How to create the code of the following video effect?

Hello there! I was searching through the internet to find anything useful regarding to one of my school projects.

I want to create something like this: https://vimeo.com/8218843

The problem is, I don’t really know where to start.
I know i maybe should use green-screen for this ‘installation’. I would use the webcam of my laptop as the source of the video, so I already downloaded the related libraries (hopefully).
But besides these, i don’t really have any clue about how to start it :confused:

I’m kind of new to processing, so sorry for being newbie, but I really want to do this project.

It looks like they are using the brightness of a pixel as that pixel’s transparency, and then just drawing the next frame over the previous one.

Continued here: How to create the code of the following video effect?