Video telephone system

• US 5,164,980 A
• Filed: 02/21/1990
• Issued: 11/17/1992
• Est. Priority Date: 02/21/1990
• Status: Expired due to Fees

• Current Assignee: Alkanox Corporation
• Original Assignee: Alkanox Corporation
• Inventors: Patel, Ashok, Bush, Daniel R.
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): Woo, Stella L.
• Application Number:
  US07/482,649
• Time in Patent Office: 1,000 Days
• Field of Search: 379/53, 379/96, 358/85
• US Class Current: 348/14.13
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H
• CPC Class Codes: G10L 19/04 using predictive techniques
• CPC Class Codes: H04N 19/619 the transform being operated outside the prediction loop
• CPC Class Codes: H04N 21/236 Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream multiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/434 Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream demultiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/4341 Demultiplexing of audio and video streams
• CPC Class Codes: H04N 7/148 Interfacing a video terminal to a particular transmission medium, e.g. ISDN

Abstract

Apparatus and method are provided for the simultaneous transmission of video information and audio information in substantially real time over an ordinary voice grade telephone line having limited bandwidth in the range of about 300-3400 Hz. Because of the limited bandwidth of the ordinary telephone line, the video and audio information are compressed before transmission thereof. Each of the video information and audio information is separately compressed, mixed together and then further compressed. After the further compression, a composite signal, which includes the mixture of video and audio information, is asynchronously transmitted over the same bandwidth of the ordinary telephone line. Upon reception, the compressed information is expanded and separate video information and audio information are reproduced for viewing and hearing by the receiving party. To reduce the size of the apparatus, application specific integrated circuits (ASICs) are employed. A state machine controller apparatus is integrated with the ASIC technology to control the transfer and storing of video information and audio information and also to control the operation of the various compression and expansion stages associated with the transmitting and receiving channels.

Claims

1. A method for transmitting and receiving video and audio signals over an ordinary telephone line having a bandwidth of about 300-3400 Hz in substantially real time, comprising:

generating a video signal having video information;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information, said step of producing including controlling the sending of said audio information from seventh memory means to means for transforming said audio information to a frequency domain from a time domain;

modulating said composite signal;

transmitting said modulated composite signal using an ordinary telephone line having a limited bandwidth in the range of about 300-3400 Hz;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

2. A method, as claimed in claim 1, wherein:

said step of transmitting includes using the same bandwidth to send both said video information and said audio information.

3. A method, as claimed in claim 1, wherein:

said step of generating a video signal includes focusing automatically a camera device to provide focused video images of an object represented by reflected light inputted to said camera device.

4. A method, as claimed in claim 1, wherein:

said step of producing includes controlling the sending of said video information from first memory means using second state machine controller means in order to compress said video information using a spatial compression mode.

5. A method, as claimed in claim 1, wherein:

said step of producing includes controlling the sending of said video information from second memory means using third state machine controller means to transform said video information to a frequency domain from a time domain.

6. A method, as claimed in claim 1, wherein:

said step of producing includes controlling the sending of said video information from fourth memory means using fifth state machine controller means in order to compress said video information using coefficient selector means.

7. A method, as claimed in claim 1, wherein:

said step of producing includes controlling the sending of said video information from fifth memory means using fifth state machine controller means in order to compress said video information using means for reducing the number of bits associated with said video information.

8. A method, as claimed in claim 1, wherein said step of generating said audio signal includes:

converting an analog audio signal to a digital audio signal;

storing digital audio information representative of said digital audio signal in seventh memory means;

wherein sixth state machine controller means controls the conversion of said analog signal to said digital signal and monitors said seventh memory means.

9. A method for transmitting and receiving video and audio signals over an ordinary telephone line in substantially real time, comprising:

generating a video signal having video information, said step of generating a video signal includes providing first means having a number of pixels with said number of pixels together comprising a frame and wherein said video signal is generated using a number of frames with an updating of frames being provided at a rate of about 7.5 frames per second;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information;

modulating said composite signal;

transmitting said modulated composite signal using an ordinary telephone line having a limited bandwidth;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

10. A method for transmitting and receiving video and audio signals over an ordinary telephone line having a bandwidth of about 300-3400 Hz in substantially real time, comprising:

generating a video signal having video information;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information, said step of producing includes compressing said video information by a factor of at least 57 times and separately compressing said audio information;

modulating said composite signal;

transmitting said modulated composite signal using an ordinary telephone line having a limited bandwidth in the range of about 300-3400 Hz;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

11. A method for transmitting and receiving video and audio signals over an ordinary telephone line in substantially real time, comprising:

generating a video signal having video information;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information, said step of producing includes compressing video information and audio information of said composite video/audio signal, said step of producing including using fast Fourier transform means for receiving both video information and audio information;

modulating said composite signal;

transmitting said modulated composite signal using an ordinary telephone line having a limited bandwidth;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

12. A method for transmitting and receiving video and audio signals over an ordinary telephone line in substantially real time, comprising:

generating a video signal having video information;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information, said step of producing includes using one of said video information and said audio information as real numbers and using the other one of said video information and said audio information as imaginary numbers;

modulating said composite signal;

transmitting said modulating composite signal using an ordinary telephone line having a limited bandwidth;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

13. A method for transmitting and receiving video and audio signals over an ordinary telephone line having a bandwidth of about 300-3400 Hz in substantially real time, comprising:

generating a video signal having video information;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information, said step of producing includes controlling the sending of said video information from sixth memory means to fast Fourier operator means using ninth state machine controller means in order to provide said fast Fourier operator means with one of real numbers and imaginary numbers using said inputted video information;

modulating said composite signals;

transmitting said modulated composite signal using an ordinary telephone line having a limited bandwidth in the range of about 300-3400 Hz;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

14. A method, as claimed in claim 13, wherein:

said step of producing includes controlling the sending of said audio information from tenth memory means to said fast Fourier operator means using said ninth state machine controller means, with said audio information being inputted to said fast Fourier operator means as the other one of said real and imaginary numbers.

15. A method for transmitting and receiving video and audio signals over an ordinary telephone line having a bandwidth of about 300-3400 Hz in substantially real time, comprising:

generating a video signal having video information;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information, said step of producing includes controlling the sending of said audio information from ninth memory means to means for selecting coefficients associated with said audio information using eighth state machine controller means;

modulating said composite signal;

transmitting said modulating composite signal using an ordinary telephone line having a limited bandwidth in the range of about 300-3400 Hz;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

16. A method for transmitting and receiving video and audio signals over an ordinary telephone line having a bandwidth of about 300-3400 Hz in substantially real time, comprising:

generating a video signal having video information;

generating an audio signal having audio information;

producing a composite video/audio signal wherein said composite signal includes a mixture of compressed video information and compressed audio information, said step of producing includes obtaining a reduced number of coefficients associated with said audio information using eighth state machine controller means;

modulating said composite signal;

transmitting said modulated composite signal using an ordinary telephone line having a limited bandwidth in the range of about 300-3400 Hz;

receiving said modulated composite signal after having been sent over the ordinary telephone line;

demodulating said modulated composite signal; and

reproducing said video information and said audio information using said composite signal.

17. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line having a limited bandwidth of between about 300-3400 Hz, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line having a limited bandwidth in the range of about 300-3400 Hz;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof, said fourth means including means for expanding compressed video information by combining previously transmitted video information with currently transmitted video information and means for expanding said audio information by combining previously transmitted audio information and currently transmitted audio information;

fifth means for displaying images using said video information; and

sixth means for generating sounds using said audio information.

18. An apparatus, as claimed in claim 17, wherein said second means includes:

transducer means for outputting an analog audio signal;

amplifier means for amplifying said analog audio signal; and

low pass filter means responsive to said amplifier means for substantially preventing the passage of signals having a frequency greater than a predetermined cut-off frequency.

19. An apparatus, as claimed in claim 17, wherein said third means includes:

means for compressing said video information using square root determining means.

20. An apparatus, as claimed in claim 17, wherein said third means includes:

means for determining a difference between previously transmitted video information and current video information.

21. An apparatus, as claimed in claim 17, wherein said fourth means includes:

means for expanding compressed video information and compressed audio information using multiplying means.

22. An apparatus, as claimed in claim 17, wherein said fourth means includes:

means for expanding compressed video information and compressed audio information using coefficients restorer means.

23. An apparatus, as claimed in claim 17, wherein said fourth means includes:

image magnifying means for receiving compressed video information and magnifying said video information to a larger frame size.

24. An apparatus, as claimed in claim 17, wherein said first means includes:

means for automatically focusing a lens of a camera device for generating an analog video signal having said video information.

25. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line, said third means includes means for providing a composite signal having said video information and said audio information mixed together;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof, said fourth means including means for decoding said mixed video/audio information to provide expanded mixed video/audio information, said fourth means including means for separating video information and audio information from said mixed video/audio information, said means for separating including inverse fast Fourier transform means, first memory means for storing said separated video information, second memory means for storing said separated audio information and state machine controller means communicating with said inverse fast Fourier transform means, said first memory means and said second memory means for controlling said fast Fourier transform means and the transfer of said separated video information and said separated audio information to said first memory means and said second memory means, respectively;

fifth means for displaying images using said video information; and

sixth means for generating sounds using said audio information.

26. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line, said third means including means for mixing said compressed video information and said compressed audio information to provide a single data stream wherein both of said video information and said audio information is adapted to be transmitted using the same bandwidth over the ordinary voice grade telephone line, said means for mixing including;

fast Fourier operating means;

memory means; and

state machine controller means communicating with said fast Fourier operator means and said memory means for controlling the operation of said fast Fourier operating means and controlling the transfer of mixed video/audio data to said data means;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof;

fifth means for displaying images using said video information; and

sixth means for generating sounds using said audio information.

27. An apparatus, as claimed in claim 26, wherein said third means further includes:

means for determining whether currently transmitted video information corresponds to previously transmitted video information in order to further compress said video information.

28. An apparatus, as claimed in claim 27, wherein said means for determining includes:

means for taking the difference between previous and current video information;

encoder means for analyzing said difference; and

state machine controller means communicating with said means for taking the difference and said encoder means for controlling each of said means for taking the difference and said encoder means.

29. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line, said third means including means for providing a composite signal having said video information and said audio information mixed together, said third means further including modulator means for modulating a carrier wave having one of two predetermined frequencies using said mixed video/audio information;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof;

fifth means for displaying images using said video information; and

sixth means for generating sounds using said audio information.

30. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof, said fourth means including means for converting video information from a time domain to a frequency domain using an inverse cosine transformation means;

fifth means for displaying images using said video information; and

sixth means for generating sounds using said audio information.

31. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof, said fourth means including means for converting audio information to a time domain from a frequency domain;

fifth means for displaying images using said video information; and

sixth means for generating sounds using said audio information.

32. An apparatus, as claimed in claim 31, wherein said means for converting includes:

inverse cosine transformation means for transforming said audio information to said time domain;

memory means communicating with said inverse cosine transformation means for receiving audio information in said time domain; and

state machine controller means for controlling said inverse cosine transformation means and transfer of said audio information to said memory means.

33. An apparatus, as claimed in claim 32, wherein:

said inverse cosine transformation means includes multiplier and accumulator means for receiving compressed audio information to be converted to said time domain.

34. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information, one of said first means and said second means including means for determining the bandwidth of the ordinary voice grade telephone line over which said video information and said audio information are to be transmitted;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof;

fifth means for displaying images using said video information; and

sixth means for generating sounds using said audio information.

35. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof;

fifth means for displaying images using said video information;

sixth means for generating sounds using said audio information; and

means for providing said video information with a security code wherein only designated receivers of said video information are adapted to obtain said video information for proper decoding after transmission.

36. An apparatus for simultaneously transmitting and receiving video and audio signals over an ordinary voice grade telephone line, comprising:

first means for generating video information;

second means for generating audio information;

third means for producing compressed video information and compressed audio information for transmission, in substantially real time, over an ordinary voice grade telephone line;

fourth means for reproducing video information and audio information from said compressed video information and said compressed audio information after transmission thereof;

fifth means for displaying images using said video information;

sixth means for generating sounds using said audio information; and

means for storing compressed video information that is adapted to be or has been transmitted over the ordinary voice grade telephone line for later expansion and display.