CTF mask from export sub-tomograms looks strange

[xu-...@mails.tsinghua.edu.cn]

Hi Dimitry,

     We have exported sub-tomograms by warp after picking particles. However, we have met some trouble.

(1) The size of CTF mask is only a half of box size we have set.

(2) The shape of CTF mask looks strange.(see in attachment)

Is it normal?Can we move on or are there something wrong in our progress?

Looking forward to your reply, thank you !

Peng Cheng

above is one of the subtomogram (boxsize: 100X100X100)

this is the coresponding CTF model (box size 51X100X100)

[alist...@gmail.com]

Seems I replied to only one person rather than on the list when I responded here, copied below

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Hi Peng,

That's all fine - the FT of a real signal (your image) has hermitian symmetry so all of the necessary info for a simple CTF model can be stored in the "half"-CTF volume

see page 2 of https://www.sjsu.edu/people/burford.furman/docs/me120/FFT_tutorial_NI.pdf for more info

Cheers,

Alister