New Compensation Principles for enhanced image quality in industrial radiology with Digital Detector Arrays

U. Ewert, U. Zscherpel, BAM, Berlin, Germany; K. Bavendiek, YXLON International GmbH, Hamburg, Germany; Jason Robbins, YXLON International Inc., Akron, OH, USA; Cliff Bueno, GE Global Research Center, Niskayuna, NY, USA; Debasish Mishra, GE Global Research, Bangalore, India; Trey Gordon, Boeing Research and Technology, Seattle, WA, USA;

Materials Evaluation, February 2010, Volume 68, Number 2, Pages 163 - 168
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Abstract:
Contrast-to-noise (CNR) management is the key element for image quality control in digital radiology. Modern DDA calibration techniques allow an extraordinary increase of CNR in comparison to all other digital detectors and film. Contrast reduction due to increase of X-ray energy can be overcompensated by noise reduction. This enables the reduction of acquisition time and increase of the thickness range per radiograph. Even limitations in the spatial resolution, constrained by the individual picture element (pixel) size of the detector, can be compensated with an increased CNR. Bad pixel management of DDAs in combination with CNR enhancement enables the safe application of this technology for film replacement. Considering these points, three compensation principles have been formulated for the implementation of DDAs as a viable film replacement technology: 1st Compensation of reduced contrast (μeff) by increased signal-to-noise ratio (SNR): If optimization of contrast cannot be achieved, the noise must be reduced (i.e., increased SNR). If contrast can be increased, there is more tolerance for higher noise (moderate or lower SNR can be used). 2nd Compensation of insufficient detector sharpness (high unsharpness) by increased SNR. 3rd Compensation of interpolation unsharpness, due to bad pixel correction, by increased SNR.