pamtopfm



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  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  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)toconvertaPFM 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  execu-
              tion.





SEE ALSO

       Netpbm(1), pfmtopam(1), pam(1)



HISTORY

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



netpbm documentation             10 April 2004         Pamtopfm User Manual(0)

Man(1) output converted with man2html