TF CTS - Transfer Function - 2D & 3D CTF correction

PURPOSE

2D & 3D CTF correction of a series of images/volumes by Wiener filtering. Accumulates a CTF corrected sum over all input files. Unlike 'TF COR', this operation divides summed input files by the summed squared CTF files adjusted by the SNR.

SEE ALSO

TF COR	[Transfer Function - CTF correction and back transfom]
TF SNR	[Transfer Function - 3D CTF correction, Freq. dependent snr]
TF C	[Transfer Function - Complex 2D]
TF C3	[Transfer Function - Complex 3D]
TF DDF	[Transfer Function - Determine Defocus & amplitude contrast]
TF DEV	[Transfer Function - Determine Envelope function]

USAGE

.OPERATION: TF CTS

.ENTER TEMPLATE FOR IMAGE FILES: img***
[Enter template name of image/volume series to be restored.]

.ENTER FILE NUMBERS OR SELECTION DOC. FILE NAME: 1-10
[Enter numbers of files. The file numbers can also be read from a selection document file where file numbers are contained in the first register (not the keys).]

.ENTER TEMPLATE FOR CTF FILE: ctf***
[Enter template name of file series containing CTFs for respective images. The CTF files have to have the same numbers as corresponding defocus groups (image files).]

.SNR: 100
[Enter Signal-to-Noise Ratio of the images.]

.OUTPUT FILE: mol003
[Enter name for output file.]

NOTES

1. 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.

2. CTF functions can be generated from 'TF C' (for 2-D) and 'TF C3' (for 3-D). All the parameters can be determined from 'TF DDF' and 'TF DEV'.

3. This operation can be used for a single image.

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.

5. Accumulates a sum over all input images/volumes by multiplying FFT of input image/volume by conjugate of CTF Fourier image. Also computes sum of the squared CTF images/volumes. Divides summed input image/volumes by the summed squared CTF images/volumes adjusted by the SNR. Finally reverse FFT transforms the output image/volume.

SUBROUTINES

RCTFSS

CALLER

UTIL1