You are very welcome to improve JPIV! There are many ways:
Please, file an issue on
https://github.com/eguvep/jpiv/issues
if something is not working as expected. I am working exclusively on Linux machines. So I especially invite Windows and Mac users to check if everything is working on these operating systems!
Write a HOWTO, send a video, add examples or tutorials. Any material can be incorporated directly into the documentation (docs folder, accessible via GitHub pages: https://eguvep.github.io/jpiv/) or via link (your home page, Vimeo, YouTube, ResearchGate, ...).
Extending JPIV via scripts is very flexible and straightforward. No matter what language (Matlab, Octave, Python, C, ...) you are using, just check the /jpivlib/jsc folder for examples how to integrate virtually any kind of script seamlessly into the JPIV workflow. A good real world example is probably:
https://github.com/eguvep/jpiv/blob/master/jpiv/jpivlib/jsc/plot_scatter.jsc
For Java Programmers: Beanshell scripts are especially suitable for prototyping JPIV classes! Because Beanshell uses (almost) pure Java syntax, the script content can usually be moved into the JPIV source code with only minor adaptions.