![]() ![]() As such, work surrounding the correction of Ewald sphere curvature has recently proved useful in the recovery of structures from experimental data. Relatively recently, structures have been solved by cryo-EM to such high resolutions that the curvature of the Ewald sphere limits their resolutions. Besides that, earth curvature correction models are traditionally carried out in image space as a correction on the image. ![]() The nature of the problem was described well by DeRosier in the context of electron microscopy, and since then, various algorithms have been proposed for correcting for Ewald sphere curvature in cryo-EM. The details behind this follow the geometric construction known as the Ewald sphere. However, due to the specifics of electron wave diffraction, the projection approximation breaks down at very high resolutions. This assumption is fundamental to the derivation of reconstruction algorithms, has enabled structures to be solved with resolutions well below 2Å, and is an excellent approximation to the underlying physical process governing the formation of the image. mentioning: Some very old slide has an extreme curvature on its surface. Standard cryo-EM 3D reconstruction algorithms are based on modelling particle images as tomographic projections of the underlying 3D structure. If you make an image editing in the image editing software after scanning (i.e.
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