A wavelet-based method for multiscale tomographic reconstruction
- Boston Univ., MA (United States). Dept. of Electrical, Computer, and Systems Engineering
- Massachusetts Inst. of Tech., Cambridge, MA (United States)
The authors represent the standard ramp filter operator of the filtered-back-projection (FBP) reconstruction in different bases composed of Haar and Daubechies compactly supported wavelets. The resulting multiscale representation of the ramp-filter matrix operator is approximately diagonal. The accuracy of this diagonal approximation becomes better as wavelets with larger numbers of vanishing moments are used. This wavelet-based representation enables them to formulate a multiscale tomographic reconstruction technique in which the object is reconstructed at multiple scales or resolutions. A complete reconstruction is obtained by combining the reconstructions at different scales. The multiscale reconstruction technique has the same computational complexity as the FBP reconstruction method. It differs from other multiscale reconstruction techniques in that (1) the object is defined through a one-dimensional multiscale transformation of the projection domain, and (2) they explicitly account for noise in the projections data by calculating maximum a posteriori probability (MAP) multiscale reconstruction estimates based on a chosen fractal prior on the multiscale object coefficients. The computational complexity of this maximum a posteriori probability (MAP) solution is also the same as that of the FBP reconstruction. This result is in contrast to commonly used methods of statistical regularization, which result in computationally intensive optimization algorithms.
- OSTI ID:
- 207912
- Journal Information:
- IEEE Transactions on Medical Imaging, Vol. 15, Issue 1; Other Information: PBD: Feb 1996
- Country of Publication:
- United States
- Language:
- English
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