Subjective evaluation of image enhancements in improving the visibility of pathology in chest radiographs
B. Plessis, Morris Goldberg, G. Bélanger, Nancy M. Hickey · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1991
In this paper we report on an experiment to compare the relevance of various image enhancement methods for improving the visibility of pathologies on digitized chest radiographs. The five pathologies tested in our trial are pulmonary nodules, air bronchograms, paratracheal abnormalities, pneumothoraces, interstitial lung diseases. The first three are examples of situations where focus is put on shape, borders and content of the pathology, the next is an example of situations where the visualization of a subtle line is required and the last one is an example of diffuse disease where the perceivability of details is important. Eight image enhancements were tested and included both pixel based gray-level transformation such as, windowing, statistical differencing, polynomial transform, histogram equalization, histogram hyperbolization, and spatial enhancement such as, unsharp masking with different masks and a Sobel detector. For each pathology we recommend two or three acceptable transformations.