**PURPOSE**- CTF corrects an image/volume by Wiener filtering. Multiplies the FFT of the input image/volume by the CTF Fourier image. Then reverse FFT transforms this to create output image/volume. Similar to operation: 'TF CTS' without SNR adjustment. Further info on CTF related operations in SPIDER. Example.

**SEE ALSO****TF CTS**[Transfer Function - CTF correction with SNR, image/volume] **TF SNR**[Transfer Function - CTF correction, using frequency dependent SNR] **TF CT**[Transfer Function - Generate a binary, phase flipping, complex, CTF correction image] **TF C**[Transfer Function - Generate a straight, complex, CTF correction image] **TF DDF**[Transfer Function - Determine Defocus & amplitude contrast] **TF DEV**[Transfer Function - Determine Envelope function]

**USAGE**- .OPERATION: TF COR

- .IMAGE/VOLUME FILE: img001

[Enter template name of image/volume. Can be in Fourier format.].CTF FILE: ctf001

[Enter name of file containing complex CTF for this image/volume. ].OUTPUT FILE: img_ctfd

[Enter name for CTF corrected output file.]

**NOTES**

- Input files can be either real or Fourier format. CTF files must be
in Fourier format. All files must have the same dimensions.
Output file is real.
- Complex CTF files can be generated using
'TF C' or 'TF CT' for 2-D images or by using
'TF C3' or 'TF CT3' for 3-D volumes.
- Theory is described in: J. Frank and P. Penczek (1995) On
the correction of the contrast transfer function in biological
electron microscopy.
*Optik*98:125-129.

**SUBROUTINES**- RCTFONE

**CALLER**- UTIL1

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