JPH10327109A - Communication equipment and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transmission efficiency by executing a function applying error correction coding to compression coding data that result from compression coding video and audio signals only as required in order to prevent quality of a transmission line from being deteriorated in the case of remote supervisory through the use of a network. SOLUTION: A CRC discrimination section 15 at a receiver side discriminates compression coding data received from a transmitter side, an error correction controller 24 receiving a discrimination signal 16 when an error rate is high provides an output of a select signal 26 to control a selector 18 and a selector 6 at the transmitter side. Thus, the selector 6 selects output data of an error correction coder 4 and the selector 18 selects output data of a correction decoder 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for remotely monitoring a road or a factory using an ATM network or the like. The present invention relates to a communication device and a communication system suitable for use in a system for encoding and transmitting compressed and encoded data to a remote monitoring center or the like, and expanding and decoding the transmitted signal to monitor roads and factories. .

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 3-280679 discloses a recording apparatus in which image data for one screen is used as a unit block and is recorded on a recording medium for each unit block. In this recording apparatus, as a processing method for recording image data, the compression ratio is increased as the supply timing of the unit block is increased, and the error correction parity bit added to the compression encoded data in proportion thereto is increased. , And the recording medium records compression encoded data, error correction parity bits, and compression rate data indicating the compression rate at the time of recording. Further, as a processing method for reproducing the image data from the recording medium, error correction decoding and decompression are performed based on the compression ratio data extracted from the reproduced image data.

According to such a processing method, a relatively large-capacity data such as a video signal is recorded while the transmission speed is suppressed in a transmission system in the apparatus. Since data compression is performed according to the timing and data redundancy is reduced according to the data compression, the image quality degradation can be minimized by adding an error correction code according to the data compression. The continuous shooting speed can be improved without changing the transmission speed.

[0004]

The first problem when the above-described processing method in the recording apparatus is used in a system for transmitting compressed and coded data to a remote monitoring center is that the processing is always performed irrespective of the quality of the transmission path. That is, error correction coding control is performed. That is, if the error correction coding is not always performed, it is impossible to guarantee the compressed and coded data for the transmission line error, and the quality of the received / reproduced video / audio is sufficient for monitoring. However, if error correction coding is always performed as described above, additional error correction parity bits are added to the compressed coded data, so extra transmission capacity is required for this parity bit. In addition, power for operating the error correction coding / decoding circuit is always required.

A second problem is that in the case of remote monitoring,
In the related art, there is no means for transmitting a control signal of the error correction encoder on the transmission side from the reception side, and the control of the error correction encoder on the transmission side is performed in a fixed manner. That is, it is not possible to recognize the deterioration of the quality of the received video image and audio data, and to freely control the error correction encoder of the video and audio encoding device on the transmission side.

The present invention has been made in order to solve the above-mentioned problems. Under the control of the receiving side, when the transmission path quality is good, error correction coding is not performed and the monitoring is performed within a range that can withstand monitoring. Transmission of only data obtained by compressing and encoding signals such as video and audio. If the transmission path quality is poor, communication that can perform transmission after performing error correction encoding on the compressed encoded data. It is an object to provide a device and a communication system using the communication device.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a communication apparatus on the transmitting side, which compresses and encodes an input signal and outputs first compressed and encoded data. Error correction coding means for performing error correction coding on the first compressed coded data and outputting second compressed coded data, and selecting one of the first and second compressed coded data. Selection means for selecting by a signal, CRC operation means for performing CRC operation processing on the selected compression-encoded data and outputting third compression-encoded data in which CRC bits are multiplexed, and said third compression-encoded data And a communication unit for transmitting the select signal to the transmission line and receiving the select signal from the transmission line.

[0008] In the communication device on the receiving side, communication means for receiving the compressed and encoded data from the transmission path and transmitting a select signal to the transmission path, and performing CRC calculation processing on the received compressed and encoded data. CRC determination means for detecting the error rate of the transmission path and comparing the detected value with a predetermined value, and the compression code according to the comparison determination result when the detected value is equal to or more than the predetermined value. Control means for outputting the select signal for turning on the error correction function on the transmission side of the coded data, error correction decoding means for error correcting and decoding the compressed and coded data processed by the CRC determining means, Selector means for selecting the compressed data subjected to the arithmetic processing or the output data subjected to the error correction decoding by the select signal; and It is provided with extension decoding means for expanding and decoding the over data.

In the transmitting-side communication device, when the selector selects the first compressed encoded data, the selector does not input the first compressed encoded data to the error correction encoding unit. May be made.

Further, in the communication device on the receiving side, when the selector selects the output data of the CRC judging means, the selector is configured not to input the output data to the error correction decoding means. Is also good.

Further, the error correction decoding means detects the error correction frame synchronization and outputs a detection signal, and the selector means makes the selection based on the select signal and the detection signal. It may be performed.

Still further, the control means may be configured to be able to set whether to output the select signal according to the result of the comparison or to output the select signal according to a manual control signal.

Further, in the communication system according to the present invention, a compression encoding means for compressing and encoding an input signal and outputting first compression encoded data, and an error correction encoding for the first compression encoded data, Error correction encoding means for outputting second compressed encoded data, first selector means for selecting one of the first and second compressed encoded data by a received select signal, and A third operation in which the coded data is CRC-processed and the CRC bits are multiplexed
And a first communication unit for transmitting the third encoded data to the transmission line and receiving the select signal from the transmission line. A third device from the transmission line
A second communication means for receiving the compressed encoded data of the above and transmitting the select signal to the transmission path, performing a CRC operation on the received third encoded data, and reducing the error rate of the transmission path. CRC detection means for detecting and comparing the detected value with a predetermined value; and turning on the error correction coding means in accordance with the comparison determination result when the detected value is equal to or more than the predetermined value. Control means for outputting a select signal; error correction decoding means for error correcting and decoding the compressed and encoded data processed by the CRC determining means; and compressed and encoded data or error correction decoding performed by the arithmetic processing A second communication device including second selector means for selecting the converted output data by the select signal, and decompression decoding means for decompressing and decoding the selected data. It is provided with a door.

[0014]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a video / audio communication system using an error correction encoding / decoding system according to a first embodiment. In FIG. 1, a video / audio input signal 1 input on the video / audio transmission side is compression-encoded in a compression encoder 2, and compressed encoded data 3 output from the compression encoder 2 is provided by a selector 6 and a selector 6. The signal is input to the error correction encoder 4. The error correction encoder 4 calculates and generates an error correction parity bit for the input compressed coded data 3, time-division multiplexes this with the compressed coded data 3, and outputs the compressed coded data 5.

In the selector 6, the compression coding is performed in accordance with a select signal 26 transmitted from the error correction controller 24 on the video / audio receiving side via the transmitting section of the receiving line interface 13 and the receiving section of the transmitting line interface 10. The encoded data 3 or the compressed encoded data 5 is selected, and the selected compressed encoded data 7 is input to the CRC calculator 8. CRC
The arithmetic unit 8 performs a CRC operation on the compressed coded data 7 according to a generator polynomial determined, multiplexes the remainder data with the compressed coded data 7, and
Is output to the transmission unit of the transmission-side line interface 10.

The transmission data 11 output from the transmission unit of the transmission line interface 10 is
The compressed and encoded data 14 input to the receiving unit 13 and output from the receiving unit of the receiving line interface 13 is input to the CRC determiner 15. The CRC determiner 15 performs the same CRC operation on the compressed and coded data 14 as the CRC calculator 8 on the video / audio transmission side, and outputs the compressed and coded data after the CRC calculation.
17 is output to the selector 18 and the error correction decoder 19, and the presence or absence of a transmission path error is detected, and a determination result signal 16 as to whether or not the error rate is equal to or greater than a predetermined threshold is provided.
Is output to the error correction controller 24.

The error correction decoder 19 performs error correction detection on the input compressed and encoded data 17, and if an error is detected, corrects the error and separates the error correction parity bit. , The compressed encoded data 20 to the selector 18
Output to When no error is detected, the error correction parity bit is separated, and the compressed and encoded data 20 is output to the selector 18. In the selector 18, the compression-encoded data is selected from the compression-encoded data 17 and the compression-encoded data 20 according to a select signal 26 output from the error correction controller 24. Output to the decompression decoder 22.

The decompression decoder 22 performs decompression decoding on the compressed and encoded data 21 output from the selector 18 and outputs a video / audio output signal 23. The error correction controller 24 sets which of the determination result signal 16 output from the CRC determiner 15 and the control signal 25 manually set by the monitor is valid. When the automatic control mode is set, a judgment result signal which is an output of the CRC judgment unit 15
16 determines whether or not to execute error correction encoding / decoding, and when the manual control mode is set, the control signal 25
Determines whether or not to execute error correction encoding / decoding, and outputs a select signal 26 for controlling the operation of the selector 18.

Here, the output video / audio output signal 23
However, if it is determined that the transmission path quality does not require error correction based on the subjective evaluation of the monitor or the determination result of the CRC determiner 15, the selector 6 and the selector 18
In, the error correction controller is set to output a select signal for selecting compressed coded data not subjected to error correction coding / decoding. As a result, the selector 6 selects and outputs the compressed coded data 3 that does not include the error correction parity bit according to the select signal 26 transmitted from the receiving side. Further, the selector 18 selects and decompresses the compressed coded data 17 by a select signal 26 for selecting the compressed coded data not subjected to the error correction coding / decoding output from the error correction controller 24. Output to the decoder 22.

If it is determined that error correction is necessary based on the subjective evaluation of the video / audio output signal 23 by the observer or the result of the judgment by the CRC judgment unit 15, the selector 6 and the selector 18 provide an error correction code. The error correction controller 24 is set so as to output a select signal 26 for selecting the compressed / encoded data subjected to the encoding / decoding. Thus, in the selector 6, the error correction encoder 4 according to the select signal 26 transmitted from the receiving side.
And selects and outputs the compressed coded data 5 which is the output of.
Further, the selector 18 selects the compressed coded data 20 by a select signal 26 for selecting the compressed coded data subjected to error correction coding / decoding output from the error correction controller 24. Output to the decompression decoder 22.

The first effect obtained by the present embodiment is an improvement in the transmission efficiency of video / audio signals. That is, the transmitted video and audio signals are sent to the monitoring center,
Based on the evaluation of the transmission path quality by CRC or the subjective evaluation of the reproduced video and audio by the supervisor, it is determined whether or not the transmission path quality requires error correction coding, and the error correction coding is executed based on the result. If the transmission path error exceeds the range that can withstand the monitoring of the supervisor,
If error correction coding can be performed and the transmission path error is within the range that can be monitored by the supervisor, the error correction coding is not performed and the error correction parity is also compressed for the video and audio signals. The transmission capacity can be allocated to the encoded data, and the transmission capacity can be minimized within a range that can withstand monitoring.

The second effect is that the operability when the error correction coding on the transmission side is performed or canceled by the supervisor at the remote place is improved, and the error correction decoding on the reception side is performed or canceled when the error correction coding is performed on the reception side. It is an improvement in operability. That is, by transmitting a control signal for controlling error correction coding on the transmission side from a remote location on the reception side, the transmission side automatically receives
It is possible to select compressed coded data without error correction coding and compressed coded data with error correction coding and send them to the transmission path, and execute or cancel error correction coding on the transmission side. This eliminates the need for a setting circuit and the like, and makes it possible to easily perform error correction coding control on the transmission side from a remote supervisor.

Next, specific embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, a video / audio input / output signal 1 is subjected to high-efficiency compression encoding in a compression encoder 2. The compressed encoded data 3, which is the output of the compression encoder 2, is input to the selector 6 and also input to the error correction encoder 4, where it is subjected to error correction encoding,
The compression coded data 5 is output to the selector 6.

Here, one embodiment of the error correction encoder 4 will be described in detail with reference to FIGS. In FIG.
A data string in which 18 bits of error correction parity bits are added to the compression encoded data of bits is defined as one frame, and an error correction frame synchronization word is added at the beginning of each frame.
An embodiment of data subjected to error correction coding so as to form a multi-frame to which S _{1 to} S ₈ are sequentially added will be described.

In FIG. 3, the compressed coded data 3 output from the compression coder 2 is transmitted to an error correction parity calculator 28.
And input to the selector 31. The error correction parity calculator 28 performs an operation on the compressed and coded data 3 using the generator polynomial g (X), and outputs an error correction parity bit 37 as the operation result. Here, the generator polynomial g which calculates an error correction parity in FIG 2 (X) is, g (X) = (X 9 + X 4 + 1) (X 9 + X 6 + X 4 + X 3 +1) ‥‥‥ (1) It is.

The multiplexing controller 29 counts the clock 27 synchronized with the compressed and encoded data 3, outputs a count value 35, and outputs a select signal 33 and a select signal 34 for controlling the selector 30, the selector 31. . The frame synchronization word transmitter 32 sequentially transmits the frame synchronization words S _{1 to} S ₈ according to the count value 35 output from the multiplexing controller 29. The selector 31 selects and outputs the compressed coded data 3 or the error correction parity bit 37 according to the select signal 33 sent from the multiplexing controller 29. Selector 30
Selects the output signal 38 of the selector 31 or the frame synchronization word 36 output from the frame synchronization word transmitter 32 in accordance with the select signal 34 output from the multiplexing controller 29, and outputs the compressed and encoded data 5. .

Next, a second embodiment of the present invention will be described. FIG. 4 shows the configuration of the video / audio transmission side, and FIG.
Indicates the configuration of the video / audio receiving side. First, FIG. 4 shows a modification of the error correction encoder and selector on the video / audio transmission side in FIG. 1, and the same parts as those in FIG. 1 are given the same numbers. In the configuration of the error correction encoder 4 and the selector 6 on the video / audio transmission side shown in FIG. 1, the compression encoded data 3 which is always the output of the compression encoder 2 and the error correction code The encoded compressed encoded data 5 and the encoded encoded data 5 are supplied to a selector 6. However, only one of the compressed and coded data is transmitted to the video / audio receiving side, and constantly operating the circuit of the error correction encoder 4 consumes extra power.

For this reason, in the present embodiment, the selector 39 is provided as shown in FIG. 4, and the selector 39 is controlled by the select signal 26 transmitted from the video / audio receiving side, so that the compressed encoded data 5 is obtained. The error correction encoder 4 is operated only when is selected. The data selected by the selector 39 is input to the CRC calculator 8 as compressed and encoded data 40.

FIG. 5 shows a modification of the error correction decoder and selector on the video / audio receiving side in FIG. As in the case of FIG. 4, a selector 41 is provided on the video / audio receiving side as shown in FIG. 5 in order to eliminate unnecessary power consumption, and a selector 41 is provided by the select signal 26 output from the error correction controller 24. By controlling 41, the compressed encoded data which is the output of the error correction
Only when 20 is selected, the error correction decoder 19 is operated. The data selected by the selector 41 is input to the decompression decoder 22 as compressed encoded data 42.

FIG. 6 shows a third embodiment of the present invention, in which the error correction decoder and selector on the video / audio receiving side in FIG. 1 are modified. When the select signal 26 output from the error correction controller 24 is output to the selector 6 and the selector 18 in FIG.
The control of the selector 6 is delayed with respect to the selector 18 by the amount by which 26 is transmitted from the receiving side to the transmitting side. If the select signal 26 is not transmitted to the transmitting side normally,
There are cases where the settings on the sending side and the receiving side are different.

In order to solve the above-mentioned problem, in the present embodiment, error-correction decoding shown in FIG. The error correction frame synchronization is detected in the device 43, and the result is input to a selector 46 as a synchronization detection signal 44,
The selector 46 selects the compressed coded data 17 or 45 based on the select signal 26 and the synchronization detection signal 44 output from the error correction controller 24.

FIG. 7 shows an embodiment of the error correction decoder 43 in FIG. 6, and FIG. 8 shows an embodiment of the selector 46 in FIG. In FIG. 7, the compression coded data 17 is input to a frame synchronization detector 47, and the frame synchronization words S _{1 to} S ₈ added to the compression coded data 5 in the error correction coder 4 on the video / audio transmission side. Detects and synchronizes, and outputs the compressed and coded data 54 to the memory 49 and the error detector 50 while aligning the beginning of the multiframe.

The error detector 50 detects an error based on the error correction parity bit added to the compressed and encoded data 54, and outputs an error correction control signal 56 to the error corrector 51. The memory 49 delays the compressed coded data 54 by the time required for error detection in the error detector 50, and outputs the compressed coded data 55 to the error corrector 51.
In the error corrector 51, the error correction control signal 56 output from the error detector 50 performs error correction on the compressed coded data 55 output from the memory 49, and outputs the compressed coded data 45. .

In FIG. 8, when the select signal 26 is in error correction and the synchronization detection signal 44 is in the synchronized state,
AND gate 60 is turned on by signal 62 from D gate 57
The compressed coded data 45 subjected to the error correction decoding is A
The data is output as compressed encoded data 21 through an ND gate 60 and an OR gate 61. Otherwise, the signal 62 is inverted and again inverted by the inverter 58, so that AND
The gate 59 is turned on, whereby the compressed coded data 17 not subjected to error correction decoding is output as the compressed coded data 21.

[0035]

As described above, according to the communication apparatus on the transmitting side according to the present invention, control for selecting compressed coded data or data obtained by performing error correction coding on the coded data is performed by a select signal received from the outside. , The above-mentioned control can be performed according to the quality of the signal received by the receiving side or the like, and thereby the transmission efficiency can be improved.

Further, according to the communication apparatus on the receiving side according to the present invention, the select signal is output in accordance with the result of the CRC determination, so that the error correction coding on the transmitting side is performed in accordance with the quality of the received signal. Can be controlled, whereby the transmission efficiency can be improved.

Further, when the error correction coding is not performed in the communication device on the transmitting side, the operation of the error correction coding means is stopped, so that power consumption can be reduced.

In the communication device on the receiving side, CRC
When the output of the judging means is selected, the operation of the error correction decoding means is stopped so that power consumption can be saved.

In addition, when error correction decoding is performed, the correction frame synchronization is detected, and a select signal is output based on the detection signal and the result of the CRC comparison and determination. It is possible to prevent a malfunction due to a difference between the settings on the transmission side and the reception side due to an abnormality in the information.

Further, by configuring so as to output the select signal based on the result of the CRC comparison or the manual control signal, it is possible to control the error correction coding on the transmitting side in the automatic mode or the manual mode. .

According to the communication system of the present invention, the receiving side outputs the select signal in accordance with the CRC determination, and the transmitting side controls the error correction coding based on the select signal. With this configuration, error correction coding can be controlled from the receiving side such as a monitoring center. For this reason, the quality of signals such as video and audio obtained by decompressing and decoding the compressed and coded data received on the receiving side can be checked. Then, error correction coding can be easily controlled, and transmission efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a communication system according to the present invention.

FIG. 2 is a configuration diagram of an error correction multi-frame configured for error correction in an error correction encoder 4 in FIG. 1;

FIG. 3 is a block diagram showing a configuration example of an error correction encoder 4 in FIG. 1;

FIG. 4 is a block diagram of a transmitting side according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a receiving side according to a second embodiment.

FIG. 6 is a block diagram of a receiving side according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing one embodiment of an error correction decoder 43 in FIG. 6;

FIG. 8 is a block diagram showing one embodiment of a selector 46 in FIG. 6;

[Explanation of symbols]

 2 Compression encoder 2 Error correction encoder 6,18,30,31,39,41,46 Selector 8 CRC operator 10 Transmitting line interface 13 Receiving line interface 15 CRC decision unit 19,43 Error correction decoding 22 Decompression decoder 24 Error correction controller 28 Error correction parity calculator 29 Multiplexing controller 32 Frame synchronization word transmitter 47 Frame synchronization detector 48,49 Memory 50 Error detector 51 Error corrector 57,59,60 AND gate 58 Inverter 61 OR gate

Claims (7)

[Claims] A compression encoding means for compressing and encoding an input signal to output first compression encoded data; and a second encoding means for error-correcting encoding the first compression encoded data to produce a second encoded data.
Error correction coding means for outputting compressed coded data of the following, selector means for selecting one of the first and second compressed coded data by a received select signal, and CRC selecting the selected compressed coded data by CRC. CRC calculating means for outputting third compressed and encoded data obtained by performing arithmetic processing and multiplexing CRC bits, and communication for transmitting the third compressed and encoded data to a transmission path and receiving the select signal from the transmission path A communication device comprising: 2. A communication means for receiving compressed encoded data from a transmission line and transmitting a select signal to the transmission line, performing a CRC operation on the received compressed encoded data, and controlling an error rate of the transmission line. CRC determination means for detecting and comparing the detected value with a predetermined value; and error correction on the transmission side of the compressed coded data in accordance with the comparison determination result when the detected value is equal to or greater than the predetermined value. Control means for outputting the select signal for turning on the function; error correction decoding means for error-correcting and decoding the compressed and encoded data processed by the CRC determining means; Selector means for selecting data or the error-correction-decoded output data by the select signal, and decompression decoding for decompression-decoding the selected data Communication and means. 3. The method according to claim 1, wherein the selector means is configured not to input the first compressed encoded data to the error correction encoding means when selecting the first compressed encoded data. The communication device according to claim 1, wherein 4. The apparatus according to claim 2, wherein when the selector selects the output data of the CRC determining means, the output data is not inputted to the error correction decoding means. The communication device as described. 5. The error correction decoding means detects an error correction frame synchronization and outputs a detection signal, and the selector means makes the selection based on the select signal and the detection signal. The communication device according to claim 2, wherein the communication is performed. 6. The control device according to claim 1, wherein said control means is capable of setting whether to output said select signal based on said comparison result or output said select signal according to a manual control signal. 3. The communication device according to 2. 7. A compression encoding means for compressing and encoding an input signal to output first compression encoded data, and an error correction encoding of the first compression encoded data to produce a second compression encoded data. Error correction encoding means for outputting, first selector means for selecting one of the first and second compressed encoded data by the received select signal, and CRC operation processing of the selected compressed encoded data. CRC operation means for outputting third compressed and encoded data multiplexed with CRC bits, and a first means for transmitting the third compressed and encoded data to a transmission path and receiving the select signal from the transmission path.
A first communication device having communication means for receiving the third compression-encoded data from the transmission path and transmitting the select signal to the transmission path; and 3 to C
CRC calculation means for performing an RC calculation process and detecting the error rate of the transmission path and comparing the detected value with a predetermined value; and a CRC determination means for determining whether the detected value is equal to or greater than the predetermined value. Control means for outputting the select signal for turning on the error correction coding means in response to the
Error correction decoding means for performing error correction decoding of the compression-encoded data subjected to the arithmetic processing by the determination means, and selecting the compression-encoded data subjected to the arithmetic processing or the output data subjected to the error correction decoding by the select signal A communication system, comprising: a second communication device having second selector means for performing decoding and decompression decoding means for decompressing and decoding the selected data.