KR0164191B1 - Video conference system with video/audio encryption /decryption function - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encryption / decryption processing apparatus for a videoconferencing system, wherein the video / audio signals of the microphones / video cameras 90a and 92 are selectively analog-digitally processed and interchanged. 60n); A first transmission line 62a by a coaxial cable arranged to exchange analog video / audio signals in the plurality of videoconferencing terminals 60a-60n; A second transmission line (62b) arranged to externally transmit digital video / audio signals in the plurality of video conferencing terminals (60a to 60n); A gateway 64 connected to the second transmission line 62b to exchange digital video / audio signals from the plurality of videoconferencing terminals 60a to 60n with external videoconferencing terminal means. And the video / audio transmission processing system including an encryption unit 96 for encrypting the video / audio signal based on a predetermined encryption signal, respectively, and the first transmission line. Performs control of the video / audio reception processing system including a reverse encryption unit 108 for performing reverse encryption processing on the video / audio signal encrypted and received via the path 62a, and controlling the encrypted signal and the reverse encryption signal. The control unit 122 is configured to be.

Description

Encryption / Decryption Processing System of Video Conference System

1 is a diagram showing the configuration of a video conferencing system in a general LAN network.

FIG. 2 is a block diagram of a representative videoconferencing terminal applied to the videoconferencing system shown in FIG.

3 is a diagram showing the configuration of a videoconferencing system to which an encryption / decryption processing apparatus according to an embodiment of the present invention is applied.

4 is a block diagram of a representative videoconferencing terminal applied to the videoconferencing system shown in FIG.

5 is a block diagram of signal processing means provided for the videoconferencing system according to the present invention shown in FIG.

6 (a) and 6 (b) show examples of an encryption unit and a reverse encryption unit applied to the videoconferencing terminal shown in FIG.

* Explanation of symbols for main parts of the drawings

60a-60n, 70a-70n: video conferencing terminal 61a, 72a: coaxial cable

62b, 72b: LAN circuit 64, 74: gateway

90a: Microphone 92: Video Camera

96: encryption unit 98: RF modulator

100: RF combiner 104: TV tuner

106: video / audio IF module 108: inverse encryption unit

120: signal conversion means 122: control unit

128, 130: video / audio encoder 134, 136: video / audio encoder

138, 144: analog-to-digital converter 140: adder

142, 148: digital-to-analog converter 146: subtractor

The present invention relates to an encryption / decryption processing apparatus for a videoconferencing system. More particularly, the present invention relates to a video / audio signal when a videoconferencing system is executed in a videoconferencing system capable of exchanging an analog videoconferencing signal at a TV level. An encryption / decryption processing apparatus of a videoconferencing system for performing an encryption process for transmission of a video signal and a reverse encryption process of a received video / audio signal through a transmission line.

As is well known, a data communication method for exchanging information by video / audio signals with a counterpart maintaining a constant distance is applied to a practical situation. In relation to such data communication, a video with a counterpart located at a relatively short distance or a long distance can be used. A videoconferencing system has also been developed to carry out videoconferencing by exchanging voice signals, and commercialization is being promoted.

According to the video conferencing system, a video camera for capturing an image of a transmission side and a microphone for inputting audio are provided, and the analog video signal and audio signal inputted from the video camera and the microphone are converted into digital signals and predetermined. The compressed video / audio data is compressed by an algorithm of an appropriate transmission medium (or transmission line), such as a dedicated line (T1 / E1), an integrated service digital network (ISDN), or a local area network. (LAN), Public switched telephone network (PSTN) and Asynchronous Transfer Mode (Asynchronous Transfer Mode) at least one of the transmission medium via the transmission medium and the compressed data of the video / audio signal received from the other party Is converted into an analog signal and restored as an image output device as a monitor and a volume output device. Is output to the speaker.

1 is a diagram showing an example of the configuration of a video conferencing system implemented by a general LAN network, wherein 10a-10n is a first group video conferencing that is accommodated in one LAN network 12 and is connected in a signal manner to enable video conferencing. 14 indicates that the first group of video conferencing terminals 10a-10n connected to the LAN network 12 exchange video / audio data even with a video conferencing terminal connected to an external LAN network. It represents a gateway (Gateway; or video conferencing server).

Reference numeral 20a-20n denotes a second group of video conferencing terminals that are accommodated in another LAN network 22 and that can exchange video / audio signals for mutual video conferencing, and 24 denotes the LAN network 22. The second group of video conferencing terminals 20a-20n connected by means of a gateway for exchanging video conferencing data even with the video conferencing terminals 10a-10n connected to the LAN network 12, for example.

In FIG. 1, 30 is a gateway 14 for the LAN network 12 to which the first group of video conferencing terminals 10a-10n are connected, and the second group of video conferencing terminals 20a-20n are connected. Dedicated lines T1 / E1 disposed between the gateways 24 to the LAN networks 22 are shown, and video conferencing terminals connected to the LAN networks 12 and 22 via the dedicated lines 30. The exchange of the desired video conference data is performed between (10a-10n, 20a-20n).

2 is a diagram showing a functional block configuration of a representative videoconferencing terminal 10a applied to the videoconferencing system shown in FIG.

In FIG. 2, reference numeral 40a denotes a microphone as a means for inputting an audio signal during a video conference, 40b denotes a speaker provided as a means for reproducing an audio signal transmitted from the other party, and 42 is an image signal capture. Represents a video camera applied as a means for.

44 is a function for performing encoding for data compression processing of the audio signal input from the microphone 40a and encoding for data compression processing of the video signal captured by the video camera 42, and in an external video conference terminal. Represents a video conference codec card that performs a decoding function for reconstructing a video signal and an audio signal transmitted in a compressed state.

Here, the videoconferencing codec card 44 preferably encodes the audio signal input from the microphone 40a and restores the audio signal from an external videoconferencing terminal to be reproduced through the speaker 40b. A voice codec 46 for decoding, a video codec for encoding the video signal captured by the video camera 42, and a video codec for decoding the video signal from an external video conference terminal. In addition, the image processing unit 48 performs an image forming process such that the image signal decoded by the image codec 48 is displayed on the PC monitor 52, and the audio codec 46 and the image. Multiplexing for transmitting the audio signal and the video signal encoded by the codec 48 and the audio signal and the video signal transmitted from the external video conference terminal The codec 46 and the video codec 48, the system layer MUX / DMUX (52) for demultiplexing such that the decoding process becomes at equipped.

In addition, 54 denotes a control unit which controls the exchange of video / audio signals for videoconferencing while totally controlling the videoconferencing process by the corresponding videoconferencing terminal 10a, and 56 denotes under the control of the control unit 54. FIG. LAN card which is in charge of signal connection with LAN network 12 for exchanging video conferencing data between video conferencing terminal which is the object of video conferencing, 58 is a video graphic under control of the control unit 54 It represents a VGA card that provides data to the overlay processing unit 50 to support a color image screen displayed on the PC monitor 52.

Therefore, according to the video conferencing system in the LAN network according to the above configuration, the audio signal input through the microphone 40a, for example, in the state where the video conferencing mode is set between a specific video conferencing terminal is transmitted to the voice codec 46. In addition to being applied, the image captured by the video camera 42 is applied to the image codec 48, and the audio signal from the microphone 42 is compressed for a compression process by a predetermined algorithm in the audio codec 46. An image, which is encoded and applied from the video camera 42, is encoded in the image codec 48 for compression processing by a predetermined algorithm.

The encoded video / signal is applied to the system layer MUX / DMUX 52 and multiplexed into a data frame structure for transmission to a terminal side which is a video conference target, and then the LAN card under the control of the control unit 54. It is applied on the LAN network 12 via 56 and transmitted to the video conferencing terminal of the other party.

On the other hand, the video conferencing data (video / audio signal) of the counterpart received through the LAN network 12 is received through the LAN card 56 and the control unit 54 to receive the system layer MUX / DMUX 52. The audio signal is demultiplexed and then applied to the corresponding voice codec 46 and the image codec 48, and the audio signal decoded by the voice codec 46 is reproduced through the speaker 46b and the image codec 48 The decoded video signal is applied to the overlay processing unit 54 and overlaid with the video graphic signal supported by the VGA card 58 under the control of the control unit 54 and displayed on the PC monitor 52. .

On the other hand, when the video conferencing data of the video conferencing terminal 10a connected to the LAN network 12 is to be transmitted to the video conferencing terminal selected from the video conferencing terminals 20a-20n connected to the LAN network 22, for example. Is connected to the video conferencing terminal 10a and the LAN network 22 through the gateway 24 provided from the gateway 14 to the dedicated line T1 / E1 30 and the LAN network 22. The specific videoconferencing terminal is connected signally, thereby enabling the exchange of video / audio for videoconferencing.

However, in the videoconferencing terminal, since the maximum transmission speed of the communication line is relatively small to transmit the analog video signals input from the microphone 40a and the video camera 42 in real time, the video signal and the audio signal for the videoconferencing. Digital conversion and data compression / restore are required.

That is, about 166 Mbps (720 x 480 x 30 x 16 = 165,888,000) per second is required to transmit 30 video signals of 720 x 480 pixels in the form of 4: 2: 2 Y Cb / Cr. About 1.544 Mbps for leased line, 128 Kbps per line for ISDN, 28.8 Kbps for PSTN, and about 10 Mbps for LAN. As a result, the ATM is less than 5 Mbps and is somewhat inadequate for an ATM having a transmission rate of approximately 155 Mbps.

Therefore, when using video communication between remote video conferencing terminals, in order to use the existing communication network, it is possible to reduce the aspect ratio of digital video and to reduce the spatial resolution and to reduce the number of screens per second, thereby increasing the amount of digital video data. In the reduced state, it is necessary to perform data compression process of several times again, and such video conference data compression process is inevitable to use the existing transmission network despite severe deterioration of image quality at the receiver side.

Therefore, in the long-distance communication where the user of the video conferencing system cannot install the communication line directly, the existing communication network must be used. Therefore, the compression transmission of data becomes indispensable, but the user establishes a 10Mbps LAN network such as an office or a small building. The video conferencing system using the LAN network is considerably disadvantageous for the following reasons.

In other words, the currently commercialized LAN network is composed of 10Mbps, which is used by many people for data exchange, and many communication obstacles are involved when exchanging video conference information requiring hundreds of Kbps. In addition, the LAN network is a packet transmission network, and since the traffic volume changes from time to time, the existing video conferencing system supporting a fixed communication speed may not be able to operate smoothly depending on the smooth amount of information communication, and the communication speed may be variable. Even if the video conferencing system is applied, a problem arises in connection with the video conferencing system having a fixed communication speed provided to another place outside the LAN network.

In view of such a problem, video conferencing between videoconferencing terminals connected in the same LAN environment is performed by exchanging analog video / audio signals, while digital video / audio data is exchanged between video conferencing terminals accommodating different LAN environments. In this case, a video conference by exchange is considered. In this case, when communication security is required for the video input from the video camera and the voice input from the microphone, the analog video / audio signal is transmitted from the video conference signal. In addition to the encryption processing for the receiver, the reverse encryption processing for the encrypted video / audio signal is required at the receiving side.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and among videoconferencing terminals accommodated in the same LAN environment, a coaxial cable (75Ω), which is suitably employed for the transmission of a television signal, is adopted as a signal transmission medium to Encrypting the analog videoconferencing signal and de-encrypting the encrypted videoconferencing signal in a videoconferencing system that performs videoconferencing with videoconferencing terminals accommodated in different LAN environments while exchanging. An object of the present invention is to provide an encryption / decryption processing apparatus for a video conference system.

In order to achieve the above object, according to a preferred embodiment of the present invention to selectively transmit the audio / video signal of the audio / video input means by analog / digital processing and to receive and reproduce the analog / digital video / audio signal of the other party A plurality of video conference terminal means; A first transmission line by a coaxial cable arranged to exchange analog video / audio signals between the plurality of video conferencing terminal means; A second transmission line arranged to perform external signal exchange for digital video / audio signals in said plurality of video conferencing terminal means; And a video conferencing server means connected to the second transmission line so as to exchange digital video / audio signals from the plurality of video conferencing terminal means with an external video conferencing terminal means. The means includes a video / audio transmission processing system comprising encryption means for encrypting the video / audio signal of the audio / video input means based on a predetermined encryption signal, and an encrypted voice which arrives via the first transmission line. Control for performing encryption / decryption processing by the video / audio reception processing system including the reverse encryption means for performing the reverse encryption process on the video signal and the encryption / decryption signal on the video / audio signal. An encryption / decryption processing apparatus of a video conferencing system equipped with a unit is provided.

Preferably, the control unit is provided with a data table in which an encryption / decryption signal is set correspondingly to a video conference channel by the video / audio signal.

Further, according to the present invention, the encryption means is an analog-to-digital converter for digitally converting the audio / video signal input from the audio / video input means, and the digital and the converted audio / video signal by adding the encrypted signal to the encryption And an 8-bit adder for processing, and a digital-analog converter for digital-to-analog converting the encrypted audio / video signal.

Further, according to the present invention, the inverse encryption means comprises: an analog-digital converter for digitally converting an encrypted audio / video signal arriving through the first transmission line, and the digitally converted audio / video signal to the inverse encryption signal. And a digital to analog converter for analog-converting the data of the decoded audio / video signal.

The audio / video transmission processing system of the video conferencing terminal means includes an RF modulator for RF modulating the encrypted video / audio signal, and a video / modulated RF / modulated channel to which a frequency band is rejected under the control of the control unit. An RF combiner is further provided for allocating a voice signal and applying the voice signal to the first transmission line.

In addition, the audio / video receiving processing system of the video conferencing terminal means includes a frequency band rejector for rejecting a frequency band allocated to the transmission of the video / audio signal, and an image / arrival received via the first transmission line. Tuner means for tuning a channel for receiving an audio signal, a video / audio IF module for IF converting a video / audio signal in the tuned channel, and the audio in the state where the IF-modulated video / audio signal is de-encrypted Audio processing means for reproducing and applying the signal to the audio output means, an NTSC decoder for decoding (R / G / B processing) the de-encrypted video signal, and for displaying the NTSC decoded video signal on a monitor. A scan converter which performs a synchronous conversion process to a VGA signal, and overlay processing means for overlaying the video signal from the scan converter with the support of a VGA card and outputting the same on the monitor; You will have

In addition, the video conferencing terminal means digitally processes the video / audio signal appearing on the second transmission line and performs digital conversion of the video / audio signal exchanged through the video conferencing server means. It is configured with.

The signal converting means is a video / audio encoder for compressing a video / audio signal modulated by the RF modulator and a multiplexing of a data frame for transmission of the encoded video / audio data and a video / audio received in a compressed state. And a system layer MUX / DMUX for performing demultiplexing of data, and a video / audio decoder for performing decoding to restore the demultiplexed video / audio data and applying the decoding to the video / audio IF module. .

According to the encryption / decryption processing apparatus of the videoconferencing system according to the present invention having the above-described configuration, the video conferencing terminal means included in the same LAN environment for the video / audio signal for videoconferencing is provided by a first coaxial cable. The video / audio signal is processed and exchanged at the TV level through the transmission line, and the video / audio data is transmitted through the second transmission means by the LAN circuit between the video conferencing terminal means accommodated in the external LAN environment. While being exchanged, the audio / video signal transmitted through the first transmission line is encrypted by adding an encryption signal under the control of a control unit included in each video conferencing terminal means, while the first transmission line is mediated. The encrypted audio / video signal, which is generated by performing the restoration, is performed by performing subtraction processing (that is, reverse encryption processing) of the encryption signal. It will work as much as possible.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

3 is a diagram showing the configuration of a videoconferencing system to which an example of the present invention is applied, and reference numerals 60a to 60n denote a first video signal processing function of a television (TV) level for video / audio signals for videoconferencing. A group video conferencing terminal is shown, and 62a is made of a coaxial cable (75Ω) suitable for transmitting a video / audio signal at a TV level, for example, for connecting the first group video conferencing terminals 60a-60n to the same environment. Represents the first transmission line.

62b transmits the data of the video / audio signal processed by the first group video conferencing terminals 60a to 60n to the video conferencing terminal housed in an external LAN environment, and the image transmitted from the external video conferencing terminal. / LAN network provided as a second transmission line for transmitting audio data to a corresponding videoconferencing terminal (e.g., 60a) among the first group of videoconferencing terminals 60a-60n.

64, the first group of videoconferencing terminals 60a-60n connected to the coaxial cable 62a and the LAN circuit network 62b exchanges video / audio data with the videoconferencing terminal connected to an external LAN communication network. Represents a gateway (or video conferencing server).

In FIG. 3, reference numerals 70a to 70n are similar to those of the first group of video conference terminals 60a to 60n while being provided as an external LAN environment for the first group of video conference terminals 60a to 60n. The second group of video conferencing terminals having a video / audio signal processing function of TV level is shown. 72a is a coaxial cable for constructing a LAN environment by interconnecting the second group of video conferencing terminals 70a-70n. 72b indicates that the video / audio signal data processed by the second group of video conferencing terminals 70a to 70n corresponds to the corresponding video conferencing terminal of the first group of video conferencing terminals 60a to 60n. Represents a LAN circuit for transmission to 60a).

In addition, 74 is a video conference terminal (e.g. 60a) in which the second group of video conference terminals 70a-70n connected to the coaxial cable 72a and the LAN circuit network 72b is connected to the coaxial cable 62a, for example. It represents a gateway for exchanging video conference data with.

80 is a LAN line network 72b to which a gateway 64 for a LAN line network 60b to which the first group of video conferencing terminals 60a to 60n is connected, and a video conference terminal 70a to 70n of the second group are connected. It is installed so as to connect the gateway 74 to the signal to the dedicated circuit (T1 / E1) as a transmission medium for transmitting video conference data between different LAN environments.

4 is a block diagram of a representative videoconferencing terminal 60a equipped with an encryption / decryption processing apparatus according to the present invention. Reference numeral 90a denotes a microphone as a means for inputting an audio signal when videoconferencing is set up. Denoted at 90b denotes a speaker for reproducing an audio signal inputted from the counterpart videoconferencing terminal when videoconferencing is executed, and 92 denotes a video camera as a means for capturing a video signal for videoconferencing.

Further, reference numeral 94 denotes that the audio signal and the video signal input from the microphone 90a and the video camera 90b are processed as an analog signal of TV level to be transmitted to the counterpart videoconferencing terminal in the same LAN environment, or the counterpart videoconference. While the audio signal and the video signal transmitted from the terminal are reproduced, the video / audio signal for video conferencing is exchanged with the video conferencing terminal in another LAN environment. If necessary, the video / audio signal processing means for performing the encryption / decryption processing on the analog video / audio signal.

Preferably, the video / audio signal processing means 94 is an encryption signal (for example, an 8-bit encryption key) applied to a control unit to be described later with respect to the audio / video signal input from the microphone 90a and the video camera 92. Data), an RF modulator 98 for RF-modulating the audio / video signal encrypted by the encryption unit 96 into a frequency band corresponding to a transmission channel, and the RF modulator 98 RF combiner assigns the RF-modulated audio / video signal to the channel rejected by the frequency band and transmits the RF-modulated audio / video signal to the coaxial cable 62a. A video / audio transmission system with (RF combiner; 100) will be installed.

In addition, the video / audio signal processing means 94 rejects the frequency band of the channel allocated to the video conference, and provides a frequency band rejector to provide a transmission frequency band of the audio / video signal by the RF combiner 100. 102 and a TV tuner 104 provided by a channel tuner for receiving an analog audio / video signal of a TV level transmitted from a video conferencing terminal of the other party included in the same LAN environment, by the TV tuner 104. A video / audio IF module 106 for performing IF (intermediate frequency) conversion processing of a video conference audio / video signal of a tuned channel, and a control described later on the audio / video signal IF processed by the video / audio IF module 106. A decoded unit 108 for restoring by applying a decoded signal (e.g., 8-bit decoded key data) applied by the unit, and processing the reproduced audio signal by the decoded unit 108 to reproduce the speaker 90b. The audio processing unit 110 to apply to the image / NTSC decoder 112 that decodes the video signal IF processed by voice IF module 106 by NTSC scan method for TV-level video playback, and displays NTSC decoded video signal by NTSC decoder 112 Video / audio reception including a scan converter 114 for converting to display and an overlay processing unit 116 for overlay processing such that the video signal converted by the scan converter 114 is displayed on the PC monitor 118. There will also be a processing system.

Also, reference numeral 120 encodes an RF-modulated video / audio signal transmitted by the RF modulator 98 when performing a video conference with a video conference terminal accommodated in an external LAN environment through the LAN line network 62b. The video / audio IF module 106 is multiplexed with a data frame structure, and demultiplexed and decoded video conference data transmitted from a video conference terminal in an external LAN environment that arrives on the LAN network 62b. Signal conversion means for subsequent playback processing to be performed.

122 controls the execution state of the videoconferencing when the videoconferencing terminal and the videoconferencing terminal of the external LAN environment executed via the LAN circuit network 62b are executed and, if necessary, the image / video by the TV tuner 104; Control unit for allocating a transmission / reception channel of an audio signal and a control unit for controlling encryption and reverse encryption of the audio / video signal. The control unit 122 is input to the microphone 90a and the video camera 92. Encrypted signal for encrypting the audio / video signal and the reverse encryption signal for restoring the encrypted audio / video signal which comes through the coaxial cable 62a in the video conference terminal of the other party are tabled and registered for each channel You will have a table.

Reference numeral 124 denotes a LAN card for supporting a function of transmitting / receiving video conference data through the LAN line network 62b under the control of the control unit 122.

In FIG. 4, reference numeral 126 denotes a VGA card for supporting screen processing of an image signal executed by the overlay processing unit 116 under the control of the control unit 122. Referring to FIG.

5 is a view showing the functional block configuration of the signal conversion means 120 shown in FIG. 3, in which the reference numerals 128 and 130 in the signal conversion means 120 are RF-modulated by the RF modulator 98. A video encoder and an audio encoder for encoding a video / audio signal, and 132 multiplexes the video / audio data encoded by the video / audio encoders 128 and 130 into a data frame structure suitable for transmission. The system layer MUX / DMUX demultiplexes the video / audio data transmitted from the video conferencing terminal (for example, 70a) in the external LAN environment, and 134 and 136 represent the video demultiplexed by the system layer MUX / DMUX 132. Represents a video decoder and an audio decoder to perform decoding processing for restoring audio data and apply the same to the video / audio IF module 106.

6 (a) and (b) are diagrams showing an example of the configuration of the encryption unit 96 and the reverse encryption unit 106 shown in FIG. 4, and the encryption unit 96 shown in FIG. Is an analog-digital converter 138 for digitally converting the audio signal input from the microphone 96a and the video signal input from the video camera 92, and the control unit for the digitally converted audio / video signal. An adder 140 that adds and encrypts an encryption signal (e.g., 8-bit encryption key data) corresponding to a transmission channel applied in 122, and converts data of an audio / video signal encrypted by the adder 140 into analog. And a digital-to-analog converter 142 applied to the RF modulator 98.

In addition, the inverse encryption unit 108 shown in FIG. 6 (b) includes an analog-digital converter 144 for digitally converting the video / audio IF signal IF-converted by the video / audio IF module 106. A subtractor 146 which subtracts and decompresses a decoded signal (for example, 8-bit decoded key data) for a reception channel applied from the control unit 122 to the digitally converted video / audio IF signal; And a digital-to-analog converter 148 for analog-converting the video / audio signal data reconstructed by the subtractor 146 and applying the same to the audio processor 110 and the NTSC decoder 112.

Next, the operation of the encryption / decryption processing apparatus of the videoconferencing system according to the present invention will be described in detail.

First, when video conferencing is performed between videoconferencing terminals connected to the same LAN environment by the coaxial cable 62a, for example, analog voice input from the microphone 90a of the videoconferencing terminal 60a and the video camera 92. The signal and the video signal are digitally converted by the analog-digital converter 138 of the encryption unit 96 and applied to the adder 140. Accordingly, the adder 140 is applied to the transmission channel in the control unit 122. The encrypted signal D1 is added to the audio / video signal to be encrypted. The encrypted audio / video signal is analog-converted by the digital-analog converter 142 and applied to the RF modulator 98 to RF. It is modulated.

The RF modulated audio signal and the video signal are assigned to the frequency band of the video conference channel CH, which is designated under the control of the control unit 122, and secured by the frequency band rejector 100, so that the coaxial cable ( A video / audio signal applied to the other side video conferencing terminal 60b, ..., 60n in the same LAN environment implemented by the coaxial cable 62a, and thus encrypted. The reverse encryption process is performed under the control of the control unit provided in the apparatus.

The encrypted audio / video signal transmitted to the videoconferencing terminal 60a through the coaxial cable 62a is tuned in a channel tuned by the TV tuner 104 under the control of the control unit 122. Then, the video / audio IF module 106 is applied to the IF conversion process, and the IF-converted video / audio signal is applied to the inverse encryption unit 108 for inverse encryption.

That is, the IF-converted video / audio signal applied to the inverse encoding unit 108 is digitally converted by the analog-to-digital converter 144 and applied to the subtractor 146. An inverse encryption signal (8-bit inverse encryption key data) corresponding to a reception channel set under the control of the control unit 122 is applied in the data table, and thus the subtractor 146 in the video / audio signal The decoded signal is subtracted to restore the original video / audio signal, and the decoded video / audio signal is analog-converted by the digital-to-analog converter 148 to perform the analog conversion on the audio processor 110 and the NTSC decoder 112. Is applied.

The voice processor 110 reproduces the decoded audio signal and outputs the same through the speaker 90b. The NTSC decoder 112 converts the decoded video signal into an R / G / B signal. Decoded and applied to the scan converter 118, and the image R / G / B signal applied to the scan converter 114 is signal-converted based on the VGA synchronization signal to be displayed on the monitor 114. The overlay processing unit 116 is applied.

The overlay processing unit 116 overlays an image signal applied from the scan converter 114 under the support of the VGA card 126 operated under the control of the control unit 122 to be reproduced on the PC monitor 118. Will print.

Therefore, in the same LAN environment constituted by the coaxial cable 62a to which the video conferencing terminals 60a (60b-60n) shown in FIG. 4 are connected, processing by encryption / decryption of video / audio signals at TV level is performed. Video conferencing becomes viable in the manner in which it is performed.

Next, a description will be given of the exchange operation of the video / audio data between the video conferencing terminal (for example, 70a) accommodated in another LAN environment via the LAN circuit network 62b. 90a) When the audio and video signals input from the video camera 92 are RF-modulated by the RF modulator 96, the video / audio encoder of the signal conversion means 120 is converted into the RF-modulated audio / video signals. 128, 130, which causes the RF modulated video / audio signal to be switched to the signal conversion means 120 between the RF modulator 98 and the RF combiner 100. By providing a switching means (not shown), the control unit 122 is enabled by appropriately controlling the path of the switching means.

Accordingly, the video / audio signal applied to the video encoder 128 and the audio encoder 130 is applied to the system layer MUX / DMUX 132 after the encoding process for compression is performed, and the system layer MUX / DMUX. In 132, the compressed encoded video / audio data is multiplexed into a data frame structure suitable for transmission and applied to the LAN network 62b through the LAN card 124 under the control of the control unit 122. .

Video / audio data for video conferencing applied on the LAN line network 62b is output on the dedicated line 80 through a dedicated network (T1 / E1) interface provided in the gateway 64 to external LAN environment. The video / audio data for video conferencing, which is transmitted to the LAN line network 72b through the gateway 74 provided for, is applied to the video conferencing terminal 72a and reproduced.

On the other hand, for example, the video / audio data applied on the LAN line network 72b in the video conferencing terminal 70a is transmitted to the first group of video conferencing terminals via the dedicated line 80 at the gateway 74. Received from the dedicated network (T1 / E1) interface 64 of the gateway 64 provided for 60a-60n and applied to the signal conversion means 120 via the LAN card 124 and the control unit 122. do.

The system layer MUX / DMUX 132 of the signal converting means 120 demultiplexes the received video / audio data and applies it to the video decoder 134 and the audio decoder 136, and the video / audio decoder. In 134 and 136, decoding processing for correspondingly restoring the video / audio data is performed and applied to the video / audio IF module 106.

Accordingly, the video / audio IF module 106 performs IF conversion on the audio signal and applies the IF signal to the audio processing unit 110 through the inverse encryption unit 108, thereby reproducing the audio signal in the audio processing unit 110. The processed voice is to be reproduced through the speaker 90b.

In addition, the video signal IF-converted by the audio / video IF module 106 is applied to the NTSC decoder 112 through the inverse encoding unit 108 and decoded into an R / G / B signal for screen reproduction. Subsequently, the signal is converted based on the VGA synchronization signal to be displayed on the monitor 118 in the scan converter 114 and then applied to the overlay processor 116. The overlay processing unit 116 overlays an image signal applied from the scan converter 114 under the support of the VGA card 120 operated under the control of the control unit 122 to be reproduced on the PC monitor 118. Through the above process, video / audio for video conference is possible between video conference terminals included in different LAN environments.

As described above, according to the encryption / decryption processing apparatus of the videoconferencing system according to the present invention, a plurality of videoconferencing terminals are connected by a coaxial cable signally and accommodated in the same LAN environment. It is possible to exchange video / audio signal for video conferencing by TV-level video / audio signal processing, and exchange video conferencing data with data conferencing structure corresponding to transmission line with video conferencing terminal in external LAN environment. In this configuration, it is possible to increase the security of the video / audio signal by performing encryption and reverse encryption on the analog audio / video signal.

Claims (5)

Multiple video conferencing terminal means (60a-60n) for selectively transmitting analog / digital processing of video / audio signals of audio / video input means (90a, 92) and receiving and reproducing analog / digital video / audio signals of the other party. And; A first transmission line (62a) by coaxial cable arranged to exchange analog video / audio signals in the plurality of video conferencing terminal means (60a-60n); A second transmission line (62b) arranged to perform external signal exchange for digital video / audio signals in said plurality of video conferencing terminal means (60a-60n); Video conferencing server means 64, connected to the second transmission line 62b to exchange digital video / audio signals from the plurality of video conferencing terminal means 60a-60n with external video conferencing terminal means. Encryption means 96 for encrypting the video / audio signals of the audio / video input means 90a and 92, respectively, on the basis of a predetermined encryption signal, in the video conferencing terminal means 60a to 60n. The video / audio reception processing system including the video / audio transmission processing system, and the reverse encryption means 108 for performing back encryption processing on the video / audio signal received by being encrypted by the encryption signal. An apparatus for encrypting / decrypting a video conferencing system, comprising: a control unit 122 for controlling a signal and a decoded signal. The apparatus of claim 1, wherein the control unit 122 includes a data table of an encryption / decryption signal for the transmission / reception channel of the video / audio signal. . The video conferencing system of claim 2, wherein the encryption / decryption signal of the data table included in the control unit 122 corresponds to a channel set during transmission / reception of the video / audio signal. Encryption / Decryption Processing Unit. The method of claim 1, wherein the encryption means (96) is a digital-to-digital converter for converting the audio / video signal input from the audio / video input means (90a, 92) and the digital-to-digital converter / The video conferencing system is characterized by comprising an adder 140 for adding a video signal to the encrypted signal and encrypting the video signal, and a digital-analog converter 142 for digital-analog converting the encrypted audio / video signal. / Reverse encryption processing unit. The apparatus of claim 1, wherein the inverse encryption means (108) comprises: an analog-digital converter (144) for digitally converting an encrypted audio / video signal received through the first transmission line (62a), and the digitally converted audio. And a subtractor 146 for sub-encoding the video signal by the de-coding signal, and a digital-analog converter 148 for analog-converting the data of the de-coded audio / video signal. Device for processing encryption / decryption of the system.