Title :
Nonuniform noise propagation by using the ramp filter in fan-beam computed tomography
Author :
Zeng, Gengsheng L.
Author_Institution :
Utah Univ., Salt Lake City, UT, USA
fDate :
6/1/2004 12:00:00 AM
Abstract :
It is observed that when the homogeneity property of the ramp filter is used to derive a filtered backprojection algorithm in fan-beam tomography, the reconstructed images have nonstationary frequency components and nonstationary noise. When a short focal-length is used, higher frequency components are amplified more at the edge of the image than at the center of the image, resulting in higher noise at the edge of the image.
Keywords :
Gaussian noise; computerised tomography; convolution; filtering theory; image reconstruction; iterative methods; medical image processing; Jacobian factor; convolution; fan-beam computed tomography; filter homogeneity property; filtered backprojection algorithm; image reconstruction; nonstationary frequency components; nonstationary noise; nonuniform noise propagation; ramp filter; short focal-length; Computed tomography; Convolution; Detectors; Digital filters; Filtering; Frequency domain analysis; Geometry; Image analysis; Image edge detection; Image reconstruction; Algorithms; Artifacts; Quality Control; Radiographic Image Enhancement; Radiographic Image Interpretation, Computer-Assisted; Reproducibility of Results; Sensitivity and Specificity; Signal Processing, Computer-Assisted; Stochastic Processes; Tomography, Spiral Computed;
Journal_Title :
Medical Imaging, IEEE Transactions on
DOI :
10.1109/TMI.2004.826943
