AC N - Auto Correlation - Normalized ||

(09/10/96)

PURPOSE

Computes the normalized auto-correlation function of image/volume by using the Fourier transform relationship.   Example.

SEE ALSO

AC [Auto Correlation ||]
AC MS [Auto Correlation - Masked and normalized ||]
CC [Cross Correlation ||]
CC N [Cross Correlation - Normalized ||]
CN [Convolution ||]
CN N [Convolution - Normalized ||]
FT [Fourier Transform ||]

USAGE

.OPERATION: AC N

.INPUT FILE: PIC001
[Enter the name of the picture to be auto-correlated.]

.OUTPUT FILE: ACF001
[Enter name of the file which will contain the auto-correlation coefficients.]

NOTES

  1. On completion of this operation, the output file will contain the auto-correlation function. The origin is at: (NX/2 + 1, NY/2 + 1, NZ/2 + 1).

  2. The input data must be real.

  3. If the data cannot fit into the memory, use the 'FT' and 'SQ' commands to calculate the ACF:
       FT
       INPUT
       FOUR

       SQ
       FOUR
       MODFT

       FT
       MODFT
       ACF

    WARNING: The orgin of the ACF calculated in this way is in (1,1,1).

SUBROUTINES

NORM3, FMRS_2, FMRS_2R, FFTMCF, FMRS_1, FMRS_3, FMRS_3R, ACRS_2, ACRS_3

CALLER

CORR1

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