JPH09116897A - Picture transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To normally multiplex and transmit encoded data even if the bit rate of picture encoding is changed and information generation quantity is changed by providing a rate controller in a picture encoding part outputting encoded data. SOLUTION: A picture transmission device 7 is constituted by the picture encoding part 8 and a media multiplex part 11 receiving encoded data from the picture encoding part 8 and multiplexing it with other data and transmitting them. The rate controller 10 is provided for the picture encoding part 8 and bit rate information and a reset signal are received from an encoder 9. Then a processing for making the bit rate to be that after a change is executed. An enable gate signal is transmitted to a transmission gate 5 and a data output period signal is outputted to a media multiplex part 11. The media multiplex part 11 is caused to receive encoded data after the bit rate is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission device capable of operating by varying a coding bit rate.

[0002]

2. Description of the Related Art FIG. 5 shows a main part of a conventional image transmission device. This Figure 5 is a collection of lecture papers of the 1990 Spring National Conference of the Institute of Information and Electronics Engineers (Volume 7, D-407, pp-7-119).
FIG. 7 is a block diagram for transferring data from the image encoding unit to the media multiplexing unit in the conventional N-ISDN network compatible image transmission apparatus configured by using the media multiplexing unit disclosed in FIG.

Here, in the conventional N-ISDN network, the speed at which information is transmitted is constant, and the network is occupied even when the information to be transmitted is not generated until it is ended once it is connected to the line and started to be used in a TV conference or the like. There was a need.

In FIG. 5, 1 is an image transmission device used in a TV conference or the like, 2 is an image encoding unit for outputting encoded data, and 3 is a rate from a television camera or the like at a rate determined by bit rate information 001. An encoder that encodes video data 002 and generates encoded data 003, 4 is a transmission buffer that temporarily stores encoded data 003, 5 is a transmission gate, and 6 is a rate determined by bit rate information 001. , 00, a media multiplexing unit that multiplexes and outputs encoded data 003, audio data, other control signals, or encoded data from other TV camera devices,
4 is a read pulse for the transmission buffer 4, and 005 is encoded data 003 for the transmission gate 5 at a constant rate.
, 006 is a clock output from the media multiplexing unit 6 to the image encoding unit 2, and 007 is multiplexed data output from the media multiplexing unit 6 to the line.

To explain the operation, the image coding unit 2
The encoder 3 is provided with the bit rate information 001 determined by the line service speed, so that the variable length encoded data (encoded data 0
03) is generated. Since it must be transmitted at a constant speed, if the amount of information of the image actually required in this variable-length coded data is small, it will not be decoded, or even if it is decoded, it will not affect the previous image. Encoded data is added.

The encoded data 003 is temporarily stored in the transmission buffer 4. Then, the media multiplexing unit 6 outputs the read pulse 00 to the transmission buffer 4 of the image encoding unit 2.
4 and the enable gate signal 005 so that the transmission gate 5 outputs the encoded data 003 at a constant rate, and the image encoding unit 2 outputs the encoded data 0.
03, the encoded data 003, voice data and other control signals are multiplexed and output to the line.

The video transmission device on the other side receives the multiplexed data 007 via the line, decodes it, and outputs it as an image or a sound, so that a video conference or the like is performed.

The conventional image transmission apparatus 1 is configured as described above in order to transmit at a constant speed such as the speed of the line used.

[0009]

The above-mentioned conventional image transmission apparatus and transmission system can be used only when the image encoding unit 1 and the media multiplexing unit 6 operate at the same bit rate. , A variable rate operation of an ATM network cannot cope with the case where the amount of information generation of the image coding unit 1 is variable according to the information of the image. That is, the media multiplexing unit 6 outputs the enable gate signal 005 and receives the encoded data 002 from the image encoding unit 1 without recognizing the changed operation rate of the image encoding unit 1 due to the change in the report generation amount. In the conventional method, a difference occurs in the read / write speed of the transmission buffer 4 and the like, and an underflow or overflow of the accumulated amount occurs, making transmission impossible.

Further, since the variable rate cannot be supported as described above, the dummy coded data is added and transmitted to occupy the connected line even if the actually required image information amount is small. However, there is a problem that the use efficiency of is significantly reduced.

The present invention has been made to solve the above problems, and an image transmission apparatus capable of image transmission even if the operating rate changes due to the variation of the information generation amount of the image encoding unit. In particular, it is an object of the present invention to provide an image transmission apparatus capable of performing image transmission by allowing the media multiplexing unit to perform multiplexing without recognizing the operation rate of the image encoding unit.

[0012]

In order to solve the above problems, this image transmission apparatus has a function of outputting a rate signal indicating an operation rate based on an increase / decrease in the amount of image information and an image based on the operation rate. An encoding unit that outputs an encoded image encoded signal, a storage unit that temporarily stores and outputs the image encoded signal, a transmission gate that inputs and outputs the image encoded signal from the storage unit, and An output period during which the transmission gate is controlled based on a rate signal to output the image coded signal so as to match the changed operation rate, and during the output of the image coded signal, signal output is being performed. An image encoding means having a control means for outputting a signal, and the image encoded signal from the transmission gate by the output period signal, multiplexed with other signals and output. It is obtained by a duplex unit.

Further, the encoding section has a function of outputting a reset signal for resetting the counter of the control means when the rate signal is output, and the control means converts the rate signal into a counter value and outputs the first signal. The ROM, a counter that counts addresses and outputs a second signal, and that is reset by the reset signal are compared with the first signal and the second signal, and when they are equal, the counter is reset. An address decoder that outputs a comparison means, a control signal that receives the second signal and controls the output of the image coded signal, and an output period signal that indicates that the signal is being output while the image coded signal is being output. And have.

Further, the encoding unit has a function of outputting a reset signal for resetting the counter of the control means when the rate signal is output, and the control means converts the rate signal into a first counter value and outputs the first signal. First table RO to output
M and a counter that counts addresses and outputs a second signal and is reset by the reset signal are compared with the first signal and the second signal, and if they are equal, the counter is reset. Comparing means, a second table ROM for converting the rate signal into a second counter value and outputting a third signal, and controlling the output interval of the image coded signal based on the second signal, An address decoder which outputs a control signal for controlling the output period of the image coded signal based on the signal No. 3 and an output period signal indicating that the signal is being output during the output of the image coded signal Is.

Further, the multiplexing means has a function of inputting image coded signals from a plurality of image coding means, and while inputting an image coded signal from any image coding means, image coding is performed from another image coding means. It has a function of outputting an output prohibition signal for prohibiting output to the plurality of image encoding means so that no signal is output, and the control means of the encoding means outputs the image encoded signal based on the output prohibition signal. It has a function of not outputting.

Further, the encoder resets the counter of the rate control means when outputting the rate signal indicating the operation rate, the control means converts the rate signal into the first counter value and outputs the first signal, and the address. To output a second signal, compare the first signal and the second signal, and reset the counter when they are equal, so that the second signal corresponds to the rate and the rate signal And outputs the third signal, and the address decoder controls the output interval of the image coded signal based on the second signal,
Since the output period of the image coded signal is controlled based on the third signal and the output period signal indicating that the signal is being output is output during the output of the image coded signal, the operation rate of the multiplexing means is increased. It is possible to correspond to the rate signal.

Further, the multiplexing means can input the image coded signal from the plurality of image coding means, and while the image coded signal is being inputted from any of the image coding means, the image code is fed from the other image coding means. Since the output prohibition signal for prohibiting the output to the other image encoding means is output so that the encoded signal is not output, and the control means of the image encoding means does not output the image encoded signal based on the output prohibition signal, Image coded signals from a plurality of image coding means can be smoothly multiplexed and output.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. An embodiment of the present invention will be described. FIG.
1 is a block diagram showing a first embodiment of the present invention. In the figure, the same components as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 7 is an image transmission device, 8 is an image encoding unit, and 9 is an encoder that changes and outputs the bit rate information 008 according to the change of the image information, and also performs an encoding process by changing the encoding bit rate. Is a enable gate signal 00 for instructing the transmission gate 5 to open and close the gate so that the bit rate is determined by the bit rate information 001 during constant speed operation.
5 is output, and bit rate information 00 is set at the variable rate.
The output gate signal 005 that instructs the transmission gate 5 to open and close the gate so that the bit rate is determined by 8 and the data output period signal 011 indicating the output state of the encoded data 010 to the media multiplexing unit 11. , A rate controller 11 for outputting
It is a media multiplexing unit that receives the encoded data 010 from and is multiplexed with other data and transmitted.

Reference numeral 009 denotes a reset signal output from the encoder 9 for resetting the count value of the following rate controller when the bit rate information 008 changes, 012
Is the multiplexed data output from the media multiplexing unit 11 to the line.

The operation will be described. If the amount of image information is near (below) a predetermined value determined by the service speed of the connection line, the encoder 9 operates at the bit rate at the beginning of the line connection. Further, the rate controller 10 outputs the enable gate signal 005 to the transmission gate 5 so that the bit rate becomes the initial bit rate, and the media multiplexer 11
, And outputs the data output period signal 008 so that the media multiplexing unit 11 can receive the encoded data 010.

Bit rate information 0
When the variable rate operation in which 08 varies, the bit rate information 0 depending on the image information amount actually required by the encoder 9 is set.
08 is changed, and the encoder 9 operates at the changed encoding bit rate to generate encoded data 010. This actually necessary image information is, for example, when the camera is shooting a person, it is said that this person "raised his hand."
An image of a portion where a change occurs due to this operation is shown. Also,
The encoder 9 sends the bit rate information 008 to the rate controller 1
The reset signal 009 is output together with the output to 0.

Then, the rate controller 10 receives the bit rate information 008 and the reset signal 009, processes the bit rate information so that the changed bit rate is obtained, outputs the enable gate signal 005 to the transmission gate 5, and at the same time, the media multiplexer 11 is operated. On the other hand, the data output period signal 011 is output and the media multiplexing unit 11 changes the bit rate to the encoded data 01.
Get 0.

The media multiplexer 11 receives the data output period signal 011 and inputs the encoded data 010, multiplexes the encoded data 010 and other data such as voice data, and outputs the multiplexed data 012 to the line.

By configuring the image transmission apparatus according to the present invention as described above, even if the media multiplexing unit 11 does not recognize the bit rate of the image encoding unit 8, the given encoded data 010 is multiplexed. It is possible to cope with the change of the bit rate and to improve the line efficiency.

Embodiment 2 FIG. Second Embodiment A second embodiment of the present invention will be described. Second Embodiment FIG. 2 shows the configuration of a rate controller of an image transmission device showing a second embodiment of the present invention. Example 2
Is a more detailed description of the rate controller of the image transmission device shown in the first embodiment, and since other configurations are the same as those in the first embodiment, the illustration and the duplicated description will be omitted.

In FIG. 2, 12 is a rate controller, and 12
a is a table ROM that outputs the pulse interval count value 013 by considering the pulse generation interval from the input bit rate information 008 to the address counter value, and 12b is the address counter value 014 input from the counter 12c and the pulse from the table ROM 12a. When the interval count value 013 becomes the same, the address counter value 0 of the counter 12c becomes 0.
The comparator 12c outputs a reset signal 015 for resetting 14, and 12c resets the address counter value 014 by the reset signal 009 from the encoder 9 or the reset signal 015 from the comparator 12b, and at the same time compares the address counter value 014 with the comparator. 12b and address decoder 1
2d is a counter for outputting the address counter value 014, and 12d is an address decoder for outputting the enable gate signal 005 and the data output period signal 011.

To explain the operation, the bit rate information 008 changed according to the change of the image information is stored in the table R.
The OM 12a receives the table, and the table 12a outputs the pulse interval count value 013 by considering the pulse generation interval of the bit rate information 008 into the address counter value. Comparator 1
2b compares the pulse interval count value 013 with the address counter value 014, and outputs a reset signal 015 for resetting the counter 12c when they are the same. The counter 12c resets the count by the reset signal 009 input when the bit rate information 008 is changed and the reset signal 015, and outputs the address counter value 014. As a result, the address counter value 014 changes corresponding to the bit rate information 008, and the enable gate signal 005 and the data output period signal 011 are also output corresponding to the changed bit rate.

The address decoder 12d outputs an enable gate signal 005 for opening the transmission gate to the transmission gate 5 only for a certain period of all the count values, and outputs the output period to the media multiplexing section 11 as a data output period signal 011. .

With the above-mentioned configuration, the address counter value 014 of the counter 12c can be changed by the bit rate information 008 that is input fluctuatingly, and the transmission gate 5 outputs the encoded data 010. It is possible to change the timing and the period in real time, and obtain an image transmission device capable of coping with the fluctuation of the bit rate.

Embodiment 3 FIG. Third Embodiment A third embodiment of the present invention will be described. Third Embodiment FIG. 3 shows the configuration of a rate controller of an image transmission device showing a third embodiment of the present invention. Example 3
Similarly to the second embodiment, the rate controller of the image transmission device shown in the first embodiment is described in more detail, and the other configurations are the same as those in the first embodiment, and therefore, illustration and overlapping description are omitted. To do.

In FIG. 3, 13 is a rate controller and 13
a is a table ROM which outputs the gate interval count value 016 by considering the address counter value from the input bit rate information 008, and 13b is the address counter value 014 and the table ROM 12a input from the counter 13c.
The comparator 13c outputs a reset signal 015 which resets the counter 13c when the gate interval count value 016 from the encoder 9 becomes the same, and 13c is a reset signal 0 from the encoder 9.
09 and the reset signal 015 from the comparator 12b reset the address counter value 014 and output the address counter value 014 to the comparator 13b and the address decoder 13e.

Reference numeral 13d is a table ROM for changing the gate width of the enable gate signal 005 from the bit rate information 008, and outputs the gate width count value 017 to the address decoder 13e. 13e is counter 1
3c, the gate interval of the enable gate signal 005 is determined by the address counter value 014, and the gate width is determined by the gate width count value 017.
05 to the transmission gate 5 and the media multiplexing unit 1
1 is an address decoder that outputs a data output period signal 011.

The operation will be described. The bit rate information 008 changed with the change of the image information is stored in the table RO.
The M13a and the table ROM 13d receive the gate interval count value 016 and the gate width count value 01, respectively.
7 is output. The gate interval count value 016 is the comparator 1
3b is compared with the address counter value 014, and when the value is the same, the comparator 13b outputs the reset signal 015 and the counter 13c is reset. The counter 13c has a reset signal 0 input when the bit rate information 008 is changed.
09 and the reset signal 015 to reset the count and output the address counter value 014. As described above, the gate output timing is determined.
The gate width is determined by the table ROM 13d.

As described above, the address counter value 014 changes corresponding to the bit rate information 008, and the enable gate signal 005 and the data output period signal 011 are also output corresponding to the changed bit rate. The address decoder 13e outputs to the transmission gate 5 the enable gate signal 005 whose output timing and width are determined by the address counter value 014 and the gate width count value 017, and also outputs the data output period signal 011 indicating the output period to the media multiplexing unit. Output to 11.

With the above-described structure, in addition to the effect similar to that shown in the second embodiment, the circuit for determining the gate interval and the circuit for determining the gate width are separated from each other. Since the gate width can be changed, it is possible to obtain an image transmission device that can more finely support a variable bit rate.

Embodiment 4 FIG. A fourth embodiment of the present invention will be described. In the image transmission apparatus according to the fourth embodiment, when the image data from a plurality of cameras or the like is multiplexed and transmitted, the data output timing from the various media other than the plurality of cameras overlaps with the media multiplexing unit. If this happens, the data may not be received normally. In consideration of this, it is necessary to prevent image encoded data and other data outputs from multiple media from overlapping during variable rate operation.
The present invention relates to an image transmission device that can be normally multiplexed.

FIG. 4 is a block diagram of an image transmission device showing a fourth embodiment of the present invention. In the figure, the same parts as those in the conventional example and the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. 14 is an image transmission device, 15 and 17 are image coding units,
In addition to the functions shown in the first embodiment, reference numerals 16 and 18 receive the output prohibiting signal 018 of the encoded data 010 from the media multiplexing unit 19 and operate the output of the enable gate signal 005 to close the transmission gate 5 and close the encoded data. A rate controller having a function of prohibiting the output of 009 is a media multiplexing unit 19 which outputs an output prohibition signal 018 so that encoded data is not overlapped and output from the image encoding unit 15 and the image encoding unit 17. is there.

The operation will be described. The media multiplexing unit 19 outputs the output prohibition signal 018 to the rate controller 16 and the rate controller 18 so that the coded data 010 is not overlapped and output from the plurality of image coding units 15 and 17.
Is output to. By sequentially stopping the output of the output prohibition signal 018, the rate controller 16 or the rate controller 18 can output the encoded data 010 from the transmission gate 5 to the media multiplexing unit 19 without overlapping by the enable gate signal 005.

According to the image transmitting apparatus shown in the fourth embodiment, the image information from a plurality of cameras is not overlapped,
In addition to being able to efficiently multiplex and transmit, it is possible to cope with changes in bit rate and to improve line efficiency.

[0040]

Since the present invention is configured as described above, it has the following effects. A rate signal indicating an operation rate is output based on an increase / decrease in the amount of image information, an image is encoded based on the operation rate and an image encoded signal is output, and a transmission gate is controlled based on the rate signal to control the image encoded signal. Is output in accordance with the above operation rate, and an output period signal indicating that the signal is being output is output during the output of the image encoded signal, and the image encoded signal from the transmission gate is output by the output period signal. Since it is received and multiplexed and output with other signals, it is possible to change the rate according to the increase or decrease in the amount of image information to be transmitted, and it is possible to improve the line efficiency.

Further, the encoder outputs a reset signal for resetting the counter of the control means when the rate signal is output, the control means resets the counter by the reset signal, and also converts the rate signal into a counter value to generate the first signal. , The address is counted, the second signal is output, the first signal and the second signal are compared, and when they are equal, the counter is reset, so that the second signal corresponds to the rate signal. Since the address decoder receives the second signal and controls the output of the image coded signal and outputs the output period signal indicating that the signal is being output during the image coded signal output, the operation rate of the multiplexing means Can correspond to the rate signal.

Further, the encoder outputs a reset signal for resetting the counter of the control means when the rate signal is output,
The control means resets the counter by the reset signal, converts the rate signal into the first counter value and outputs the first signal, counts the address and outputs the second signal, and outputs the first signal and the first signal. The second signal corresponds to the rate, and the rate signal is converted into the second counter value to output the third signal, and the address decoder outputs the third signal. The output interval of the image coded signal is controlled based on the second signal, the output period of the image coded signal is controlled based on the third signal, and the signal output is being performed during the output of the image coded signal. Since the output period signal is output, the operation rate of the multiplexing means can be made to correspond finely to the rate signal.

Further, the multiplexing means can input the image coded signals from the plurality of image coding means, and while inputting the image coded signals from any of the image coding means, the image coding is performed from the other image coding means. Since the output prohibition signal for prohibiting the output to the other image encoding means is output so that the encoded signal is not output, and the control means of the image encoding means does not output the image encoded signal based on the output prohibition signal, Image coded signals from a plurality of image coding means can be smoothly multiplexed and output.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image transmission device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a rate controller shown in a second embodiment of the present invention.

FIG. 3 is a block diagram of a rate controller shown in a third embodiment of the present invention.

FIG. 4 is a block diagram of an image transmission device shown in a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional image transmission device.

[Explanation of symbols]

 7 Image Transmission Device 8 Image Encoding Unit 9 Encoder 10 Rate Controller 11 Multiplexing Unit 12 Rate Controller 13 Rate Controller 14 Image Transmission Device 15 Image Encoding Unit 16 Rate Controller 17 Image Encoding Unit 18 Rate Control Vessel 19 multiplexing unit

Claims (4)

[Claims] 1. An encoding unit having a function of outputting a rate signal indicating an operation rate based on an increase / decrease in the amount of image information, and a function of encoding an image based on the operation rate and outputting an image encoded signal, Storage means for temporarily storing and outputting the coded image signal, a transmission gate for inputting and outputting the coded image signal from the storage means, and the image coding signal for controlling the transmission gate based on the rate signal Is output so as to match the operation rate, and a control means for outputting an output period signal indicating that the signal is being output while the image encoded signal is being output; An image transmission apparatus comprising: a multiplexing unit that receives the image coded signal from the transmission gate by a period signal, multiplexes it with another signal, and outputs the multiplexed signal. 2. The encoding unit has a function of outputting a reset signal for resetting the counter of the control unit when the rate signal is output, and the control unit converts the rate signal into a counter value and outputs the first signal. A ROM, a counter which counts addresses and outputs a second signal, and which is reset by the reset signal is compared with the first signal and the second signal, and when they are equal, the counter is reset. And a control signal for receiving the second signal and controlling the output of the image coded signal, and outputting an output period signal indicating that the signal is being output during the output of the image coded signal. The image transmission device according to claim 1, further comprising an address decoder. 3. The encoding unit has a function of outputting a reset signal for resetting the counter of the control unit when the rate signal is output, and the control unit converts the rate signal into a first counter value and outputs the first signal. The first table ROM for output, the counter for counting addresses and outputting the second signal, and the counter reset by the reset signal are compared with the first signal and the second signal, and are equal. In this case, a comparison means for resetting the counter, a second table ROM for converting the rate signal into a second counter value and outputting a third signal, and an output of an image coded signal based on the second signal A control signal for controlling the interval and controlling the output period of the image coded signal based on the third signal, and an output indicating that the signal is being output during the output of the image coded signal. Image transmission apparatus ranging first claim of claims, characterized in that it comprises an address decoder for outputting the while the signal. 4. The multiplexing means has a function of inputting an image coded signal from a plurality of image coding means, and an image coded from another image coding means while an image coded signal is being input from an arbitrary image coding means. It has a function of outputting an output prohibition signal for prohibiting output to the plurality of image coding means so that no signal is output, and the control means of the image coding means has an image coding signal based on the output prohibition signal. The image transmission apparatus according to claim 1, wherein the image transmission apparatus has a function of not outputting.