Share Email Print

Proceedings Paper

Digital Image Processing: Effects Of Metz Filters And Matched Filters On Detection Of Simple Radiographic Objects
Author(s): Heang -Ping Chan; Kunio Doi; Charles E. Metz
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

We studied the effect of image processing with Metz filters and matched filters on the detection of simulated low-contrast square objects superimposed on radiographic mottle. The signal-to-noise ratios (SNRs) of original and processed images were calculated based on the perceived statistical decision theory model by taking into account the internal noise of a human observer's eye-brain system. Threshold contrasts for objects of various sizes were predicted by assuming a threshold SNR of 3.8 which was determined previously for a 50% correct detection in 18 alternative forced-choice experiments. The relative performance of various image processing techniques was also evaluated experimentally with a contrast-detail diagram method. The simulated images were generated by a high-quality digital image processing and simulation system. The digitized images were Fourier-trans-formed, filtered, inversely Fourier-transformed, and/or contrast-enhanced to produce the processed images. The contrast-detail curves of the original or processed images were obtained by averaging the results of four image samples and twelve observers. Both the theoretical prediction and the C-D experiment demonstrated an improvement in detectabilities of the simple test objects over those of the original images. However, the observers seemed to under-read the filtered images in the sense that the improvement in obser-ver performance was slightly less than the prediction. This is probably caused by the changes in appearance of the object and the noise texture in the filtered images. The usefulness and limitations of the Metz filters and matched filters in comparison with other image processing techniques are discussed.

Paper Details

Date Published: 15 June 1984
PDF: 13 pages
Proc. SPIE 0454, Application of Optical Instrumentation in Medicine XII, (15 June 1984); doi: 10.1117/12.939362
Show Author Affiliations
Heang -Ping Chan, The University of Chicago (United States)
Kunio Doi, The University of Chicago (United States)
Charles E. Metz, The University of Chicago (United States)

Published in SPIE Proceedings Vol. 0454:
Application of Optical Instrumentation in Medicine XII
Samuel J. Dwyer; Roger H. Schneider, Editor(s)

© SPIE. Terms of Use
Back to Top