NORMTIFF(1)						      General Commands Manual						       NORMTIFF(1)

NAME

       normtiff - tone-map and convert RADIANCE picture or HDR TIFF to standard TIFF

SYNOPSIS

       normtiff [ options ] input output.tif

DESCRIPTION

       Normtiff  prepares  a Radiance picture or high dynamic-range TIFF for output to a display or hard copy device.  If the dynamic range of the
       scene exceeds that of the display (as is usually the case), normtiff will compress the dynamic range of the picture such that both dark and
       bright  regions are visible.  In addition, certain limitations in human vision may be mimicked in order to provide an appearance similar to
       the experience one might have in the actual scene.

       Output is always an uncompressed RGB TIFF, which must be named on the command line along with the input file.  If  the  input  file  has  a
       ".tif"  or  ".tiff"  extension,	normtiff attempts to read it as a TIFF.  Otherwise, normtiff first tries opening it as a RADIANCE picture,
       only opening it as a TIFF if it fails header inspection.  (See the getinfo(1) program.)	If the input is neither a RADIANCE picture  nor  a
       high dynamic-range TIFF, the program reports an error and exits.

       The following command line options are understood.  Since this program is very similar to pcond(1), several of the switches are identical.

       -b	 Toggle  8-bit	black and white (grayscale) TIFF output.  If the input is a grayscale TIFF, this switch is automatically selected.
		 Otherwise, the output defaults to 24-bit RGB.

       -z	 Output LZW-compressed TIFF (smaller file).

       -h	 Mimic human visual response in the output.  The goal of this process is to produce output that correlates strongly  with  a  per-
		 son's subjective impression of a scene.  This switch turns on both the -s and -c switches, described below.

       -s	 Toggle  the  use  of the human contrast sensitivity function in determining the exposure for the image.  A darker scene will have
		 relatively lower exposure with lower contrast than a well-lit scene.

       -c	 Toggle mesopic color correction.  If parts of the image are in the mesopic or scotopic range where the cone  photoreceptors  lose
		 their	efficiency, this switch will cause a corresponding loss of color visibility in the output and a shift to a scotopic (blue-
		 dominant) response function.

       -l	 Toggle the use of a linear response function versus the standard dynamic range compression algorithm.	This may make  some  parts
		 of the resulting image too dark or too bright to see.

       -u Ldmax  Specifies  the  top  of the luminance range for the target output device.  That is, the luminance (in candelas/m^2) for an output
		 pixel value of (R,G,B)=(255,255,255).	This parameter affects tone mapping only when the -s switch is on.  The default  value	is
		 100 cd/m^2.

       -d Lddyn  Specifies  the  dynamic  range  for  the target output device, which is the ratio of the maximum and minimum usable display lumi-
		 nances.  The default value is 32, which is typical for CRT monitors.

       -p xr yr xg yg xb yb xw yw
		 Specifies the RGB primaries for the target output device.  These are the 1931 CIE (x,y) chromaticity values for red, green,  blue
		 and white, respectively.

       -g gamma  Specifies  the  output  device gamma correction value.  The default value is 2.2, which is appropriate for most CRT monitors.	(A
		 value of 1.8 is common in color prepress and color printers.)

EXAMPLES

       To convert a RADIANCE picture to an 8-bit grayscale TIFF:

	 normtiff -b scene.hdr sceneb.tif

       To condition a high dynamic-range TIFF for a particular film recorder with known color primaries, dynamic range and gamma response:

	 pcond -d 50 -g 2.5 -p .580 .340 .281 .570 .153 .079 .333 .333 orig.tif filmrgb.tif

       To simulate human visual response on a monitor with known maximum luminance:

	 normtiff -h -u 80 scene.hdr sceneh.tif

REFERENCE

       Greg Ward Larson, Holly Rushmeier, Christine Piatko, ``A Visibility Matching Tone Reproduction Operator for High  Dynamic  Range  Scenes,''
       IEEE Transactions on Visualization and Computer Graphics , December 1997.

       http://positron.cs.berkeley.edu/gwlarson/pixformat/

AUTHOR

       Greg Ward Larson

ACKNOWLEDGMENT

       This work was supported by Silicon Graphics, Inc.

SEE ALSO

       getinfo(1), pcond(1), pflip(1), pvalue(1), protate(1), ra_xyze(1), rpict(1), ximage(1)

RADIANCE
							      2/25/99							       NORMTIFF(1)