NAME¶
pfsinppm - Load images or frames in PBM formats
SYNOPSIS¶
pfsinppm (<file> [--linear] [--absolute <max_lum>] [--frames
<range>] [--skip-missing]) [<file>...]
DESCRIPTION¶
pfsinppm command loads images in PBM formats (PPM, PNM or PGM) and writes
pfs stream to the standard output. The
pfs stream is usually
piped to another program for further processing. To detect the format
automatically based on the extension, use
pfsin command. For more
information on PBM formats, refer to the NetPBM web page
(
http://netpbm.sourceforge.net/).
Note that PPM or PNM images are low dynamic range. Therefore pixel values
(0-255) are scaled to 0-1 before storing them in pfs stream. Similarly, before
writing low dynamic range image from pfs stream, pixel values are multiplied
by 255. By default, the 'LUMINANCE' tag is set to 'DISPLAY'. The '--linear'
switch can force the inverse sRGB transformation and provide linear data. In
this case the 'LUMINANCE' tag is set to 'RELATIVE'. '--absolute' switch can be
used to convert pixels to absolute luminance values.
To read images from standard input use a single dash '-' instead of filename.
The images are read until EOF is reached.
Each file 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. See the
OPTIONS section below for details.
OPTIONS¶
- --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.
- --skip-missing
- Skip up to ten frames in a row if corresponding files are missing.
Otherwise the program stops reading sequence at the first file that does
not exists. This switch does not apply to the first frame in a sequence.
This switch can be useful if there is a rendered animation where some of
the frame has not been generated.
- --linear, -l
- Converts pixel values to linear luminance (XYZ), assuming the sRGB color
space for the input image. The maximum pixel value (255,255,255) is mapped
to Y=1. LUMINANCE tag is set to RELATIVE.
- --absolute <max_lum>, -a <max_lum>
- --absolute converts pixel values to an absolute linear luminance
(XYZ), that is the color space, in which channel Y contains luminance
given in cd/m^2. The sRGB color space is assumed for the input image. The
maximum pixel value (255,255,255) is mapped to Y= <max_lum>.
<max_lum> is typically set to 80 [cd/m^2] for a CRT monitor.
LUMINANCE tag is set to ABSOLUTE. --absolute process images
almost the same as --relative, but additionally it scales all
pixels by <max_lum>.
EXAMPLES¶
- pfsinppm frame%04d.ppm --frames 0:10 | pfsview
-
Read frames from files frame0000.ppm, frame0001.ppm, ..., frame0010.ppm and
show them using pfsview.
BUGS¶
Please report bugs and comments on implementation to the discussion group
http://groups.google.com/group/pfstools
SEE ALSO¶
pfsin(1),
pfsout(1)