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Journalism of Courage
Even as we watched Jake fly his Banshee over the subliminal floating mountains in Avatar,some of us complained of headaches from the 3D experience. This was attributed to the focus-convergence problem. In the real world,our eyes automatically focus and converge at the same distancefor instance,when looking at an object that is near,the eyeballs rotate and look inwards to bring the object into auto-focus. While watching a 3D movie,our eyes are required to focus on the screen but converge at different distances to perceive different illusions of depth. If the convergence pointwhere the left and right camera lens axes meetis behind the object,the object appears in front of the screen; and if the point is in front of the object,the object appears behind the screen. This decoupling of focus and convergence puts a strain on the eyes. However,engineering 3D content in accordance with what is comfortable to the human eyeby minimising the distance between the focus and convergence pointsis the least of the problems facing the 3D industry. Its all about the display, says Sudhir Dixit,director of HP Labs,Bangalore,one of the several research labs across the world working on delivering a true,glasses-free 3D experience.
To understand this,try closing one eye and pouring water from a glass into a narrow-mouthed bottle. It becomes a struggle because our eyes are about 65 mm away from each other,they see an object from slightly different angles,producing two different images of the same object that are stitched together by the brain to form a 3D image. This is the reason people with one eye do not see in 3D. The ability to sense depth by the difference in image angle between the two eyes and perceive a single cyclopean image of the world is called stereoscopic vision. And the difference in the position of the object viewed from two different pointsin this case,the two eyesis called parallax. A still from a 3D movie is made up of two superimposed images of different polarisations. 3D glasses contain different polarisation filters in each eye and each eye sees only one of the two images simultaneously projected on the screen,perceiving depth. TV companies are now working on autostereoscopic displays that dont require viewers to wear glasses. In a regular display,each pixel displays the same colour in all directions and there is no parallax,and no depth. A light field display,on the other hand,is one where pixels display different colours in each direction,so that there is horizontal as well as vertical parallax. This is real 3D, Dixit says.
Now,3D is coming to mobile phones armed with dual-lens cameras. But is a paradigm shift to 3D really justified? 3D viewing has been shown to increase understanding of abstract information and a truly immersive experience must be a 3D one. This is what HP Labs India,which has worked on multimodal integration of touch,voice and face recognition in 2D interfaces,is interested in. Our interaction with computers is complex,a touch and gesture paradigm,supported by face and speech recognition and other intelligent systems make the experience easier. And its happening. Computing companies have demonstrated features where,depending on the fixation of the users gaze on a certain icon,a file opens without any command, Dixit says. Translating gesture recognition and touch into 3D,is a greater challenge. Id say we are about 10 years away,if not more,from developing a 3D system where everything is real-world-like and natural, he says.
