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2013
Conference Paper
Titel
An accurate method to determine the image lag of flat-panel detectors
Abstract
Ghosting artefacts can lead to significant reduction in image quality, for example a reduction in spatial resolution and contrast in the reconstructed image. Residual signals of previous frames are added to the current frame while the weights of this influence decays exponentially with respect to time. According to the nature of the image lag it follows that the influence correlates with the height of image information changes in a short frame sequence. That means that the higher the absolute derivation values of the projections with respect to time, the higher the influence of the image lag. This effect becomes in general relevant within very fast data acquisition and at height image change rates. Within this paper we will present a simple method to determine the image lag. Based on the standard ASTM E 2597 – 07 (ASTM 2007) which describes various characterization methods for digital detector arrays, we want to advance the method of image lag determination with the intention to be able to cope with these image lag artefacts. While this contribution especially refers to indirect converting X-ray detectors the effect occurs also with direct converting X-ray detectors (Zhao et al. 2005).