Man page - pfsabsolute(1)
Packages contas this manual
- pfsintiff(1)
- pfsrotate(1)
- pfsout(1)
- pfsabsolute(1)
- pfsstat(1)
- pfs_automerge(1)
- pfsplotresponse(1)
- pfsouttiff(1)
- pfsdisplayfunction(1)
- pfscat(1)
- pfsinppm(1)
- pfstag(1)
- pfspanoramic(1)
- pfssize(1)
- pfsindcraw(1)
- pfscut(1)
- pfsoctavergb(1)
- pfsinme(1)
- pfsoutrgbe(1)
- pfsoutppm(1)
- pfshdrcalibrate(1)
- pfsouthdrhtml(1)
- dcraw2hdrgen(1)
- pfsinhdrgen(1)
- pfsin(1)
- pfsgamma(1)
- pfsextractchannels(1)
- pfsinpfm(1)
- pfsclamp(1)
- pfsinimgmagick(1)
- pfsretime(1)
- pfsinyuv(1)
- pfsoutyuv(1)
- pfsinrgbe(1)
- pfsinexr(1)
- pfspad(1)
- pfsoctavelum(1)
- pfsoutpfm(1)
- pfsflip(1)
- jpeg2hdrgen(1)
- pfsoutimgmagick(1)
- pfsoutexr(1)
- pfscolortransform(1)
apt-get install pfstools
Manual
| 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 multiplied 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>.