# pamtopfm - Convert Netpbm image to PFM (Portable Float Map) - man(1) - [phpMan]

_Pamtopfm_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown)                General Commands Manual               _Pamtopfm_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown)

## 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)](https://www.chedong.com/phpMan.php/man/Netpbm/1/markdown).

       **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).

       [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)](https://www.chedong.com/phpMan.php/man/pfmtopam/1/markdown) 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=_

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


### -endian=

              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)](https://www.chedong.com/phpMan.php/man/Netpbm/1/markdown), [**pfmtopam**(1)](https://www.chedong.com/phpMan.php/man/pfmtopam/1/markdown), [**pam**(1)](https://www.chedong.com/phpMan.php/man/pam/1/markdown)


## 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)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown)