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arXiv 2104.05495cs.CVeess.IV
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一种用于图像分割的MRF-UNet专家积

An MRF-UNet Product of Experts for Image Segmentation

School of Biomedical Engineering & Imaging Sciences, KCL(伦敦国王学院生物医学工程与影像科学学院);Athinoula A. Martinos Center for Biomedical Imaging, MGH and HMS(马萨诸塞总医院与哈佛医学院阿西努拉·A·马蒂诺斯生物医学影像中心);Wellcome Center for Human Neuroimaging, UCL(伦敦大学学院惠康人类神经影像中心);Institute of Cognitive Neuroscience, UCL(伦敦大学学院认知神经科学研究所);Institute of Neurology, UCL(伦敦大学学院神经病学研究所)

Mikael Brudfors, Yaël Balbastre, John Ashburner, Geraint Rees, Parashkev Nachev, Sébastien Ourselin, M. Jorge Cardoso

摘要:

虽然通过反向传播训练的卷积神经网络(CNN)在语义分割任务中取得了前所未有的成功,但众所周知,它们在分布外的数据上很难。另一方面,马尔可夫随机场(MRF)对标签上的简单分布进行编码,尽管比UNets灵活性低,但不太容易过度拟合。在本文中,我们建议通过计算UNet和MRF的分布的乘积来融合这两种策略。由于该产品是棘手的,我们解决了一个近似分布使用迭代平均场方法。由此产生的MRF-UNet通过反向传播联合训练。与其他使用条件随机场(CRF)的作品相比,MRF不依赖于成像数据,这应该允许更少的过拟合。我们在3D神经成像数据上显示,这种新型网络提高了对分布外样本的泛化能力。此外,它允许减少参数的总数,同时保持高精度。这些结果表明,当主要集成到CNN模型中时,经典的MRF平滑先验可以允许较少的过度拟合。我们的实现可以在https://github.com/balbasty/nitorch上获得。

英文摘要:

While convolutional neural networks (CNNs) trained by back-propagation have seen unprecedented success at semantic segmentation tasks, they are known to struggle on out-of-distribution data. Markov random fields (MRFs) on the other hand, encode simpler distributions over labels that, although less flexible than UNets, are less prone to over-fitting. In this paper, we propose to fuse both strategies by computing the product of distributions of a UNet and an MRF. As this product is intractable, we solve for an approximate distribution using an iterative mean-field approach. The resulting MRF-UNet is trained jointly by back-propagation. Compared to other works using conditional random fields (CRFs), the MRF has no dependency on the imaging data, which should allow for less over-fitting. We show on 3D neuroimaging data that this novel network improves generalisation to out-of-distribution samples. Furthermore, it allows the overall number of parameters to be reduced while preserving high accuracy. These results suggest that a classic MRF smoothness prior can allow for less over-fitting when principally integrated into a CNN model. Our implementation is available at https://github.com/balbasty/nitorch.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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