No, they're just putting out enough light to override the background, then showing dimmer areas for black
Right, that's how all existing HMD systems work - but generally not with the whole FOV re-rendered so it's not so cut and dry.
Note that such a system doesn't give you black ever. It gives you muddy [insert lens color on the grey spectrum].
The case you describe ends up with what is practically an opaque lens that is replicating the environment that is not virtual. So you might as well just use VR with camera pass through at that point.
Right, that's how all existing HMD systems work - but generally not with the whole FOV re-rendered so it's not so cut and dry.
Note that such a system doesn't give you black ever. It gives you muddy [insert lens color on the grey spectrum].
The case you describe ends up with what is practically an opaque lens that is replicating the environment that is not virtual. So you might as well just use VR with camera pass through at that point.