Title :
Image restoration in computed tomography: restoration of experimental CT images
Author :
Rathee, Satyapal ; Koles, Zoly J. ; Overton, Thomas R.
Author_Institution :
Dept. of Appl. Sci. in Med., Alberta Univ., Edmonton, Alta., Canada
fDate :
12/1/1992 12:00:00 AM
Abstract :
It is pointed out that to restore experimental computed tomography (CT) images which have been blurred by a spatially variant point spread function (PSF), a quadrant symmetry method which simultaneously optimizes storage requirements for the estimated PSFs and computational speed is used. The quadrant symmetry approach required less than 0.579 Megawords of storage for 9×9 pixel spatially variant PSFs in a 256×256 pixel image, allowing image restoration in Cartesian coordinates. A locally adaptive restoration method formulated using a noise prewhitening filter derived from the measured noise power spectrum, the conjugate gradient method was used to obtain a numerical solution. Restored images for a resolution phantom and for a cadaver femur are presented
Keywords :
computerised tomography; medical diagnostic computing; medical image processing; Cartesian coordinates; blurred images restoration; cadaver femur; computational speed; conjugate gradient method; experimental CT images restoration; locally adaptive restoration method; noise power spectrum; noise prewhitening filter; numerical solution; quadrant symmetry approach; resolution phantom; spatially variant point spread function; storage requirements optimization; Adaptive filters; Computed tomography; Gradient methods; Image restoration; Image storage; Noise measurement; Optimization methods; Pixel; Power measurement; Spatial resolution;
Journal_Title :
Medical Imaging, IEEE Transactions on
