Television – Two-way video and voice communication – User positioning
Reexamination Certificate
1998-06-11
2001-09-11
Loomis, Paul (Department: 2743)
Television
Two-way video and voice communication
User positioning
C348S014160, C379S093170
Reexamination Certificate
active
06288740
ABSTRACT:
BACKGROUND OF THE INVENTION
Video conferencing systems allow for simultaneous exchange of audio, video and data information among multiple conferencing sites. Systems known as multipoint control units (MCUs) perform switching functions to allow three or more sites to intercommunicate in a conference. The MCU links multiple video conferencing sites together by receiving frames of digital signals from the sites, processing the received signals, and retransmitting the processed signals to appropriate sites. The digital signals include audio, video, data and control information. In a switched conference, the video signal from one of the conference sites, typically that of the loudest speaker, is broadcast to each of the participants. In a continuous presence conference, video signals from two or more sites are spatially mixed to form a composite video signal for viewing by conference participants.
In a typical continuous presence conference, the video display is divided into quadrants and up to five sites are selected at conference setup from the sites in the conference for display in the quadrants. Up to five combination organized into the four quadrants, are created statically and are fixed for the conference. Each combination is referred to as a video mix and each selected site views a video mix comprising the other four sites such that a selected site never receives its own video signal. One of the video mixes is also selected as a broadcast mix for viewing by those remaining sites in the conference that are not among the five selected sites.
In the typical continuous presence conference, no attempt is made to associate any particular site with a particular display quadrant. That is, the quadrant organization used does not provide for a site to appear in the same quadrant in each of the five video mixes. Since the five selected sites are chosen at conference setup, this selection remains static throughout the conference, unless a particular selected site leaves the conference, in which case one of the unselected sites may be selected as a replacement.
In another conference system, it is possible to display video information from an unselected site in a single video mix that is broadcast to all sites in the conference. However, since only one broadcast video mix is provided, each of the four sites in the broadcast mix sees its own video.
SUMMARY OF THE INVENTION
According to the present invention, a method and apparatus are provided for continuous presence conferencing having voice-activated quadrant selection. Accordingly, a multipoint control unit receives video signals from plural sites. Anchored sites are selected from the plural sites and assigned to respective anchored regions of a composite video image. A switched site is selected according to a selection process and assigned to a switched region of the composite video image. A rotating site is further selected from the plural sites and is assignable to any of the anchored and switched regions. The video signals are processed in the multipoint control unit according to the composite video image assignments to provide composite video signals for transmission to the plural sites.
According to an aspect of the invention, the selection process for selecting the switched site includes evaluating audio signals received from the conference sites to determine a dominant audio signal and selecting the site associated with the dominant audio signal. The switched site is selected at time intervals such that the particular site selected can differ depending on the dominant audio signal at the particular time interval.
The composite video signals include first composite video signals comprising video signals from each anchored site in their respective anchored regions and the video signal from the switched site in the switched region, except that the video signal from the rotating site takes the place of the anchored site intended to receive the particular first composite video signal. A second composite video signal comprises video signals from each anchored site in their respective anchored regions and the video signal from the switched site in the switched region. A third composite video signal comprises video signals from each anchored site in their respective anchored regions and the video signal from the rotating site in the switched region.
The respective first composite video signals are transmitted from the multipoint control unit to the associated anchored sites. The second composite video signal is transmitted to the rotating site and the third composite video signal is transmitted to the switched site. The remaining unselected sites in the conference receive the second composite video signal if the audio signal of the switched site is dominant relative to the audio signal of the rotating site, otherwise the third composite video signal is sent to these remaining sites.
From the perspective of the conference sites, the video signal of the switched site appears in the switched region of each composite video signal sent to the anchored sites and the rotating site, the video signal of the rotating site appears in the switched region of the composite video signal sent to the switched site, and the video signal of the rotating site appears in the respective anchored region of the composite video signal sent to each anchored site.
An apparatus of the invention comprises a multipoint control unit having a receiver for receiving video signals from the plural sites. A control processor selects anchored sites from the plural sites and assigns them to anchored regions of a composite video image. The control processor further selects a switched site according to a selection process and assigns the switched site to a switched region of the composite video image. A video processor processes the video signals according to the composite video image assignments to provide composite signals for transmission to the plural sites.
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Globerson Mark Alan
Lai Jim Jiansu
Ezenia! Inc.
Hamilton Brook Smith & Reynolds P.C.
Loomis Paul
Ramakrishnaiah Melur
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