EP0730365A2
Expired / Lapsed
EP
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Audio communication control unit
Assignee: NTT Inc
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Filing: 1996-02-29
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Granted: —
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Expires: 2016-02-29
Abstract
Abstract In a channel branching part input audio signals from at least three terminals connected to a switching part are branched to left- and right-channels audio signals, then in a sound image control part the left- and right-channel audio signals are processed using sound image control parameters in such a manner as to impart them target positions different for each terminal, then in an mixing part all left-channel audio signals corresponding to the respective terminals are mixed together into a left-channel mixed audio signal and all he right-channel audio signals are mixed together into a right-channel mixed audio signal, and in a terminal-associated branching part these left- and right-channel mixed audio signal are distributed and sent to all the connected terminals.
Inventors
- 👤 Ikuichiro Kinoshita
- 👤 Shigeaki Aoki
- 👤 Manabu Okamoto
- 👤 Nobuo Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 21:56
CPC Classifications
H; H04; H04S; H04S3/00; H04M; H04M3/00; H04M3/42; H04M3/56; H04M3/568
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
241 words
An audio communication control unit for teleconferencing which is connected via communication network to a plurality of terminals, comprising: a switching part for switching audio signals received from N terminals via said communication network, N being an integer equal to or greater than three; N input channels connected to said switching part and supplied with the input audio signals from said N terminals, respectively; a channel branching part for branching each of said input audio signals from said N input channels to K branched audio signals of K branched channels, K being an integer equal to or greater than 2; sound image control part for processing said K branched audio signals of said K branched channels corresponding to each of said N input channels with corresponding one of N parameter sets each including K sound image control parameters of predetermined kind or kinds to produce sound-image controled audio signals of K branch channels corresponding to esch of said N input channels, at least one of said N parameter sets being different from the other parameter sets according to target position of said terminals; mixing part for mixing said sound-image controlled audio signals of K branch channels corresponding respectively to said N terminals, for each branch channel, to thereby generate mixed audio signals of K channels; and a terminal-associated branching part for branching said mixed audio signals of K channels in correspondence with said N terminals for input into said switching part.
Claim 2
Dependent Claim
125 words
The audio communication control unit of claim 1, further comprising: a speaker selecting part provided between said N input channels and said channel branching part, for selecting input audio signals to be mixed together from said input audio signals inputted into said N input channels via said switching part and for outputting said selected input audio signals; N selected audio signal channels for applying said selected input audio signals from said speaker selecting part to said channel branching part; and a signal processing control part for controlling said speaker selecting part so that one of said input audio signals to be processing by said at least one of said N parameter sets, is outputted to a predetermined one of said N selected audio signal channels.
Claim 3
Dependent Claim
159 words
The audio communication control unit of claim 1, comprising signal processing control part for deciding top-priority one of said N input audio signals as an audio signal of a principal speaker and the other remaining input audio signals as audio signals of other speakers; wherein said branching number K is two and wherein: said channel branching part branches each of said N input audio signal fed thereto from said N input channels into first- and second branch channel audio signals and outputs them as said K branched audio signals; and said sound image control part includes a phase control part which, under the control of said signal processing control part, sets said first- and second branch channel audio signals corresponding to said principal speaker's audio signal to be in-phase with each other and sets said first- and second-channel audio signals corresponding to said other speakers' audio signals from said other selected to be in opposite plases to each other.
Claim 4
Dependent Claim
223 words
The audio communication control unit of claim 2, wherein said branching number K is two and wherein: said signal processing control part decides top-priorit y one of said N input audio signals as an audio signal of a principal speaker and the other remaining input audio signals as audio signals of other speakers; said speaker selecting part outputs, on the basis of the results of decision by said signal processing control part, said principal speaker's audio signal and said other speakers' audio signals to said predetermined one of said N selected audio signal channels and the other remaining selected audio signal channels, respectively, for input to said channel branching part; said channel branching part branches each of said N input audio signals applied thereto and outputs first- and second-branch channel audio signals as said branched audio signals of said K branch channels; and said sound image control part includes a phase control part which, under the control of said signal processing control part, sets said first- and second branch channel audio signals corresponding to said principal speaker's audio signal from said predetermined one selected audio hannel to be in-phase with each other and sets said first- and second branch channel audio signals corresponding to said other speakers' audio signals from said other selected audio channels to be in opposite plases to each other.
Claim 5
Dependent Claim
47 words
The audio communication control unit of claim 3 or 4, wherein said sound image control part includes an attenuation part which attenuates said other speakers' audio signals to a level lower than that of said principal speaker's audio signal under the control of said signal processing part.
Claim 6
Dependent Claim
187 words
The audio communication control unit of claim 1, wherein said branching number K is two and wherein: said channel branching part branches each of said N input audio signal fed thereto into first and second branch channel audio signals and output them as said K branched audio signals; said signal processing control part decides top-priorit y one of said N input audio signals as an audio signal of a principal speaker and the other remaining input audio signals as audio signals of other speakers; and said signal processing control part sets said N parameter sets to said sound image control part such that said sound image control part attenuates said second branch channel audio signal corresponding to said decided principal speaker's audio signal by a first value sufficiently larger than the attenuation value of said first branch channel audio signal corresponding to said decided principal speaker's audio signal and attenuates said first branch channel audio signals corresponding to said other speakers' audio signals by a second value sufficiently larger than the attenuation value of said second branch channel audio signals corresponding to said other speakers' audio signals.
Claim 7
Dependent Claim
227 words
The audio communication control unit of claim 2, wherein said branching number K is two and wherein: said signal processing control part decides top-priorit y one of said N input audio signals from said N input channels as an audio signal of a principal speaker and the other remaining input audio signals as audio signals of other speakers; said speaker selecting part outputs said principal speaker's audio signal and said other speakers' audio signals to said predetermined one of said N selected audio channels and the other remaining selected audio signal channels, respectively, for input to said channel branching part; said channel branching part branches each of said N input audio signals applied thereto into first and second branch channel audio signals and output them as said K branched audio signals; and said sound image control part includes an attenuation part which, under the control of said signal processing control part, attenuates said second branch channel audio signal from said predetermined one selected audio channel by a first attenuation value sufficiently larger than the attenuation value of said first branch channel audio signal from said predetermined one selected audio channel and attenuates each of said first-channel audio signals from said remaining selected audio channel by a second value sufficiently larger than the attenuation value of said second branch channels audio signals from said remaining selected audio channels.
Claim 8
Dependent Claim
85 words
The audio communication control unit of claim 2, further comprising an utterance detection processing part for monitoring levels of said input audio signals fed through said N input channels via said switching part from respectively corresponding said N terminals and for detecting the utterance at each of said N terminals and wherein said signal processing control part decides a principal speaker on the basis of the utterance detected by said utterance detection processing part and controls said speaker selecting part according to the decision result.
Claim 9
Dependent Claim
87 words
The audio communication control unit of claim 3 or 6, further comprising an utterance detection processing part for monitoring levels of said input audio signals fed through said N input channels via said switching part from respectively corresponding said N terminals and for detecting utterance at each of said N terminals and wherein said signal processing control part decides a principal speaker on the basis of the utterance detected by said utterance detection processing part and controls said sound image control part according to the decision result.
Claim 10
Dependent Claim
189 words
The audio communication control unit of claim 2, further comprising Q audio signal processing parts each composed of said channel branching part, said sound image control part and said mixing part, Q being an integer equal to or greater than two, and N conference selecting parts, and wherein: said terminal-associated branching part branches said K-channel mixed audio signals from each of said Q audio signal processing parts in correspondence with said N terminals; said N conference selecting parts each selects one or more groups from Q groups of said K-channel mixed audio signals branched for each terminal by said terminal-associated branching part in response to the control of said signal processing control part mixes said selected one or more groups of K-channel mixed audio signals for each channel and outputs the mixed signals as a group of K-channel audio signal; and in response to a control by said signal processing control part based on conference participation request signal, said speaker selecting part outputs said input audio signals from the terminals to be participated to said selected audio signal channels corresponding to said one or more audio signal processing parts.
Claim 11
Dependent Claim
61 words
The audio communication control unit of claim 10, wherein each of said conference selecting part mixes together said K-channel mixed audio signals from one or more of said audio signal processing parts designated by said conference participation request signal from said corresponding terminal and outputs the mixed signal as said K-channel mixed audio signal to be distributed to said corresponding terminal.
Claim 12
Dependent Claim
68 words
The audio communication control unit of claim 1, further comprising control for determining each of said N parameter sets which correspond N target positions of sound sources different for respective said N terminals, wherein said sound image control part operates each of said N parameter sets on the corresponding K channel branched audio signals to produce K channels of said sound image controlled audio signal for each terminal.
Claim 13
Dependent Claim
29 words
The audio communication control unit of claim 12, wherein the branching number K is two and each of said N parameter sets is a pair of acoustic transfer functions.
Claim 14
Dependent Claim
85 words
The audio communication control unit of claim 10, 11, 12 or 13, wherein said signal processing control part detects the number of terminals participating in a teleconference by detecting signals requesting to participate in said teleconference from said N terminals, determines said target positions for said participating terminals according to said detected number of participating terminals, determines said sound image control parameters of N sets corresponding to said determined target positions and provides said determined sound image control parameters to said sound image control part.
Claim 15
Dependent Claim
44 words
The audio communication control unit of claim 14, wherein said signal processing control part detects the number N of said terminals connected thereto via said switching part and determines target positions for said terminals to be symmetric left-right positions at intervals of 180/(N-1) degrees.
Claim 16
Dependent Claim
58 words
The audio communication control unit of claim 1, further comprising a cancelling part for cancelling from each of said K-channel mixed audio signals distributed by said terminal-associated branching part to each of said N terminals, respectively, the component of each of said K-channel sound-image controlled audio signals from said sound image control part corresponding to said each terminal.
Claim 17
Dependent Claim
44 words
The audio communication control unit of claim 1, further comprising a multiplexing part for multiplexing said K-channel mixed audio signals, distributed by said terminal-associated branching part in correspondence with each of said terminals, into one-channel audio signal for input into to said switching part.
Claim 18
Dependent Claim
111 words
The audio communication control unit of claim 1, wherein Q sets of said mixing part and said terminal-associa ted branching part are provided, Q being an integer equal to or greater than 2, said audio communication control unit further comprises: a combination assignment part for applying said K-channel sound-image controlled audio signal from said sound image control part, which corresponds to each of said N terminals, to designated one or more mixing parts; and an inter-combination mixing part for mixing together, for each channel, said K-channel mixed audio signals distributed from one or more of said terminal-associated branching parts and for outputting said channel-associated mixed audio signals to said each terminal.
Claim 19
Dependent Claim
116 words
The audio communication control unit of claim 1, wherein Q sets of said channel branching part, said sound image control part, said mixing part and said terminal-associated branching part are provided, Q being an integer equal to or greater than 2, and said audio communication control unit further comprises: combination assignment part for applying said input audio signal from each of said N terminals via said switching part to designated one or more of said channel branching parts; and an inter-combination mixing part for mixing together, for each channel, said K-channel mixed audio signals distributed from designated one or more of said terminal-associated branching parts and outputting said channel-associated mixed audio signal to said each terminal.
Claim 20
Dependent Claim
92 words
The audio communication control unit of claim 18, wherein said K channels are left and right channels and said sound image control parts each generate, for each terminal, a stereo audio signal of left and right channels as said sound-image controlled audio signal by convolving said branched audio signals of said left and right channels corresponding to said each terminal, respectively, with a pair of acoustic transfer functions used as said sound image control parameters, which correspond to a target position of a sound source different for each of said N terminals
Claim 21
Dependent Claim
91 words
The audio communication control unit of claim 20, further comprising a signal processing control part which detects the number of all terminals participating in any of said Q teleconferences by detecting signals requesting to participate in said common teleconferences from said terminals, determines target positions of the same number as said number of conference participating terminals, determines said pairs of acoustic transfer functions as said sound image control parameters corresponding to said determined target positions and provides said determined pairs of acoustic transfer functions to said sound image control parts, respectively.
Claim 22
Dependent Claim
76 words
The audio communication control unit of claim 14, wherein upon each change in the number of conference participating terminals by a request to participate in or leave each of said teleconferences, said signal processing control part updates said target positions according to the new number of conference participating terminals and updates said pairs of transfer functions according to said updated target positions and sets said updated pairs of transfer functions in said sound image control parts.
Claim 23
Dependent Claim
46 words
The audio communication control unit of claim 21, wherein, letting the numbers of terminals participating in all teleconferences be represented by M, said signal processing control part determines said target positions for all conference participating terminals to be symmetric left-right positions at intervals of 180/(M-1) degrees.
Claim 24
Dependent Claim
97 words
The audio communication control unit of claim 19, wherein said K channels are left and right two channels and said Q sound image control parts corresponding to said teleconferences each generate, for each terminal, a stereo audio signal of left and right channels as said sound-image controlled audio signal by convolving a pair of acoustic transfer functions as said sound image control parameters, which correspond to a target position of a sound source different for each of said N terminals, into said branched audio signals of said left and right channels corresponding to said each terminal, respectively.
Claim 25
Dependent Claim
89 words
The audio communication control unit of claim 24, further comprising a signal processing control part which detects the number of terminals participating in each of said teleconferences by detecting signals requesting to participate in said each teleconference from said N terminals, determines pairs of acoustic transfer functions corresponding to target positions of the same number as said detected number of participating terminals for said each teleconference and sets said determined pairs of acoustic transfer functions in that one of said sound image control parts corresponding to said each teleconference.
Claim 26
Dependent Claim
50 words
The audio communication control unit of claim 25, wherein, letting the number of terminals participating in each teleconference be represented by M P , said signal processing control part determines said target positions for all conference participating terminals to be symmetric left-right positions at intervals of 180/(M P -1) degrees.
Claim 27
Dependent Claim
94 words
The audio communication control unit of claim 25, wherein upon each change in the number of terminals participating in any one of said teleconferences by a request to participate in or leave said any one teleconference, said signal processing control part updates said target positions of said any one teleconference according to the new number of conference participating terminals, updates said pair of transfer functions according to said updated target positions and sets said updated pair of transfer functions in that one of said sound image control parts corresponding to said any one teleconference.
Claim 28
Dependent Claim
105 words
The audio communication control unit of claim 1, further comprising: N switches which are inserted respectively in said N input channels and pass therethrough or interrupt said input audio signals; and an utterance detection part which decides, from said input audio signals on said input audio signal channels, whether terminals corresponding to said input audio signals are in a speaking state, and controls said switches so that said switches in said input channels decided to be in the speaking state pass said input audio signals and said switches in said input channels decided not to be in the speaking state interrupt said input audio signals.
References Cited (Backward Citations)
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