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phisto (1)
NAME
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phisto - compute a luminance histogram from one or more RADIANCE pictures |
SYNOPSIS
DESCRIPTION
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Phisto is a script that calls pfilt(1),
rcalc(1) and histo(1) to compute a histogram of
log luminance values for foveal samples in the given picture
files. A foveal sample covers approximately 1 degree, though
this script does not use this exact area. The minimum and
maximum values are determined, and 100 histogram bins are
uniformly divided between these extrema. Foveal samples less
than 1e-7 candelas/sq.meter are silently ignored. If no
picture is named on the command line, the standard input is
read. |
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The primary function of this script is to precompute
histograms for the pcond(1) program, which may then
be used to compute multiple, identical exposures. This is
especially useful for animations and image
comparisons. |
EXAMPLE
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To compute two identical tone mappings for image1.pic and
image2.pic: |
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phisto image1.pic image2.pic > both.histo
pcond -I -h image1.pic < both.histo > image1m.pic
pcond -I -h image2.pic < both.histo >
image2m.pic |
AUTHOR
SEE ALSO
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