People can see in 3D with only one eye: scientists

Scientists, including one of Indian-origin, have proven for the first time that people don't need two eyes to see 3D images.
Researchers at the University of St Andrews have found that contrary to popular belief, it is possible to see in 3D with just one eye.
Dr Dhanraj Vishwanath, a psychologist at the University said that it is possible to experience vivid 3D vision simply by looking through a small hole.
The research has implications for people who have just one eye or difficulties with double-eye vision.
The study also has wide implications for 3D technology, because it suggests that there are other (possibly cheaper) methods by which the 3D experience can be created.

Current thinking is that the two visual images (one from each eye), when combined in the visual cortex of the brain, produce our sense of depth that produces the 'special' 3D effect.

The study suggests that, in fact, both eyes are not necessary for this '3D experience'.
"We have demonstrated experimentally, for the first time, that the same 'special way' in which depth is experienced in 3D movies can also be experienced by looking at a normal picture with one eye viewing through a small aperture (circular hole)," Vishwanath said.
"While this effect has been known for a long time, it is usually dismissed. Now we have shown that it is in fact real, and the perceptual results are exactly like stereoscopic 3D, the kind seen in 3D movies. Based on this finding, we have provided a new hypothesis of what the actual cause of the 3D experience might be," Vishwanath said.

Since the invention of the stereoscope (the technology behind 3D movies) in 1838, the conventional assumption is that this added feeling of depth can only occur when the real world or a 3D stereoscopic image is viewed with 2 eyes.
"Most people understand what 3D is - for example, when watching a 3D movie with special goggles, objects appear more vividly three-dimensional, they seem real, and they look like you could reach out and touch them," Vishwanath explained.
"There is also a sense of real space. This is also the way depth, space and 3D objects are experienced when the real world is viewed with two eyes by people who have 'normal' binocular (2 eye) vision," he added.

"Our findings and preliminary results suggest that our method could be used to allow people with misaligned eyes (strabismics) to experience what it is like to actually see in 3D," he said.
Vishwanath added that the real 3D experience in movies can be induced simply by increasing the resolution of images. Such methods could also help avoid some of the problems associated with stereoscopic 3D such as fatigue, nausea and headaches.