Three-dimensional Television: From Science-fiction to Reality

Moving three-dimensional images have been depicted in many science-fiction films. This has contributed to 3D video and 3D television (3DTV) to be perceived as ultimate goals in imaging and television technology. This vision of 3DTV involves a ghost-like, yet high quality optical replica of an object that is visually indistinguishable from the original (except perhaps in size). These moving video images would be floating in space or standing on a tabletop-like display, and viewers would be able to peek or walk around the images to see them from different angles or maybe even from behind (Fig. 1.1). As such, this vision of 3DTV is quite distinct from stereoscopic 3D imaging and cinema. 3D photography, cinema, and TV actually have a long history; in fact, stereoscopic 3D versions of these common visual media are almost as old as their 2D counterparts. Stereoscopic 3D photography was invented as early as 1839. The first examples of 3D cinema were available in the early 1900s. Various forms of early 2D television were developed in the 1920s and by 1929, stereoscopic 3DTV was demonstrated. However, while the 2D versions of photography, cinema, and TV have flourished to become important features of twentieth century culture, their 3D counterparts have almost disappeared since their peak around 1950. Our position is that this was not a failure of 3D in itself, but a failure of the then only viable technology to produce 3D, namely stereoscopy (or stereography). Stereoscopic 3D video is primarily based on the binocular nature of human perception, and it is relatively easy to realize. Two simultaneous conventional 2D video streams are produced by a pair of cameras mimicking the two human eyes, which see the environment from two slightly different angles. Then, one of these streams is shown to the left eye, and the other one to the right eye. Common means of separating the right-eye and left-eye views are glasses with colored transparencies or polarization filters. Although the technology is quite simple, the necessity to wear glasses while viewing has often been considered as a major obstacle in front of wide acceptance of 3DTV. But perhaps more importantly, within minutes after the onset of viewing, stereoscopy frequently causes eye fatigue and feelings similar to that experienced during motion