NAME

       jpeghotp - find hot or dead pixels in otherwise black or white JPEG images

SYNOPSIS

       jpeghotp [OPTION]... JPEG-FILE [PIXEL-BLOCKS-FILE]

DESCRIPTION

       Jpeghotp automatically finds hot pixels in an otherwise black JPEG image (default) or dead
       pixels in an otherwise white JPEG image (if the --invert option is specified). The  output
       is  suitable  as  a  pixel block specification file for the jpegpixi(1) program. A typical
       application is to process an image taken with a digital camera with CCD defects.

       To obtain a black image, take a picture in total darkness or with covered lens. To  obtain
       a while image, take an overexposed picture of a well-lit piece of white paper.

       JPEG-FILE is the filename of the JPEG image to read. It can be -, which refers to standard
       input.

       PIXEL-BLOCKS-FILE is the name of the file to write the coordinates and sizes  of  the  hot
       (or  dead)  pixel  blocks  to.  If it is omitted, the coordinates and sizes are written to
       standard output.

OPTIONS

       -t THRESHOLD, --threshold=THRESHOLD
              Specify the threshold between  noise  and  signal.  Pixel  luminosities  below  the
              threshold  are  considered CCD noise, luminosities above are considered hot pixels.
              THRESHOLD must be a number between 0 and 100 followed by a percent  character  (%).
              The default is 10%.

       -i, --invert
              Invert  the  image.  If this option is specified, dead pixels in an otherwise white
              image instead of hot pixels in an otherwise black image are found.

       -c, --comments
              Output comments with the luminosities of the hot (or dead) pixel blocks.  This  can
              be helpful in hand tuning the pixel blocks file.

       --help Display a short help text and exit immediately.

       --version
              Display version information and exit immediately.

BUGS

       Please report bugs to <martin-jpegpixi@zero-based.org>.

COPYRIGHT

       Copyright © 2003, 2004, 2005 Martin Dickopp

       Jpeghotp  is  free  software;  it may be copied and/or modified under the terms of the GNU
       General Public License version 2 or (at your  option)  any  later  version.  There  is  NO
       warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       jpegpixi(1)

       The jpegpixi homepage: http://www.zero-based.org/software/jpegpixi/