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CNN-Based Projected Gradient Descent for Consistent CT Image Reconstruction

delete2018-06-01
delete280
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OA
AI
H
Harshit Gupta *
K
Kyong Hwan Jin
N
Nguyen, Ha Q.
M
Michael T. McCann
M
Michaël Unser
DOI:10.1109/TMI.2018.2832656delete
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Abstract

Abstract

En 中文
We present a new image reconstruction method that replaces the projector in a projected gradient descent (PGD) with a convolutional neural network (CNN). Recently, CNNs trained as image-to-image regressors have been successfully used to solve inverse problems in imaging. However, unlike existing iterative image reconstruction algorithms, these CNN-based approaches usually lack a feedback mechanism to enforce that the reconstructed image is consistent with the measurements. We propose a relaxed version of PGD wherein gradient descent enforces measurement consistency, while a CNN recursively projects the solution closer to the space of desired reconstruction images. We show that this algorithm is guaranteed to converge and, under certain conditions, converges to a local minimum of a non-convex inverse problem. Finally, we propose a simple scheme to train the CNN to act like a projector. Our experiments on sparse-view computed-tomography reconstruction show an improvement over total variation-based regularization, dictionary learning, and a state-of-the-art deep learning-based direct reconstruction technique.
Keywords:
Deep learning
inverse problems
biomedical image reconstruction
low-dose computed tomography
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Journal

IEEE Transactions on Medical Imaging cover
IEEE Transactions on Medical Imaging
IF:
9.8
Papers:
6.2K
Citations:
3.7W

Organization

S
swiss federal institutes of technology domain
Scholars:
9.0W
Papers: 8.0W
Citations: 163