Math Forum / Math Software / MATLAB / October 2005

A previous post suggested using the MATLAB image toolbox, which is an
add-on to the standard version of MATLAB. The literature/web
documentation on the toolbox does not specifically say that the toolbox
supports ljpeg, but it supports generically DICOM. At the bottom of this
page

http://www.mathworks.com/applications/imageprocessing/demos.html

is the statement that if you are a licensed MATLAB user you can download
a 30-day trial of the product.

I searched the web over and found that ljpeg is very poorly supported,
and multiple implementations exist for it. My image-conversion standby,
ImageMagick, requires a special add-in to read this format and you must
create the patch yourself. One page suggested using xmedcom

http://sourceforge.net/projects/xmedcon/

but I have no ljpeg files so I could not tell you if it would work for you.

Good Luck!

Some folks have recommended using IMREAD -- which is in MATLAB, by the
way, not the Image Processing Toolbox.  The function is fairly smart and
can usually tell the format of the file, regardless of the extension.
In fact, if the extension is unknown (or absent) it will actually go
through and test for each of the supported file formats, which are given
in IMFORMATS.

Can IMREAD handle this kind of file (.ljpeg)?  I don't know.  If it's
lossless JPEG, quite probably.  If it's JPEG-LS, no.

Jeff Mather
Image Processing Team
The MathWorks, Inc.