Noise characterization of combined Bellini-type attenuation correction and frequency-distance principle restoration filtering
- College of the Holy Cross, Worcester, MA (United States). Dept. of Mathematics
- Univ. of Massachusetts Medical Center, Worcester, MA (United States). Dept. of Nuclear Medicine
In this paper, the authors investigate how successive processing of the projection data with Bellini-type (BT) attenuation correction, frequency-distance principle (FDP) restoration filtering, and filtered-backprojection (FBP) reconstruction propagates noise into the reconstructed image. The BT methods, which are Fourier-domain correction techniques, are all exact solutions to the attenuated Radon transform under the constraints of uniform attenuation and a convex object contour. The FDP states that points in the object at a specified distance from the center-of-rotation will contribute predominantly to particular regions of the Fourier transform-series expansion of the sinogram. Using this frequency-distance information, the nonstationary response of the collimator can ideally be deconvolved using an inverse filter. In the presence of noise, however, the FDP filter needs to be regularized in order to control noise amplification caused by the deconvolution. The noise is characterized by calculating the population covariance matrix of the projection data after successive processing with BT attenuation correction and FDP filtering and of the reconstructed image after FBP reconstruction. This is done for a simulated point-source located near the edge of an elliptical, uniformly attenuating medium. In the study, the authors consider the two implementational combinations of BT correction and FDP filtering that allow for sequential processing of the projection data, which they call mirroring and no mirroring.
- OSTI ID:
- 458235
- Report Number(s):
- CONF-951073--
- Journal Information:
- IEEE Transactions on Nuclear Science, Journal Name: IEEE Transactions on Nuclear Science Journal Issue: 6Pt2 Vol. 43; ISSN 0018-9499; ISSN IETNAE
- Country of Publication:
- United States
- Language:
- English
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