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TF CTF - Transfer Function - CTF correction

(2/23/97)

PURPOSE

Restore a volume by Wiener filtering. When two or more volumes with different defoci are used, the gaps in the CTFs will be filled.

SEE ALSO

TF [Transfer Function - defocus dependent]
TF C [Transfer Function - complex]
TF C3 [Transfer Function - complex 3D]
TF CT [Transfer Function - phase flipping, complex, ternary]
TF CT3 [Transfer Function - complex, ternary 3D]
TF D [Transfer Function - display]
TF DDF [Transfer Function - determine defocus and amplitude contrast]
TF DEV [Transfer Function - determine envelope function]
TF DNS [Transfer Function - determine and delete noise background]
TF FL [Transfer Function - flip sign of Fourier transform]
TF MFL [Transfer Function - make filter file for 'TF FL']

USAGE

.OPERATION: TF CTF

.INPUT FILE: MOL001
[Enter name of volume to be restored.]

.CTF FILE: TF001
[Enter name of file containing CTF for the previous volume.]

.INPUT FILE: *
[Enter '*' if no more files are to be processed.]

.SNR : 100
[Enter signal-to-noise ratio of the volumes.]

.OUTPUT FILE: MOL003
[Enter name for output file.]

NOTES

  1. Input files can be either real or Fourier. CTF files must be in Fourier format. All files must have the same dimensions and must be 3D. Output file is real.

  2. CTF functions can be generated from 'TF C3'. All the parameters can be determined from 'TF DDF' and 'TF DEV'.

  3. Memory requirement: 3*(NSAMxNROWxNSLICE)+2*NSAM

  4. The 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

RCTFS, MULFC3, DIVCR3, DVCR

CALLER

UTIL1

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