论文标题
带有波前初始化的Ptychographic重建
Ptychographic reconstruction with wavefront initialization
论文作者
论文摘要
X射线Ptychography是一种提供超高空间分辨率的尖端成像技术。在Ptychography中，相位检索，即从仅强度测量值中恢复复杂的有价值信号，可以利用用重叠照明测量的衍射模式中包含的信息的冗余。对于比探针大得多的样品，我们表明在迭代过程中，大量信息必须从样品边缘传播到中心。这构成了使用平坦初始化的算法的重建速度的固有限制。在这里，我们在实验上证明，通过利用从测量的衍射模式作为初始化检索的低分辨率样品波前可以实现大量计算速度。此外，我们表明这种方法避免了由于强阶段梯度而导致的相位奇异性伪像。波前初始化在计算上是快速的，并且与非卵形样品兼容。因此，所提出的方法很容易适应，这意味着广泛使用的Pychographic Reconstruction算法。
X-ray ptychography is a cutting edge imaging technique providing ultra-high spatial resolutions. In ptychography, phase retrieval, i.e., the recovery of a complex valued signal from intensity-only measurements, is enabled by exploiting a redundancy of information contained in diffraction patterns measured with overlapping illuminations. For samples that are considerably larger than the probe we show that during the iteration the bulk information has to propagate from the sample edges to the center. This constitutes an inherent limitation of reconstruction speed for algorithms that use a flat initialization. Here, we experimentally demonstrate that a considerable improvement of computational speed can be achieved by utilizing a low resolution sample wavefront retrieved from measured diffraction patterns as initialization. In addition, we show that this approach avoids phase singularity artifacts due to strong phase gradients. Wavefront initialization is computationally fast and compatible with non-bulky samples. Therefore, the presented approach is readily adaptable with established ptychographic reconstruction algorithms implying a wide spread use.
