Correct Histogram for Spread due to Noise
Correct Histogram for Spread due to Noise
This option attempts to reconstruct the underlying intensity histogram
from a knowledge of the measured intensity histogram and the point spread
function that alters the intensity histogram through the noise introduced
to the system.
Histogram data from Buffer or File ?
{If histogram from buffer}
Histogram of what buffer ?
The histogram may be evaluated on the image contained in any valid buffer.
{If histogram from buffer}
Histogram of Window or whole Screen ?
The histogram may be evaluated on the image contained within a window (<W>)
or on the entire contents (<S>) of the buffer specified by the previous
entry.
{If histogram from buffer}
Window Selection: Region to evaluate histogram of
If the answer to the previous question specified that the histogram was to
be produced on the contents of a window, then the window selection submenu
is produced to enable the window to be specified. Information on operation
of DigImage windows may be found under the [H Help] option within the
submenu.
{If histogram from file}
Name of source file for histogram ?
Specify the name of the file already containing histogram information.
DigImage assumes the information is contained in two columns, the first an
integer specifying the intensity, and the second a numeric value (integer
or real) specifying the frequency or number of pixels. Lines not starting
with this combination will be ignored. If an intensity value is not
specified, then it will be assumed to have zero frequency. Note that the
files produced as output by both this option and [;EI Intensity histogram]
will be read correctly by this procedure.
Half width of point spread due to noise ?
Plot histogram in what buffer ?
This entry specifies the buffer in which the histogram is to be plotted.
Any valid buffer may be used; the buffer selected will be made the current
output buffer.
The histogram will be scaled between LowInten and HiInten to make full use
of the available plot space.
Use what intensity as LowInten ?
The range of intensities over which the plots are scaled, and the average
and standard deviation of the intensity are calculated, may be specified
using this and the following entry. Only intensities equal to and exceeding
the value specified by this entry (and less than or equal to that in
the next entry) will be used.
Use what intensity as HiInten ?
The value specified here is used in conjunction with the previous entry to
restrict the range of intensities used in calculating averages, scales etc.
Write data to which file (blank to suppress, .DAT default extension) ?
The histogram data will be written to the file specified at this prompt.
A blank name indicates that no file to be created. The format of the file
is:
Intensity, nPixels, CPixels, CFraction
where nPixels is the number of pixels of intensity Intensity in the
specified window, CumulativePixels is the number of pixels of the
specified intensity or less, and CumulativeFraction is the fraction of the
window occupied by Intensity or lower intensities.
Statistics based on selected intensity range:
Mean intensity : !!R0 = !!GR0
Standard deviation: !!R1 = !!GR1
RMS intensity : !!R2 = !!GR2
Minimum intensity : !!R3 = !!R3
Maximum intensity : !!R4 = !!R4
Errors, Warnings and Messages
Error Message:
Unable to open input histogram file
Warning Message:
Unable to open output histogram file
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DigImage User Documentation
Stuart Dalziel,
last page update: 19 February 1996