simple image recognition and 2d overlay

Hello Everyone,

I've come accross a pretty nice app here 

https://www.pryntcases.com

that overlays videos on photos. 

I'd be interested to try out IR and 2D AR with vuforia, the following way :

- Vuforia recognises an image from a dataset

- Vuforia tracks the image outer countours (always white borders on the image) & orientation.

- Image outer corners are made available to the app (essentially to draw a rectangle on each of the vertice).

- Image's orientation with respect to the target image (up/down) is made available to the app.

i've downloaded the vuforia tutorials, and manage to get them to work.

I'm pulling my air to understand the engine life cycle, and most notably, what sort of event is sent to the app, when the engine has a matching pattern. Is there a document you  could advise me to read just to get some insights ? In the imageTarget app, I still can figure out when the hell the engine says ' I got a match'.

In the above 4 points, I can do the first one, it's very difficult to find adequate information for the last 3.

Can anyone just dive me pointers for them ?

thanks !

-A