AC NS - Self Correlation - Normalized ||

PURPOSE

Computes the self-correlation function of a picture by using the Fourier transform relationship. The dimension of the picture need not be a power of two (see 'FT' for restrictions). Works for 2D and 3D.

SEE ALSO

AC N	[Auto Correlation - Normalized ||]
AC S	[Self 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 NS

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

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

NOTES

1. On completion of this operation, the output file will contain the self-correlation function. The origin is at (INT(NSAM/2) + 1, INT(NROW/2) + 1, INT(NSLICE/2) + 1). The SCF is not normalized.

2. The type of input data can be either real or Fourier.

3. The self-correlation function is defined in "Correlation functions revisited", M. van Heel, M. Schatz, E. Orlova. Ultramicroscopy, 46, (1992) 307-316; as inverse Fourier transform of the square root of the modulus of the Fourier transform of the input image.

SUBROUTINES

FMRS_2, FMRS_2R, FFTMCF, FMRS_1, FMRS_3, FMRS_3R, ACRS_2S, ACRS_3S

CALLER

CORR1