The flowchart of helical processing

Submitted by holmeschiu on Fri, 2010-02-19 17:58

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Electron Microscopy and Image Processing

Hi,

I am very interested in your TMV reconstruction and read the published paper in JMB. I have read the script and the flowchart PDF from your website.

There is a box in the flowchart with a title of script name, 'ctftilt-prep-master.amy/ctftilt-prep.amy mkdefgrps.csh', saying that '(A) convolutes each segment of image stack with determined CTF (B) generates......' I understand that if we multiply the Fourier transform of the image and the calculated CTF, we have a phase-unaffected and amplitude-weighted Fourier transform of object. However, I am a little bit confused with the legend (A). The right thing to do is 'to convolute each segment of image stack with the Fourier transform of determined CTF' or 'to multiply each segment of Fourier transform of image stack with determined CTF. ' Do I understand correctly?

Please feel free to give me any correction. Thanks for your help!

niko Mon, 2010-02-22 14:43

The meaning of the legend is that the Fourier transform of each image in the stack (which represents a segment of the helical particle) is multiplied by the two-dimensional CTF. I agree that the legend is a bit confusing. The multiplication in Fourier space would be equivalent to a convolution of each image with its CTF-related point-spread function (the inverse Fourier transform of the CTF).