Three-dimensional (3D) reconstruction of electron tomography (ET) has emerged as an important technique in analyzing structures of complex biological samples. However most of existing reconstruction methods are not suitable for extremely noisy and incomplete data conditions. We present an adaptive simultaneous algebraic reconstruction technique (ASART) in which a modified multilevel access sche...

SPECT images are observation data acquired by a gamma-camera following an orbit around the patient’s body, at regularly spaced angles. A reconstructed image is the discrete representation of a slice or cross-section of the isotope distribution within the patient, transversal to the gamma-camera rotation axis. Bayesian reconstruction methods have been extensively used to reconstruct medical imag...

An iterative method is presented for computed tomography imaging spectrometer (CTIS) image reconstruction in the presence of both photon noise in the image and postdetection Gaussian system noise. The new algorithm, which assumes the transfer matrix of the system has a particular structure, is evaluated experimentally with the result that it is significantly better, for larger problems, than bo...

Electron Magnetic Resonance Imaging (EMRI) is emerging as a potential tool for noninvasive imaging of free radicals in biological systems. The EMR images are generally reconstructed using the filtered back projection (FBP) method, because of its speed and simplicity. But, the FBP method fails when reconstruction is attempted with limited number of projections or with noisy projections. In addit...

We study empirically four algebraic-reconstruction techniques (ART methods): Kaczmarz’s method, Symmetric Kaczmarz, Randomized Kaczmarz, and Simultaneous ART (SART). The performance of these methods depends on a relaxation parameter, whose role has not been understood completely. We use a simple heuristic for finding a good relaxation parameter for each of these methods and investigate their be...

We determined the variations in seismic structure beneath southern California by using a tomographic method of inversion on teleseismic P delays recorded with the Southern California Array. The algorithm employed was a modified form of an Algebraic Reconstruction Technique (ART) used in medical X-ray imaging. Deconvolution with an empirically estimated point spread function was also used to hel...