Dealing with frame cancellation for stereoscopic displays in 3D user interfaces

This paper aims at reducing the ocular discomfort created by stereoscopy due to the effect called “frame cancellation”, for movies and interactive applications. This effect appears when a virtual object in negative parallax (front of the screen) is clipped by the screen edges; stereopsis cue lets observers perceive the object popping-out from the screen while occlusion cue provides observers with an opposite signal. Such a situation is not possible in the real world. This explains some visual discomfort for observers and leads to a poor depth perception of the scene. This issue is directly linked to the physical limitations of the display size that may not cover the entire field of view of the observer. To deal with these physical constraints we introduce two new methods in the context of interactive applications. The first method consists in two new rendering effects based on progressive transparency that aim to preserve the popping-out effect of the stereo. The second method focuses on adapting the interaction of the user, not allowing him to place virtual objects in an area subject to frame cancellation. Both methods have been evaluated and have shown a good efficiency in comparison to the state of the art approaches.