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 ||]
RT SQ	[Rotate and Shift - image, Quadratic 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 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. Whether or not the sign of the shift depends on how the shift values were determined. For example if 'CC' and 'PK' are used to determine the shift, the signs depend on 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