title: Figure of image quality and information capacity in digital mammography.
abstract: OBJECTIVE
  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.
  
  
  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 60.86 × 10(3) and 78.96 × 10(3) bits/mm(2).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Biomedical Engineering, School of Technological Applications, Technological Educational Institution of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: Christos M
authors.initials: CM
authors.lastname: Michail
authors.affiliation: Department of Biomedical Engineering, School of Technological Applications, Technological Educational Institution of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: Nektarios E
authors.initials: NE
authors.lastname: Kalyvas
authors.affiliation: Department of Biomedical Engineering, School of Technological Applications, Technological Educational Institution of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Valais
authors.affiliation: Department of Computer Science, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Fudos
authors.affiliation: Department of Biomedical Engineering, School of Technological Applications, Technological Educational Institution of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: George P
authors.initials: GP
authors.lastname: Fountos
authors.affiliation: Delta Digital Imaging Centre, 6 Semitelou Street, 11528 Athens, Greece.
authors.forename: Nikos
authors.initials: N
authors.lastname: Dimitropoulos
authors.affiliation: Department of Electronic Engineering, School of Technological Applications, Technological Educational Institute (TEI) of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: Grigorios
authors.identifier: 0000-0002-1697-3670
authors.initials: G
authors.lastname: Koulouras
authors.affiliation: Department of Electronic Engineering, School of Technological Applications, Technological Educational Institute (TEI) of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: Dionisis
authors.identifier: 0000-0001-6388-2803
authors.initials: D
authors.lastname: Kandris
authors.affiliation: Department of Energy Technology Engineering, School of Technological Applications, Technological Educational Institute (TEI) of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: Maria
authors.identifier: 0000-0002-4638-7939
authors.initials: M
authors.lastname: Samarakou
authors.affiliation: Department of Biomedical Engineering, School of Technological Applications, Technological Educational Institution of Athens, Egaleo, 12210 Athens, Greece.
authors.forename: Ioannis S
authors.initials: IS
authors.lastname: Kandarakis
mesh_terms: D000465:Algorithms; D006801:Humans; D008327:Mammography / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D059629:Signal-To-Noise Ratio