DragonFly On-Line Manual Pages

CRW(1)                 DragonFly General Commands Manual                CRW(1)

NAME
     crw - Process RAW Canon PowerShot photos

SYNOPSIS
     crw [-c] [-s num] [-g num] [-b num] [-r num] [-l num] [-B num] [-L num]
         [-bw] [-inside] [-2] [-3] [-4] files

DESCRIPTION
     The crw utility processes RAW output files (.crw) from Canon Powershot
     digital cameras, typically converting them into .ppm files.  By default,
     crw uses a gamma of 0.8 (the lower the brighter) and a low-light
     compensation value of 16 (higher values == more compensation, 0
     disables).  Different CCDs also have different scaling factors for their
     filter components.  This program will automatically scale filter
     components for the CCD (though our values may not be entirely correct.
     The red scaling for the CanonG2 was wrong in the original program, before
     I fixed it).  The program renormalizes the data to a scaling of
     1.0/1.0/1.0 before applying adjustments specified on the command line.

     The resolution of the output file will typically be somewhat smaller then
     the resolution of the raw .crw file due to edge effects during
     processing.  RAW files contain one color per pixel in a matrix which must
     be processed to synthesize the missing colors and generate photo output.
     You can see the raw CCD matrix (with thermal noise and filter
     compensation by default) by running the program with the option: -s -1.

     The following options are available:

     -c    Generate the converted image file on the standard output.  If not
           specified the image file is generated using the input filename with
           an appropriately replaced extension.

     -s num
           Specify the smoothness factor.  Currently only -1 and 0 may be
           specified.  -1 will cause crw to transfer the raw CCD pixels to the
           standard output in the requested image file format.  The default is
           0.  You can produce a certain degree of smoothing by changing the
           low-light adjustment, which is the

     -L    option.

     -g num
           Set the gamma.  The default is 0.8.  A value of 1.0 will produce
           output with no gamma correction.  Lower values will produce
           brighter output images.  Gamma is a non-uniform exponential
           adjustment of the image brightness that tends to bring out darker
           areas of an image.  This only works for .ppm image output.

     -b num
           Set the brightness.  Brightness is a more uniform, linear
           brightening of the image.  The default is 1.0.  A higher value will
           produce a brighter image.  We recommend using the gamma adjustment
           whenever possible instead of the brightness adjustment.

     -r num
           Set the red scaling.  The default is 1.0.  The red and blue scaling
           factors are typically used to compensate for artificial lighting.

     -l num
           Set the blue scaling.  The default is 1.0.  The red and blue
           scaling factors are typically used to compensate for artificial
           lighting.

     -B num
           This option may be used to set the thermal noise compensation.  The
           only valid values are 0 or 1.  The default is 1, enabling
           compensation.  Setting this option to zero disables thermal noise
           compensation.  Thermal noise produces a baseline value for the CCD
           pixels.  The actual CCD data contains a 'black border' area on all
           four sides which the processing program uses to determine the
           baseline.  The baseline is then subtracted from the data.  It is
           not typically useful to disable noise compensation.

     -L num
           Set the lowlight compensation factor.  The default is 16.  A value
           of 0 will disable lowlight compensation.  Lowlight compensation
           changes the bleedover in the weighted compensation algorithm used
           to generate the missing colors in the output photo.  The higher the
           value, the more of an 'averaging' effect we get (the weighting
           becomes less important).  The result is a softening of the edge
           enhancement processing and more blending of adjacent pixels,
           reducing the apparent noise in the output image when you view it.
           Lowlight compensation does not seem to adversely effect normal
           photos so the default is set fairly high.

     -bw   Black-and-white output.  This only works for .ppm image output.
           The magnitude is calculated and stored into all three color guns to
           produce a black and white picture.

     -inside

     -indoor
           Set the red scale to 0.7 to compensate for indoor lighting (same as
           using -r 0.7).  If not specified we assume outdoor lighting (par
           1.0 for red and blue scale options).

     -2    Generate a 24-bit PPM file (default)

     -3    Generate a 48-bit PSD (Adobe Photoshop) file

     -4    Generate a 48-bit PNG

     files
           Specify one or more files to process.  Unless -c is specified crw
           will generate an output file named after the input file with an
           appropriate extension change.

SEE ALSO
     /usr/ports/graphics/s10sh

HISTORY
     The crw utility was created by Dave Coffin in 1997.  Matt Dillon reworked
     the main interpolation algorithm extensively in this port and is
     currently maintaining it for FreeBSD.

BSD 4                            June 16, 2002                           BSD 4