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

Provided by: jpegpixi_1.1.1-4.1build1_amd64

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.