Here are a few image processing and analysis algorithm demonstrations that I wrote in the late 1990s, using the then-new Java programming language. More recently, I have been converting these demonstrations to mobile apps in my spare time, of which there is little so those projects are not yet complete.
A Java applet that demonstrates the circular Hough transform for finding circles in images.
A demonstration of active contours (also called "snakes") using Java.
An applet that demonstrates several different image halftoning techniques.
An applet that implements several spatial image filters, including two edge-preserving noise-smoothing filters that I designed in my research.
An 8-page tutorial on linear programming that I wrote in 1998.