attention so far. We will analyze two compensation methods for medical CT data and compare the characteristics of the displacement compensated wavelet transform with video data. We will show that for thorax CT data the transform coding gain can be improved by a factor of 2 and the quality of the lowpass band can be improved by 8 dB in terms of PSNR compared to the original transform without compensation.