Controls in this area allow the user to smooth the data in a variety of ways.
- De-Zing
This button, if clicked, will remove "zingers" from the image. These are pixels
that
have substantially (and astatistically) more intensity than all of their
neighbors. (Specifically, pixels that deviate by more than five standard
deviations from all four of their nearest neighbors).
This can be a problem particularly with some CCD detectors.
The
pixel is replaced with the average of the surrounding nearest-neighbor pixels. Note that this
process is irreversible, although the
original data file is untouched. If you are unhappy with the results, you will
have to
read in the data again.
Note also that the algorithm may falsely identify pixels as "zingers" if you
have very sharp Bragg peaks, with widths on the order of several pixels.
The dezing-ing process can take several seconds; a
progress bar lets you know how far you have gotten.
- Smooth
This button, if clicked, will locally smooth the image, by replacing each pixel
with
an average including that pixel and the surrounding pixels. This may help in
identifying interesting features in a noisy image. It should not ordinarily have
a
big effect on line plots, but the process does actually throw away some
information,
so you should probably not do it before making publication-quality plots.
Note that this
process is irreversible, although the
original data file is untouched. If you are unhappy with the results, you will
have to
read in the data again. For most applications the Condense option may
in many cases be closer to what you want. The smoothing process can take several seconds; a
progress bar lets you know how far you have gotten.
- Condense
This button, if clicked, condenses the image by summing together
multiple pixels. The drop-down menu above it
specifies how many pixels are to be combined--for example, if 3x3 is selected then
each region of 3x3=9 pixels is summed into one pixel, resulting in a
dataset that is 1/9 the size of the original with each pixel containing on the order of
9 times the original value. Like the Smooth option, this
may help in
identifying interesting features in a noisy image.
However, it does a better job than Smooth on low statistics data, since
the data are summed rather than averaged so that no counts are thrown away.
It also has the effect of speeding up subsequent calculations, since the
size of the dataset over which calculations are done is substantially
reduced. The net effect is as if you had a detector with lower spatial
resolution (larger pixels). If you are unhappy with the results, you will
have to
read in the data again. The condensing process can take several seconds; a
progress bar lets you know how far you have gotten.
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