pfsoctavelum(1) [debian man page]

pfsoctavelum(1) 					      General Commands Manual						   pfsoctavelum(1)

NAME

       pfsoctavelum - Process luminance in pfs stream using Octave

SYNOPSIS

       pfsoctavelum <octave_program>

DESCRIPTION

       Use this command to execute a GNU Octave program on luminance channel of each frame in the pfs stream. octave_program must be given in quo-
       tation marks ("") and must not produce any output (it can output to stderr, not to stdout). Color channels are scaled proportionaly to  the
       luminance channel. Luminance channel is represented by matrix Y.

       Note: This command requires GNU Octave.

EXAMPLES

       pfsinrgbe frames_%04d.hdr | pfsoctavelum "Y = conv2( Y, gaussian( 10, 1/5 )*gaussian( 10, 1/5 )', 'same' );" | pfsview

       Blur the sequence of frames with gaussian blur and show the result with pfsview.

BUGS

       Please report bugs and comments to Rafal Mantiuk <mantiuk@mpi-sb.mpg.de>.

																   pfsoctavelum(1)

pfsabsolute(1)						      General Commands Manual						    pfsabsolute(1)

NAME

       pfsabsolute - Convert luminance in images to absolute measure

SYNOPSIS

       pfsabsolute <dest Y> [<src Y>] [--verbose] [--help]

DESCRIPTION

       pfsabsolute  applies  all necessary operations to convert an image from relative luminance (tag LUMINANCE is RELATIVE) or display-dependent
       luma (tag LUMINANCE is DISPLAY) to absolute luminance values. When the luminance in an image is absolute (tag LUMINANCE set  to	ABSOLUTE),
       the  Y  channel represents physical luminance in cd/m^2. Absolute luminance levels are useful for some tone mapping algorithms and also for
       image or video compression.

       The argument <dest Y> denotes the level of luminance that relative luminance <src Y> should be rescaled to. The luminance is in fact multi-
       plied  by  the  ratio <dst Y>/<src Y>. <src Y> is normally relative luminance checked with pfsview in the spot where the absolute luminance
       <dest Y> is measured, known or guessed. If <src Y> is omitted, the value 1 is assumed, so <dest Y> is just a scaling factor.

       In case if display-depended luma (tag LUMINANCE is DISPLAY), the inverse gamma correction is applied (assuming sRGB color space).  In  such
       case <dest Y> is usually the maximum luminance of a display (e.g. 80 cd/m^2).

       This command always sets LUMINANCE tag to ABSOLUTE.

EXAMPLES

       pfsin memorial.hdr | pfsabsolute 20 0.04 | pfsview

	      Multiply	luminance  in  memorial  image, so that relative luminance 0.04 becomes 20 cd/m^2. Normally, the value 0.04 is check using
	      pfsview in the spot, where the absolute luminance (which equals in this case 20 cd/m^2) is known.

       pfsin lena.png | pfsabsolute 80 | pfsview

	      Convert lena image from sRGB color space to absolute XYZ, assuming maximum luminance of the monitor 80 cd/m^2.

SEE ALSO

       pfsgamma(1) pfsinppm(1)

BUGS

       Please report bugs and comments to Rafal Mantiuk <mantiuk@mpi-sb.mpg.de>.

																    pfsabsolute(1)