pfsstat(1) General Commands Manual pfsstat(1)NAME
pfsstat - Show frame / image statistics
SYNOPSIS
pfsstat
DESCRIPTION
This command will show a short text statistic on each image in the pfs stream. In the statistics you can find:
File - name of the input file
Width, Height - image dimensions
Minimum - minimum luminance of an image(*), given in linear
units (relative luminance in cd/m^2) and logarithmic units
Maximum - maximum luminance of an image(*)
Average - average luminance of an image(*)
Mean - mean luminance of an image(*)
(*) Before min, max, average, median and dynamic range is computed, the following processing is performed on an image: 1) negative and zero
values are replaced with the smallest positive value (to compute logarithms); 2) the image is low-pass filtered. The low-pass filtering
removes few very dark or very bright pixels that can significantly influence estimation of the dynamic range. The percentile, instead of a
low-pass filter, is sometimes used for the same purpose. However, a low-pass filter is preferred to the percentile in pfstools since, tak-
ing into account the processing that is happening in the human visual system, low-frequency band filter is more plausible.
Note: This command requires GNU Octave.
EXAMPLES
pfsin memorial.hdr | pfsstat
Show statistics for the memorial image.
BUGS
Please report bugs and comments to Rafal Mantiuk <mantiuk@mpi-sb.mpg.de>.
pfsstat(1)
Check Out this Related Man Page
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)
I neead a script which converts low values to the spaces, When I used
sed -e 's/\x00/\x20/g' inputfile command it is removing the low values but not replacing it with spaces. Please help me. Its Uregent. Thanks
Sam (12 Replies)
I am trying to find the minimum maximum and average from one file which has values
Received message from https://www.demandmatrix.net/app/dm/xml] in milliseconds.
Received message from https://www.demandmatrix.net/app/dm/xml] in milliseconds.
Received message from... (5 Replies)
I would like to have some help in calculating 5th percentile value of column 2 for each site, the input is like below:site val1 val2
002 10 25.3
002 20 25.3
002 30 25.3
002 40 20
002 50 20
002 60 20
002 70 20
002 80 30
002 90 30
002 100 30
002 120 30
003 20 30.3
003 20 30.3
003 30 20... (2 Replies)