Stereoscopic Television

television systems designed to give the viewer the impression of seeing three-dimensional images. Three-dimensional perception is based on binocular vision. In stereoscopic television, two images of the same object are transmitted from two positions spaced apart a certain distance (the transmission base length). The two images obtained in this way form a stereopair. During reception, the two images are seen by the viewer separately—the left image by the left eye and the right image by the right eye. Several systems of stereoscopic, black-and-white and color television designed for television broadcasting are in the development stage. Systems for other applications have been developed.

In black-and-white stereoscopic television systems, the two images of a stereopair can be transmitted either simultaneously or consecutively. In the simultaneous method, the signals of the paired images may be transmitted either by two television cameras using two separate channels or by a single camera equipped with two television camera tubes using a single channel, for example, with frequency division to separate the signals corresponding to the left and right images. In consecutive transmission, the two images of a stereopair are projected onto vertically or horizontally adjacent regions of the photocathode of a single television camera tube by means of an optical attachment consisting of a mirror system or two prisms. The projected images are then transmitted consecutively on a single channel.

In simultaneous transmission, the separation of images at the television receiver can be achieved either by the use of special eyeglasses or with the aid of a raster screen. The former technique requires two kinescopes, a mirror stereoscope, and polarized or colored eyeglasses; it is the only method used in practical applications. In consecutive transmission, a single kinescope receives the two images of a stereopair, which are then separated by a rotating disk with colored filters.

Stereoscopic color television systems may also use either simultaneous or consecutive transmission. Each method can be used for the transmission of colors and brightness gradations in the images of a stereopair. Separation techniques for the images of a colored stereopair are the same as in black-and-white systems, except that the method of receiving colored anaglyphs is also possible.

Each system requires a very wide frequency bandwidth. As a result, one of the principal tasks in the development of stereoscopic television is the search for new methods of narrowing the bandwidth. This problem has been partially solved in stereoscopic black-and-white and color television systems by using a standard bandwidth compatible with conventional black-and-white systems. The future development of stereoscopic television will proceed from advances in the design of multiangle and holographic systems.