pfsgamma(1) [debian man page]

pfsgamma(1)						      General Commands Manual						       pfsgamma(1)

NAME

       pfsgamma - Apply gamma correction to color or gray-scale images

SYNOPSIS

       pfsgamma [--gamma <gamma> | --inverse-gamma <inv-gamma>] [--mul <multiplier>]

DESCRIPTION

       Use  this  command  to  gamma correct a stream of pfs images. Gamma correction is equivalent to raising value of R, G and B (or Y for gray-
       scale images) channels to 1/gamma power. More information on gamma correction can be found at:

       http://www.poynton.com/notes/colour_and_gamma/GammaFAQ.html

       This command can work on color images, in which case XYZ channels are transformed to RGB space, then they are gamma corrected  before  they
       are converted back to XYZ. For gray-scale images (only Y channel and XZ missing) gamma correction is applied only to Y channel.

       Data can be multiplied by an optional multiplier before gamma correction.

       Note:  gamma  correction  will set the 'LUMINANCE' tag to 'DISPLAY' thus cancelling any sRGB correction when saving to LDR files (like PPM,
       TIFF). This will also cause a warning message when saving to HDR files, because the intensities after gamma  correction	are  not  linearly
       related to luminance any more.

OPTIONS

       --gamma <gamma>, -g <gamma>
	      Perform  gamma correction (input^(1/gamma)). This can be used to convert images from relative luminance or radiance to pixel values.
	      Default value: 1.0

       --inverse-gamma <inv-gamma>, -i <inv-gamma>
	      Perform inverse gamma correction (input^(gamma)). This can be used to convert images from pixel values to relative radiance or lumi-
	      nance.

       --mul <mul>, -m <mul>
	      Multiply data by this value before gamma correction. Default value: 1

EXAMPLES

       pfsin memorial.hdr | pfsgamma -g 1.8 -m 10 | pfsout memorial_gc.ppm

	      Multiply memorial image by 10, gamma correct it and save to memorial_gc.ppm.

SEE ALSO

       pfsin(1) pfsout(1) pfsdisplayfunction(1)

BUGS

       Please report bugs and comments to the pfstools discussion group (http://groups.google.com/group/pfstools).

																       pfsgamma(1)

pfsoutimgmagick(1)					      General Commands Manual						pfsoutimgmagick(1)

NAME

       pfsoutimgmagick - Write images or frames using Image Magick library

SYNOPSIS

       pfsoutimgmagick [--linear] [--quality <val>] [--bit-depth] [--frames <range>]) <file> [<file>...]

DESCRIPTION

       This  command  can  write images or frames in the multitude of image formats supported by the ImageMagick library. This includes but is not
       limited to: BMP, JPG, PNG, GIF, EPS, TIFF, DPX. See the manual page of ImageMagick for the full list of available formats.

       pfsoutimgmagick reads images or frames in pfs format from the Standard Input and writes them under the specified file name(s).

       The input of pfsinimgmagick must be within 0-1 range. If LUMINANCE tag set is set to RELATIVE or ABSOLUTE, the linear values will be  gamma
       corrected, assuming sRGB color space. Use --linear switch to disable gamma correction.

       The  images  are stored using the bit-depth for which the ImageMagick library was compiled (default is 16 bit). Note that some formats (for
       example JPEG) do not support encoding more than 8 bits per color channel. To use higher bit-depths, store images in the PNG format.

       This command stores 'ALPHA' channel if it is present in the pfs stream.

       Each file name can contain a %d pattern, which is substituted with frame numbers. The pattern has the same syntax as C printf command.  For
       example, you can use %04d to make the frame number four digit with proceedings zeros. You can select the frames using the following options
       (the options must be always given after the file name):

       --frames <range>
	      Range is given in mathlab / octave format:

	      startframe:step:endframe

	      Frame numbers start with startframe (default 0), are increased by step (default 1) and stop at endframe You can skip  one  of  those
	      values, for example 1:100 for frames 1,2,...,100 and 0:2: for frame 0,2,4,... up to the last file that exists.

       --srgb, -s
	      Apply  the  sRGB non-linearity (approximately 2.2 gamma) before writing a file. This can be used instead of using pfsgamma -g 2.2 to
	      store the result of some tone-mapping operators. The option will compress contrast to make sure that tone values are properly  shown
	      on a display. It should be only used with linearized (not gamma corrected) images that are normalized to the 0-1 range.

       --quality <val>, -q <val>
	      Set JPEG/PNG compression level from 1 to 100. Default 75.

       --bit-depth <val>, -b <val>
	      Enforce  bit-depth  (per	color  channel).  The allowed values are from 8 to 32. If not specified, the bit depth from the pfs stream
	      ('BITDEPTH' tag) will be used instead. If the 'BITDEPTH' tag is missing, the ImageMagick default value will be  used  (usually  16).
	      The bit depth of actually stored file may be lower of that specified, if the file format does not support higher bit depths.

EXAMPLES

	pfsin test.jpg | pfsout test.png
	      Convert from one image format to another.

	pfsin --linear test.jpg | pfsout --srgb test.png
	      The same as above, but apply inverse gamma correction after reading an image (--linear) and then apply gamma correction before writ-
	      ing an image (--srgb).

BUGS

       pfsoutimgmagick can not write frames to the standard output.

       Please report bugs and comments on implementation to the discussion group http://groups.google.com/group/pfstools

SEE ALSO

       pfsout(1) ImageMagick(1)

																pfsoutimgmagick(1)