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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!). Command uses mix-radix FFT - the images need not have power-of-two dimensions.

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 NSAM/2+1,NROW/2+1]

.(F)ULL OR (H)ALF OUTPUT FILE: F
[F results in a autocorrelation function file with dimensions 2*NSAM,2*NROW (useful for mask radius =>MAX(NSAM/4,NROW/4). H results in a autocorrelation function file with dimensions NSAM,NROW (enough if one is interested only in lower order ACF coeffs. or mask radius is small)]

NOTES

  1. See documentation on 'AC' for the location of the origin.

  2. For non-masked autocorrelation function use AC.

  3. Memory requirements: 2*(NSAM+2)*NROW

  4. Implemented by Paul Penczek.

SUBROUTINES

MACF, MACF_P, FMRS_2, FMRS_1, FFTMCF, ACRS_2

CALLER

CORR1

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