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WO Saxton

Publications and source records attributed to WO Saxton.

2 recordsLinked to original sources
PubMed2000

A new way of measuring microscope aberrations

Two-fold astigmatism, three-fold astigmatism and misalignment (coma) can be found from the orientations only of the diffractograms of a set of images with injected beam tilts--typically eight images with tilts of equal magnitude and azimuths 45 degrees apart. The spherical aberration must be determined independently, and the defocus is not measured; however, the measurement required is very much simpler than the measurement of image displacements or induced defocus/astigmatism values, and no calibration of the microscope magnification is needed.

Journal Article↗
PubMed1996

Semper: Distortion Compensation, Selective Averaging, 3-D Reconstruction, and Transfer Function Correction in a Highly Programmable System

The Semper system was developed 20 years ago to address problems of 2-D image averaging and transfer function correction. User extendibility was an important design requirement, and a very considerable body of extensions have been written in the interim; this paper reviews those most relevant to macromolecular structure determination by 2-D and 3-D electron microscopy. The techniques best provided for are distortion-compensated averaging (correlation averaging and local unbending), selective averaging (of several kinds), 3-D reconstruction of 2-D crystals, and transfer function estimation and correction. The (normally interactive) control language is flexible enough to be a frequently preferred alternative to programming at any lower level.

Journal Article↗