JPH04266255A - Video telephone system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video telephone device that transmits and receives audio information and image information via a digital communication line.

0002

[Prior Art] As is well known, a video telephone device communicates audio information and image information at the same time.
N (Integrated Service and
There are also videophone devices that are capable of transmitting and receiving audio information and image information using digital communication lines such as the Digital Network (Integrated Digital Communication Network).

[0003] In such a video telephone device, when simultaneously communicating audio information and image information, there have conventionally been two methods as follows.

[0004] One method is to communicate audio information and image information separately using a plurality of channels.

[0005] The other method is to communicate on a single channel by allocating in advance the amount of information to be handled for each of the audio information and image information to be communicated within the amount of information that can be communicated on one channel. It is a method.

[0006]

[Problem to be Solved by the Invention] In the method (2) above, audio information and image information are transmitted and received using multiple channels, so the audio information and image information occupy multiple channels of the digital communication line. This had the disadvantage of interfering with communication using ordinary telephones other than videophone devices, facsimile machines, personal computers, etc.

[0007] Furthermore, in the method (2) above, the amount of audio information and image information is allocated within the range that can be communicated on a single channel, so compared to the case where only audio information is communicated on one channel, There was a problem that the sound quality deteriorated. Furthermore, it is not possible to communicate with a videophone device using method (■), which communicates audio information and image information over multiple channels, as it is, and a very complex system is required to achieve compatibility. Therefore, it is extremely difficult to realize in practice.

The present invention was devised in view of the above circumstances, and although it is based on a system in which audio information and image information are communicated over a single channel, it is possible to avoid deterioration in the sound quality of the audio information. Moreover, it is an object of the present invention to provide compatibility with a multi-channel type video telephone device.

[0009]

[Means for Solving the Problems] The videophone device according to the present invention includes a means for synthesizing an audio information signal and an image information signal to be transmitted, and a means for synthesizing a received audio/image synthesis information signal into an audio information signal and an image information signal. The apparatus includes means for separating the sound information signal into the sound information signal, means for detecting a silent portion in the audio information signal, and means for inserting the image information signal into the silent portion period when the silent portion is detected.

0010

[Operation] In an audio information signal, there are always meaningful voiced parts and meaningless silent parts as audio information. By inserting the image information signal into the silent portion of the audio information signal using the period of the silent portion, the audio information signal and the image information signal are combined into one information signal. The combined information signal can be transmitted and received via a single channel.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the electrical configuration of a video telephone device according to an embodiment of the present invention.

This video telephone device is roughly divided into an audio processing system and a video processing system, each of which is controlled by a system control section 4. Audio information and image information are transmitted and received with the other party's videophone device via a digital communication line 1 and a communication interface 2. In this communication interface 2, 2
Multiplexing/separation of two information channels (B channel) and one control channel (D channel) is performed. That is, when going from the audio processing section 5 and the image processing section 11 to the digital communication line 1, multiplexing is performed, and conversely,
When going from the digital communication line 1 to the audio processing section 5 and the image processing section 11, separation is performed.

First, the audio processing system will be explained.

During transmission, the audio processing unit 5 inputs an analog audio signal from the transmitter 8 and forms a digital audio information signal after performing processing such as A/D conversion.
It is transmitted to the combination/separation processing section 3. The synthesis/separation processing section 3 is controlled by the system control section 4, synthesizes the audio information signal and the image information signal, and sends the synthesized audio/image synthesis information signal to the communication interface 2 on the information channel (B channel). Supplied as a signal. The communication interface 2 multiplexes the audio/image synthesis information signal and the control signal from the system control section 4 and transmits it to the other party's videophone device via the digital communication line 1.

At the time of reception, the multiplexed signal transmitted from the other party's videophone device via the digital communication line 1 is separated into an audio/image synthesis information signal and a control signal at the communication interface 2, and the control information is is sent to the system control section 4, and an audio/image synthesis information signal is sent to the synthesis/separation processing section 3. The audio/image synthesis information signal is separated into a digital audio information signal and an image information signal by the synthesis/separation processing unit 3, and the audio information signal is subjected to processing such as D/A conversion by the audio processing unit 5 and converted into an analog signal. A voice signal is formed and sent to the handset 7.

Next, the image processing system will be explained.

At the time of reception, the digital image information signal inputted from the other party's videophone device to the synthesis/separation processing section 3 via the digital communication line 1 and the communication interface 2 and separated from the audio information signal is decoded. The serial data is converted into parallel data in the circuit 10, and the compressed data is decoded by the image processing section 11, and then stored in the image memory 12. Furthermore, the image data stored in the image memory 12 is
After being converted into an analog image signal by the D/A converter 13, it is displayed on the monitor 15 via the video output unit 14.

At the time of transmission, an analog image signal captured by the television camera 18 is sent to the A/D converter 16 via the video input section 17, where it is converted into digital image data and then stored in the image memory. It is temporarily stored in 12. After the image data read from the image memory 12 is compressed by the image processing section 11, it is encoded with high efficiency by the encoding circuit 9 to form a digital image information signal. This image information signal is sent to the synthesis/separation processing unit 3, and the audio/image synthesis information signal synthesized with the audio information signal is supplied to the communication interface 2 as an information channel signal, and is combined with a control signal from the system control unit 4. The multiplexed data is transmitted via the digital communication line 1 to the other party's video telephone device.

The call control unit 19 uses the control channel to perform call origination and call reception processing for line connection. An operation signal from the operation section 21 for inputting a dial number when making a call is sent to the system control section 4 via the operation interface 20.

[0020] Now, the television camera 18 is stored in the image memory 12.
Assume that image data captured by . The audio information signal S1 input from the transmitter 8 to the audio processing unit 5 is
Usually, as shown in Figure 3, the part A where the audio level changes
1, A2, A3, and portions B1, B2 where the audio level does not change and maintains a constant level are alternately repeated.

[0021] The former part A1 where the audio level changes,
Let A2 and A3 be sound parts. The latter portions B1 and B2 where the audio level is constant can be considered to be silent portions that are meaningless as audio information.

Therefore, under the control of the system control unit 4, the voice recognition unit 6 extracts the silent portion B1 from the voice information signal S1 input from the transmitter 8 to the voice processing unit 5.
, B2 are detected. As mentioned above, in the synthesis/separation processing section 3, the image information signal read from the image memory 12 and sent via the image processing section 11 and the encoding circuit 9, and the audio sent from the audio processing section 5 are processed. The audio/image synthesis information signal is created by synthesizing the information signal with the system control unit 4, the voice recognition unit 6, and the synthesis is performed according to the flowchart shown in FIG.
and a synthesis/separation processing section 3 are organically coupled.

Looking at the process in FIG. 2, first, step n1
It is determined whether the audio information is a silent part, and if it is a silent part, that is, if it is not a sound part, step n2
In step n3, the image information signal is taken into the synthesis/separation processing section 3, and in step n3, an image flag FV and an end flag FS are added to identify the taken-in image information and audio information (both are shown in the figure). 4), step n
In step 5, the audio information signal and the image information signal are synthesized. Then, in step n6, the audio/image synthesis information signal is transmitted to the other party's video telephone device via the communication interface 2 and the digital communication line 1.

However, if it is determined in step n1 that the part is not a silent part, that is, if it is a sound part, the process proceeds to step n4, where the input of the image information signal to the synthesis/separation processing section 3 is prohibited, and then the process proceeds to step n4. Then, the synthesis in step n5 is performed. In this case, since no image information signal is taken in and only the audio information signal exists, the synthesis in this case essentially results in only the audio information. Then, this audio/image synthesis information signal consisting only of audio information is transmitted via the digital communication line 1 to the video telephone device of the other party.

FIG. 4 specifically shows the format of the audio/image synthesis information signal created in steps n1 to n5. That is, first, the voice recognition unit 6 detects the voiced portion A1, so that voice data S1 is formed corresponding to the voiced portion A1.

Next, in order to detect the silent part B1, the voice recognition unit 6 adds an image flag FV for distinguishing image information from audio information immediately after the audio data S1, and following this image flag FV, Silent part B1
Insert image data V1 for a period corresponding to the period of
Furthermore, an end flag FS for distinguishing audio information from image information is added.

Furthermore, when the sound part A2 is detected, the audio data S2 is immediately after the end flag FS.
is inserted, and when a silent portion B2 is detected, an image flag FV, image data V2, and end flag FS are inserted. Thereafter, similarly, the operation of inserting audio data during the sound portion and inserting the image data together with the image flag and the end flag during the silent portion is repeated alternately.

[0028] Furthermore, at the time of reception, processing is performed in the reverse order to the above-described process, and the image information is displayed on the monitor 15, and the audio information is heard on the receiver 7. That is, digital communication line 1 and communication interface 2
Analyzes the audio/image synthesis information signal input to the synthesis/separation processing section 3 via the synthesis/separation processing section 3. When the image flag FV is detected, the signal portion up to the detection of the end flag FS is sent to the decoding circuit 10 as an image information signal.
Once stored in the image memory 12 via the image processing unit 11,
Further, the data is read out from there and displayed on the monitor 15 via the D/A converter 13 and the video output section 14. Further, when the end flag FS is detected, the signal portion up to the detection of the image flag FV is sent to the audio processing section 5 side as an audio information signal, and a sound is emitted from the receiver 7.

[0029] By doing the above, it is possible to transmit all the meaningful voiced parts as audio information. Therefore, the quality of the audio information does not deteriorate. However, the image information is transmitted during the silent period, which is meaningless as audio information, and there is no need to transmit audio information during this period, so the image information is transmitted using the same channel as the audio information. Can send and receive. In other words, although the system transmits and receives audio information and image information using a single channel, the quality of the audio information does not deteriorate.

[0030] Since only one channel is occupied for transmitting and receiving audio information and image information, the remaining channel can be used for transmitting and receiving by other communication devices such as facsimiles and personal computers. be. Furthermore, as long as the above-mentioned functions are provided, it is possible to transmit and receive audio information and image information to and from a videophone device that transmits and receives audio information and image information using separate channels.

[0031]

As described above, according to the present invention, the silent portion of the audio information signal is utilized and the image information signal is inserted into the period of the silent portion. It is possible to send and receive signals and image information signals. Although the audio information signal and the image information signal are transmitted and received on the same channel, since the image information signal is inserted into the silent portions that are meaningless as audio information, the quality of the audio information does not deteriorate. Furthermore, since the audio information signal and the image information signal are transmitted and received on a single channel, other channels can be used for transmission and reception by communication equipment other than the videophone device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the electrical configuration of a video telephone device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment.

FIG. 3 is a waveform diagram of an audio information signal.

FIG. 4 is a format diagram of an audio/image synthesis information signal according to the embodiment.

[Explanation of symbols]

1 Digital communication line 2 Communication interface 3 Synthesis/separation processing section 4 System control section 5 Audio processing section 6 Speech recognition section 7　　　　Telephone receiver 8. Transmitter 11 Image processing section 12 Image memory 15 Monitor 18 TV camera

Claims (1)

[Claims] 1. Means for synthesizing an audio information signal and an image information signal to be transmitted; means for separating a received audio/image synthesis information signal into an audio information signal and an image information signal;
1. A video telephone device comprising means for detecting a silent portion in an audio information signal, and means for inserting an image information signal into the silent portion period when the silent portion is detected.