Stereoscopic 3D

Stereoscopic 3D (S3D) is a technique that produces an illusion of depth in a moving image by displaying two slightly different images to the right and left eye of the observer . This ability is based on the characteristics of the human visual system. The eyes, being positioned horizontally in the head, receive two views of the visual scene - one for the left-eye and another for the right-eye. The views overlap but differ slightly since they originate from two distinct perspectives. The visual system interprets and processes the information gathered from the two images to produce stereoscopic depth. The binocular system is very good at coordinating the movement of the eyes, which move constantly even during fixation. From a functional point of view, the images of both eyes fall on the fovea when fixating binocularly on a point. The fovea is the part of the back of the eye that has the highest acuity. According to Tam et al. (2011), “an object fixated binocularly is imaged on the same relative coordinates in the left-eye and right-eye views and it is perceived as a single percept, i.e., it is seen as a single object.”

To look at a new object located at a different distance, the point of fixation is altered. The two eyes move at the same time and in opposite directions so that the new object is imaged in the center of each eye’s fovea. When the new object is closer the eyes move inward (convergence). On the contrary, when the new object is farther away the eyes move outward (divergence). This process is called vergence and it is related to accommodation .

After the success of James Cameron’s Avatar, stereoscopic 3D was promoted has having advantages in different media like movies, 3DTV, and games. Indeed, the Sony Playstation 3 and Nintendo 3DS offered stereoscopic 3D gaming in a console format. On PC, S3D was available through driver-based solutions like Nvidia 3D Vision or TriDef .

Back in 2010, S3D was on the cusp of becoming a mass consumer product, with cinemas showing an increasing number of movies in 3D, TV channels launching 3D broadcasts of sport events, and companies selling 3DTV sets and Blu-ray 3D players. Despite the technological advances, the practical production of S3D content that produces a natural and comfortable viewing experience is still a challenge. The challenge arises from the complex interplay of human visual perception and the restriction of display devices, which can lead to discomfort after prolonged use. The majority of the 3D display technology is based on displaying a stereo image on a flat screen. This has the advantage of reproducing stereo cues like vergence. On the other side, other depth-cues like accommodation are neglected. The discrepancy between accommodation and vergence generates distorted perception, visual fatigue, headache, and dizziness .