Jpegpixi - JPEG pixel interpolator
==================================


What is it?
-----------

"Jpegpixi" is short for "JPEG pixel interpolator". The intent of the
program is to interpolate pixels in JFIF images (commonly referred to
as "JPEG images"). This is useful to correct images from a digital
camera with CCD defects. For example, if one pixel is always bright
green, this pixel can be interpolated away with jpegpixi.

Jpegpixi is unique in that it tries to preserve the quality of the
JFIF image as much as possible. Usual graphics programs decode JFIF
images when they are loaded, and re-encode them when they are saved,
which results in an overall loss of quality. Jpegpixi, on the other
hand, does not decode and re-encode the image, but manipulates the
encoded image data (known as the "discrete cosine transformation
coefficients"). Therefore, the blocks (typically 8x8, 8x16, or 16x16
pixel areas) which contain the pixels to be interpolated are minimally
disturbed, and other blocks remain pixel-by-pixel identical to the
original image.

Jpegpixi is a command line utility. It is Free Software, released
under the GNU General Public License (GPL). The full text of the GPL
is contained in the file `COPYING'.

This software is based in part on the work of the Independent JPEG Group.
See `README.jpeglib' for copyright and license information.


Installation
------------

The file `INSTALL' contains general installation instructions. If you
have not yet read it, please do so now.

To build jpegpixi, you must have the JPEG library by the Independent
JPEG Group (version 6b or later) installed. It can be downloaded from
<ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz>.

You can specify the location of the JPEG library when you run the
`configure' script with the option `--with-jpeglib' or the options
`--with-jpeglib-include' and `--with-jpeglib-lib'. Please type
`./configure --help' for more information.


Usage
-----

Please read the manual page for detailed instructions. For a usage
example, please see the "Example" section on the jpegpixi homepage at
<http://www.zero-based.org/software/jpegpixi/>.
