A predictive classified vector quantizer and its subjective quality evaluation for X-ray CT images

Author

Lee, Heesub ; Kim, Yongmin ; Riskin, Eve A. ; Rowberg, Alan H. ; Frank, Mark S.

Author_Institution

Dept. of Electr. Eng., Washington Univ., Seattle, WA, USA

Volume

14

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

397

Lastpage

406

Abstract

The authors have developed a new classified vector quantizer (CVQ) using decomposition and prediction which does not need to store or transmit any side information. To obtain better quality in the compressed images, human visual perception characteristics are applied to the classification and bit allocation. This CVQ has been subjectively evaluated for a sequence of X-ray CT images and compared to a DCT coding method. Nine X-ray CT head images from three patients are compressed at 10:1 and 15:1 compression ratios and are evaluated by 13 radiologists. The evaluation data are analyzed statistically with analysis of variance and Tukey´s multiple comparison. Even though there are large variations in judging image quality among readers, the proposed algorithm has shown significantly better quality than the DCT at a statistical, significance level of 0.05. Only an interframe CVQ can reproduce the quality of the originals at 10:1 compression at the same significance level. While the CVQ can reproduce compressed images that are not statistically different from the originals in quality, the effect on diagnostic accuracy remains to be investigated

Keywords

computerised tomography; image sequences; medical image processing; vector quantisation; visual perception; DCT coding method; Tukey´s multiple comparison; X-ray CT head images; analysis of variance; bit allocation; classification; compression ratio; decomposition; diagnostic accuracy; human visual perception characteristics; image quality judgement; medical diagnostic imaging; prediction; predictive classified vector quantizer; side information; subjective quality evaluation; Analysis of variance; Bit rate; Computed tomography; Data analysis; Discrete cosine transforms; Head; Humans; Image coding; Visual perception; X-ray imaging;

fLanguage

English

Journal_Title

Medical Imaging, IEEE Transactions on

Publisher

ieee

ISSN

0278-0062

Type

jour

DOI

10.1109/42.387720

Filename

387720