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TF MFL - Transfer Function - Make FiLter file for 'TF FL'

(09/05/96)

PURPOSE

Generate a filter file from electron optical parameters of micrograph. The filter file is used for CTF correction in the operation 'TF FL'.

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 CTF [Transfer Function - CTF correction]
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]

USAGE

.OPERATION: TF MFL

.FILE DIM NSAM : 256
[ Enter the file dimension. Note that this is a 1D file.]

.MAX. SP. FREQ. [A-1] : 0.1314
[Enter the spatial frequency limit in unit of 1/Angstroems. The maximum spatial frequency= 1/(2*pixel size).]

.DEFOCUS [A] : 10000
[Enter the defocus in Angstroems. Convention is that overfocus is negative, underfocus is positive.]

.AMPLITUDE CONTRAST: 0.01
[Enter the amplitude contrast in angle unit.]

.WAVELENGTH [A] : 0.037
[Enter the electron wavelength in Angstroems.]

. SPHERICAL ABERRATION CS [MM] : 2.7
[Enter the spherical aberration coefficient in mm.]

.FILTER FILE: sch001
[Enter the file name of filter.]

NOTES

  1. The filter contain three values, 1, -1, and 0. Zero is assigned to CTF values less than 0.08. Thus, it resembles a band-pass filter. It reduces noise at points where the CTF passes through zero.

SUBROUTINES

CTFFIL

CALLER

UTIL1

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