基于亚像素扫描的超分辨技术在高分辨X射线显微镜中的应用

Application of Super-resolution Technique Based on Sub-pixel Scanning in High-resolution X-ray Microscopy

在不改变现有硬件条件的情况下,开展超分辨扫描重建方法,可以在不增加系统成本的基础上提高高分辨X射线显微镜的成像性能.设计了基于亚像素扫描的超分辨扫描模式,按照设计的调制方式进行亚像素位移的移动,采集多幅具有互补信息的低分辨率图像;然后基于系统的点扩散函数,对高分辨率图像进行复原;最后结合POCS超分辨重建算法重建出高分辨图像.实验结果表明,10倍光耦探测器下的衬度噪声比提高了20%左右,空间分辨力提高了0.2μm(约15%),细节分辨能力超过探测器像素尺寸1.35μm的限制,可以看到在低分辨率图像中看不到的细节.实验说明用超分辨技术提高高分辨X射线显微镜的分辨率是有意义的.

Developing super-resolution scanning and reconstruction method on the existing hardware can improve imaging performance and saving the cost to upgrade hardware.In this paper,a super-resolution scanning mode based on sub-pixel scanning is designed and a series of low-resolution images of the sample is acquired through modulating the position of the sample.Then,the point spread function derived by processing the edge spread function is employed to the image restoration of the low-resolution image series.Finally,super-resolution reconstruction algorithm based on POCS is used to reconstruct superresolution images.The experiments conducted on the high-resolution X-ray microscope equipped with a 10 times optical lens coupling detector show that the contrast-to-noise ratio increases about 20%,the spatial resolution has been improved about 0.2μm（about 15%）,the detail resolution can exceed the limits of pixel size of the detector and more details are seen than low-resolution images.The experiment′s results illustrate that the super-resolution technique has great potential in improving the spatial resolution of the high-resolution X-ray microscope.