JPH0461489A - Video conference system - Google Patents

Abstract

PURPOSE:To realize the video conference system with high general-purpose application and full of presence without increase in the transmission cost by revising adaptively the pattern synthesis method during communication depending on a content of a sent picture. CONSTITUTION:The system consists of a picture input section 11, a picture synthesis section 12, a picture coding section 13, a transmission line control section 14, a picture decoding section 15, a picture demultiplexer section 16, a picture output section 17 and a mode changeover section 18. When both camera inputs are a full scene pattern, the mode changeover section 18 selects the spatial split mode for the transmission of a picture and when the full pattern transmission is required in the case of a zoom-up pattern or the like, the section 18 selects the time division mode for the picture transmission. Thus, even during communication, since the pattern synthesis method is properly selected depending on the picture, the advantage of the respective pattern synthesis methods is utilized. Thus, the low transmission cost is realized and the video conference system is realized with simple constitution and full of presence.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention connects conference halls located at distant locations through communication lines and mutually transmits images and sounds.
This invention relates to a video conference system for holding meetings between multiple people.

[Prior Art] With the development and popularization of digital transmission paths represented by ISDN, advances in image processing technology, and development of high-speed digital signal processing technology, the demand for realizing various image communication services has increased significantly in recent years. It's coming. Among these, one of the most anticipated services is the videoconferencing service.Videoconferencing connects conference halls between remote locations via communication lines, and transmits information such as images, audio, and documents in both directions. By doing so, this information can be shared and the conference can be held in the same environment as in the same conference hall, making it possible to easily overcome temporal and geographical constraints.

Among the information handled in a video conference, image information in particular has a large amount of information, is highly real-time, and has a large impact on the sense of realism of the video conference.

Generally, in video conferencing, image information is

First, the signal is converted into a digital signal, then redundancy suppressed and encoded through appropriate processing, compressed to an amount of information suitable for the transmission path, and sent to the communication line.

FIG. 3 shows a schematic block diagram of the configuration of an image information processing section of a conventional video conference system.

An image signal from an iI image input device such as a television camera is input to an image input section 31, and is subjected to preprocessing such as A/D conversion and filter processing. The digitized image signal is subjected to redundancy suppression encoding in the image encoding unit 33, encoded into a code string with an appropriate amount of information, and sent to the line through the transmission line control unit 34 and received from the line. The code string is decoded by an image decoding unit 35 via a transmission path control unit 34 to restore a digital image signal. This image signal is outputted to the image output section 37 by D/
Post-processing such as A conversion and filter processing is performed, and the signal is output to a disk gray or the like, and ii@ is displayed.

It was. In video conferencing systems, it is said that the limit for distinguishing the facial expressions of participants is usually to display 3 to 4 people on one screen. In some cases, a method is used in which images are input using separate television cameras and the images are combined and transmitted.

An example of the operation when performing screen composition will be described below.

Wi image signals from two TV cameras, each t'
It is sent from the L-both image input section 31 to the image composition section 32. In the image synthesis section 32, the upper and lower 1/4 parts of each input screen are removed, and only the central 1/2 part is extracted, as shown in FIG. 4(a). These two screens are combined vertically as one screen (hereinafter referred to as space division mode) and sent to the image encoding unit 33. On the receiving side, an il image decoding unit 35
The decoded image signal is sent to the image separation section 36.

In the image separation unit 36, the screen that has been vertically combined on the transmission side is separated into two screens again, and each screen is sent to the image output unit 37.
will be displayed on the display.

Another possible synthesis method is to switch the input system for each image frame (hereinafter referred to as time division mode) as shown in FIG. 4(b). At this time, the image composition section 32
switches the image input system for each frame and sends it to the image encoding section 33.

On the contrary, the image separation unit 36 on the receiving side switches the output system for each frame and performs display.

In the time division mode, the operation is equivalent to multiplexing and transmitting two independent systems of images on a transmission path.

[Problem M to be solved by the invention] However, in the video conference system, when the space division mode is used, the entire screen cannot be transmitted, so it is necessary to transmit the entire screen, such as when zooming in on the caller. In some cases, only one series of input images can be transmitted.

In the case of time division mode, the transmission path is divided and used for each image system, so only half of the transmission path capacity used for one input image is allocated, and the transmitted image There is a problem in that the quality of images deteriorates and a higher bandwidth transmission path is required in order to obtain high quality images.

The present invention has been made in view of the above-mentioned points, and even when screens from multiple input systems are combined and transmitted as one screen, the transmission cost can be realized at low cost, and a television with a simple configuration can provide a sense of realism. The purpose is to provide a video conference method for holding meetings.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides an image input means for inputting an image signal from a television camera or the like.

An image encoding means for encoding an image signal, a transmission line control means for transmitting encoded image data to a transmission line or receiving it from a transmission line, an image decoding means for decoding received image data, and an image signal. image display means for displaying the image on a monitor display, etc.; image synthesis means for synthesizing the two systems of input image signals; image separation means for separating the image signals into two systems; Communication means includes a space division mode in which a series of input Wi image signals is divided into regions and synthesized into each region, and a mode switching means for selecting a time division mode in which the input system is switched for each image frame. In the co-mode switching unit 18, either mode of the space division mode or the time division mode is adaptively selected and switched. When both inputs are full-view screens, the image is transmitted by switching to space division mode, and when it is necessary to transmit the entire screen, such as a zoom-up screen, it is switched to time-division mode and the image is transmitted. to transmit.

With this, even during communication, an appropriate screen composition method can be selected depending on the image, so that the advantages of each screen composition method can be utilized.

[Embodiment] Next, an example of the video conference system according to the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a schematic block diagram of the configuration of the image information processing section of the video conference system of the present invention.

The operations of the Wii image input section 11, image encoding section 13, transmission path control section 14, image decoding section 1, etc., and image output section 17 are similar to those of the conventional video conference system.

The video conference system of the present invention includes a mode switching section 18. In the mode switching unit 18, when both inputs are full-view screens, the image is switched to the space division mode and the image is transmitted, and when it is necessary to transmit the entire screen such as a zoom-up screen, 1 Switch to time division mode and transmit agA.

An example of the operation when performing screen composition will be described below. Figure 2 shows an example of screen composition.

Each of the two television cameras captures a panoramic image of 3 to 4 people, and the images from each camera are sent to an image synthesis unit 12.
In the spatial division mode, the upper and lower regions of the screen are combined and transmitted.

When the screen from one TV camera changes to a zoom-up screen of the speaker, etc., and it becomes necessary to transmit the entire screen, the mode switching unit 18 changes the screen compositing method to the image combining unit 12 from the spatial division mode to Instructs to switch to split mode. That is, the image synthesis unit 12 changes its operation so that the zoomed-up screen from one television camera and the panoramic screen from the other television camera are switched and transmitted frame by frame.

At this time, for the zoom up screen, the entire screen
As for the panoramic screen, it is only necessary to transmit 1/2 of the screen by removing 1/4 of the top and bottom, so more of the capacity of the transmission path can be used for the zoom-up screen, resulting in better image quality than the normal time-sharing mode. You can get .

When the images from both television cameras are returned to the full-view screen, the mode switching unit 18 sends an instruction to the image combining unit 12 to change the operation to combining the screens in the space division mode.

On the receiving side, the opposite operation should be performed.
When the screens are combined in the space division mode, the single image separation unit 16 separates the combined screen into upper and lower parts and outputs them for display.

Then, when the transmission side mode is changed to the time division mode, the mode switching section 18 instructs the Wi image separation section 16 to change the operation mode. The image separation unit 16 operates to allocate output systems for each frame of the transmitted image.

[Effects of the Invention] As explained above, according to the video conference system of the present invention, it is possible to adaptively change the screen composition method during communication depending on the content of the transmitted image, so it is possible to create flexible images. It can correspond to transmission.

Furthermore, the limited capacity of the transmission path can be used more efficiently.

Therefore, a highly versatile and realistic video conference system can be provided without increasing transmission costs.

13・ 18・ Image encoding section ・Transmission line control section Picture [Part 1 Image separation section Image output section Mode switching section

[Brief explanation of the drawing]

11] is a schematic block diagram showing the configuration of an actual example of this invention, FIG. 2 is a diagram showing an example of mode switching of screen composition according to the invention, and FIG. 3 is a conventional image processing unit of a video conference system. FIG. 4 is a schematic block diagram showing an example of the configuration of the screen, and FIG. 4 is a diagram showing an example of combining screens. 11... Image input unit 12... Image synthesis unit

Claims (1)

[Claims] (1) An image input means for inputting an image signal from a television camera, etc., an image encoding means for encoding the image signal, and a transmission line for transmitting encoded image data to or receiving the encoded image data from the transmission line. A control means, an image decoding means for decoding the received image data, an image display means for displaying the image signal on a monitor display, etc., an image synthesizing means for synthesizing the two systems of input image signals, and separating the image signal into two systems. a space division mode in which two series of input image signals are divided into regions of one image frame and combined into each region according to the content of the image to be transmitted and received; and an input system for each image frame. and a mode switching means for selecting a time division mode for switching, and adaptively selecting and switching between the space division mode and the time division mode during communication. A video conferencing method.