Updated: 12 April 2005
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cameratopam - convert raw camera image to PAM
All options can be abbreviated to their shortest unique prefix. You
may use two hyphens instead of one to designate an option. You may
use either white space or an equals sign between an option name and
This program is part of Netpbm.
cameratopam converts from any of dozens of raw camera image
formats to PAM.
Digital still cameras often can produce images in a special raw
format in addition to something more standard such as TIFF or JFIF
(JPEG). Software supplied with the camera allows you to manipulate
the image using information which is lost when the camera converts to
the common format. A particular camera model often has a unique raw
- Report to Standard Error the format of the input image but don't
generate an output image. Program fails if it cannot recognize the
- Report to Standard Error details of the processing.
- Use simple bilinear interpolation for quick results. The default
is to use a slow, high-quality adaptive algorithm.
- Half-size the output image. Instead of interpolating, reduce
each 2x2 block of sensors to one pixel. Much faster than
- Interpolate RGB as four colors. This causes a slight loss of
detail, so use this only if you see false 2x2 mesh patterns in blue
- Show the raw data as a grayscale image with no interpolation.
This is good for photographing black and white documents.
- Automatic color balance. The default is to use a fixed
color balance based on a white card photographed in sunlight.
- Use the color balance specified by the camera. If
cameratopam can't find this, it prints a warning and reverts to
- Further adjust the color balance by multiplying the red and blue
channels by these values. Both default to 1.0.
- Change the output brightness. Default is 1.0.
- By default, cameratoapm clips all colors to prevent pink
hues in the highlights. Combine this option with
-brightness=0.25 to leave the image data completely unclipped.
- Write raw camera colors to the output file. By default,
cameratoapm converts to sRGB colorspace.
- For cameras based on the Fuji Super CCD SR, this option causes
cameratopam to use the secondary sensors, in effect
underexposing the image by four stops to reveal detail in the
highlights. cameratopam silently ignores this option for all
- This option causes cameratopam to generate a variation on
PAM that has "linear" color samples. In true PAM, each
sample in the image raster is gamma-corrected; i.e. it is essentially
proportional to brightness. With the linear option,
cameratopam generates an image in which the samples are instead
proportional to light intensity.
Without -linear, the image maxval is 255, so the image
contains one byte per sample. With -linear, the maxval is
65535, so the image contains two bytes per sample.
Without -linear, cameratopam uses a 99th percentile
white point. With -linear, it doesn't. I don't know what that
cameratopam was new in Netpbm 10.28 (June 2005).
It was derived from the program dcraw by Dave
Coffin, by Bryan Henderson in April 2005. Bryan replaced the part
that generates the Netpbm output image and removed the Adobe Photoshop
output function. Bryan changed the command syntax and made other
small changes to make the program consistent with Netpbm. He also
split the source code into manageable pieces (dcraw has a
single 5000 line source file).
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