基于剪切波变换的冷冻电镜电子断层数据的完全三维重构

项目名称： 基于剪切波变换的冷冻电镜电子断层数据的完全三维重构

项目编号： No.31470037

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 张艳

作者单位： 中国科学院生物物理研究所

项目金额： 30万元

中文摘要： 制约冷冻电子断层三维重构技术的一个瓶颈问题是缺失楔问题。该问题是由数据收集时样品只能在有限角度内倾转（比如-70度到70度之间）导致的，严重影响了重构结果的分辨率。实际上，该问题可以归结为信号的不均匀稀疏采样。近年来发展的压缩感知理论在图像处理，信号传导等领域广泛应用。该理论通过在一定基底下稀疏表示信号，从而对信号压缩，达到提升信号传输速率，降低信息存储成本等目的。而压缩感知技术的实现，其最重要的理论基石即是信号的稀疏表示。信号的稀疏表示有诸如传统的小波变换，曲波变换等不同的变换方法，各有利弊。剪切波变换是一种新颖的变换方法，较传统的方法除了具有多分辨的优点外，还具有多方向性，效率高等优势。而剪切波变换在冷冻电镜三维重构领域尚未有应用。本课题将用剪切波变换方法进行冷冻电子断层数据的稀疏表示，将三维重构问题转化为目标优化问题来实现冷冻电子断层数据的完全三维重构，消除重构结果的缺失楔现象。

中文关键词： 缺失楔；电子显微镜；电子断层三维重构；压缩感知；目标优化

英文摘要： The bottle of 3D reconstruction in the field of cryo electronic tomography is missing wedge, which is caused by data collection under limited angles such as from -70 degree to 70 degree. This badly affects the resolution of reconstruction result. Actually, this problem is caused by the unevenly signal sampling. Compressed sensing theories developed in recent years were used widly in image processing, signal transduction. According to compressed sensing theories, signals were sparsely represented under some basis to compress the signals. Then the efficience of signal transmission will be improved and the storage cost could be reduced. The fundamental theory of compressed sensing is sparse representation of signals. There are different methods for sparse representation of signals such as traditional wavelets transform, curvelets transform. Each has its advantages and disadvantages. This project will use shearlets transform to make sparse representation of cryo electronic tomograph data. Then obtain the complete reconstruction of cryo electronic tomograph data by transforming the 3D reconstruction problem to the objective optimization problem，in order to eliminate the phenomenon of missing wedge.

英文关键词： missing wedge；electron microscopy；3D reconstruction of electron tomography；compress sensing；objective optimization