Patent Publication Number: US-7912196-B2

Title: Voice conference apparatus, method for confirming voice in voice conference system and program product

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-095428, filed on Mar. 30, 2006, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The present invention relates to a voice conference apparatus and a method and program product for confirming voice in a voice conference system. 
     2. Description of the Related Art 
     In a voice conference apparatus or TV conference apparatus for an electronic conference system using terminals connected via a network, communication line, or the like, a method for confirming whether or not an other party can hear a voice of an own party is as follows. 
     JP-A-2004-186870 discloses a method for measuring a voice pressure of a voice outputted from a speaker of the other party&#39;s terminal and using the measured value as voice level information to visually display the voice level information on the own party&#39;s terminal connected via a network. 
     JP-A-2004-48329 discloses a sound confirmation method in a network conference system. The sound confirmation method includes reproducing received voice data, detecting a voice volume of the reproduced voice and informing the other party&#39;s terminal of the voice volume as response data. 
     JP-A-2005-269498 discloses a video conference system, wherein a voice output level (unit is decibel (dB)) of a voice outputted from another party&#39;s terminal is collected and the voice output level is displayed as voice quality information (representing a voice volume) on an image of an own terminal display screen. 
     However, in a voice confirmation method for confirming whether or not an other party can hear an own voice in the known electronic conference system, merely the voice pressure level of the voice reproduced in the other party is confirmed and it is not possible to confirm how much good quality a voice is reproduced in the other party&#39;s terminal. 
     For example, even when there is no problem in the voice pressure level, a desired voice quality cannot be guaranteed at the other party&#39;s terminal due to quality degradation in a communication path, a CODEC quality, or the like. That is, there is a case where an inputted voice is transmitted from an own terminal and reproduced at the other party&#39;s terminal together with different acoustics, noises, or the like, and the voice is not reproduced as much as the desired clear quality. In this case, when outputted voice pressure level is good, an abnormal in the voice quality may be not detected. In addition, even when a defect in the voice quality is detected, it is difficult to detect where the cause of the defect is according to the known voice confirmation method. 
     SUMMARY 
     An aspect of the invention provides a voice conference apparatus that confirms whether a voice inputted at own party and transmitted from the own party is reproduced at other party&#39;s terminal with desired clear voice quality; a method and program product for confirming a voice in a voice conference system. 
     Another aspect of the invention provides a voice conference apparatus including: a communication unit that transmits and receives a first voice signal to and from another apparatus via a network; an output unit that reproduces the first voice signal received by the communication unit and outputs the reproduced first voice signal as a first voice; an input unit that collects the first voice and a second voice generated by a voice source, as a second voice signal; a separating unit that separates the second voice signal into a third voice signal originated from the first voice and a fourth voice signal originated from the second voice; and a selecting unit that selects one of the third voice signal and the fourth voice signal. The communication unit transmits the one of the third voice signal and the fourth voice signal selected by the selecting unit to the other apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a diagram illustrating a configuration of a voice conference system according to an embodiment of the invention; 
         FIG. 2  is a flowchart explaining a method for confirming a voice in the voice conference system using the voice conference apparatus according to the embodiment of the invention; 
         FIG. 3  is a flowchart explaining separate sequences of step S 8  in  FIG. 2 ; 
         FIG. 4  is a diagram illustrating a technique wherein the voice level is measured in advance before transmission, and then the attenuated voice level is amplified as much as the measured voice level at the time of receiving the voice; 
         FIG. 5  is a diagram illustrating an example of amplifying the voice signal; 
         FIG. 6  is a flowchart illustrating an example of sequences for detecting where a problem is in the voice conference system using the voice conference apparatus according to the embodiment of the invention; 
         FIG. 7  is a diagram illustrating a method for detecting a problem in the voice output unit; 
         FIG. 8  is a diagram illustrating a method for detecting a problem in the voice input unit; 
         FIG. 9  is a diagram illustrating a method for detecting a problem between the communication units; 
         FIG. 10  is a diagram illustrating a method for detecting a problem between the communication units; and 
         FIG. 11  is a diagram illustrating a configuration of a voice conference system according to a modified example of the embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a voice conference apparatus and a method and program product for confirming a voice in a voice conference system according to an embodiment of the invention will be described in detail with reference to drawings. 
       FIG. 1  is a diagram illustrating a configuration of a voice conference system according to an embodiment of the invention. According to the embodiment, in the voice conference system transmitting and receiving voice data to and from a plurality of apparatuses at locations including an location A (a first location) and a location B (a second location) connected via a network, it will be described that a voice transmitted from a voice conference apparatus  10 A (a first apparatus) at the location A to a voice conference apparatus  10 B (a second apparatus) at the location B (the second location) is confirmed. 
     In a voice conference system  1  shown in  FIG. 1 , the voice conference apparatus  10 A has a communication unit (communication unit)  11 A, a voice output unit (output unit)  13 A, a voice input unit (input unit)  14 A, and a switch control unit (selecting unit controller)  15 A. In addition, the conference system  10 B has a communication unit (communication unit)  11 B, a desired voice extracting unit (separating unit)  12 B, a voice output unit (output unit)  13 B, a voice input unit (input unit)  14 B, and a switch (selecting unit)  16 B. 
     Further, the voice conference apparatus  10 A at the location A and the voice conference apparatus  10 B at the location B may have the similar configuration. In this case, the voice conference apparatus  10 A may further include a desired voice extracting unit and a switch (selecting unit) (not shown), in addition to the above-described configuration and the voice conference apparatus  10 B may further include a switch control unit (switching unit controller) (not shown) in addition to the above-described configuration. In such a configuration, when the voice conference apparatus  10 A at the location A and the voice conference apparatus  10 B at the location B have the similar configuration, a voice transmitted from the voice conference apparatus  10 B at the location B to the voice conference apparatus  10 A at the location A can be confirmed in a similar manner. 
     The desired voice extracting unit  12 B includes an adaptive filter  121 , a first subtracter  122 , and a second subtracter  123 . The desired voice extracting unit  12 B carries out an echo cancellation function of removing an echo component VAba from a voice signal VAba+VBba inputted to the voice conference apparatus  10 B at the location B and an echo extraction function of extracting the echo component VAba of a voice signal VAab transmitted from the voice conference apparatus  10 A from the voice signal VAba+VBba. 
     The component VBba is a voice signal in which the voice input unit  14 B collects and inputs a voice VBb (for example, a voice or sound of persons in a conference room at the location B) generated from a voice source at the location B. The voice signal VAab transmitted from the voice conference apparatus  10 A at the location A are reproduced and outputted from the voice output unit  13 B. A voice VAb is a voice just before the voice input unit  14 B collects the voice or an attenuated voice of the reproduced and outputted voice signal VAab from the voice output unit  13 B. 
     In addition, the voice signal VAba is generated from the voice VAb and the voice signal VAba which is collected together when the voice input unit  14 B collects the voice VBb. 
     The voice conference apparatus  10 A has the switch control unit  15 A, can transmit a control signal from the switch control unit  15 A using the communication units  11 A and  11 B, and can be controlled the switch  16 B by the control signal. Accordingly, the voice conference apparatus  10 A can switch to any one of the echo cancellation function and echo extraction function of the voice conference apparatus  10 B. 
       FIG. 2  is a flowchart explaining a method for confirming a voice in the conference system using the voice conference apparatus according to the embodiment of the invention. 
     First, when it is confirmed whether or not the voice VAa (for example, a voice or sound of a person in a conference room at the location A) inputted from the location A is normally reproduced at the location B, a switch control unit switches and selects the switch  16 B from b to a (step S 1 ) 
     At the location B, the control signal is received from the switch control unit at the location A, and then the switch  16 B is switched from b to a (step S 2 ). When the switch  16 B is switched to b, the known echo cancellation function of the voice conference apparatus extracts the voice component VBba at the location B from the voice signal VAba+VBba inputted in the location B. In contrast, when the switch  16 B is switched to a, the voice component VAba is extracted at the location A from the voice signal VAba+VBba inputted at the location B. 
     Next, the voice input unit  14 A collects the voice VAa generated by a voice source at the location A (step S 3 ). The collected voice is transmitted as the voice signal VAab from the communication unit  11 A of the voice conference apparatus  10 A (step S 4 ). The transmitted voice signal VAab is received by the communication unit  11 B of the voice conference apparatus  10 B (step S 5 ), and then is outputted from the voice output unit  13 B (step S 6 ). 
     Next, the voice signal VAab outputted from the voice output unit  13 B is collected as an echo VAb by the voice input unit  14 B (step S 7 ). The voice VBb generated by the voice source at the location B is also collected together by the voice input unit  14 B, which is the original function. 
     The desired voice extracting unit  12 B separates the collected voice signal VAba+VBba into the voice components VAba and VBba (step S 8 ). 
     The sequence of separation in step S 8  will be described with reference to  FIG. 3 . The adaptive filter  121  in the desired voice extracting unit  12 B generates a pseudo-echo in order to remove the echo component VAba from the voice signal VAab at the location A and the voice component VBba extracted by the first subtracter  122  (step S 8 - 1 ). 
     Strictly speaking, the pseudo-echo does not have the same value as the echo component VAba of the voice signal VAba+VBba inputted in the location B. However, since the technology on the echo cancellation is the known technology, the explanation will be omitted and it is considered that the generated echo has the same value as the echo component VAba for a brief explanation. 
     The first subtracter  122  subtracts the pseudo-echo component VAba generated in the adaptive filer  121  from the voice signal VAba+VBba inputted in the location B to extract the voice component VBba generated at the location B (step S 8 - 2 ) 
     The second subtracter  123  subtracts the voice component VBba extracted in the first subtracter  122  from the voice signal VAba+VBba inputted at the location B to extract the echo component VAba of the voice generated from the voice source at the location A (step S 8 - 3 ). 
     The sequence of extracting the voice component is just one example. Any method of extracting the echo component VAba of the voice generated from the voice source at the location A and the voice component VBba generated in the location B from the input voice VAba+VBba can be used. 
     The flowchart of  FIG. 2  will be described again. 
     Since the switch  16 B has already switched to a in steps S 1  and S 2 , the desired voice extracting unit  12 B selects the echo component VAba from the voice components VAba and VBba separated in the desired voice extracting unit  12 B (step S 9 ). The echo component VAba is transmitted from the communication unit  11 B to the communication unit  11 A (step S 10 ). The echo component VAba transmitted from the communication unit  11 B is received by the communication unit  11 A (step S 11 ) and the received echo component VAba is outputted from the voice output unit  13 A (step S 12 ). 
     According to the above-described sequences, the voice signal VAab at the location A reproduced at the location B returns to the location A as the echo component VAba in order to confirm and determine whether or not the voice is normally reproduced in the location B (step S 13 ). 
     As for a determining method, for example, a method of human hearing and a method in which when a difference is in a permissible range by comparing voice waveforms of the echo component VAba outputted from the voice output unit  13 A and the input voice VAa, there is no problem (OK) are used depending on a situation or determination accuracy. 
     When the determination result has no problem (OK), it can be determined that the voice inputted from the location A is normally outputted in the location B. 
     The condition that the determination result has no problem (OK) may satisfy the relation, VAa≈VAab≈VAb≈VAba. Accordingly, it is desirable that the voice conference system according to the embodiment may be extended to meet the condition. 
     The method of meeting the condition is not particularly limited, but an example of the method will be described below. 
     First, in order to guarantee the condition VAa≈VAab, it is conceivable that a change in the voice level through the transmission path from the communication unit  11 A to the communication unit  11 B is compensated, for example. Likewise, in order to guarantee the condition VAb≈VAba, it is conceivable that a change in the voice level through the transmission path from the communication unit  11 B to the communication unit  11 A is compensated, for example. 
       FIG. 4  is a diagram illustrating a technique wherein the voice level is measured in advance before transmission, and then the attenuated voice level is amplified as much as the measured voice level at the time of receiving the voice. 
     As shown in  FIG. 4 , a voice level-measuring unit  19 A measures the voice level of the transmitted voice signal in advance. 
     The measured voice level is represented as V for convenience sake. The measured voice signal is transmitted to the communication unit  11 B via the communication unit  11 A. A voice level-measuring unit  19 B measures the received voice signal in the voice conference apparatus  10 B. 
     In this event, the measured voice level is represented as V/α for convenience sake. Sequentially, an amplifier  1  amplifies the voice signal. How much the voice level is amplified is determined by a value obtained from the voice level-measuring units  19 A and  19 B (amplified by α times in the example shown in  FIG. 4 ). 
     In addition, a noise removing unit that removes noise of the transmission path can be provided. 
     A voice level-measuring unit that measures the voice level of the voice VAa and adjusts the voice level of the voice to be outputted to the voice output unit  13 B at the location B to the voice level VAab may be provided. 
     To approximate the voice levels, that is, to guarantee the condition VAab≈VAb is achieved by returning the echo VAb to the location A in the embodiment of the invention. However, the voice level of the echo VAb is actually attenuated depending on a distance between the voice output unit  13 B and the voice input unit  14 B. 
     Accordingly, the voice level of the voice signal VAab is measured in advance at the time of outputting the voice signal from the voice output unit  13 B so as to become VAab≈VAb, and then the voice component VAba extracted from the desired voice extracting unit  12 B is amplified as much as the voice level of the voice signal VAab. 
       FIG. 5  is a diagram illustrating an example amplifying the voice signal so as to become VAab≈VAb. 
     As shown in  FIG. 5 , the voice level of the voice signal VAab outputted from the voice output unit  13 B is measured by a second voice level-measuring unit  20 B. 
     In addition, the second voice level-measuring unit  20 B is disposed near the voice output unit  13 B in which the voice level of the voice signal VAab is not attenuated. The voice level of the voice signal VAab is represented as V for convenience sake. 
     The voice level of the output voice signal VAab is attenuated and is inputted to the voice input unit  14 B. When the voice signal VAab is inputted, the voice level of the echo VAb is represented as V/β for convenience sake. The echo component VAba is extracted from the voice inputted by the voice input unit  14 B in the desired voice extracting unit  12 B. The extracting echo is amplified by the second amplifier  21 B until the level measured by the second voice level-measuring unit  20 B. That is, in this event, the extracting echo is amplified by β times. 
     When a headset and the like are used as the voice output unit  13 B, an echo does not occur at all. Accordingly, when the effect is confirmed, the voice output unit  13 B and voice input unit  14 B may be shorted, for example. 
     That is, a voice input unit that input voice to the voice input unit  14 B may be provided, so that the voice signal VAab generated by the voice output unit  13 B become VAab≈VAb, 
     In addition, when the result is determined to have a problem (NG), it is easy to detect where the problem occurs and to specify what the problem is in the voice conference system by extending the configuration according to the embodiment of the invention. Hereinafter, in the voice conference system using the voice conference apparatus according to the example of the invention, an example of sequences for detecting where the problem is at the time of confirming the voice will be described with reference to  FIG. 6 .  FIG. 6  is a flowchart illustrating the example of the sequences for detecting where the problem is. 
     The sequence for detecting the problem in the specific unit described below is not limited to following methods of detecting the problem, but other method may be applied. 
     (1) Voice Output Unit  13 A 
     First, a sequence for detecting a problem is executed in the voice output unit  13 A as shown in  FIG. 6  (step S 21 ).  FIG. 7  is a diagram illustrating a method of detecting the problem in the voice output unit  13 A. 
     As shown in  FIG. 7 , a sample voice-generating unit  22 A is provided in the voice conference apparatus  10 A. 
     When the sample voice-generating unit  22 A is executed, the switch control unit  15 A is controlled and a switch  25 A is switched so that a sample voice (voice pressure) Vc is outputted by the voice output unit  13 A. 
     In this event, the outputted voice (voice pressure) is represented as Vca. The voice pressures Vc and Vca are compared, and then when the difference is in the permissible range, it is determined that there is no problem in the voice output unit  13 A and when the difference is out of the permissible range, it is determined that there is a problem in the voice output unit  13 A. 
     (2) Voice Input Unit  14 A 
     Next, a sequence for detecting the problem is executed in the voice input unit  14 A as shown in  FIG. 6  (step S 22 ).  FIG. 8  is a diagram illustrating a method of detecting the problem in the voice input unit  14 A. 
     When it is determined that there is no problem in the voice output unit  13 A in the check (1), a voice Vin is inputted to voice input unit  14 A, the switch control  15 A is controlled, a switch  26 A is switched, the Vin is loop-backed, and then the Vin is outputted from voice output unit  13 A in  FIG. 8 . The outputted voice Vout and Vin are compared, and then when the difference is in the permissible range, it is determined that there is no problem in the voice input unit  14 A and when the difference is out of the permissible range, it is determined that there is a problem. 
     (3) Communication Unit  11 B to Communication Unit  11 A 
     Next, a sequence of detecting the problem is executed in the communication unit  11 B to the communication unit  11 A as shown in  FIG. 6  (step S 23 ). 
       FIG. 9  is a diagram illustrating a method of detecting the problem in the communication unit  11 B to the communication unit  11 A. 
     When a sample voice-generating unit  22 B is provided in the voice conference apparatus  10 B to perform the problem detection, the switch control unit  15 A is controlled, the switch  25 B is switched to b, a sample voice (voice pressure) Vd passes from the communication unit  11 B to the communication unit  11 A, and then the sample voice Vd is outputted from the voice output unit  13 A. 
     In this event, the outputted voice (voice pressure) is represented as Vda. The sample voice Vd and the outputted voice Vda are compared, and then when the difference is in a permissible range, it is determined that there is no problem in the communication unit  11 B to the communication unit  11 A and when the difference is out of the permissible range, it is determined that there is a problem. 
     (4) Communication Unit  11 A to Communication Unit  11 B 
     Next, a sequence of detecting the problem is executed in the communication unit  11 A to the communication unit  11 B as shown in  FIG. 6  (step S 24 ). 
       FIG. 10  is a diagram illustrating a method of detecting the problem in the communication unit  11 A to the communication unit  11 B. 
     When it is determined that there is no problem in the voice output unit  13 A, the voice input unit  14 A, and the communication  11 B to the communication  11 A until the check (3), the inputted voice Vin is inputted to the voice input unit  14 A to transmit the voice from the communication  11 A to the communication unit  11 B. 
     In this event, the switch control unit  15 A is controlled, a switch  26 B is switched to a, and the voice received by the communication unit  11 B is loop-backed to be returned to the communication unit  11 A. The voice which is loop-backed and returned is outputted by the voice output unit  13 A. The outputted voice Vout and the inputted voice Vin are compared, and then when the difference is in a permissible range, it is determined that there is no problem in the communication unit  11 A to the communication unit  11 B and when the difference is out of the permissible range, it is determined that there is a problem. 
     (5) Adaptive Filter  121   
     Next, a sequence of detecting the problem is executed in the adaptive filer  121  as shown in  FIG. 6  (step S 25 ). 
     In the configuration ( FIG. 1 ) of the present embodiment, when it is not found that there is any problem until the check (4) and the voice level (voice pressure) of the voice signal VAba is larger than 0, that is, when any voice is heard from the voice conference apparatus  10 B, but the voice is different from the inputted voice VAa, it can be determined that there is a problem in the adaptive filter  121 . 
     In addition, when it is determined above, it is required that the configuration for practically meeting VAab≈VAb is provided. 
     (6) Voice Output Unit  13 B 
     Next, a sequence of detecting the problem is executed in the voice output unit  13 B as shown in  FIG. 6  (step S 26 ). 
     When it is not found that there is any problem until the check (5), that is, when the voice level (voice pressure) of the voice signal VAba is 0, the switch control unit  15 A of the configuration ( FIG. 1 ) according to the embodiment of the invention is controlled, the switch  16 B is switched to b, and then it is determined whether or not the voice occurring in the location B is heard. 
     In this event, when any voice is heard, it can be determined that there is a problem in the voice output  13 B and when any voice is not heard, it can be determined that there is a problem in the voice input unit  14 B. 
     Next, a modified example of the described example will be described below. 
       FIG. 11  is a diagram illustrating a configuration of a voice conference system  100  according to the modified example of the embodiment of the invention. 
     What an analog signal is transmitted according to the above-described example is explained, but as shown in  FIG. 11 , the modified example in which the inputted voice is digitally encoded to be transmitted to another location is given. 
     According to the modified example, after the inputted voice signal VAab is digitally encoded by an encoder  23 A of the voice conference apparatus  10 A at the location A, the digitally encoded data DVAba is transmitted and decoded by a decoder  24 B of the voice conference device  10 B in the location B. Likewise, the inputted echo component VAba is digitally encoded by the encoder  23 B of the voice conference apparatus  10 B at the location B and then the digitally encoded data DVAba is transmitted to be decoded by the decoder  24 B of the voice conference apparatus  10 A in the location A. In such a modified example, the transmitted data is transformed into the digital signal. 
     According to the modified example, the voices VAa and VAba can be compared at the location A. Accordingly, it is easy to compare the voices VAa and VAba since it is possible that the produced voice does not overlap the inputted voice by delaying time for some while and the like until the voice VAba is outputted by the voice output unit  13 A. 
     As described in detail above, according to the embodiment there is provided a voice conference apparatus  10 B including: a communication unit  11 B that transmits and receives a first voice signal VAab to and from another apparatus via a network; an voice output unit  13 B that reproduces the first voice signal VAab received by the communication unit  11 B and outputs the reproduced first voice signal as a first voice VAb; an voice input unit  14 B that collects the first voice VAb (echo) and a second voice VBb generated by a voice source, as a second voice signal VAba+VBba; a desired voice extracting unit  12 B that separates the second voice signal VAba+VBba into a third voice signal VAba originated from the first voice and a fourth voice signal VBba originated from the second voice VBb; and a selecting unit  16 B that selects one of the third voice signal VAba and the fourth voice signal VBba. The communication unit  11 B transmits the one of the third voice signal VAba and the fourth voice signal VBba selected by the selecting unit  16 B to the other apparatus. 
     According to the configuration above, in a voice conference system wherein a voice signal is transmitted between the plurality of apparatuses connected via a network, the voice signal VAba of the echo of the inputted voice transmitted from the other location (location A) connected via the network to the other location (location A) can be returned. Therefore, it can be confirmed at the other location (the location A) whether or not a voice with the desired clear quality is reproduced at the location (location B) in which the voice conference apparatus  10 B is there. 
     In addition, according to the embodiment, there is provided a method for confirming a communication in a voice conference system including a voice conference apparatus  10 A and a voice conference apparatus  10 B connected to the voice conference apparatus  10 A via a network. The method includes: collecting a first voice VAa generated from a first voice source around the voice conference apparatus  10 A as a first voice signal VAab; transmitting the first voice signal VAab to the voice conference apparatus  10 B from the voice conference apparatus  10 A; reproducing the transmitted first voice signal VAab by the voice conference apparatus  10 B; outputting the reproduced first voice signal VAab as a second voice VAb; collecting the second voice VAb and a third voice VBb generated from a second voice source around the voice conference apparatus  10 B as a second voice signal VAba+VBba at the voice conference apparatus  10 B; separating the second voice signal VAba+VBba into a third voice signal VAba originated from the second voice VAb and a fourth voice signal VBba originated from the third voice VBb; transmitting the third voice signal VAba to the voice conference apparatus  10 A; reproducing the transmitted third voice signal VAba; and determining whether or not the first voice VAa is normally reproduced by the voice conference apparatus  10 B by comparing the first voice VAa generated from the first voice source around the voice conference apparatus  10 A with the reproduced third voice signal VAba. 
     According to the configuration, in the voice conference system, the voice inputted from the own location can be confirmed whether or not the voice is reproduced with the desired clear quality in the other location. Accordingly, since it is easy to confirm whether or not the own voice is heard in the other location, the participants&#39; uneasiness over the system in the conference can be removed. 
     In addition, when the voice conference system is installed, it is required that a person in charge of the work is necessary both at the locations in order to confirm whether or not the voice is heard. However, a person in charge of the confirming work can be stationed only in the single location to treat the work, thereby reducing the burden. 
     Further, when a problem occurs in the voice conference system, it is easy to detect where the problem is and to specify what the problem is in the voice conference system. 
     In this manner, in the voice conference system which transmits and receives the voice data to and from the plurality of locations connected via the network, since the voice signal resulting from the echo of the inputted voice transmitted from the other location (own location) connected via the network can return to the other location, it can be confirmed in the other location to which the voice signal is returned whether or not the voice is reproduced with a desired clear voice quality in the location (other location) in which the voice conference apparatus is installed. 
     In addition, the invention is not limited to the above-described embodiment, but, for example, is also employed as a method for confirming whether or not an own voice is heard to an other party in a TV conference system of an electronic conference system using a terminal connected via a network, a communication line, or the like. Further, the invention can be also applied to a remote class and the like carried out in the remote location via the network, the communication line, or the like.