Image Halftoning

An educational Java applet

Purpose

This applet demonstrates several different image halftoning techniques described in the book Digital Halftoning by Robert Ulichney (Cambridge: The MIT Press, 1987).

Instructions

To start the applet, click on the "Start Halftone Applet" button above. A new window with several pop-up menus and two images will appear. Select the image you would like to halftone from the top menu. The second menu allows you to select from the different major halftoning methods described in Ulichney's book. The third menu changes for each different major technique, and allows you to select the specific variety of the method to use. When you have made your selections, click on one of the buttons below the menus to display the halftoned image on either the left or right, or to display the original image on either side. If you have selected an image different from the one currently displayed, the original image will be displayed on the side opposite from the one you have chosen. Captions below the images describe the halftoning method and variety used. Click on the close button of the applet window or on the "Stop Halftone Applet" button on this page to stop the applet.

Comments

I haven't developed this applet for any particular reason other than to hone my Java skills a little and because I thought it might be interesting and informative to a few people. I did do some research on halftoning in 1993 at Bell Laboratories, but the algorithms I helped develop are not included in this applet. If you do find this applet helpful in any way, I'd like to hear about it. Contact me at mark@markschulze.net.

Download

In 2007, I redeveloped this applet into an application with a more conventional user interface. I haven't developed a slick distribution package for it, but if you would like to try it out on your system, feel free to download this JAR file and try it on your system. If you have Java installed on your system, you should be able to double-click the JAR file and have the application run. After opening an image in the File menu, you can use the Halftone menu to select which algorithm to use and the results will be displayed.

References

1. R. Ulichney. Digital Halftoning. Cambridge: MIT Press, 1987.
T. N. Pappas. "Blue noise and model-based halftoning." In B. E. Rogowitz and J. P. Allebach, eds., Human Vision, Visual Processing, and Digital Display V. Proc. SPIE, v. 2179 (1994) pp. 182-194. (San Jose, California, Feb. 6-10, 1994.) Abstract

See also other related work on my algorithms page.