CTF determination from image stack

Submitted by Unknown on Tue, 2013-04-16 13:01

Forums

ctffind & ctftilt

I'm trying to figure out whether CTFFIND3 is able to estimate the CTF for a stack of images rather than for a single large image. After looking through the paper on CTFFIND3 and the Fortran code, my conclusion is that the program will not use a stack of images. Is this correct? Do you have a program that will use a stack of images to estimate CTF?

niko Tue, 2013-04-16 13:02

You are correct. However, you could montage all your images into one big image, then use CTFFIND3 with a box size that is the same as that of your original particle images. CTFFIND3 will then re-box all the original images and perform a CTF fit.

donghua Tue, 2015-06-02 16:15

Dear Niko,
You said that montage all the images into one large image before using CTFFIND3 on an image stack. Could you please tell which program can simply do montage for an image stack?
Thanks a lot.
Dong-Hua

Alexis Tue, 2015-06-02 21:35

Hello Dong-Hua,

If your goal is to estimate the CTF from a stack of images (for example, frames of a movie), you could simply use ctffind4, which accepts stacks as input.

Otherwise, I'm not sure what the easiest way to montage images is, but I would begin by looking at IMOD, EMAN2 etc to see if there is a program for this purpose.

Alexis