Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation

Segmentation of density maps obtained using cryo-electron microscopy (cryo-EM) is a challenging task, and is typically accomplished by time-intensive interactive methods. The goal of segmentation is to identify the regions inside the density map that correspond to individual components. We present a...

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Main Authors: Pintilie, Grigore Dimitrie, Zhang, Junjie, Chiu, Wah, Gossard, David C.
Other Authors: Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Format: Article
Language:en_US
Published: Institute of Electrical and Electronics Engineers 2009
Online Access:http://hdl.handle.net/1721.1/49519
https://orcid.org/0000-0001-7706-6954
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author Pintilie, Grigore Dimitrie
Zhang, Junjie
Chiu, Wah
Gossard, David C.
author2 Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
author_facet Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Pintilie, Grigore Dimitrie
Zhang, Junjie
Chiu, Wah
Gossard, David C.
author_sort Pintilie, Grigore Dimitrie
collection MIT
description Segmentation of density maps obtained using cryo-electron microscopy (cryo-EM) is a challenging task, and is typically accomplished by time-intensive interactive methods. The goal of segmentation is to identify the regions inside the density map that correspond to individual components. We present a multi-scale segmentation method for accomplishing this task that requires very little user interaction. The method uses the concept of scale space, which is created by convolution of the input density map with a Gaussian filter. The latter process smoothes the density map. The standard deviation of the Gaussian filter is varied, with smaller values corresponding to finer scales and larger values to coarser scales. Each of the maps at different scales is segmented using the watershed method, which is very efficient, completely automatic, and does not require the specification of seed points. Some detail is lost in the smoothing process. A sharpening process reintroduces detail into the segmentation at the coarsest scale by using the segmentations at the finer scales. We apply the method to simulated density maps, where the exact segmentation (or ground truth) is known, and rigorously evaluate the accuracy of the resulting segmentations.
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spelling mit-1721.1/495192022-10-03T10:27:36Z Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation Pintilie, Grigore Dimitrie Zhang, Junjie Chiu, Wah Gossard, David C. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology. Department of Mechanical Engineering Pintilie, Grigore Pintilie, Grigore Dimitrie Gossard, David C. Segmentation of density maps obtained using cryo-electron microscopy (cryo-EM) is a challenging task, and is typically accomplished by time-intensive interactive methods. The goal of segmentation is to identify the regions inside the density map that correspond to individual components. We present a multi-scale segmentation method for accomplishing this task that requires very little user interaction. The method uses the concept of scale space, which is created by convolution of the input density map with a Gaussian filter. The latter process smoothes the density map. The standard deviation of the Gaussian filter is varied, with smaller values corresponding to finer scales and larger values to coarser scales. Each of the maps at different scales is segmented using the watershed method, which is very efficient, completely automatic, and does not require the specification of seed points. Some detail is lost in the smoothing process. A sharpening process reintroduces detail into the segmentation at the coarsest scale by using the segmentations at the finer scales. We apply the method to simulated density maps, where the exact segmentation (or ground truth) is known, and rigorously evaluate the accuracy of the resulting segmentations. 2009-10-30T13:11:12Z 2009-10-30T13:11:12Z 2009-04 Article http://purl.org/eprint/type/ConferencePaper http://hdl.handle.net/1721.1/49519 Pintilie, Grigore Dimitrie et al. “Identifying components in 3D density maps of protein nanomachines by multi-scale segmentation.” IEEE/NIH Life Science Systems and Applications Workshop. 2009. 44-47. https://orcid.org/0000-0001-7706-6954 en_US http://dx.doi.org/10.1109/LISSA.2009.4906705 IEEE/NIH Life Science Systems and Applications Workshop Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Institute of Electrical and Electronics Engineers Grigore Pintilie
spellingShingle Pintilie, Grigore Dimitrie
Zhang, Junjie
Chiu, Wah
Gossard, David C.
Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation
title Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation
title_full Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation
title_fullStr Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation
title_full_unstemmed Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation
title_short Identifying Components in 3D Density Maps of Protein Nanomachines by Multi-scale Segmentation
title_sort identifying components in 3d density maps of protein nanomachines by multi scale segmentation
url http://hdl.handle.net/1721.1/49519
https://orcid.org/0000-0001-7706-6954
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