Ubuntu Manpage: jpegpixi - interpolate pixels in JFIF (JPEG) image files

NAME

       jpegpixi - interpolate pixels in JFIF (JPEG) image files

SYNOPSIS

       jpegpixi [OPTION]... SOURCE DEST [[D:]X,Y[,S]|[,SX,SY]]...

DESCRIPTION

Jpegpixi interpolates pixels or pixel blocks in JFIF images files (commonly referred to as
"JPEG images"). This is useful to correct images from a digital camera with CCD defects.
Only DCT blocks which contain pixels to be interpolated are decoded and re-encoded, and
the re-encoding is performed with exactly the same parameters with which the image has
originally been encoded. Therefore, the image quality is preserved as much as possible.

SOURCE and DEST are the filenames of the source file and the destination file,
respectively. In both cases, - can be used, which refers to standard input or standard
output.

The destination filename is followed by any number of pixel or pixel block specifications.
It starts with an optional direction specifier (D), which can be 2 for 2-dimensional
interpolation (the default), V or v for 1-dimensional vertical interpolation (e.g. to
remove horizontal stripes), or H or h for 1-dimensional horizontal interpolation. X,Y are
the coordinates of the pixel or the upper-left corner of the pixel block. S is the size
of the pixel block (1 by default). Alternatively, separate sizes can be specified for the
width (SX) and the height (SY).

All numbers (X, Y, S, SX, SY) can be expressed as absolute coordinates/sizes or
percentages of the image size. If a number is followed by a percent character (%), it is
interpreted as a percentage, otherwise as an absolute number.

OPTIONS

       -f FILE, --blocks-file=FILE
              Read pixel block specifications from file FILE in addition to the command line. The
              file should contain one specification ([D:]X,Y[,S]|[,SX,SY]) per line. Empty  lines
              are ignored. The file may also contain comments, which start with an octothorpe (#)
              and extend to the end of the line.

       -m METHOD, --method=METHOD
              Use interpolation method  METHOD  (default:  linear).   See  section  INTERPOLATION
              METHODS below.

       -v, --verbose
              Display the coordinates and size of each pixel block that is interpolated.

       -i, --info
              Display  information about the image, such as the size of the image, the colorspace
              in which it is encoded, and sampling rates for the different components.

       -s, --strip
              Do not copy comment and extra markers from the source to the destination file. This
              strips preview images, EXIF data, and similar information.

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

       --version
              Display version information and exit immediately.

INTERPOLATION METHODS

       0, av, average
              The  pixels  adjacent  to  the  pixel  block  are  averaged. The resulting color is
              assigned to all pixels in the block. For 1-dimensional interpolation, this is  done
              separately for one pixel wide, horizontal or vertical stripes.

       1, li, linear
              The  pixels which have a distance of 1 from the pixel block are used to calculate a
              bilinear surface (2-dim), or a group of linear curves (1-dim), which is  then  used
              to assign colors to the pixels in the block.

       2, qu, quadratic
              The  pixels  which  have  a  distance of 2 or less from the pixel block are used to
              calculate a biquadratic surface (2-dim), or a group of  quadratic  curves  (1-dim),
              which is then used to assign colors to the pixels in the block.

       3, cu, cubic
              The  pixels  which  have  a  distance of 3 or less from the pixel block are used to
              calculate a bicubic surface (2-dim), or a group of cubic curves (1-dim),  which  is
              then used to assign colors to the pixels in the block.

BUGS

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

COPYRIGHT

       Copyright © 2002, 2003, 2004, 2005 Martin Dickopp

       Jpegpixi  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.