pamtopfm(1) - phpMan

Pamtopfm User Manual(0)                                                   Pamtopfm User Manual(0)



NAME
       pamtopfm - Convert Netpbm image to PFM (Portable Float Map)


SYNOPSIS
       pamtopfm [-endian={big|little}] [-scale=float] [imagefile]

       All  options  can be abbreviated to their shortest unique prefix.  You may use two hyphens
       instead of one.  You may separate an option name and its value with white space instead of
       an equals sign.


DESCRIPTION
       This program is part of Netpbm(1).

       pamtopfm  reads  a Netpbm image (PNM or PAM) and converts it to a PFM (Portable Float Map)
       image.

       The PFM (Portable Float Map) image format is a lot like PPM, but uses floating point  num-
       bers  with  no maxval to achieve a High Dynamic Range (HDR) format.  That means it doesn't
       have a concept of absolute color and it can represent generic light intensity  information
       rather  than  just  visual information like PPM does.  For example, two pixels that are so
       close in intensity that the human eye cannot tell them apart are not visually distinct, so
       a  visual image format such as PPM would have no reason to use different sample values for
       them.  But an HDR format would.

       There are details of the PFM format in the PFM Format Description" (1).

       USC's HDRShop program <http://www.debevec.org/HDRShop>  and a program called Lefty use it.

       pamtopfm creates a color PFM image if its input is RGB (PPM) and a  non-color  PFM  other-
       wise.

       Use pfmtopam(1) to convert a PFM image to Netpbm format.



OPTIONS
       -scale=float

              This specifies the scale factor of the PFM image.
                   Scale factor is a component of the PFM format.
                   Default is 1.0.


       -endian={big|little}

              This specifies the endianness of the PFM image.  The samples
                   in the raster of a PFM image are 4 byte IEEE floating point
                   numbers.  A parameter of the IEEE format, and therefore the PFM
                   format, is endianness, i.e. whether the specified bytes are
                   ordered from low addresses to high addresses or vice versa.

              big means big endian -- the natural ordering;
                   little means little-endian, the Intel-friendly ordering.

              Default is whichever endianness the machine on which pamtopfm
                   runs uses internally, which results in the faster execution.




SEE ALSO
       Netpbm(1), pfmtopam(1), pam(1)


HISTORY
       pamtopfm was added to Netpbm in Release 10.22 (April 2004).

DOCUMENT SOURCE
       This  manual page was generated by the Netpbm tool 'makeman' from HTML source.  The master
       documentation is at

              http://netpbm.sourceforge.net/doc/pamtopfm.html

netpbm documentation                      10 April 2004                   Pamtopfm User Manual(0)

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