2022Pant ExitWave
Citation
Pant, Apoorv / Banerjee, Manidipa / Khare, Kedar. Quantitative phase imaging of single particles from a cryoEM micrograph. 2022. Optics Communications, Vol. 506, p. 127588
Abstract
We show that de-focused single particle micrographs recorded using a cryo-electron microscope (cryoEM) system may be processed like a Fresnel zone in-line hologram to obtain physically meaningful quantitative phase maps associated with individual particles. In particular, a region-of-interest (ROI) of the de-focused micrograph surrounding a particle can be numerically back-propagated, in order to determine accurate de-focus information for single particles based on the sparsity-of-gradient merit function. Further with the knowledge of de-focus information, an iterative Fresnel zone phase retrieval algorithm using image sparsity constraints can accurately estimate the quantitative phase information associated with a single particle. The proposed methodology which can correct for both de-focus and spherical aberrations is a deviation from the image processing chain currently used in single particle cryoEM reconstructions. Our illustrations as presented here suggest that the phase retrieval approach applies uniformly to de-focused image data recorded using the traditional CCD detectors as well as the newer direct electron detectors.
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Links
https://www.sciencedirect.com/science/article/pii/S0030401821008373