Abstract:
A visual indicator is employed on screen at each station of a video teleconference to inform respective participants of their place in a talk request queue. The indicators are controlled automatically in accordance with designer-chosen conference parameters. Optional system failsafe mechanisms protect against system lock-up.

Description:
This is a continuation of application Ser. No. 08/306,623 filed on Sep. 15, 1994, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to video teleconferencing and, more particularly, to techniques for controlling the source of the audio portion of a video teleconference. 
     During the course of a video teleconference involving three or more participating stations, it is often difficult for the participants to know who wishes to talk next. This problem can be exacerbated by time delays inherent in the system (i.e. &#34;audio latency&#34;). These time delays are not so problematic for the case of just two participants, but when three or more participants are involved significant confusion can be caused. If coordination of the video and audio (i.e. &#34;lip synched video&#34;) is desired, it is not practical to eliminate the time delays, since significant time is required to implement the necessary video compression and decompression algorithms needed for transmission of the video images on moderate bandwidth channels. 
     It would therefore be considered highly desirable to have a method for allowing all participants in a video teleconference to be made aware of who wishes to speak next, and to provide a logical and fair arrangement for allocating speaking opportunities. 
     SUMMARY OF THE INVENTION 
     The Applicant has determined that the preferred way to inform the teleconference participants of their respective &#34;right to talk&#34; (or transmit other data) statuses is to provide each of them with a visual indication of their individual status, to wit: 
     (1) Green (meaning &#34;It is OK for you to talk now&#34;); 
     (2) Yellow (meaning &#34;Your request to talk has been received, so be ready to talk when you get a green signal&#34;); and 
     (3) Red (meaning &#34;To talk now will be fruitless, because no one else will hear you. If you wish to talk, please press your talk request key and you will be entered at the end of the talk request queue&#34;). 
     The above-mentioned color visual indicator would normally be on screen at each station location throughout the course of the teleconference. The system is controlled either by specific hardware logic installed at each station or by some teleconference interactive software installed at each station. 
     Various other features for establishing parameters for automatically controlling the teleconference format and procedure are also included. Also, with some embodiments, printed messages and instructions to the various participants will appear on the respective video screens. The system can include a failsafe arrangement so that faulty hardware or software at an individual station does not jeopardize the entire teleconference. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 depicts a typical video screen employing the technique of the instant invention. 
     FIG. 2 shows a typical videoconference involving four stations. 
    
    
     DETAILED DESCRIPTION 
     The Applicant has discovered a preferred technique for implementing a video teleconference involving three or more stations. The basic idea comprises providing a visual indicator to each participant to apprise each of their current &#34;speaking status&#34;. 
     Preferably, the appropriate indicator will appear directly on each participant&#39;s video screen as shown by the light bulb symbol 105 in FIG. 1. Therein also on video screen 101 are the speaker&#39;s video image 102 (on the left), and the video image of that station&#39;s participant 103 (on the right). Also, there may be a short control message block 104. This block will indicate to a speaker when others wish to speak, and will tell the others their place in the talk request queue. When that station&#39;s participant is the one speaking, the previous speaker is preferably displayed on the left, thereby keeping that station&#39;s participant&#39;s image on the right. As an alternate embodiment, a participant&#39;s window may be at the same place on the display, but instead of indicating who the previous speaker is by position on the display, there would be some indication in the window frame displaying his face. 
     The light bulb indicator 105 serves as a reminder to all participants of their own individual speaking status. The current speaker being heard by all the participants will have a green bulb, while all the other participants will have either a yellow or red bulb. A yellow bulb will indicate to that participant that as soon as the current speaker is finished, that participant will be expected by all participants to speak next. A red bulb will indicate to that participant that it is not yet near time to speak from that terminal. Only those who express an interest in speaking by pressing their respective local &#34;talk request&#34; keys will eventually get a yellow light and then a green light as they move up in the talk request queue. The talk request key could also be voice-activated. The optional comment block 104 can indicate that participant&#39;s place in the speaking queue, or can provide other pertinent information. 
     FIG. 2 shows apparatus for a typical video conference of four participants, comprising a common video transmission medium 200 with connections 201 (A-D) tapped in to connect conference stations 202 (A-D) together. 
     Note that the speaker is shown on the left at each terminal except at the speaker&#39;s own terminal (in this case terminal C), where the speaker&#39;s image remains on the right where it usually is, and the immediately-previous speaker&#39;s image is displayed on the left. 
     A main purpose of the method of the instant invention is to provide a systematic, fair, logical, predictable format for teleconferencing that eliminates confusion and is easy to learn. Although being machine controlled (either by hardwired logic circuits or by software), the system is potentially tailorable for various possible expected human characteristics. The implementations of the method will be easily accomplished by those skilled in the arts of processor programming and logic circuit design in accordance with the nuances of the particular computer environment being used for the teleconferencing. 
     The method includes many features not considered in the basic format discussed above. In particular, the system for implementing the method may include the ability to handle several potentially disruptive events: 
     (1) Two or more participants press their respective talk request keys at the same time. In this case the system may arbitrarily choose one before the other. 
     (2) The speaker with the yellow light does not begin to speak immediately when the yellow light turns to green. Here the system design allows for a specified time delay (possibly operator-adjustable) to occur before the system switches the &#34;talk now&#34; option to the next in line in the talk request queue. A typical time delay for this purpose might be 3 seconds, for example. The speaker can also implement, by key or voice command relinquishment of the right to speak. 
     (3) One or more requests to speak are made while a speaker is talking. Here, the speaker is allowed to continue to speak or transmit images until a stoppage of speaking or transmitting occurs for a particular length of time (for example, 3 seconds). (This time is in addition to any system audio latency due to the transmission process.) Once this threshold is met, the speaker&#39;s light turns red and the next up in the talk request queue gets a green light to go ahead and speak to the group. 
     (4) There could be confusion over who should be able to speak first in the conference. In a preferred embodiment, the person who initiates the conference will have the first opportunity to speak. 
     (5) A hardware failure may occur at one or more of the conference stations. This can be dealt with in various ways, two of which are: (a) a maximum time for any speaker to &#34;hold the floor&#34; can be imposed when others have requested to speak (once this time is exceeded, the green light is switched to the next in the speaking queue) wherein a prior visual indication is given to the speaker when he is about to lose the right to speak. This could be done by blinking the green light, or by providing a time countdown display on the speaker&#39;s local video display; and (b) at regular intervals (e.g. every 5 seconds) all stations automatically communicate with the station having the green light with a systems update signal request (if the update signal request is not answered by the station with the green light, that station will be considered by the system to be inoperable, and the next station in the talk request queue will be granted the green light). 
     It is to be understood that the invention is not limited to the details described above, but is defined rather by the scope of the appended claims and their fair equivalents.