Matlab JPEG Toolbox
This toolbox contains Matlab
routines for manipulating JPEG files. While Matlab's built-in IMREAD
and IMWRITE functions provide basic conversion between JPEG files and
image arrays, they do not provide access to the details of the JPEG
image, such as the JPEG coefficients or the quantization tables.
The routines in this package provide additional functionality for
directly accessing the contents of JPEG files from Matlab, including
the Discrete Cosine Transform (DCT) coefficients, quantization tables,
Huffman coding tables, color space information, and comment markers.
It is assumed that the user of this software has a good understanding
of both the JPEG compression standard and Matlab data
structures.
The following Matlab functions are included in this distribution:
jpeg_read Read a JPEG file into a JPEG object struct
jpeg_write Write a JPEG object struct to a JPEG file
jpeg_qtable Generate standard JPEG quantization tables
bdct Blocked discrete cosine transform
ibdct Inverse blocked discrete cosine transform
bdctmtx Blocked discrete cosine transform matrix (2D, full transform)
quantize Quantize BDCT coefficients (using a quantization table)
dequantize Dequantize BDCT coefficients, using center bin estimates
im2vec Reshape 2D image blocks into an array of column vectors
vec2im Reshape and combine column vectors into a 2D image
This software is based in part on the work of the Independent JPEG
Group (IJG), as it makes use of IJG's free JPEG code library,
available
here. If the MEX file binaries provided in this distribution are
not the ones you need for your system, you will need to download IJG's
code library and install it on your system before compiling the source
code. See "Installing" in the README file for more details.
This software is free for educational and non-profit use. See the
README
file for licensing information.
Download:
Gzipped tar file (59k, jpegtbx_1.4.tar.gz)
PKZip archive (63k, jpegtbx_1.4.zip)
README file (12k, README)