CHARACTERIZING AND CORRECTING IMAGE DISTORTIONS ON THE TECNAI MICROSCOPES

表征和校正 TECNAI 显微镜上的图像失真

• 批准号: 7722819
• 负责人: DAVID N MASTRONARDE
• 金额: $ 1.84万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7722819
• 关键词: Computer Retrieval of Information on Scientific Projects Database; Data; Funding; Grant; Height; Image; Institution; Measures; Microscope; Positioning Attribute; Process; Research; Research Personnel; Resources; Rotation; Series; Source; Specimen; Staging; Standards of Weights and Measures; Stream; United States National Institutes of Health; data acquisition; improved; lens; programs; reconstruction; size; tomography

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Since starting to acquire data on our Tecnai microscopes, we have been concerned about image distortions impairing the quality of our tomographic reconstructions. The problem is particularly severe with images from the Gatan Imaging Filter (GIF), because of distortions induced in both the GIF and the low magnification lens mode needed to use the GIF. We developed a program to solve for the image distortion field from a set of pairs of overlapping images of a specimen at two stage positions. The two images of a pair should overlap by about 55%, and pairs at four distinct orientations must be obtained. Our data acquisition program, SerialEM, has a routine to acquire these pairs easily, so it is now straightforward to acquire such data and compute an image distortion field. Another kind of distortion occurs with a tilted specimen, because it is sitting in a gradient in which magnification and image rotation vary with Z height. The effect of this gradient shows up prominently when a montage is taken of overlapping images of a tilted specimen. There are substantial errors when trying to shift the frames into register; the errors are eliminated when gradient distortions are corrected for. The gradient can be measured easily by taking images with the specimen at two different Z heights and determining the size change and rotation between them. The gradient depends only on beam intensity, so by recording beam intensity during each tilt series it is possible to correct images for this gradient. Corrections for both kinds of gradients have been incorporated into our standard processing stream for tomography, so they are easy for users to apply. So far, correcting for the GIF image distortion field has been found to improve image alignment substantially, while correcting for the gradients has given insignificant improvements.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 自从开始获取有关Tecnai显微镜的数据以来，我们一直担心图像失真会损害层析成像重建质量。 由于GIF和使用GIF所需的低放大镜头模式引起的扭曲，GATAN成像过滤器（GIF）的图像尤其严重。 我们开发了一个程序来从两个阶段位置的一组标本的重叠图像中求解图像失真场。 一对的两个图像应重叠约55％，并且必须在四个不同方向上对成对。 我们的数据采集程序Serialem具有一个常规，可以轻松获取这些对，因此现在可以直接获取此类数据并计算图像失真字段。 另一种变形是用倾斜的样品发生的，因为它位于梯度中，放大倍数和图像旋转随z高度变化。 当拍摄倾斜标本的重叠图像的蒙太奇时，该梯度的效果显着地显示出来。 试图将框架转移到寄存器时存在重大错误。校正梯度失真时消除了误差。 可以通过在两个不同的z高度上拍摄样品并确定它们之间的尺寸变化和旋转来轻松测量梯度。 梯度仅取决于光束强度，因此，通过在每个倾斜系列中记录光束强度，则可以为此梯度校正图像。 对两种梯度的更正已纳入我们的标准处理流中以进行断层扫描，因此用户易于申请。 到目前为止，已经发现对GIF图像失真场的校正可以大大改善图像对齐，同时校正梯度已经给出了微不足道的改进。