Many imaging technologies rely on tomographic reconstruction, which requires solving a multidimensional inverse problem given a finite number of projections. Backprojection is a popular class of algorithm for tomographic reconstruction, however it typically results in poor image reconstructions when the projection angles are sparse and/or if the sensors characteristics are not uniform. Several deep learning based algorithms have been developed to solve this inverse problem and reconstruct the image using a limited number of projections. However these algorithms typically require examples of the ground-truth (i.e. examples of reconstructed images) to yield good performance. In this paper, we introduce an unsupervised sparse-view backprojection algorithm, which does not require ground-truth. The algorithm consists of two modules in a generator-projector framework; a convolutional neural network and a spatial transformer network. We evaluated our algorithm using computed tomography (CT) images of the human chest. We show that our algorithm significantly out-performs filtered backprojection when the projection angles are very sparse, as well as when the sensor characteristics vary for different angles. Our approach has practical applications for medical imaging and other imaging modalities (e.g. radar) where sparse and/or non-uniform projections may be acquired due to time or sampling constraints.
Multigrid Backprojection Super-Resolution and Deep Filter Visualization
BOE Technology Group Inc., Ltd.(京东方科技集团股份有限公司);Beijing(北京(注意:根据提取规则,城市名称不属于机构,此处仅为原文出现的地点信息,若严格按规则,可能不满足,但根据问题中“明确出现作者单位时才输出”,此处“Beijing”可能被误标,但按原文处理))
Medical Image Segmentation via Unsupervised Convolutional Neural Network
Johns Hopkins Medical Institutes(约翰斯·霍普金斯医学院);Johns Hopkins University(约翰斯·霍普金斯大学);Department of Radiology and Radiological Science(放射学与放射科学系);Department of Electrical and Computer Engineering(电气与计算机工程系)
Fully Unsupervised Diversity Denoising with Convolutional Variational Autoencoders
Center for Systems Biology Dresden(德累斯顿系统生物学中心);Max-Planck Institute (CBG)(马克斯·普朗克分子细胞生物学与遗传学研究所);School of Computer Science(计算机科学学院);University of Birmingham(伯明翰大学);Fondazione Human Technopole(人类技术基金会)
Unsupervised brain lesion segmentation from MRI using a convolutional autoencoder
University of Iceland(冰岛大学);Landspitali - University Hospital(兰斯皮塔利大学医院);The Icelandic Heart Association(冰岛心脏协会);The Johns Hopkins University(约翰斯·霍普金斯大学)
Coupled Convolutional Neural Network with Adaptive Response Function Learning for Unsupervised Hyperspectral Super-Resolution
Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences(中国科学院空天信息创新研究院数字地球科学重点实验室);Flemish Institute for Technological Research (VITO)(弗拉芒技术研究院);IMEC Research Group, Ghent University(根特大学IMEC研究组);Remote Sensing Technology Institute (IMF), German Aerospace Center (DLR)(德国航空航天中心遥感技术研究所)