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
       numbers  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 ⟨https://vgl.ict.usc.edu/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
       otherwise.

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

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common  Options  ⟨index.html#commonoptions⟩  ), pamtopfm recognizes the following command
       line 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