The Local Maximum Search Module
This module allows to search for local maxima in two-dimensional
datasets stored within a SICS histogram memory. All commands
act upon the current content of the histogram memory. The following
commands are understood:
- lowmax stat hm
- calculates the average and the maximum count in the frame
currently held in histogram memory hm.
- lowmax search hm
- searches the frame held in histogram memory hm for local
maxima. Local maxima are returned as sets of three numbers which are
the x and y coordinates and the intensity. Each set of numbers is
separated from the next one by the @ symbol.
- lowmax cog hm x y
- calculates the center ogf gravity for the pixel at coordinates x
and y in histogram memory hm. Four numbers are returned: the new x and
y coordinates, the intensity of the peak and the number of points
contributing to the peak.
- lowmax steepness val
- accesses the steepness parameter for the peak search. With a
parameter val sets a new value, without print the current value.
- lowmax window val
- accesses the window parameter for the peak search. With a
parameter val sets a new value, without print the current value.
- lowmax threshold val
- accesses the thresholds parameter for the peak search. With a
parameter val sets a new value, without print the current value.
- lowmax cogwindow val
- accesses the cogwindow parameter for the peak search. With a
parameter val sets a new value, without print the current value.
- lowmax cogcontour val
- accesses the cogcontour parameter for the peak search. With a
parameter val sets a new value, without print the current value.
The local maximum search can be tuned through the parameters: The
window parameter sets the size of the quadratic area for which a
candidate pixel must be the local maximum. Threshold sets a minimum
count rate for a local maximum. Steepness sets a minimum difference to
the borders of the window used for the local maximum search which must
be fulfilled.
The center of gravity calculation can be tuned mainly through the
cogcontour parameter which determines at which percentage of the
maximum value of the peak the center of gravity calculation
stops. Cogwindow is the size of the area in which a center of gravity
is calculated. Can be set rather generously.