Video teleconferencing system employing aspect ratio transformation

• US 5,280,540 A
• Filed: 10/09/1991
• Issued: 01/18/1994
• Est. Priority Date: 10/09/1991
• Status: Expired due to Fees

• Current Assignee: Telcordia Technologies Incorporated (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Bell Communications Research, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Tohme, Henri E., Judd, Thomas H., Addeo, Eric J., Bianchi, Michael H.
• Primary Examiner(s): Chan, Wing F.
• Application Number:
  US07/774,182
• Time in Patent Office: 832 Days
• Field of Search: 379/53, 379/54, 379/202, 379/204-206, 358/140-143, 358/85, 358/55, 358/77
• US Class Current: 348/14.1
• CPC Class Codes: H04N 7/15 Conference systems

Abstract

A teleconferencing system (100, 100'"'"') provides a wide aspect ratio view at each site utilizing a single NTSC camera (250, 350) and projector (260,360). At the transmitting end of a teleconference, a transformation element (280, 380, 510, 610) maps a wide aspect ratio field of view into the field of view of an NTSC camera. The transformation is reversed at the receiving end of the teleconferencing system.

Claims

1. A teleconferencing system comprising

first and second stations in communication with each other, each station including means for generating a video image for transmission to the other station and for receiving a video image transmitted form the other station, each station including means for transforming an aspect ratio of a video image generated by it, said transforming means comprising an electronic circuit including a resampling circuit for transforming the aspect ratio of said image received from said generating means, said resampling circuit including means for interpolating said image and means for decimating said image, and each station including means for reversing an aspect ratio transformation in a video image received by it.

2. The teleconferencing system of claim 1 wherein said reversing means comprises an electronic circuit including

means for receiving said image from said other station and for converting said image into components,

an image resampling circuit for reverse transforming the aspect ratio of said image by processing said components producing a reversed-transformed signal, said resampling circuit including means for interpolating and means for decimating said image, and

means for coding said reverse-transformed signal from said resampling circuit.

6. The teleconferencing system of claim 1 wherein said resampling circuit comprises

means for transforming the aspect ratio of said image received from said NTSC camera.

7. The teleconferencing system of claim 6 wherein said transforming means comprises means for interpolating said image.

8. The teleconferencing system of claim 6 wherein said transforming means comprises means for decimating said image.

9. The teleconferencing system of claim 1 wherein said electronic circuit of said transformation element further comprises

means for receiving said image from said NTSC camera and for converting said image into components to be processed at said resampling circuit and

means for converting an output signal from said resampling circuit and for coding said output signal for transmission to said receiving station.

10. The teleconferencing system of claim 1 wherein said reversing means for reversing said transformation comprises an electronic circuit connected to said means for displaying said image on said screen, said electronic circuit of said reversing means including

means for receiving said image from said transmitting station and for converting said image into components,

an image resampling circuit for reverse transforming the aspect ratio of said image by processing said components producing a reversed-transformed signal, said resampling circuit including means for interpolating and means for decimating said image, and

means for coding said reverse-transformed signal from said resampling circuit to be displayed by said displaying means.

3. A video teleconferencing station comprising

an NTSC camera for generating a first NTSC video image for transmission to a remote station,

transformation means for transforming said first video image to map a wide aspect field of view into said first NTSC video image, said transformation means comprising a resampling circuit connected to an electronic output of said camera, said resampling circuit including means for interpolating and means for decimating said first video image, and

an NTSC projector for receiving a second NTSC video image from said remote location including means for reversing a transformation introduced into said second NTSC video image at said remote location for forming a wide aspect ratio image for display at said station.

4. A teleconferencing system comprising

first and second stations in communication with each other, each station including means for generating a video image for transmission to the other station and for receiving a video image transmitted from the other station, each station including a codec which includes means for coding the video image generated at said generating means and for transforming an aspect ratio of the video image generated at said generating means and means for decoding the video image transmitted from the other station and for reversing an aspect ratio transformation transmitted from the other station.

5. A teleconferencing system comprising

a transmitting station comprising an NTSC camera and a transformation element coupled to said NTSC camera for introducing a transformation into an image produced by said NTSC camera to map a wide aspect ratio field of view into said image produced by said NTSC camera, said transformation element comprising an electronic circuit connected to an output of said NTSC camera, wherein said electronic circuit comprises an image resampling circuit, and

a receiving station connected to said transmitting station by a transmission channel, said receiving station comprising means for receiving said NTSC image generated by said NTSC camera including reversing means for reversing said transformation introduced into said NTSC image at said transmitting station and means for displaying said image on a screen having a wide aspect ratio to provide a wide aspect view of said image produced by said NTSC camera at said receiving station.