What is the focus distance of a 3D screen?

Question

I've thought long and hard about wheter this is the appropriate section for this question, because I guess it's kind of an interdisciplinary subject.

My understanding of stereopsis (please, correct me if I'm wrong), basically depends of the way we cross our eyes when we attempt to see objects at different distances. The more "our eyes are crossed", the greater the difference between the images we receive in each eye, which it's more effective to look at closer objects. In order for an object to be in focus, it needs to be at the point where the vision of the eyes intersect (including "at infinity" for very far away objects).

Now, with this mindset, how would such a gadget as Oculus VR work? It consists of two separate screens (one for each eye) attached directly on an helmet-like device strapped to the user's head. It is capable of convincing 3D representations and has similar features which make it of close interest for gaming and similar applications.

So, my question is: in order to deliver such an illusion of depth, do the users' eyes need to be focused at the screen's distance, or at the represented objects' distance?

Sorry for the long question :P

Thanks in advance!

Answer 1

There are a number of aspects to the perception of a 3D world. While looking into how cinema and TV 3D systems work recently, I found the following Wikipedia articles useful on how the illusion of a 3D world is generated:

• Stereoscopy
• Depth perception

The articles on 3D Television, 3D film and Head-mounted displays have some coverage of the issues with 3D display systems, since they do not work the same for all individuals.

Generally 3D display systems ignore convergence and accommodation as a mechanism for generating depth and instead depend on parallax and the brain being able to assemble an approximation of the 3D scene without the information from those cues.

In head-mounted display systems such as the Oculus Rift the image focus is usually at infinity.