JPH07307711A - Multiplex transmission system - Google Patents

Abstract

PURPOSE:To execute a program production with mobility and efficiently without installing a cable and from an arbitrary camera location and by a few crew. CONSTITUTION:When a camera select signal is transmitted by the multiplex transmitter 27 of a relay car C, a camera/transmission unit receiving this camera select signal assigns high image quality component data to the high image quality data transmission area which is preliminarily allocated within a frequency band by an image/sound compression encoder and transmits the data by the multiplex transmitter. When the relay car C receives high image quality component data by a multiplex receiver 21, the high image quality component data and the low resolution component data corresponding to the high image quality component data are composited by a video/sound decoder 22 and the composite result is outputted to a monitor group 24 and a main line selection switch/adjusting control console 25 via a demultiplexer 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission system for wirelessly transmitting a plurality of images and sounds between a plurality of information transmitting stations and a base station using the same frequency band.

[0002]

2. Description of the Related Art Conventionally, an analog technical method has been used for transmitting a plurality of images and sounds. Video 2 channel transmission by time axis compression is described in, for example, TV magazine, vol.35, No.8, pp25.
-30 (1981), and field or frame switching dual-screen transmission is described in, for example, TV magazine, vo.
L.47, No.10, pp1323-1331 (1993), it has been developed mainly on the image spatial and temporal composite technology.
In addition, the digital multi-channel video transmission technology uses the simple frequency allocation of video data that is video compressed, as described in TV magazine, vol.47, No.4, pp467-473 (1993). It is intended for multiple channel transmission, and compression / layer coding was not applied from the viewpoint of a program production system.

[0003]

A plurality of conventional video transmission techniques is merely a technique for transmitting a plurality of videos, and is used for comprehensive video transmission such as relay broadcasting, video selection, and video check. It is incomplete as a program production system. For example, it is not possible to flexibly perform video transmission for program production, such as operating a video from a camera installation location without a cable and while moving the camera position.

An object of the present invention is to solve the above-mentioned problems, and to perform program production flexibly and efficiently by laying a cable from a given camera position by a small number of crews, without laying a cable. To provide a transmission system.

[0005]

[Means for Solving the Problems]

1) The multiplex transmission system according to the present invention is a multiplex transmission system for wirelessly transmitting a plurality of video and audio using the same frequency band between a plurality of information transmission stations and a base station, wherein each of the information transmission stations Is a microphone, digital encoding means for digitally encoding a sound signal from the microphone, a relay camera, and a low-resolution component data and a low-resolution component by hierarchical compression encoding of a video signal from the relay camera. Converting means for converting the component data into high image quality component data obtained by subtracting from the video signal, low resolution component data obtained by the converting means, and audio data digitally encoded by the digital encoding means. , Audio data / low resolution component data allocating means to be allocated to an area allocated to the information transmitting station in the frequency band, and a camera select signal And a high image quality component data allocating means for allocating the high image quality component data to a pre-allocated high quality image data transmission area in the frequency band, the base station is configured to receive the received high image quality data. A synthesizing unit for synthesizing the component data and the low resolution component data corresponding to the high quality component data, the low resolution component data as the video image data sent back to the information transmitting station, and the audio data related to the video image sending data. And video / audio data allocating means for allocating to a pre-allocated area in the frequency band, and control command signal data allocation for allocating control command signal data including the camera select signal to a pre-allocated area in the frequency band And means.

2) In the multiplex transmission system described in 1) above, the control command signal data includes a camera control signal to each of the relay cameras in addition to the camera select signal.

[0007]

In the present invention, each information transmitting station hierarchically compresses and encodes the video signal from the relay camera by the converting means,
Low-resolution component data, high-resolution component data obtained by subtracting the low-resolution component data from the video signal, obtained low-resolution component data, and audio data digitally encoded by digital encoding means. Is allocated by the audio data / low resolution component data allocating means to a region of the frequency band allocated to the information transmitting station, and when the camera select signal is received, the high quality component data is allocated within the frequency band. The high image quality component data allocating means allocates the image quality improving data transmission area allocated in advance, and the base station synthesizes the received high image quality component data and the low resolution component data corresponding to the high image quality component data by the synthesizing means. , The low resolution component data as sending back video data to the information transmitting station and the sending back video data. Audio data to be transmitted to a pre-allocated area in the frequency band and allocated by the video / audio data allocating means, and control command signal data including the camera select signal is assigned to a pre-allocated area in the frequency band. It is assigned by the signal data assigning means.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows a plurality of video and audio transmission systems according to an embodiment of the present invention. This transmission system
It is composed of a plurality of cameras / transmission units U and one relay vehicle C. Usually, a crew is composed of a plurality of cameras and transmission units U.

FIG. 2 shows the camera / transmission unit U shown in FIG.
Shows the configuration of. The camera / transmission unit U has a microphone 10
A camera 11 for relay coverage, a video / audio compression encoder 12, a multiplex transmitter (outgoing side) 13, a multiplex receiver (outgoing side) 14, an audio / video / control command decoder 15, and a news gathering system control unit. 16 and.

The image / audio compression encoder 12 is a microphone 10.
The audio signal from is digitally encoded. The image / sound compression encoder 12 obtains by subtracting the low resolution component data (video information enough to determine a video) and the low resolution component data from the video signal by hierarchical compression coding of the video signal from the camera 11. The low-resolution component data obtained by conversion into high-quality component data and the digitally encoded audio data are allocated to the area of the frequency band allocated to the camera / transmission unit U. The image / audio compression encoder 12 is for allocating the high image quality component data to a pre-allocated high image quality improvement data transmission area within the frequency band when the camera select signal is received by the multiplex receiver 14. The multiplex transmitter (sending side) 13 multiplexes the compressed image from the image / audio compression encoder 12.

The multiple receiver (sending side) 14 is a relay vehicle C.
It is for receiving the sending back video, the sending back sound and the image control command signal data from. The image / sound / control command decoder 15 decodes image control command signal data received by the multiplex receiver (sending side) 14. The news gathering system control unit 16 follows the image control command from the image / control command decoder 15 and the camera 11 and the image / audio compression encoder 1.
2 and the multiplex transmitter (sending side) 13 are controlled.

FIG. 3 shows the structure of the relay vehicle C shown in FIG.
The relay vehicle C includes a multiple receiver 21 and a video / audio decoder 2
2, a demultiplexer 23, a monitor group 24, a main line selection switch / adjustment control desk 25, a return video / audio /
Control command transmission encoder 26 and multiplex transmitter 27
Have and.

The multiple receiver 21 is a camera / transmission unit U.
For receiving compressed video information and audio signals from. The video / audio decoder 22 decodes the compressed video information and audio signal received by the multiplex receiver 21. The video / audio decoder 22 synthesizes the high image quality component data received by the multiplex receiver 21 and the low resolution component data corresponding to the high image quality component data. The demultiplexer 23 is the video / audio decoder 2
The image from 2 is demultiplexed.
The monitor group 24 monitors the image demultiplexed by the demultiplexer 23.

The main line selection switch / adjustment control console 25 is for switching the audio and video to the main line and outputting a return video / control command. Send back video / audio
The control command transmission encoder 26 encodes the return video / audio / control command from the main line selection switch / adjustment control console 25. The multiplex transmitter 27 transmits the return video, the return voice, and the control command encoded by the return video / audio / control command transmission encoder 26.

Next, the hierarchical compression coding will be described with reference to FIG.

By the compression encoding, the video signal of one camera is compressed to, for example, 10 Mbps. The hierarchical compression coding is, for example, MPEG2 (moving picture image coding expe
rtsgroup phase2) Spatial Scalable (spatial resolution scalable).

The first layer L1 (31) is lower layer video data obtained by roughly sampling the original image by downsampling. Subtracting the lower layer video data 32 for which time prediction is performed, lower layer prediction error video data Get 33. By encoding the prediction error data 33, lower layer transmission video data 34 is obtained.

The data 35 obtained by up-sampling the video obtained by decoding the video data of the lower layer and the video data 36 of the upper layer for which time prediction has been performed are combined and subtracted from the original video signal 37 to predict the upper layer. Error video data 38 is obtained. Then, the upper layer prediction error video data 38 is encoded to obtain the upper layer transmission video data 39. Further, the data 39 is decoded to obtain the upper layer prediction error video data 40, which is combined with the video data (video data obtained by combining the data of the upper layer + the data of the lower layer for which time prediction is performed one frame before) 41. Therefore, the next time prediction data 42 is obtained.

By this method, for 10 Mbps original video data, the low resolution component data of 1.5 Mbps and the low resolution component are subtracted from the original original video data by down-sampling in the horizontal and vertical directions of the video. Convert to the remaining 8.5 Mbps high-quality component data. Then, the low-resolution component data and the high-quality component data are respectively subjected to OFDM (orthogonal frequency division).
on multiplex: Orthogonal frequency multiplexing).

Next, OFDM modulation will be described.

The OFDM modulation is made by performing an IFFT (Inverse Fast Fourier Transform) on a plurality of carriers orthogonal to each other within a required bandwidth. Carriers obtained by IFFT are aggregated (summed) to create a composite wave for each symbol period, the carrier frequency is cos-modulated (cosine modulation) and sin-modulated (sine modulation), and both modulated waves are combined. To obtain a digital modulated wave.

All carriers (waves) of OFDM modulation are, for example, 2048 waves. As for the number of carriers of low-resolution component data and audio data, for example, if 145 waves are used for one camera, a total of 870 waves are used for 6 cameras. These carriers are all cameras by a multiple modulation or a specific group has a specific area within a frequency band, for example, as shown in FIG.
It is allocated to the area indicated by 51 in (a).

As for the high image quality component data, only the camera image selected by the camera select signal of one or more control commands is displayed in the high image quality data transmission area within the frequency band, for example, at 52 in FIG. 5 (a). It is allocated to the area shown. For example, when 450 waves are used for one camera, 900 waves are used in a design that enables transmission of two high resolution component data.

The sent-back video is sent to a specific area in the frequency band, for example, an area indicated by 53 in FIG. 5A, such as 145, so that each relay cameraman can monitor the broadcast video from the relay vehicle or the relay point. Waves are assigned.

The control command signal data is a camera control signal from the relay vehicle or relay point to each camera,
A specific area within the frequency band for sending back control / selection information for main broadcast and, in some cases, next video to each camera, including a camera video image quality enhancement component data selection signal, for example, FIG. For example, 133 waves are assigned to the area indicated by 54.

The audio signal from the microphone 10 is digitally encoded by the image / audio compression encoder 12, and the camera 1
The video signal from 1 is hierarchically compression-encoded by the video / audio compression encoder 12 to be converted into low-resolution component data and high-quality component data obtained by subtracting the low-resolution component data from the video signal. The low-resolution component data and the digitally encoded audio data are allocated to the area of the frequency band allocated to the camera / transmission unit U (see FIG. 5A). Then, the hierarchical compression-encoded low-resolution data and audio data are transmitted by the multiplex transmitter 13.

On the other hand, the low resolution data and the audio data (see FIG. 5B) received by the multiplex receiver 21 are
It is decoded by the video / audio decoder 22 and output to the monitor group 24 and the main line selection switch / adjustment control console 25 via the demultiplexer 23.

The main line selection switch / adjustment control table 25
In accordance with the operation of, the multiplex transmitter 27 of the relay vehicle C transmits the return video / audio and control command data to the camera / transmission unit U.

When the camera select signal is transmitted from the relay vehicle C, the camera / transmission unit U which has received the camera select signal allocates the high image quality component data in advance within the frequency band by the image / audio compression encoder 12. The data is allocated to the image quality improvement data transmission area and transmitted by the multiplex transmitter 13.

When the relay vehicle C receives the high image quality component data by the multiplex receiver 21 (see FIG. 5B), the video / audio decoder 22 responds to the high image quality component data and the high image quality component data. The low resolution component data to be combined is combined, and the combined result is output to the monitor group 24 and the main line selection switch / adjustment control console 25 via the demultiplexer 23.

As described above, a plurality of images of the relay broadcast are transmitted from a plurality of camera positions by using a limited frequency bandwidth, and a return image which is indispensable for a program production system such as a relay and various control commands are transmitted. Can be realized.

[0033]

As described above, according to the present invention,
With the configuration as described above, it is possible to flexibly and efficiently perform program production from a desired number of crews from any camera position without laying a cable.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a camera / transmission unit U shown in FIG.

3 is a block diagram showing a configuration of a relay vehicle C shown in FIG.

FIG. 4 is an explanatory diagram for explaining hierarchical compression encoding.

FIG. 5 is a diagram showing an example of allocation of low resolution data, high image quality data, return video data, control commands, and audio signals in one frequency band.

[Explanation of symbols]

10 Microphone 11 Camera 12 Video / Audio Compression Encoder 13 Multiple Transmitter (Sending Side) 14 Multiple Receiver (Sending Side) 15 Image Sound / Control Command Decoder 16 Coverage System Control Unit 21 Multiple Receiver (Relay Car Side or Relay Point Side) 22 Video / Audio Decoder 23 Demultiplexer 24 Monitor Group 25 Main Line Selection Switch / Adjustment Control Desk 26 Send-back Video / Audio / Control Command Transmission Encoder 27 Multiple Transmitter (at Relay Vehicle Side or Relay Point Side)

Claims (2)

[Claims] 1. A multiplex transmission system for wirelessly transmitting a plurality of images and voices between a plurality of information transmission stations and a base station using the same frequency band, wherein each of the information transmission stations comprises a microphone, Digital encoding means for digitally encoding an audio signal from a microphone, a relay camera, and low resolution component data by hierarchical compression encoding of a video signal from the relay camera, and the low resolution component data to the video signal. A conversion means for converting into high quality component data obtained by subtracting from the low resolution component data obtained by the conversion means, and audio data digitally encoded by the digital encoding means, among the frequency bands. Of the audio data / low resolution component data allocating means to be allocated to the area allocated to the relevant information transmission station, and when the camera select signal is received. High-quality component data allocating means for allocating the high-quality image component data to a high-quality image data transmission area allocated in advance within the frequency band, wherein the base station receives the high-quality image component data and the high-quality image component data. A synthesizing unit for synthesizing low-resolution component data corresponding to the data, low-resolution component data as video data sent back to each information transmitting station, and audio data related to the video data sent back are previously stored in the frequency band. A return video / audio data allocating means for allocating to the allocated area, and a control command signal data allocating means for allocating the control command signal data including the camera select signal to a pre-allocated area in the frequency band. Characteristic multiplex transmission system. 2. The multiplex transmission system according to claim 1, wherein the control command signal data includes a camera control signal to each of the relay cameras in addition to the camera select signal.