A stereoscopic color television system in which operation of a plurality of color television cameras photographing the same object is switched over in turn per period of a color synchronization subcarrier to send forth video outputs from the plural color television cameras in succession. A stereoscopic color television picture tube includes a lenticular lens assembly whose lenticular lenses are each formed with an equal width to the horizontal pitch of apertures of a shadow mask or meshy focusing grid, and which is positioned between the shadow mask and face plate and also provided with a phosphor screen on the focal plane of the lenticular lens assembly, the phosphor screen being formed of a plurality of sets of red, green and blue phosphor stripes formed with an equal width to the vertical pitch of apertures of the shadow mask or meshy focusing grid. The color television picture tube further includes vertically arranged red, green and blue electron guns. The electron guns are provided in the same number of groups as the television cameras used, and operation of the groups of the electron guns is changed over successively, each time the operation of the color television cameras is switched over. Or, the color television picture tube includes one set of vertically arranged electron guns and electrostatic deflection electrodes or an electromagnetic deflection device arranged so as to horizontally shift electron beams from the set of electron guns, each time the operation of the plural color television cameras is changed over.

A three-dimensional television system comprising an adapted transmitter (1'), which in further respects does not differ from a color television system in accordance with the PAL, NTSC or SECAM-standard. The three-dimensional display in the standard receiver (2) is based on the use of two colors, an observer observing a color picture display screen (10) through differently colored glasses (19, 20). In the transmitter (1'), a first picture pick-up device (12) is coupled to an input of a matrix-coding circuit (4, 5) via a low-pass filter (14). The filter (14) has a bandwidth which is not more than the bandwidth of the color difference signal channels in the decoding-matrix circuit (7, 8) of the receiver (2). In order to improve the picture quality, a second picture pick-up device (13) may be coupled via a low-pass filter (17) having a wider bandwidth to a different input of the matrix-coding circuit (4, 5).

Five color television cameras take pictures of an object. A video signal from the central camera is transmitted by circuitry substantially the same as the circuitry used in existing color television system. The video signal is subtracted from four video signals from the other cameras, two located on the left side of the central camera and the remaining two on the right side thereof, thus generating four video difference signals. A carrier wave is used of frequency 1/n (n is an integer) of the color sub-carrier frequency, and placed within the lower sideband of the reference frequency of an assigned channel. The spectrum distribution of the wave remains in interleaving relation with the spectrum distribution of a luminance signal from the central camera. The carrier wave is divided into two-phase carrier waves. Each of these carrier waves is divided into a positive halfwave and a negative halfwave. The resultant four halfwaves are amplitude-modulated by the four video difference signals, and the amplitude-modulated halfwaves are superposed one upon another, thus providing a composite wave. The composite wave is band-limited so that it does not exceed the bandwidth of the channel assigned and then transmitted. At the receiving side, five video signals are reproduced. Three electron beams corresponding to the three primary colors, are in synchronism with the five video signals, thereby to reproduce five pictures in stereoscopic relation on the focal plane of a lenticular lens screen.

Intrusion detection apparatus employing two spaced-apart TV cameras having ines of observation which intersect to form a three dimensional monitored locale of interest and a TV monitor having a display tube and connected to respond to output signals from said TV cameras. The cameras and monitors being synchronized to identify the presence and location of an intruder object in said locale of interest. In another aspect the invention comparator-adder analyzing circuitry is provided between the cameras and monitor such that the monitor is actuated only when the video from both cameras is identical at a given instant. Assuming each camera is directed to observe a different background and that the focus is adjusted to substantially eliminate background signals, then only signals from the intruder object are observed and it is observed only in the monitored locale.

Method and apparatus for producing a three dimensional television image by presenting stereoptican pairs of images to the viewers eyes. One of the stereoptican partners is presented most of the time while the second stereoptican partner is flashed on and off rapidly. Under the proper conditions with the second stereoptican partner being flashed on for a suitably short period of time at the proper repetition rate, the viewer is not consciously aware of its presence and effectively perceives the picture as a three dimensional image.