Name
ssamp-bw — convert spectral sample data into a monochrome image
Synopsis
ssamp-bw [-v ] [-s squarefilesize] [-w file_width] [-n file_height] [-l lower_wavelen] [-u upper_wavelen] [-m minval] [-M maxval] file.ssamp
DESCRIPTION
ssamp-bw(1) reads a ssamp(5) format file of spectral samples for the named file, and produces a monochrome image in bw(5) format. The spectral definition is read from a second file named file.ssamp.spect
Using the
-l
and
-u
parameters, a filter is constructed to select the energy collected
over a portion of the spectrum.
This filter is convolved with each pixel of the two-dimensional input
file and the power levels are summed into a two-dimensional array of
scalor results.
The scalor array is scanned to compute the maximum and minimum
power levels encountered in this image.
These are used to drive an "automatic gain control" algorithm
which maximizes the use of the limited 0..255 intensity output range.
Using the
-m
and
-M
options, either the minimum or maximum values (or both) may
be over-ridden from the command line.
This is particularly useful when processing a series of
ssamp
files
(e.g. for an animation sequence)
and you don't want the gain control settings changing
from frame to frame.
The
-v
option sets "verbose" mode,
causing the spectral sampling definition and the filter kernel to be
printed on standard error.
EXAMPLE
ssamp-bw -s512 -M0.3 -l3000 -u5000 moss.ssamp | bw-fb -s512
This converts the energy received in the 3-5 micron ("mid-IR") band into a monochrome image, clamping any power greater than 0.3 to a value of 255 in the output, and displays this monochrome image on the current framebuffer.
DIAGNOSTICS
If the pix file is shorter than expected, or the size parameters are given incorrectly, an error is printed.
If the spectral range specified for the filter is outside the spectral range sampled in the input file, the program aborts with an error.
