JPH1032804A - Video conference equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video conference equipment which can realize a noise elimination function, corresponding to a zoom level of a camera. SOLUTION: This equipment is provided with a camera 8 which is provided with a zoom function, a microphone 1 which inputs a voice for an area picked up by the camera 8, a control part 9 which controls zooming of the camera 8 and recognizes a zoom level and a noise elimination means (DSP: digital signal processing circuit) 3, and the part 9 sets such a noise elimination level in the following way, in response to the zoom level of the camera 8. The higher the zoom level becomes, the higher a noise elimination level of the means 3 becomes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video conference apparatus, and more particularly to a voice control technique for the same.

[0002]

2. Description of the Related Art In general, many cameras used in video conference equipment have a zoom function. If you want to capture all participants and make the atmosphere of the whole meeting an image, lower the zoom level (called wide), and if you want to close up one speaker, raise the zoom level (called tele). .

At the same time, many video conference devices have a function of removing noise from voice input from a microphone. This noise removal function performs control such that if the level is below a certain level, it is regarded as noise and cut according to the level or energy value of the input voice. The threshold value (noise removal level) to be cut is fixedly set in advance.

In addition, 16 standards such as ITU-T recommendation G722
In the case of performing a KHz voice codec or the like, the echo canceling function divides the input voice band into two in order to reduce the processing amount to the same level as that of a general 8 KHz voice codec, and the high frequency range has little echo component. Taking advantage of this fact, the noise is removed instead of the echo cancellation processing. This high-frequency noise removal function is called a noise suppressor, and the operation reference value at this time is fixedly set in advance as a noise suppressor coefficient.

Further, when the microphone input has an automatic gain control function (AGC), the gain is increased for small input voices such as wide ones based on a reaction speed coefficient fixedly set in advance. The volume is raised, and the volume is lowered by decreasing the gain for a loud input voice in the case of tele or the like.

[0006]

However, in such a conventional video conference apparatus, as described above, the threshold value (noise elimination level) to be cut by the noise elimination function is fixed, and therefore, the zooming function is supported. No change in the presence of the sound was obtained. In other words, if the noise removal level is set to a relatively large value, the participants speak with a relatively small voice even if the speech is significant in the wide range, so that the significant speech is cut off as noise. Also, if the noise removal level is set to a relatively small level, even voices other than the speaker enter in the case of telephoto, making it difficult to hear the voice of the speaker. In the case of tele, it is considered that a certain person (speaker) speaks with a loud voice to some extent, so that the level to be cut as noise may be higher. On the other hand, if you're wide, everyone may be talking a little quietly, so the level of noise should be reduced. This is also true for a high-frequency noise removal function called a noise suppressor.

[0007] In the case of a microphone input having an auto gain control function, a significant speech comes in at a large volume in the case of tele, and it can be regarded as small in the case of wide, but the response speed coefficient is reduced in the case of the conventional device. Because of the fixed setting, it was not possible to achieve optimal auto gain control for zooming.

Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a video conference apparatus capable of realizing a noise removing function corresponding to a zoom level.

It is another object of the present invention to provide a video conference apparatus capable of realizing a noise removing function corresponding to a zoom level even in a high-frequency noise removing function called a noise suppressor.

It is another object of the present invention to provide a video conference apparatus capable of realizing an automatic gain control function which is optimal for each zoom.

[0011]

According to one aspect of the present invention, a camera having a zoom function, a microphone for inputting sound in an area photographed by the camera, A control unit that controls the zoom of the camera and recognizes a zoom level, and a noise removing unit that removes noise based on a preset noise removal level with respect to the input voice from the microphone, and the control unit includes: According to the zoom level of the camera, the higher the zoom level, the higher the noise elimination level of the noise elimination means is set.

According to a second aspect of the present invention, there is provided a camera having a zoom function, a microphone for inputting sound in an area photographed by the camera, and a control unit for controlling the zoom of the camera and recognizing a zoom level. And, as an echo canceling function, the input voice is divided into low and high bands, low band is subjected to echo cancellation processing, and high band is subjected to noise removal processing based on a preset noise suppressor coefficient.
An echo canceller that combines the bands with each other, wherein the control unit sets the noise suppressor coefficient of the echo canceller higher as the zoom level increases in accordance with the zoom level of the camera.

According to a third aspect of the present invention, there is provided a camera having a zoom function, a microphone for inputting sound in an area photographed by the camera, and a control unit for controlling the zoom of the camera and recognizing a zoom level. An automatic gain controller that automatically adjusts the gain based on a reaction speed coefficient set in advance for the input voice from the microphone,
The control unit, according to the zoom level of the camera, sets a smaller response speed coefficient of the auto gain controller as the zoom level becomes higher, and increases the response speed of the auto gain controller for a large volume, and sets the response speed to a small volume. On the other hand, the reaction speed is reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a video conference apparatus according to each invention of the present application. Here, only a main part (mainly an audio processing system) according to the invention is shown.

In the figure, 1 is a microphone, 2 is a microphone 1
This is an A / D converter which samples an analog audio signal input from the A / D converter at a predetermined sampling frequency and A / D converts the analog audio signal into a digital audio signal.

Reference numeral 3 denotes a DSP circuit (digital signal processing circuit) capable of performing various digital processing by software on an input digital signal to realize various processing functions. , A noise removal function, an echo cancellation function, and an AGC (auto gain control) function for the digital audio signal. 4 is a DSP circuit similar to the above, and this DSP circuit 4 is a voice CODEC (codec).
In this case, encoding of transmission audio data output from the DSP circuit 3 and decoding of the received encoded audio data are performed. Each of the DSP circuits 3 and 4 has a built-in ROM and RAM as its peripheral devices.

Reference numeral 5 denotes a communication control device which is connected to a communication line such as an ISDN and performs various protocol controls related to video conference communication.

6 indicates that the received voice data is the voice COD.
This is a D / A converter that D / A converts a digital audio signal decoded and output by the EC DSP circuit 4 and outputs the obtained analog audio signal to the speaker 7. Note that the received digital audio signal output from the DSP circuit 4 is input to another DSP circuit 3 and is used in its echo canceling function.

Reference numeral 8 denotes a camera with a zoom function. Reference numeral 9 denotes a control unit for controlling the camera 8, each of the DSP circuits 3 and 4, the communication control unit 5, and each unit of the device (not shown).
It is composed of ROM, RAM and the like. Here, the zoom of the camera 8 is controlled by the control unit 9, and the control unit 9 always recognizes the zoom level of the camera 8.

Next, the operation of the video conference apparatus configured as described above will be described.

First, the operation according to the embodiment of the present invention will be described with reference to a flowchart shown in FIG. 2 and a zoom level / noise removal level correspondence table shown in FIG.

The control unit 9 controls the zoom of the camera 8 and constantly recognizes the zoom level and checks whether the zoom level has changed (N in decision 101).
o loop). When a change in the zoom level is detected, the zoom level at that time is checked (Yes in decision 101 →
Process 102). Then, referring to a preset zoom level / noise elimination level correspondence table as shown in FIG. 3, a noise elimination level corresponding to the zoom level at that time is determined, and output to the DSP circuit 3 as control data. ,
It is set in the noise removal function section (process 103). Then, the process returns to the determination 101 again, and the change in the zoom level is monitored.

In the audio processing system, audio is taken in from the microphone 1 and converted into digital data by the A / D converter 2.
Transfer to the DSP circuit 3. The DSP circuit 3 performs a noise removal process on the input digital audio data according to the noise removal level set by the control unit 9. The audio data output from the DSP circuit 3 is
A predetermined encoding process is performed by the SP circuit 4, sent out to the line via the communication control device 5, and sent to the other party's video conference device.

In this manner, the level of the significant voice in the sound field is determined from the zoom level of the camera 8 and the noise elimination level is changed, so that the noise elimination function suitable for the contents of the conference at that time is operated. Can be done.

Next, the operation according to the second embodiment of the present invention will be described with reference to a flowchart shown in FIG. 4 and a zoom level / noise suppressor coefficient correspondence table shown in FIG.

First, the operation of the echo canceller will be described.
A brief description will be given. The echo canceller generates a pseudo echo signal by performing a predetermined filter operation on the audio signal received and output into the conference room, and performs echo removal by subtracting the pseudo echo signal from the input audio signal.

The principle is that, for example, in the case of 8 KHz sampling, when performing echo cancellation of 0.1 second (echo reverberation time), 800 coefficients are prepared for 800 samples, and 8 coefficients are obtained for one sample (for 125 μs).
Basically, a 00-order product-sum operation is performed. Then 16
In the case of KHz, since the 1600-order product-sum operation must be performed within 62.5 μs, which is the half of the above, about four times the calculation capability is required.

In the case of 16 KHz, there is a technique that divides the frequency band into a high frequency band and a low frequency band, and treats each band as 8 KHz data. At this time, since there is not much echo component in the high band, echo cancellation processing is performed only in the low band, noise removal processing is performed in the high band, and the original 16K
Hz. That is, the 16 kHz echo canceller may include the same noise removing function (noise suppressor) as described above.

In this case, in the present embodiment, the same control as the control of the noise removing function in the above embodiment is performed for this noise suppressor.

That is, the control unit 9 checks whether or not the zoom level of the camera 8 has changed (determination 20 in FIG. 4).
1 No loop), when a change in zoom level is detected,
Check the zoom level at that time (Y in decision 201)
es → process 202). Then, referring to a preset zoom level / noise suppressor coefficient correspondence table as shown in FIG. 5, a noise suppressor coefficient corresponding to the zoom level at that time is determined, and is output to the DSP circuit 3 as control data. Is set in the echo cancel function section (process 203). Then, the process returns to the judgment 201 again to monitor the change of the zoom level.

In the audio processing system, audio is taken in from the microphone 1 and converted into digital data by the A / D converter 2.
Transfer to the DSP circuit 3. The DSP circuit 3 performs an echo canceling process on the input digital audio data, including a high-frequency noise removing process according to the noise suppressor coefficient set by the control unit 9. DSP circuit 3
The audio data output from is subjected to a predetermined encoding process by the next DSP circuit 4, sent out to the line via the communication control device 5, and sent to the other party's video conference device.

In this way, the level of the significant sound level in the sound field is determined from the zoom level of the camera 8 and the operation level of the noise suppressor in the echo canceling function is changed, so that it is suitable for the contents of the conference at that time. Noise suppressor function can be operated.

Next, the operation according to the third embodiment of the present invention will be described with reference to the flowchart shown in FIG. 6 and the zoom level / AGC reaction speed coefficient correspondence table shown in FIG.

As in the above-described embodiment, the control unit 9
In addition to controlling the zoom of the camera 8, the zoom level is always recognized to check whether the zoom level has changed (No loop of the determination 301). When the change in the zoom level is detected, the zoom level at that time is checked (Yes in determination 301 → process 302). Then, as shown in FIG. 7, a preset zoom level / AG
The AGC reaction speed coefficient corresponding to the zoom level at that time is determined with reference to the C reaction speed coefficient correspondence table, output to the DSP circuit 3 as control data, and set in the AGC function unit (process 303). And, again, the above-mentioned judgment 301
Return to and monitor the change in zoom level.

In the audio processing system, audio is taken in from the microphone 1 and converted into digital data by the A / D converter 2.
Transfer to the DSP circuit 3. The DSP circuit 3 performs an automatic gain control process on the input digital audio data according to the AGC reaction speed coefficient set by the control unit 9. The audio data output from the DSP circuit 3 is subjected to a predetermined encoding process by the next DSP circuit 4, sent out to the line via the communication control device 5, and sent to the other party's video conference device.

In this manner, the level of the significant sound level in the sound field is determined from the zoom level of the camera 8 and the response speed coefficient of the auto gain controller is changed. Since the response speed of the auto gain controller becomes faster and the response speed becomes slower for a small sound volume when the camera is wide, the auto gain control function suitable for the content of the conference at that time can be operated.

In the above embodiment, the noise removing function according to the first aspect, the echo canceling function according to the second aspect, and the AGC function according to the third aspect are separately described for easy understanding. As described above, these may be performed independently, or two or all of them may be performed simultaneously.

[0039]

As described above, according to the first aspect of the present invention, a camera having a zoom function, a microphone for inputting audio of an area photographed by the camera, and a zoom of the camera are controlled. A control unit for recognizing a zoom level,
Noise removing means for removing noise based on a noise removal level set in advance for the input sound from the microphone, wherein the controller removes the noise as the zoom level becomes higher according to the zoom level of the camera. Because the noise reduction level of the means is set high, the level of the significant sound in the sound field is determined from the zoom level of the camera, and the noise reduction level is changed, so it is suitable for the contents of the meeting at that time There is an effect that the noise removing function can be operated.

According to the second aspect of the present invention, a camera having a zoom function, a microphone for inputting sound in an area photographed by the camera, and control for controlling the zoom of the camera and recognizing the zoom level As an echo cancel function, the input sound is divided into low and high frequency bands, low frequency is subjected to echo cancellation processing, and high frequency is subjected to noise removal processing based on a preset noise suppressor coefficient. An echo canceller that combines them in a band, and the control unit sets the noise suppressor coefficient of the echo canceller higher as the zoom level increases according to the zoom level of the camera. Judgment of the level of the significant sound in the sound field and the operation level of the noise suppressor in the echo cancellation function Order to reduction, there is an effect that it is possible to operate the noise suppressor functions suitable to the content of the conference at that time.

According to the third aspect of the present invention, a camera having a zoom function, a microphone for inputting sound in an area photographed by the camera, and control for controlling the zoom of the camera and recognizing the zoom level Unit, comprising an auto gain controller that automatically adjusts the gain based on a reaction speed coefficient set in advance with respect to the input voice from the microphone, and the control unit, according to the zoom level of the camera,
As the zoom level becomes higher, the reaction speed coefficient of the auto gain controller is set smaller, and the reaction speed of the auto gain controller is increased for a large volume, and the reaction speed is decreased for a small volume.
Judging the level of the significant sound level in the sound field from the zoom level of the camera and changing the reaction speed coefficient of the auto gain controller, it is possible to operate the auto gain control function suitable for the content of the meeting at that time. effective.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of an embodiment of a video conference apparatus according to each invention of the present application.

FIG. 2 is a flowchart showing an operation according to the embodiment of the invention described in claim 1;

FIG. 3 is a diagram showing a zoom level / noise removal level correspondence table.

FIG. 4 is a flowchart showing an operation according to the embodiment of the invention described in claim 2;

FIG. 5 is a diagram showing a correspondence table between a zoom level and a noise suppressor coefficient.

FIG. 6 is a flowchart showing an operation according to the embodiment of the invention described in claim 3;

FIG. 7 is a diagram showing a correspondence table between a zoom level and an AGC reaction rate coefficient.

[Explanation of symbols]

 Reference Signs List 1 microphone 2 A / D converter 3, 4 DSP circuit 5 communication control device 6 D / A converter 7 speaker 8 camera with zoom function 9 control unit

Claims (3)

[Claims] A camera having a zoom function; a microphone for inputting audio of an area photographed by the camera; a control unit for controlling zoom of the camera and recognizing a zoom level; A noise removing unit that removes noise based on a preset noise removing level, wherein the control unit increases the noise removing level of the noise removing unit as the zoom level increases in accordance with the zoom level of the camera. A videoconferencing device characterized by setting. 2. A camera having a zoom function, a microphone for inputting sound in an area photographed by the camera, a control unit for controlling zoom of the camera and recognizing a zoom level, and an input sound as an echo canceling function. The band is divided into a low band and a high band, and the low band performs an echo cancellation process, the high band performs a noise removal process based on a preset noise suppressor coefficient, and then has an echo canceller that performs band synthesis on them. The video conference apparatus, wherein the control unit sets the noise suppressor coefficient of the echo canceller to be higher as the zoom level becomes higher, according to the zoom level of the camera. A camera having a zoom function; a microphone for inputting audio of an area photographed by the camera; a control unit for controlling zoom of the camera and recognizing a zoom level; An automatic gain controller that automatically adjusts a gain based on a reaction speed coefficient set in advance, wherein the control unit adjusts the reaction speed coefficient of the auto gain controller as the zoom level increases as the zoom level of the camera increases. A videoconferencing device characterized in that the response speed of the auto gain controller is set to be low for a large volume and the response speed is decreased for a low volume.