TELEVISION TELEPHONE SYSTEM

• US 3,668,312 A
• Filed: 04/02/1970
• Issued: 06/06/1972
• Est. Priority Date: 04/10/1969
• Status: Expired due to Term

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Kazuyuki Yamamoto, Ryoichi Matsuda
• Inventors: Matsuda, Ryoichi, Yamamoto, Kazuyuki
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Leibowitz, Barry
• Application Number:
  US05/025,136
• Time in Patent Office: 796 Days
• Field of Search: 178/6.5,6.8 340/324A,152,154 280/214,217 179/2TV
• US Class Current: 348/14.12
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: H04N 7/147 Communication arrangements, e.g. identifying the communication as a video-communication, intermediate storage of the signals selecting H04Q

Abstract

A television-telephone system for information transmission in a subscriber-subscriber communication mode or subscriber-computer communication mode, wherein the information transmission is effected between an information receiving party and a transmitting party, which may be a computer. A position indicating signal can be sent back from the receiving party to the transmitting party by using a light-pen and a signal switching network. The position indicating signal is sent to the transmitting party to indicate a command of the receiving party by displaying the position indicating signal superposed on the transmitted picture, or this indication information may be further processed and utilized by the transmitting party to form a definite digital indication of the position information.

Claims

1. In a television-telephone communication system including a plurality of telephone-television sets each including a television transmitting circuit and a television receiver, said television receiver including first display means for displaying an image corresponding to a received raster-scanned television signal which is transmitted by a television signal transmitting means coupled to said system, said television signal including an image signal and synchronizing pulses, the improvement comprising:

a. light pen means at a first television-telephone set and adapted to be positioned at a desired point of the displayed image to detect the light of the raster of the received television signal and to produce a position indicating signal identifying the position of said desired point;

b. signal separation means at said first television-telephone set for separating said received synchronizing pulses from said receive television signal; and

c. signal mixing means connected to the transmitting circuit of said first television-telephone set for mixing together said position indicating signal and the separated synchronizing pulses to form a composite indicating signal, whereby said transmitting circuit transmits said composite indicating signal to said transmitting means to indicate thereat said desired point on the displayed image.

2. A television-telephone communication system as defined in claim 1 wherein said light-pen means comprises:

a. a photoelectric element responsive to the light from said displayed image, and b. switch means at one end thereof adapted to be mechanically operated when pressed against the surface of said display means to activate said photoelectric element to permit the production of said position indicating signal.

3. A television-telephone system as defined in claim 1 further comprising:

a. means at said first television-telephone set for coupling the received image signal to said mixing means to produce a modified composite indicating signal including said image signal, and b. second display means at said transmitting means for receiving said modified composite indicating signal and for displaying both the image corresponding to said image signal and a spot corresponding to said position indicating signal, the location of the displayed spot corresponding to the position of said light-pen means at said desired point of the displayed image on said first display means.

4. A television-telephone system as defined in claim 1 wherein said transmitting means comprises a computer which further comprises means for receiving and processing said composite indicating signal to identify the location of saId desired point of said image.

5. A television-telephone system as defined in claim 4 further comprising:

a. means at each television-telephone set for generating a selecting signal corresponding to a desired image, and b. means for transmitting said selecting signal to said computer, said computer being programmed to respond to said selecting signal to transmit a television signal containing the image identified by said selecting signal.

6. A television-telephone system as defined in claim 5 further comprising:

a. means at said transmitting means for separating said synchronizing pulses from said composite indicating signal and for dividing said synchronizing pulses into horizontal and vertical synchronizing pulses, b. individual digital counting means for counting the number of vertical and horizontal synchronizing pulses between the beginning of each television scanning cycle and the occurrence of said position indicating signal, said digital counting means producing digital signals representing the counts of said horizontal and vertical synchronizing pulses, and c. means for transmitting said digital signals to said computer as an indication of the position of said light-pen means.

7. A television-telephone system as defined in claim 1 wherein said transmitting means is another one of said television-telephone sets.

8. A television-telephone system as defined in claim 1 wherein the transmitting circuit of each television-telephone set includes a television camera and a local oscillator producing transmitting synchronizing pulses, and further comprising switch means selectively responsive to the non-use and use positions of said light-pen means to operate said switch means to first and second positions, respectively;

the first position of said switch means connecting said television camera and said local oscillator to said transmitting circuit and disconnecting said light-pen means and said signal separating means from said transmitting circuit; and

the second position of said switch means disconnecting said television camera and said local oscillator from said transmitting circuit and connecting said light-pen means and said signal separating means to said transmitting circuit.

9. In a method of communicating between a plurality of television transceivers and a transmitting means which transmits a raster-scanned television signal including an image signal and synchronizing pulses, the improvement comprising:

a. receiving at a first transceiver the television signal and displaying the image signal;

b. placing a light pen at a desired point of the displayed image;

c. detecting with the light pen the light of the raster of the displayed image and producing a position indicating signal identifying the desired point;

d. separating the synchronizing pulses from the television signal received at said first transceiver;

e. combining the position indicating signal with the separated synchronizing pulses to form a composite indicating signal; and

f. transmitting the composite indicating signal to said transmitting means to indicate thereat said desired point on the displayed image.

10. The improved method as defined in claim 9 further comprising:

a. combining said image signal with said composite indicating signal to produce a modified composite indicating signal;

b. receiving said modified composite indicating signal at said transmitting means; and

c. displaying at said transmitting means both the image corresponding to said image signal and also a spot corresponding to said desired point of the image displayed at said first transceiver.