xenial (1) ra_tiff.1.gz

Provided by: radiance_4R1+20120125-1.1_amd64 bug

NAME

       ra_tiff - convert RADIANCE picture to/from a TIFF color or greyscale image

SYNOPSIS

       ra_tiff [ -z|-L|-l|-f|-w ][ -b ][ -e +/-stops ][ -g gamma ] { in.hdr|- } out.tif
       ra_tiff -r [ -x ][ -g gamma ][ -e +/-stops ] in.tif [ out.hdr|- ]

DESCRIPTION

       Ra_tiff  converts  between RADIANCE and TIFF image formats.  The -g option specifies the exponent used in
       gamma correction; the default value is 2.2, which is the recommended value for TIFF images.

       The -b option can be used to specify an 8-bit greyscale TIFF output file.  The  type  of  input  file  is
       determined automatically.

       The  -z  option  will  result in LZW compression of the TIFF output file.  The -L option specifies SGILOG
       compression, which is recommended to capture the full dynamic range of the  Radiance  picture.   However,
       since  many TIFF readers do not yet support this format, use this option under advisement.  The -l option
       specifies SGILOG24 compressed output, which has less dynamic range than SGILOG, but  may  be  smaller  in
       some  cases.  (It is usually larger.)  The -f option specifies 32-bit IEEE floating-point/primary output,
       which is the highest resolution format but results in very large files, since each  RGB  pixel  takes  96
       bits  (12  bytes)  and  does  not compress well.  The -w option specifies 16-bit/primary output, which is
       understood by some photo editing software, such  as  Adobe  Photoshop.   Decompression  is  automatically
       determined for TIFF input.

       The  -e  option  specifies  an  exposure compensation in f-stops (powers of two).  Only integer stops are
       allowed, for efficiency.

       The -r option invokes a reverse conversion, from a TIFF  image  to  a  RADIANCE  picture.   The  RADIANCE
       picture  file can be taken from the standard input or sent to the standard output by using a hyphen ('-')
       in place of the file name, but the TIFF image must be to or from a file.  The -x option can  be  used  to
       specify an XYZE Radiance output file, rather than the default RGBE.

EXAMPLES

       To convert a Radiance picture to SGILOG-compressed TIFF format:

         ra_tiff -L scene1.hdr scene1.tif

       To later convert this image back into Radiance and display using human visibility tone-mapping:

         ra_tiff -r scene1.tif scene1.hdr
         ximage -e human scene1.hdr

AUTHOR

       Greg Ward Larson
       Sam Leffler

ACKNOWLEDGEMENT

       Work on this program was initiated and sponsored by the LESO group at EPFL in Switzerland.  Additions for
       the SGILOG data encoding were sponsored by Silicon Graphics, Inc.

BUGS

       Many TIFF file subtypes are not supported.
       A gamma value other than 2.2 is not properly recorded or understood if recorded in the TIFF file.

SEE ALSO

       pfilt(1), ra_bmp(1), ra_bn(1), ra_ppm(1), ra_pr(1), ra_pr24(1), ra_t8(1), ra_t16(1), ximage(1)