CRM: Centro De Giorgi
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Mathematical and Computational Aspects of Machine Learning

Unrolled ISTA and convolutional neural networks for limited-angle tomography reconstruction

speaker: Mathilde Galinier (Università degli studi di Modena e Reggio Emilia)

abstract: Computed Tomography makes use of computer-processed combinations of many X-ray measurements of an object, taken from different angles, and attempts to recover the inner structure of the object from the data. In the case of limited-angle tomography, the reconstruction problem is severely ill-posed and the traditional reconstruction methods, e.g. filtered backprojection (FBP), do not perform well. In this work, we investigate a brand-new method for limited-angle tomography reconstruction, based on the unrolled version of the ISTA algorithm where each iteration contains a convolutional neural network (CNN). The idea of this project has emerged from the observation that the backprojection operator can be approximated by a sequence of convolutions applied to the original object in the wavelet domain. Thus, each CNN has the same structure as the previously mentioned sequence of convolutions.

Wed 9 Oct, 17:20 - 17:40, Aula Dini
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