Quest 2 controller Differentiation

I am interested in developing my own VR hardware, so I was wondering how the Oculus Quest 2 discerned the left touch from the right touch in its vision processing. The rings are mirrored, but the blob pattern doesn't seem to be unique enough for it to tell based on that, and it seems to know automatically. I have a few running theories but I was hoping someone had a concrete answer. Thanks

(No, I'm not trying to make 3rd party touch controllers, yes, I know the headset won't track 3rd party controllers)