CTF Estimation » History » Version 11
Anchi Cheng, 05/09/2011 01:25 PM
| 1 | 1 | Amber Herold | h1. CTF Estimation |
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| 3 | 5 | Anke Mulder | Image formation in EM is distorted by modulation of a contrast transfer function (CTF). Distortion depends on the physical parameters of the microscope, such as keV and lens abberations. Correcting for these aberrations is done by comparing the experimentally observed power spectral density (PSD) of EM images to a theoretically generated CTF. |
| 4 | 1 | Amber Herold | |
| 5 | 4 | Anke Mulder | h2. Available CTF Procedures: |
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| 7 | 3 | Amber Herold | # [[Ace Estimation]] |
| 8 | # [[Ace 2 Estimation]] |
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| 9 | 10 | Anke Mulder | # [[CtfFind Estimation]] |
| 10 | 1 | Amber Herold | |
| 11 | |||
| 12 | 4 | Anke Mulder | h2. Appion SideBar Snapshot: |
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| 14 | 6 | Anke Mulder | !http://emg.nysbc.org/attachments/209/Picture_114.png! |
| 15 | 4 | Anke Mulder | |
| 16 | 8 | Anke Mulder | h2. Notes, Comments, and Suggestions: |
| 17 | 4 | Anke Mulder | |
| 18 | 11 | Anchi Cheng | If you have a large range of defocus in your data, one parameter set or even one estimation method may not work for all of them. In this case, you can start a separate run but choose a different parameters that only process those with low confidence results. Next appion processing (stack making) will pick the result with highest confidence value image by image to be used. Note that Ace and Ace 2 have in general equivalent confidence values while CtfFind values tend to lower which makes it harder to mix and match currently. See forum http://emg.nysbc.org/boards/13/topics/990 |
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| 20 | 9 | Anke Mulder | !http://emg.nysbc.org/attachments/282/Picture_83.png! |
| 21 | 8 | Anke Mulder | !http://emg.nysbc.org/attachments/277/Picture_81.png! |
| 22 | 7 | Anke Mulder | ______ |
| 23 | 4 | Anke Mulder | |
| 24 | [[Particle Selection|< Particle Selection]] | [[Stacks|Create Particle Stack >]] |
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| 25 | 1 | Amber Herold | |
| 26 | ______ |