Query: phisto
OS: osf1
Section: 1
Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar
PHISTO(1) General Commands Manual PHISTO(1) NAME
phisto - compute a luminance histogram from one or more RADIANCE pictures SYNOPSIS
phisto picture .. DESCRIPTION
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 max- imum values are determined, and 100 histogram bins are uniformly divided between these extrema. Foveal samples less than 1e-7 cande- las/sq.meter are silently ignored. If no picture is named on the command line, the standard input is read. The primary function of this script is to precompute histograms for the pcond(1) program, which may then be used to compute multiple, iden- tical exposures. This is especially useful for animations and image comparisons. EXAMPLE
To compute two identical tone mappings for image1.hdr and image2.hdr: phisto image1.hdr image2.hdr > both.histo pcond -I -h image1.hdr < both.histo > image1m.hdr pcond -I -h image2.hdr < both.histo > image2m.hdr AUTHOR
Greg Ward Larson SEE ALSO
histo(1), pcond(1), pfilt(1), pvalue(1), rcalc(1), total(1) RADIANCE
3/12/98 PHISTO(1)