1D Autocorrelation function
1D Autocorrelation function
===========================
This option evaluates the one-dimensional autocorrelation functions for
the rows or columns of an image within a window. The autocorrelation
function is then displayed graphically with intensity corresponding to
correlation.
Autocorrelation function of which buffer ?
This entry selects the buffer containing the image to be correlated. Any
valid buffer may be used. The buffer chosen will then be displayed while
window selection takes place.
Autocorrelation on Window or whole Screen ?
The 1D FFT may be evaluated for a window or the entire screen. If the
region selected is not 2^n pixels, then the data will be padded out to 2^n
with a linear function connecting the intensities on the two boundaries of
the window.
{If window selected}
Window Selection: Region to calculate autocorrelation for
If a window is selected for autocorrelation, then the Window Selection
submenu is produced to enable specification of the required window. For
more information on the window selection submenu, refer to [H Help] within
this submenu.
Autocorrelation in Horizontal or Vertical direction ?
The autocorrelation functions may be generated for all the lines (<H>) or
all the columns (<V>) within the selected window. If functions for both
lines and columns are required, then it is necessary to invoke this
facility twice.
Display autocorrelations on which buffer ?
The buffer specified here will be made the current output buffer and the
results of the autocorrelation calculations displayed on it with
intensities representing the correlation. A correlation of -1 is given as
an intensity of 0, 0 with an intensity of 128 and 1 with an intensity of
255. The mean autocorrelation function is displayed in row or column zero.
Write mean autocorrelation function to what file (.DAT default extension;
Blank to suppress) ?
If a file name is specified here, then the mean power spectrum for the
specified window will be written to it for use by other programs.
Message:
Evaluating autocorrelation functions...
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DigImage User Documentation
Stuart Dalziel,
last page update: 19 February 1996