free image software

updated 1999-07-20

Here are some cuspy programs I wrote. I hope you like them.

Please tell me <d.cary@ieee.org> Feedback Form if you find any bugs in these programs or find an improved way of doing something.

Installation

To install these files:

  1. create a directory on your hard disk (perhaps "mirror").
  2. Download everything in the http://OIL.okstate.edu/~caryd/program/ directory to your directory ("mirror"), including the folder named "private". (Or just download the ".zip" file that includes these other files).
  3. Start up Matlab, and add this new directory ("mirror") to the search path (use File | Set Path | Browse | Add to Path... | OK | Close ).

Usage

Once these files have been installed, type 

   help imwrite_compressed
at the MatLab command prompt, copy and paste the suggested command sequence, and make sure it does what it claims to do.

The help command 

	cd private
   help huffman_compress
is your friend. Each file in this directory has "help" information.

Theory

The imwrite_compressed() and the imread_compressed() routines use data compression routines in the /private directory. These routines were originally downloaded from http://www.ee.umn.edu/users/kieffer/programs.html and were originally written by John C. Kieffer. They have been heavily modified for speed by David Cary. (I have renamed Kieffer's original routine for generating a optimal Kraft vector via David Huffman's algorithm from "huffmancode" to "sorted_kraft").

For theoretical information on how these routines work, see ftp://oz.ee.umn.edu/users/kieffer/seminar/notes3.pdf ftp://oz.ee.umn.edu/users/kieffer/slides/slide12.ps ftp://oz.ee.umn.edu/users/kieffer/slides/slide20.ps .

For implementation notes on how I got them to work so (relatively) fast, look at the comments in the source code.

ftp://oz.ee.umn.edu/users/kieffer/slides/slide38.ps has a simple MatLab procedure that takes the transition probabilities of a Markov transition matrix and finds the stationary distribution (usually the one the system will settle into).

Started 1999-04-06:DAV: David Cary

return to index // end http://OIL.okstate.edu/~caryd/program/about.html