ROC-Analyse zur Bildnachverarbeitung digitaler Thoraxaufnahmen

Abstract

Storage phosphor radiographs are equal to the tested analog screen-film-system. The optimization of post-processing can be helpful in the prevention of routine multiple documentations.

Effects of Varying Filter Kernel Sizes on the Image Quality of Interstitial Lung Diseases

“…Although the edge-enhanc ing imaging mode (DLR II) and the small filter ker nel S 5 slightly improve the signal-to-noise ratio at a spatial frequency of 2 lp/mm (17), linear details can often only be differentiated from vascular and rib contours with great difficulty because these struc tures are represented as enhanced. Large filter ker nels, by comparison, improve the image characteris tics by a higher number of interrelated pixels, an ef fect which is described by PROKOP et al (20).…”

Roc-Analysisc of Detection Performance by Analogue and Digital Plain Film Systems in Chest Radiography

“…On the other hand, digital luminescence radio graphs can be produced without difficulty by using existing X-ray equipment and are now providing good image quality not only in upright but also in portable chest radiography (7,10,13,20,29,30,32,37). By means of electronic exposure compensation, high contrast range of object, and optimisation of contrast and brightness, the digital technology in creases the transparency of the radioabsorbent me diastinum (4,19,38).…”

“…All digital images were obtained by using the unsharp masking technique (1,17). The images were sub jected to optimised frequency-filtered image post processing with a kernel size of S 40 (11.31x11.31 mm) and an enhancement factor k=l .5 with Gaussian filtering (20). In addition, a special image processing algorithm, called adaptive enhancement (AE), was used in which only the image sections in the poorly penetrated mediastinal and diaphragmatic regions were subjected to edge enhancement (k= 1.0) while in the region of the lung parenchyma the image charac teristics were left unchanged.…”

“…Various technical inno vations designed to further optimise image quality have therefore been tried. In addition to "L-films" with lower contrast and a wider dynamic range (24) and lung filters (25,34), which have been used for some time to enhance transparency in the mediasti num, these include the AMBER technique (2,5,14,31,35) and digital luminescence radiography (7, 13, 20,21,27,29,32). However, some of these proce dures are cumbersome to use or require additional expensive technology.…”

Computer aided diagnosis in chest radiography

“…Similarly we shall not go into detail about studies that quantify the performance of radiologists, usually through observer studies, when image quality parameters of the chest radiographs are varied (e.g. [170,169,166,254,46,50,210]). Furthermore, research on classifiers that estimate probabilities that patients exhibit a certain disease, given a number of features from clinical information and/or output of computer algorithms is largely ignored here since this work belongs to the field of pattern classification instead of medical image processing.…”