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BioMed Research International
Volume 2014, Article ID 634856, 11 pages
http://dx.doi.org/10.1155/2014/634856
Research Article

Figure of Image Quality and Information Capacity in Digital Mammography

1Department of Biomedical Engineering, School of Technological Applications, Technological Educational Institution of Athens, Egaleo, 12210 Athens, Greece
2Department of Computer Science, University of Ioannina, 45110 Ioannina, Greece
3Delta Digital Imaging Centre, 6 Semitelou Street, 11528 Athens, Greece
4Department of Electronic Engineering, School of Technological Applications, Technological Educational Institute (TEI) of Athens, Egaleo, 12210 Athens, Greece
5Department of Energy Technology Engineering, School of Technological Applications, Technological Educational Institute (TEI) of Athens, Egaleo, 12210 Athens, Greece

Received 21 November 2013; Revised 10 February 2014; Accepted 15 February 2014; Published 8 May 2014

Academic Editor: Hidetaka Arimura

Copyright © 2014 Christos M. Michail et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives. In this work, a simple technique to assess the image quality characteristics of the postprocessed image is developed and an easy to use figure of image quality (FIQ) is introduced. This FIQ characterizes images in terms of resolution and noise. In addition information capacity, defined within the context of Shannon’s information theory, was used as an overall image quality index. Materials and Methods. A digital mammographic image was postprocessed with three digital filters. Resolution and noise were calculated via the Modulation Transfer Function (MTF), the coefficient of variation, and the figure of image quality. In addition, frequency dependent parameters such as the noise power spectrum (NPS) and noise equivalent quanta (NEQ) were estimated and used to assess information capacity. Results. FIQs for the “raw image” data and the image processed with the “sharpen edges” filter were found 907.3 and 1906.1, correspondingly. The information capacity values were and  bits/mm2. Conclusion. It was found that, after the application of the postprocessing techniques (even commercial nondedicated software) on the raw digital mammograms, MTF, NPS, and NEQ are improved for medium to high spatial frequencies leading to resolving smaller structures in the final image.