نتایج جستجو برای: filtered backprojection contrast to noise ratio

تعداد نتایج: 10727429  

Journal: :Applied and Computational Harmonic Analysis 1999

2012
Yang De-gui Li Xiang

In recent years, many researchers have made a lot of works and achieved remarkable results. The system effect distance is deduced from different aspects in [1, 2]. Target range is obtained based on the target movement model in [3]. [4] studies the passive ranging of ground target in mono-static and single band condition based on radiance difference between target and background. Ranging express...

Journal: :Medical physics 2003
Yangbo Ye Jiehua Zhu Ge Wang

Computed tomography (CT) is one of the most important areas in the modern science and technology. The most popular approach for image reconstruction is filtered backprojection. It is essential to understand the limit behavior of the filtered backprojection algorithms. The classic results on the limit of image reconstruction are typically done in the norm sense. In this paper, we use the method ...

2008
Adam Wunderlich Frédéric Noo

We consider noise in computed tomography images that are reconstructed using the classical direct fan-beam filtered backprojection algorithm, from both fulland short-scan data. A new, accurate method for computing image covariance is presented. The utility of the new covariance method is demonstrated by its application to the implementation of a channelized Hotelling observer for a lesion detec...

2002
Mats I. Pettersson

ABSTRACT A likelihood ratio test is proposed for moving target detection in an ultra wide frequency band and wide antenna beam (wide band) SAR system. The developed method combines time domain fast backprojection SAR processing methods with moving target detection. It saves computational load when all relative speeds can be tested using the same clutter suppressed sub-aperture beams. The propos...

Journal: :Magnetic resonance in medicine 2006
C A Mistretta O Wieben J Velikina W Block J Perry Y Wu K Johnson

Recent work in k-t BLAST and undersampled projection angiography has emphasized the value of using training data sets obtained during the acquisition of a series of images. These techniques have used iterative algorithms guided by the training set information to reconstruct time frames sampled at well below the Nyquist limit. We present here a simple non-iterative unfiltered backprojection algo...

2015
Daniël M. Pelt Kees Joost Batenburg

In computed tomography, algebraic reconstruction methods tend to produce reconstructions with higher quality than analytical methods when presented with limited and noisy projection data. The high computational requirements of algebraic methods, however, limit their usefulness in practice. In this paper, we propose a method to approximate the algebraic SIRT method by the computationally efficie...

2009
E. A. Borisch C. R. Haider R. C. Grimm S. J. Riederer

INTRODUCTION The use of a pre-contrast reference image, referred to as a mask, to suppress background signal and improve output contrast-to-noise ratio (CNR) through subtraction is common in contrast-enhanced MR angiography. It is critical that this operation be performed to optimize output image quality. As has been previously reported [1-3] it is advantageous to use complex subtraction for th...

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