JP3212645B2 - Image / audio transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image / audio data transmission system using a digital public network such as an ISDN network.
The present invention relates to an audio transmission system.

[0002]

2. Description of the Related Art Conventionally, devices for transmitting a still image using an analog telephone subscriber line have been developed and used for various monitoring purposes. However, in the above-described conventional still image transmission apparatus, since the transmission speed of the analog telephone subscriber line is low, it takes about 30 seconds to transmit an image for one screen of the television to the other party, which requires an object. Since the movement of the image cannot be transmitted, it is required to reduce the transmission time of the image.

However, in recent years, a digital public network such as the INS network 64 has been established nationwide as a basic interface of the ISDN network, and the transmission time of the still image has been reduced by utilizing this high speed. A still image transmission device using the INS network 64 or the like has been developed. However, even though the data transmission speed of the digital public network is high, the data transmission speed is only about 64 Kbps, and a normal television screen cannot be transmitted to the other party in real time. For this reason, if you want to transmit the image to the other party with emphasis on the movement of the subject,
A method of transmitting the still image as much as possible per unit time by reducing the resolution (spatial frequency) of the image to be transmitted or increasing the screen update time has been sought.

[0004] For example, in the case of a video telephone apparatus using the digital public network, it is usual to update images by sending them to the other party at a speed of several sheets per second, and the movement of the subject is emphasized. However, since the resolution is reduced as described above, there is a disadvantage that a detailed portion is not transmitted and a transmitted image is often unclear.

[0005]

In an apparatus for transmitting both an image and sound simultaneously to the other party using a digital public network as described above, since the transmission speed of the digital public network is limited, the apparatus for transmitting an image and audio is limited. When the number of images that can be sent per unit time is increased with emphasis on movement, the resolution must be reduced accordingly, and there is a drawback that the transmitted image becomes unclear because small parts are not transmitted. .

The present invention relates to the above conventional image / audio transmission system.
It was made to solve the problems that have
The purpose is to properly transmit the parts related to the motion of the image,
Do not reduce the resolution of small parts of the image
To provide an image / audio transmission system.

[0007]

SUMMARY OF THE INVENTION Image / audio according to the present invention
The transmission system transmits the image data of the TV camera at one end.
Transmission to the TV monitor at the other end via the image transmission means
And audio data from the microphone at the one end.
To the audio receiving unit at the other end via the audio transmitting means
Video / audio transmission system,
Image encoding means for encoding image data of
Image compression means for compressing the encoded image data,
An image transmission channel for transmitting compressed image data;
Voice transmission for transmitting voice data from the microphone
Channel and audio data output from the microphone
A silence detecting means for detecting whether or not there is no silence;
If a silence state is detected by the silence detection means,
From the encoded image data in place of the audio data
The image data of the portion related to the obtained motion is
Image data transmitting means for transmitting the image data via
The image data transmitted through the transmission channel
For motion transmitted over the audio transmission channel
A television monitor at the other end by combining the image data of
Image data receiving means for sending the image data to
You.

[0008]

In the image / audio transmission system of the present invention ,
The image data of the TV camera at one end is
To the microphone and the microphone at the one end
To transmit the audio data to the audio receiving unit at the other end.
In an image / audio transmission system, compressed image data
Transmitted over the image transmission channel,
These audio data are transmitted on an audio transmission channel,
Silent state where no audio data is output from the microphone
Is detected, the code is used instead of the voice data.
Image data of motion related parts obtained from
Data is transmitted through the audio transmission channel and the image data is transmitted.
On the data receiving side, the data is transmitted via the image transmission channel.
The transmitted image data is transmitted through the audio transmission channel.
The image data of the part related to the motion transmitted by
And sent to the television monitor at the other end.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the ISDN image / audio transmission system of the present invention. 1 is an image / audio transmission device for transmitting image and audio data on the digital public network 50 or receiving image and audio data on the digital public network 50, and 2 is an image / audio data transmitting device for transmitting an image of a subject. A television camera input to the image / sound transmission device 1 as data, a monitor television 3 for reproducing and displaying the image data received by the image / sound transmission device 1, and a conversion device 4 for converting sound into sound data. A microphone for inputting the data to the image / audio transmission apparatus 1; a speaker 5 for outputting the audio data received by the image / audio transmission apparatus 1 to the outside; And a keypad 7 for inputting a signal to a line and connecting to a line.
It is a DSU that adjusts the transmission speed between the network and the digital public network 50. The image / audio transmission apparatus 1 is an A / D converter 1 for converting analog data into digital data.
1, 12; D / A converters 13 and 14 for converting digital data into analog data; coding / decoding units 15 and 16 for coding or decoding data; and a line control unit for performing transmission and the like. 17 and the like.

FIG. 2 shows the image / audio transmission apparatus 1 shown in FIG.
3 is a block diagram showing a detailed example of a main part of FIG. 17 is a compression circuit for compressing encoded image data, 18 is a moving image extraction circuit for extracting a moving part from the encoded image data, and 19 is an expansion circuit for expanding received image data. , 20 is a moving image synthesizing circuit for synthesizing the received moving image portion into a still image system, 21 is a switch for switching between an image signal and a video signal, 22 is a switch for distributing the image signal and the video signal to another path, and 23 is an audio signal. A voice detection circuit for detecting the presence / absence, 24 is a control circuit for performing switching control of the switch 21, 25 is an image detection circuit for detecting presence / absence of image data from received data, and 26 is a control for performing switching control of the switch 22. Circuits, 27 and 28 are amplifiers for amplifying analog image data, 29 and 30 are amplifiers for amplifying analog audio data, and 31 and 32 are amplifiers for amplifying digital image signals. 33 and 34 is an amplifier for amplifying the digital image data or voice data. 111 is an encoding circuit for performing PCM encoding of digital image data, 112 is P
A decoding circuit for decoding CM encoded image data into original image data, an encoding circuit 161 for PCM encoding digital audio data, and a reference numeral 162 for PCM encoded audio data as original audio data Is a decoding circuit for decoding the data. The above 1
11 and 112 correspond to the encoding / decoding unit 11 in FIG.
Reference numerals 61 and 162 correspond to the encoding / decoding unit 16 in FIG.

Next, the schematic operation of this embodiment will be described with reference to FIG. First, when the operator inputs the telephone number information of the other party's transmission device from the keypad 6, the line control unit 17 of the image / audio transmission device 1 digitally transmits a dial signal corresponding to the inputted telephone number information via the DSU 7. The data is sent out over the public network 50 and a line is connected to the image / audio transmission device of the other party. Thereafter, the image data (analog) of the subject captured by the television camera 2 is
After being converted into digital data by the A / D converter 11 of the audio transmission device 1, the digital data is encoded by the encoding / decoding unit 11. The image data encoded in this way is DSU
7 and transmitted to the digital public network 50. At this time, the audio data (analog) collected by the microphone 4 is transmitted to the A / D converter 1 of the image / audio transmission device 1.
2 after being converted to digital audio by the encoding / decoding unit 16
After that, the data is transmitted to the digital public network 50 via the DSU 7. The digital public network 50
The above image data (digital) is transmitted to the image /
After being received by the audio transmission device 1 and decoded by the code / decoding unit 15, it is converted into analog image data by the D / A converter 13. Thereafter, the analog image data is output to the monitor television 3 and output as an image. At this time, audio data (digital) on the digital public network 50 is transmitted via the DSU 7 to the image / audio transmission device 1.
After being decoded by the code / decoding unit 16, it is converted into an analog voice by the D / A converter 14.
This analog audio data is output to the speaker 5 and amplified outside.

FIG. 2 shows the image / audio transmission apparatus 1 shown in FIG.
It is a figure explaining the more detailed operation of. TV camera 2
The analog image data input from the A / D converter 11 is amplified by the amplifier 27,
After being converted into data, the data is input to an encoding circuit 111, where it is encoded into PCM digital image data. The image data encoded in this way is further subjected to compression processing such as pixel thinning and predictive encoding (DPCM) in a compression circuit 17, and is further added with a line number to form a transmission frame. The signal is amplified by the signal 31 and transmitted to the first B channel (B1) on the upstream of the digital public network 50. On the other hand, at this time, the moving image extraction circuit 18
Then, a moving image portion is extracted for each frame from the image data encoded in step (1), and the extracted portion is output to the terminal a of the switch 21. On the other hand, at this time, the analog audio data collected by the microphone 4 is amplified by the amplifier 29, input to the audio detection circuit 23, and further input to the A / D converter 12. The voice detection circuit 23 detects the presence or absence of voice data and outputs this to the control circuit 24. On the other hand, A /
The audio data digitized by the D converter 12 is encoded by an encoding circuit 161 to become PCM audio data, which is then output to a terminal b of a switch 21. At this time, the control circuit 24 switches the switch 21 to the terminal b during the period when the voice detection circuit 23 is detecting voice data, and during the period when the voice detection circuit 23 is not detecting a voice signal,
Control for switching the switch 21 to the terminal a is performed. Therefore, the data in which the moving image data is inserted between the audio data is taken out from the terminal c of the switch 21, and is amplified by the amplifier 33. (B2).

On the other hand, image data on the first downstream B channel of the digital public network 50 is amplified by the amplifier 32, expanded by the expansion circuit 19, and then sent to the decoding circuit 112 via the moving image synthesis circuit 20. Is entered. The image data input to the decoding circuit 112 is converted into analog image data by the D / A converter 13, amplified by the amplifier 28, and output to the monitor television 3. At this time, the audio data and the moving image data on the second downstream B channel of the digital public network 50 are amplified by the amplifier 34 and then input to the moving image detecting circuit 25. The moving image detection unit 25 outputs the input data to the terminal c of the switch 21 as it is, and at this time, notifies the control circuit 26 of the presence or absence of the moving image data. As a result, the control circuit 26 switches the switch 22 to the terminal a when there is moving image data, and switches the switch 22 to the terminal b when there is no moving image data. As a result, audio data is taken out from the terminal b of the switch circuit 22. The audio data is decoded by the decoding circuit 162 and then the analog audio data is output by the D / A converter 14.
Data. The audio data analogized in this way is amplified by the amplifier 30, and then output to the speaker 5. Also, moving image data is extracted from the terminal a of the switch 22 and is input to the moving image synthesis circuit 20. The moving picture synthesizing circuit 20 converts the inputted moving picture data into a decompressing circuit 19.
, And outputs the obtained image data to the decoding circuit 112. As a result, the data obtained by adding the image data to the moving image data is decoded from the decoding circuit 112 and the D / A
Output to the converter 13. The D / A converter 13 converts the input image data into an analog signal and outputs it to the amplifier 28. The amplifier 28 outputs the input image data and outputs it to the monitor television 3. Thus, the image / audio transmission device 1 facing the digital public network 50 can simultaneously transmit the image and the audio to the other party.

FIG. 3 is a block diagram showing a detailed example of the moving picture extraction circuit 18 shown in FIG. The image data encoded by the encoding circuit 111 is input to the compression circuit 17 of FIG. 1 via the frame memory 27 and is also input to the subtracter 181 of the image extraction circuit 18. This subtractor 181
Is input with the image data of the previous cycle held in the delay frame memory 183, the image data of the previous cycle of one frame is subtracted from the current image data of one frame, and the difference (moving image data) Is output to the switch 21 in FIG. On the other hand, since the moving image data is added to the image data of the previous cycle by one frame by the adder 182, the addition result becomes the same as the image data of the current frame, and this is written to the delay frame memory 183. Thereafter, the above operation is repeated, and eventually, moving image data for each frame is extracted from the subtracter 181 of the moving image extracting circuit.

FIG. 4 is a block diagram showing a detailed example of the moving picture synthesizing circuit 20 shown in FIG. Terminal a of switch 21
The moving image data extracted from the frame memory 28 is added to the downstream first B-channel image data input from the frame memory 28 by the adder 201, and then input to the decoding circuit 112. As a result, the decoding circuit 112 adds the downlink second data to the image data input from the downlink first B channel.
The image data to which the moving image data input from the B channel is added is decoded, and the decoded image data is input to the D / A converter 13 to be returned to analog image data.

Here, when a normal conversation is carried out using the image / sound transmission system shown in FIG. 1, the silence period during which no sound data is transmitted to the second B channel is 5 in total.
Since it is said to be 0%, it is possible to send a considerable amount of moving image data using the second B channel.

According to the present embodiment, the image / audio transmission device 1
Transmits image data to the other party via the first B channel of the digital public network 50, and transmits audio data to the other party via the second B channel of the digital public network 50,
By transmitting moving image data extracted from the image data to the other party through the second B channel when the audio data is interrupted, it is possible to substantially increase the capacity of the image data to be transmitted per unit time. This makes it possible to send a large number of image data per unit time without sacrificing the image resolution and the like, so that the movement of the subject can be realistically transmitted with a clear image.

[0018]

As described above, the image / audio transmission of the present invention is carried out.
According to the transmission system, image data is compressed and transmitted
Since the image is transmitted via the channel, an appropriate image transmission speed
Voice transmission channel in silence
Of motion related to image data
Image data is transmitted, and the image related to motion is appropriate
This has the effect of being reproduced. In addition, silence
Video data of motion related parts
Data is transmitted, so voice data may
And not.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an ISDN image / audio transmission system according to the present invention.

FIG. 2 is a block diagram showing a detailed example of a main part of the image / audio transmission device shown in FIG. 1;

FIG. 3 is a block diagram showing details of a moving image data extraction circuit and a moving image data synthesis circuit shown in FIG. 2;

FIG. 4 is a block diagram showing a detailed example of the moving picture synthesis circuit shown in FIG. 1;

[Explanation of symbols]

1 ... Video / audio transmission device 11, 12 ... D /
A conversion circuit 13, 14 A / D conversion circuit, 17 compression circuit, 18 moving image extraction circuit, 19 expansion circuit, 20 moving image synthesis circuit, 21, 22 switch, 23 sound detection circuit 24, 26 ... Control circuit 25 ... Image detection circuit 27-34 ... Amplifier 111,161 ... Coding circuit 112,162 ...
Decoding circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04M 11/00-11/10 H04N 7/10 H04N 7/14-7/173 H04N 7/20-7 / twenty two

Claims (1)

(57) [Claims] An image data of a television camera at one end is displayed.
When transmitting to the TV monitor at the other end via the image transmission means
In both cases, audio data from the microphone at one end is
The signal is transmitted to the voice receiving unit at the other end via the voice transmitting means.
Image encoding system for encoding image data of the television camera in an image / audio transmission system
Means for compressing the encoded image data
And an image transmission channel for transmitting the compressed image data
And an audio transmission for transmitting audio data from the microphone.
Transmission channel and silence without audio data output from the microphone
A silence detecting means for detecting whether or not the state is, when a silence state is detected by the silence detecting means,
Is the encoded image data in place of the audio data?
The image data of the part related to the movement obtained from the
Means for transmitting image data transmitted through the channel, and image data transmitted through the image transmission channel.
Movement transmitted to the data through the audio transmission channel.
The image data of the portion related to
That includes the image data receiving means for sending the Bimonita
Characteristic image / audio transmission system .