https://3demmethods.i2pc.es/index.php?action=history&feed=atom&title=2003Velazquez_ARMA 2026-05-24T20:37:26Z Revision history for this page on the wiki MediaWiki 1.44.2 https://3demmethods.i2pc.es/index.php?title=2003Velazquez_ARMA&diff=1860&oldid=prev 2009-05-21T08:15:12Z

<p></p> <p><b>New page</b></p><div>== Citation ==<br /> <br /> J.A. Velázquez-Muriel, C.O.S.Sorzano, J.J. Fernández, J.M. Carazo. A method for estimating the CTF in electron microscopy based on ARMA models and parameter adjusting. Ultramicroscopy 96, 1:17-35. (2003)<br /> <br /> [http://scholar.google.com/scholar?hl=en&amp;lr=&amp;newwindow=1&amp;cites=14827085864633020972 Cited by]<br /> <br /> == Abstract ==<br /> <br /> In this work, a powerful parametric spectral estimation technique, 2D-auto regressive moving average modeling<br /> (ARMA), has been applied to contrast transfer function (CTF) detection in electron microscopy. Parametric techniques<br /> such as auto regressive (AR) and ARMA models allow a more exact determination of the CTF than traditional<br /> methods based only on the Fourier transform of the complete image or parts of it and performing some average<br /> (periodogram averaging). Previous works revealed that AR models can be used to improve CTF estimation and the<br /> detection of its zeros. ARMA models reduce the model order and the computing time, and more interestingly, achieve<br /> increased accuracy. ARMA models are generated from electron microscopy (EM) images, and then a stepwise search<br /> algorithm is used to fit all the parameters of a theoretical CTF model in the ARMA model previously calculated.<br /> Furthermore, this adjustment is truly two-dimensional, allowing astigmatic images to be properly treated. Finally, an<br /> individual CTF can be assigned to every point of the micrograph, by means of an interpolation at the functional level,<br /> provided that a CTF has been estimated in each one of a set of local areas. The user need only know a few a priori<br /> parameters of the experimental conditions of his micrographs, for turning this technique into an automatic and very<br /> powerful tool for CTF determination, prior to CTF correction in 3D-EM.<br /> The programs developed for the above tasks have been integrated into the X-Windows-based Microscopy Image<br /> Processing Package (Xmipp) software package, and are fully accessible at www.biocomp.cnb.uam.es.<br /> <br /> == Keywords ==<br /> <br /> CTF estimation, parametric models<br /> <br /> == Links ==<br /> <br /> Article http://www.ncbi.nlm.nih.gov/pubmed/12623169<br /> <br /> == Related software ==<br /> <br /> http://xmipp.cnb.csic.es/twiki/bin/view/Xmipp/Assign_CTF<br /> <br /> == Related methods ==<br /> <br /> == Comments ==</div>

WikiSysop