falsecolor - make a false color RADIANCE picture
falsecolor [ -i input ][ -p picture ][ -cb | -cl ][ -e ][ -s scale ][
-l label ][ -n ndivs ][ -lw lwidth ][ -lh lheight ][ -log decades ][ -m
mult ][ -spec ][ -r redv ][ -g grnv ][ -b bluv ]
Falsecolor produces a false color picture for lighting analysis. Input
is a rendered Radiance picture.
By default, luminance is displayed on a linear scale from 0 to 1000
nits, where dark areas are blue and brighter areas move through the
spectrum to red. A different scale can be given with the -s option.
If the argument given to -s begins with an "a" for "auto," then the
maximum is used for scaling the result. The default multiplier is 179,
which converts from radiance or irradiance to luminance or illuminance,
respectively. A different multiplier can be given with -m to get
daylight factors or whatever. For a logarithmic rather than a linear
mapping, the -log option can be used, where decades is the number of
decades below the maximum scale desired.
A legend is produced for the new image with a label given by the -l
option. The default label is "Nits", which is appropriate for standard
Radiance images. If the -i option of rpict(1) was used to produce the
image, then the appropriate label would be "Lux".
If contour lines are desired rather than just false color, the -cl
option can be used. These lines can be placed over another Radiance
picture using the -p option. If the input picture is given with -ip
instead of -i, then it will be used both as the source of values and as
the picture to overlay with contours. The -cb option produces contour
bands instead of lines, where the thickness of the bands is related to
the rate of change in the image. The -n option can be used to change
the number of contours (and corresponding legend entries) from the
default value of 8. The -lw and -lh options may be used to change the
legend dimensions from the default width and height of 100x200. A
value of zero in either eliminates the legend in the output.
The -e option causes extrema points to be printed on the brightest and
darkest pixels of the input picture.
The -spec option reinstates the old, spectral color scale used in the
original falsecolor. The remaining options, -r, -g, and -b are for
changing the mapping of values to colors. These are expressions of the
variable v, where v varies from 0 to 1. These options are not
recommended for the casual user.
If no -i or -ip option is used, input is taken from the standard input.
The output image is always written to standard output, which should be
To create a false color image directly from rpict(1):
rpict -vf default.vp scene.oct | falsecolor > scene.hdr
To create a logarithmic contour plot of illuminance values on a
rpict -i -vf default.vp scene.oct > irrad.hdr
rpict -vf default.vp scene.oct > rad.hdr
falsecolor -i irrad.hdr -p rad.hdr -cl -log 2 -l Lux > lux.hdr
Work on this program was initiated and sponsored by the LESO group at
EPFL in Switzerland.
getinfo(1), pcomb(1), pcompos(1), pextrem(1), pfilt(1), pflip(1),
protate(1), psign(1), rpict(1), ximage(1)