AC MS - Auto Correlation - Masked and normalized ||

(02/18/98)

PURPOSE

Calculates autocorrelation coefficients for circular mask. Coefficients are normalized. Image is padded with zeros. Works only for real images (not their Fourier transforms!).   Example.

SEE ALSO

AC [Auto Correlation ||]
AC N [Auto Correlation - Normalized ||]

USAGE

.OPERATION: AC MS

.INPUT FILE: PIC001
[Enter the name of the file to be autocorrelated.]

.OUTPUT FILE: MAC001
[Enter name of the file which will contain AC coeffs.]

.MASK RADIUS: 25
[Enter radius of the circular mask which will be centered at NX/2+1, NY/2+1]

.(F)ULL OR (H)ALF OUTPUT FILE: F
[F results in a autocorrelation function file with dimensions 2*NX,2*NY (useful for mask radius =>MAX(NX/4,NY/4).

H results in a autocorrelation function file with dimensions NX, NY (enough if one is interested only in lower order ACF coeffs. or mask radius is small)]

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). The ACF is not normalized.

  2. For non-masked autocorrelation function use 'AC'.

  3. Implemented by Paul Penczek.

SUBROUTINES

MACF, MACF_P, FMRS_2, FMRS_1, FFTMCF, ACRS_2

CALLER

CORR1

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