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. The files `optpixi.c' and `optpixi.h' are built from `jpegpixi.opag', and the files `opthotp.c' and `opthotp.h' are built from `jpeghotp.opag', with `opag', a command line option parser generator. If you want to modify `jpegpixi.opag' or `jpeghotp.opag', but don't have `opag' installed, you can donwload it from <http://www.zero-based.org/software/opag/>. Version 0.7.0 or later is required. You can also specify the location of the `opag' executable when you run the `configure' script with the option `--with-opag'. 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/>.
