man > pamtopfm(1)

Pamtopfm User Manual(1)                General Commands Manual               Pamtopfm User Manual(1)

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 in‐
       stead 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) im‐
       age.

       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 in‐
       tensity  that the human eye cannot tell them apart are not visually distinct, so a visual im‐
       age 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).

       ]8;;https://vgl.ict.usc.edu/HDRShop/\USC's HDRShop program]8;;\  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 ]8;;index.html#commonoptions\ Common Options]8;;\ ), 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

netpbm documentation                        10 April 2004                    Pamtopfm User Manual(1)