[3dem] 3dem Digest, Vol 142, Issue 60

[류범한]

Hi, Anchi

Cool explanation!

And here’s a question to your comment.

How the borderline; 85% nyquist has been determined and what limits that 15%?
DQE or some other limitations in detector?
And the value 15% is empirical or theoretical?


Best regards,
Han


Bumhan Ryu

Postdoctoral Researcher
Korea Basic Science Institute (KBSI)
161 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si
Chungcheongbuk-do, Republic of Korea

Office) 043-240-5329



2019. 6. 28. 오전 12:24, Anchi Cheng <acheng at nysbc.org> 작성:

> Hi, Mohamed,
> 
> Just want to answer the first part of your first question.
> 
> Even though the signal you get in super-resolution mode is real, it is very dampened by DQE
> of the detector.  Let’s say you have a signal count of 100 above the background across all frequency.
> If DQE at your detector pixel limit is 0.2, and at 0.8 at zero frequency.  The output of that signal to
> your image becomes 100*0.2 = 20 in the former and 80 in the latter.  This only gets worse as
> you go into super-resolution frequency.
> 
> Since protein or other biomolecule do not give strong signal at high resolution to start with,
> my “signal across all frequency” assumption above is already false.  You can see that information
> get through to your image at high frequency is much lower in reality.
> 
> If your 1Å pixel data does not give reconstruction resolution to 85% Nyquist resolution (2.35 Å resolution
> for 1 Å pixel) with all the modern single-particle processing tricks, the problem is in the specimen.  The very
> dampened signal in the super resolution range by unbinning your images is not going to help you.
> 
>> 1-  Will my resolution improve if I do not apply bining? 
> 
> Best,
> 
> Anchi Cheng
> NYSBC
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