Techniques to alleviate the effects of view aliasing artifacts in computedtomography

Due to practical limitations in data acquisition, 3-D computed tomography s ystems must attempt to provide rapid reconstructions of acceptable quality from a Limited number of views. The use of convolution backprojection (CBP) for image reconstruction from an inadequate number of projections, results in view aliasing artifacts. In this paper we investigate different post-pr ocessing methods of alleviating the effects of view aliasing artifacts. Two distinct methods and their variants are considered. The first, termed the intermediate view reprojection (IVR) method, involves estimating a set of i ntermediate views by reprojection, followed by a reconstruction using the a ugmented sec of views. The second, termed the error-correction (EC) method, incorporates a correction on the initial reconstruction based on the proje ction-domain error. Suitable modifications and variants of the above method s are indicated. Of the methods discussed, the IVR method is simple, tends to reduce the effects of artifacts with less susceptibility to secondary ef fects, and is applicable to region-of-interest reconstructions. (C) 1999 Am erican Association of Physicists in Medicine.