How to use an other physical camera for detection real object?

hello, I want to connect an other camera to my computer and use it for track object on an area because one camera will be used for the ar, but my problems are, how can I choose which camera is gonna be used? and how can I track my Objects?

I am totally not sure to understand the use case you are trying to achieve ?

I think we had some public AR image tracking examples? @bghgary

I think @carolhmj is talking about this: (open with Chrome for Android, enable WebXR incubation in chrome://flags)

But I’m not sure this will answer the OP’s question.