深度神经网络端对端训练有素,将(嘈杂)图像映射到干净的图像的测量值非常适合各种线性反问题。当前的方法仅在数百或数千张图像上进行训练,而不是在其他领域进行了数百万个示例。在这项工作中,我们研究是否可以通过扩大训练组规模来获得重大的性能提高。我们考虑图像降解,加速磁共振成像以及超分辨率,并在经验上确定重建质量是训练集大小的函数,同时最佳地扩展了网络大小。对于所有三个任务,我们发现最初陡峭的幂律缩放率已经在适度的训练集大小上大大减慢。插值这些缩放定律表明,即使对数百万图像进行培训也不会显着提高性能。为了了解预期的行为,我们分析表征了以早期梯度下降学到的线性估计器的性能。结果正式的直觉是,一旦通过学习信号模型引起的误差,相对于误差地板,更多的训练示例不会提高性能。
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Noninvasive X-ray imaging of nanoscale three-dimensional objects, e.g. integrated circuits (ICs), generally requires two types of scanning: ptychographic, which is translational and returns estimates of complex electromagnetic field through ICs; and tomographic scanning, which collects complex field projections from multiple angles. Here, we present Attentional Ptycho-Tomography (APT), an approach trained to provide accurate reconstructions of ICs despite incomplete measurements, using a dramatically reduced amount of angular scanning. Training process includes regularizing priors based on typical IC patterns and the physics of X-ray propagation. We demonstrate that APT with 12-time reduced angles achieves fidelity comparable to the gold standard with the original set of angles. With the same set of reduced angles, APT also outperforms baseline reconstruction methods. In our experiments, APT achieves 108-time aggregate reduction in data acquisition and computation without compromising quality. We expect our physics-assisted machine learning framework could also be applied to other branches of nanoscale imaging.
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The de facto standard of dynamic histogram binning for radiomic feature extraction leads to an elevated sensitivity to fluctuations in annotated regions. This may impact the majority of radiomic studies published recently and contribute to issues regarding poor reproducibility of radiomic-based machine learning that has led to significant efforts for data harmonization; however, we believe the issues highlighted here are comparatively neglected, but often remedied by choosing static binning. The field of radiomics has improved through the development of community standards and open-source libraries such as PyRadiomics. But differences in image acquisition, systematic differences between observers' annotations, and preprocessing steps still pose challenges. These can change the distribution of voxels altering extracted features and can be exacerbated with dynamic binning.
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