SH F - Shift - using Fourier interpolation ||

PURPOSE

Shifts a picture or a volume by a specified vector using Fourier interpolation.

SEE ALSO

SH	[Shift - using bilinear interpolation ||]

USAGE

.OPERATION: SH F

.INPUT FILE: PIC001
[Enter the name of the image/volume to be shifted.]

.OUTPUT FILE: SHI001
[Enter name of output file where the shifted image is to be kept.]

.SHIFT COMPONENTS IN X, Y & Z: -5.2, 6.5
[Enter the shift vector components.]

[In the above example, PIC001 will then be shifted by -5.2 units in the x direction and 6.5 units in the y direction, and the result will be written into SHI001.]

NOTES

1. The shift parameters can be specified by reference to the temporary register: -X11,-X12, will input the components (with inverted sign) of a shift vector found in a previous 'CC' and 'PK X11,X12' operation. Whether or not the sign has to be inverted follows from the order of argument files in the 'CC' operation.

2. DNEW (K,I) = DOLD (K',I')
   where K' = K + KSH, I' = I + ISH
   Note that the shift is circular, i.e., the image is repeated in all directions.
   The effective new coordinate pair is:
   K' = MOD (K + KSH, NSAM)
   I' = MOD (I + ISH, NROW)
   Because of the use of the circular shift, SH F has the effect of multiplying the Fourier transform with:
   exp (2 [pi] j (KSH * KX/NSAM + ISH * KY/NROW))
   

SUBROUTINES

SHIFT_PF, FMRS_3, SHIFT_3D, FMRS_3R, FFTMCF, FMRS_2, FMRS_2R

CALLER

UTIL2