Defect Interpolation in Digital Radiography - How Object-Oriented Transform Coding Helps

T. Aach, V. Metzler


Today's solid state flat panel radiography detectors provide images which contain artifacts caused by lines, columns and clusters of inactive pixels. If not too large, such defects can be filled by interpolation algorithms which usually work in the spatial domain. This paper describes an alternative spectral domain approach to defect interpolation. The acquired radiograph is modelled as the undistorted image multiplied by a known binary defect window. The window effect is then removed by deconvolving the window spectrum from the spectrum of the observed, distorted radiograph. The basic ingredient of our interpolation algorithm is an earlier approach to block transform coding of arbitrarily shaped image segments, that extrapolates the segment internal intensities over a block into which the segment is embedded. For defect interpolation, the arbitrarily shaped segment is formed by a local image region with defects, thus turning extrapolation into defect interpolation. Our algorithm reconstructs both oriented structures and noise-like information in a natural-looking manner, even for large defects. Moreover, our concept can also be applied to non-binary defect windows, e.g. for gain correction.

Original languageEnglish
Title of host publicationMedical Imaging 2001: Image Processing
Number of pages12
Publication date01.01.2001
ISBN (Print)978-0819440082
Publication statusPublished - 01.01.2001
EventMedical Imaging 2001 - San Diego, United States
Duration: 17.02.200122.02.2001


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