Schrödinger’s Zebra: Applying Mutual Information Maximization to Graphical Halftoning — Source Code

This code is the implementation of the quantum halftoning algorithm from “Schrödinger’s Zebra: Information Theory, Quantum Mechanics, and Halftoning”, by Antal Spector-Zabusky and Donald Spector, presented at MaxEnt 2017.

The program is written in Haskell, and requires GHC 8. It uses the Stack tool for installing dependencies (including GHC itself) and building.

Building and running the program

• Setup (once only): Install Stack, make sure it is in your path, and execute the command stack setup in this directory.

• Build: Execute the command stack build in this directory.

• Run: Run the command ./quantum-halftone in this directory; for usage information, run ./quantum-halftone --help. (You can also run stack exec quantum-halftone -- --help; it’s the same thing.)

Sample command lines

The following two sample command lines run the quantum halftoning algorithm with the same parameters:

• Each grayscale inpixel is expanded to a 3×3 grid of black and white outpixels.
• The grayscale input file is input.png.
• Twenty output files are produced, named output01.png through output20.png.
• The initial output image is a quantum halftoning of the whole image (instead of a blank white or black canvas).
• The whole image is re-halftoned to produce each of the output images (instead of re-halftoning a single pixel at a time).

With the long forms of the comand-line arguments, this can be run as

./quantum-halftone --expand-by=3 --start=image --refresh=image --count=20 \
                   input.png 'output*.png'

With the short forms of the comand-line arguments, this can be run as

./quantum-halftone -e3 -si -ri -n20 input.png 'output*.png'

Licensing

This code is available under the permissive open-source 3-clause BSD license; see the LICENSE file for more information.