Ptychographic inversion algorithms for intensity data in various experimental configurations.

这个项目是关于一种叫做重叠关联的计算成像技术的新应用。重叠关联最初是解决衍射图案中的相位问题的一种方法。与全息术类似，它可以测量散射波的相位以及强度。然而，该方法现在被认为在只能测量图像的情况下有更广泛的应用。其他的发展意味着它也可以科普所谓的“多模式”在成像实验（两个不相关的图像现象发生在一个单一的数据集），如振荡的“混合状态”。该方法使用的变体相同的核心反演算法中使用的“传统”重叠关联。该项目的具体目标是了解这些算法在“强度型”重叠关联反演中的性能限制。这种通用技术的应用可能包括提高天文望远镜的分辨率性能，解决非等平面盲解卷积问题的新方法，以及使用其模态特性进行消息加密。如果计算成功，将在光学台上收集的模型数据上测试算法。迄今为止，最初的工作集中在重叠关联中的基本不对称性上。在“实空间”重叠关联中，测量衍射图案的强度，在“傅立叶重叠关联”中，测量图像的强度。通过互易性原理，两种类型的数据应该包含相同的信息，而实际上，这些不同模式中的相位和模量重建的质量非常不均匀（在实空间重叠关联中，相位质量好，模量差，对于傅立叶重叠关联，反之亦然）。我们已经确定了原因，现在正试图纠正相关的重建算法，以克服这种技术的基本限制。

The project is about new applications of a computational imaging technique called ptychography.Ptychography was originally a solution to the phase problem in diffraction patterns. Similar to holography, it can measure the phase of scattered waves as well as just their intensity.However, the method is now seen to have much wider applications in situations where only images can be measured. Other developments mean that it can also cope with what are called 'multiple modes' in an imaging experiment (two unrelated image phenomena occurring in a single data set) such an oscillating 'mixed state'.The method uses variants on the same core inversion algorithm used in 'conventional' ptychography. The specific aims of the project will be to understand the limits of the performance of these algorithms in 'intensity-type' ptychographic inversion. Applications of this generic technique could include improving the resolution performance of astronomical telescopes, a new way of tackling the non-isoplanic blind deconvolution problem, and using its modal properties for message encryption. If calculations are successful, the algorithms will be tested on model data collected on the optical bench.To date, initial worked has centred on a fundamental asymmetry in ptychography. In 'real-space' ptychography, the intensity of diffraction patterns is measured, in 'Fourier ptychography' the intensity of images is measured. Via the principal of reciprocity, both types of data should contain identical information, whereas in fact the quality of the phase and modulus reconstructions in these different modes is very uneven (good quality phase, poor modulus in real-space ptychography, and vice versa for Fourier ptychography). We have determined the reason for this and are now trying to rectify the relevant reconstruction algorithms to overcome this fundamental limitation in the technique.