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Proceedings Paper

Observer detection of image degradation caused by irreversible data compression processes
Author(s): Ji Chen; Michael J. Flynn; Barry Gross; David Spizarny
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Paper Abstract

Irreversible data compression methods have been proposed to reduce the data storage and communication requirements of digital imaging systems. In general, the error produced by compression increases as an algorithm''s compression ratio is increased. We have studied the relationship between compression ratios and the detection of induced error using radiologic observers. The nature of the errors was characterized by calculating the power spectrum of the difference image. In contrast with studies designed to test whether detected errors alter diagnostic decisions, this study was designed to test whether observers could detect the induced error. A paired-film observer study was designed to test whether induced errors were detected. The study was conducted with chest radiographs selected and ranked for subtle evidence of interstitial disease, pulmonary nodules, or pneumothoraces. Images were digitized at 86 microns (4K X 5K) and 2K X 2K regions were extracted. A full-frame discrete cosine transform method was used to compress images at ratios varying between 6:1 and 60:1. The decompressed images were reprinted next to the original images in a randomized order with a laser film printer. The use of a film digitizer and a film printer which can reproduce all of the contrast and detail in the original radiograph makes the results of this study insensitive to instrument performance and primarily dependent on radiographic image quality. The results of this study define conditions for which errors associated with irreversible compression cannot be detected by radiologic observers. The results indicate that an observer can detect the errors introduced by this compression algorithm for compression ratios of 10:1 (1.2 bits/pixel) or higher.

Paper Details

Date Published: 1 May 1991
PDF: 9 pages
Proc. SPIE 1444, Medical Imaging V: Image Capture, Formatting, and Display, (1 May 1991); doi: 10.1117/12.45177
Show Author Affiliations
Ji Chen, Henry Ford Hospital (United States)
Michael J. Flynn, Henry Ford Hospital (United States)
Barry Gross, Henry Ford Hospital (United States)
David Spizarny, Henry Ford Hospital (United States)

Published in SPIE Proceedings Vol. 1444:
Medical Imaging V: Image Capture, Formatting, and Display
Yongmin Kim, Editor(s)

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