相干X射线衍射成像（缩写为CDI）是一种新型的无透镜成像方法，具有单分子成像的巨大潜力。然而传统的平面波CDI对光源的高相干性要求，对样品尺寸的严格限制，及重建收敛慢、解不唯一的明显缺陷，大大限制了其普及应用。新近出现的扫描CDI方法则克服了上述缺点，有望成为未来三代光源的主流成像方法。本项目将依托上海光源，系统地探讨各种实验条件和参数对扫描CDI成像质量的影响规律，努力提高实验信噪比，抑制或消除实验系统的不稳定性及各种退相干效应，从而完善该方法及实验平台，使其能用于细胞及纳米催化剂的研究中；对比研究聚焦扫描CDI和平行光扫描CDI的特点和差异，及软线和硬线扫描CDI的优劣；建立和发展具有位置校正、背底扣除、光源涨落修复、部分相干光和宽带光重建等功能的新型扫描CDI重建算法及软件。本项目的研究不仅有助于提升上海光源的极限空间分辨能力，而且还将有力推动扫描CDI方法学本身的发展和完善。

The coherent X-ray diffractive imaging (the abbreviation is CDI) is a novel lensless imaging method with the great potential of imaging single molecule. However, the conventional plane-wave CDI requires full coherence of light source, rigidly limits the sample size and has the significant defaults of nonunique solution and slow convergence, which greatly depress the popularization and application of CDI method. The newly emerging scanning CDI (SCDI) overcomes the above shortcomings and will probably become one of the main imaging methods of the future synchrotron radiation light source. In this project which will be based on Shanghai Synchrotron Radiation Facility (SSRF), we will systematically explore the influence of various experimental conditions and parameters on the imaging quality of scanning CDI, to increase the signal-noise ratio with efforts, and restrain or eliminate the system unstabilities and various decoherence effects, which will help to perfect the method and the experiment platform and push them forward into applications in the research of cells and nano-catalysts. The focusing-light SCDI and the parallel-light SCDI will be investigated contrastively, and the soft X-ray SCDI and the hard X-ray SCDI will be studied comparatively. We will build up and develop new SCDI reconstruction algorithms which will be able to correct the scanning positions, remove the background noise, retrieve the fluctuating intensities of the incident light, and reconstruct the images from a partial coherent light or a broadband light. The research of this project will not only help SSRF to improve its spatial resolution power, but also promote the development and perfecting of the CDI methodology in itself.