Creating 3D content is a complex process and care needs to be taken that the viewing experience does not cause discomfort. However the 3D content is created, the technical and physiological aspects need to be considered, as it is very easy for technical issues to exist in 3D material which may possibly result in an unpleasant experience for the viewer.
In order to facilitate and speed the adoption of 3D technology in the home, it is of paramount importance that the viewing experience is of the highest order. The early adopters of 3D in the home will view it and share their opinions – bad as well as good – with their friends. These early adopters should receive the best possible 3D experience, and it is up to the industry to ensure that the 3D content delivered during these early stages and beyond is of the highest possible quality – and that can only be achieved by a detailed understanding of the obstacles and pitfalls which will allow these to be avoided.
The biggest problem is that we are trying to create the illusion of 3D from a flat source, whereas in nature, our 3D perception is the result of viewing truly 3-Dimensional material, and our senses are optimized for that. It is not just a case of presenting a slightly different image to each eye and leaving the rest to the brain’s processing: there are issues of focus and convergence which can upset the viewing experience and, in a significant number of people, lead to unpleasant side effects which persist beyond the viewing.
‘Cardboarding’
This occurs a lot with movies that have been converted from 2D to 3D – objects on the screen appear to be at different depths, but are themselves totally flat, just like a series of cardboard cutouts.
Extreme Divergence
Divergence is the turning of the eyes inward or outward together to look at close or distant objects. Objects which appear to be well behind the screen require the eyes to turn outwards, which is normally accompanied by distance focusing, but because the image is still at the same distance (the screen), this can make it difficult or impossible to focus on the object. This is especially significant with children whose eyes are closer together, and often results in eye-strain and / or an uncomfortable viewing experience.
Extreme negative parallax
This is the opposite condition where the object appears well in front of the screen, causing the eyes to turn inwards and the brain to assume that it needs to focus closer – which is at odds with the image still being at the same distance from the viewer. Again, an uncomfortable experience can result, and the effects on children’s eyesight development are still by no means fully understood.
Abrupt depth changes
When there are abrupt scene changes and the accompanying depth change is significant, the viewer’s eyes must quickly converge or diverge while at the same time resisting the natural reflex to refocus, again leading to an abrupt and uncomfortable experience.
Multiple reference points
This occurs when additional objects, such as titles, burned-in text, menu buttons, scores, statistics etc. and the depth of these does not correspond with the video content which is playing. It is then very tiring for the viewer to constantly select and change what he is focusing on.
These are only the major pitfalls from a much longer list, and highlight just how difficult it can be to create the optimum 3D experience for the viewer. Even with all of the planning and attention to both creative and technical details, issues can still arise which can negatively impact the 3D experience for the viewer, and it is in this respect that there is sill a fair way to go.
Avoiding and correcting these issues as much and as soon as possible is paramount in ensuring the quickest adoption of 3D technology in the homes of consumers.