AbstractID: 7862 Title: Contrast enhancement by digital equalization (CEDE) in chest radiography
We are developing an image processing algorithm for use in radiography which is
conceptually similar to the Advanced Multiple Beam Equalization Radiography
(AMBER) system. This contrast enhancement by digital equalization (CEDE) algorithm
uses chest digital projection data to generate a template which is used to reduce the
dynamic range of the acquired data. Two key parameters relate the region of interest
(ROI) and the smoothing kernel size (KS). In this study, we investigated the importance
of the ROI and KS for processing chest radiographs. Three chest radiographs were
obtained using a commercial CR system, with image receptor air kerma of at least 10
µGy. Images were processed using the CEDE algorithm with ROI values between 162 &
5122 pixels and KS values between 64 and 512. For each chest radiograph, between 40
and 45 combinations of ROI/KS were investigated, with processed chest images
displayed on a 5 megapixel dual monitor display. An experienced chest radiologist
compared the image quality of the CEDE algorithm with that of the corresponding
original chest x-ray using a five point scale (1 = significantly poorer; 3 = no difference; 5
= significantly improved). The optimal ROI was found to be ~2562, and the optimal KS
was also ~256. The CEDE algorithm markedly improved visibility of the trachea,
thoracic aorta, retro-cardiac structures and the azygo-esophageal recess line. Major
improvements in overall image quality were achieved, with average scores for the
optimal parameters typically ranging between 4 and 5.