X-ray single-particle imaging involves the measurement of a large number of noisy diffraction patterns of isolated objects in random orientations. The missing information about these patterns is then computationally recovered in order to obtain the 3D structure of the particle. While the method has promised to deliver room-temperature structures at near-atomic resolution, there have been significant experimental hurdles in collecting data of sufficient quality and quantity to achieve this goal. This paper describes two ways to modify the conventional methodology that significantly ease the experimental challenges, at the cost of additional computational complexity in the reconstruction procedure. Both these methods involve the use of holographic reference objects in close proximity to the sample of interest, whose structure can be described with only a few parameters. A reconstruction algorithm for recovering the unknown degrees of freedom is also proposed and tested with toy model simulations. The techniques proposed here enable 3D imaging of biomolecules that is not possible with conventional methods and open up a new family of methods for recovering structures from datasets with a variety of hidden parameters.

中文翻译：

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参考增强型X射线单粒子成像

X射线单粒子成像涉及以随机方向测量孤立对象的大量噪声衍射图样。然后，通过计算方式恢复有关这些模式的缺失信息，以获得粒子的3D结构。虽然该方法已承诺以接近原子的分辨率提供室温结构，但在收集足够质量和数量的数据以实现此目标方面存在重大实验障碍。本文介绍了两种修改常规方法的方法，这些方法显着缓解了实验挑战，但以重建过程中额外的计算复杂性为代价。这两种方法都涉及在与感兴趣的样品非常接近的位置使用全息参考物，其结构只能用几个参数来描述。还提出了一种用于恢复未知自由度的重构算法，并通过玩具模型仿真对其进行了测试。本文提出的技术使生物分子的3D成像成为常规方法无法实现的，并开辟了新的方法系列，可从具有各种隐藏参数的数据集中恢复结构。