JPS62290287A - Image transmission method - Google Patents

Abstract

PURPOSE:To simultaneously enable plural images to be displayed on a single display device, by transmitting picture data in plural rectangular areas, within the frame period of a picture memory, and reading and holding transmitted picture data in the rectangular area of the picture memory, within the frame period of a reception memory. CONSTITUTION:A position detecting means 10a outputs an on-state at every refresh of a picture memory 16, at the time of generating the rectangular area by a reading position from the picture memory 16, and outputs an off-state other than the rectangular area. The picture data is written at a transmission buffer 11 in the on-state time of the output of the position detecting means 10a, and the content of the transmission buffer 11 is transmitted in order through a communication line. A position detecting means 10b outputs the on-state, at the time of generating the rectangular area by the picture to be written, and outputs the off-state other than the rectangular area. When the output of the position detecting means 10b goes to the on-state, the transmission data is read from a reception buffer 12, then being written on the picture memory 16. A written picture data is sent to a display device.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an image transmission method for simultaneously transmitting moving images and/or still images in a plurality of areas.

[Conventional technology]

2. Description of the Related Art Video conferencing is conventionally known as a conversational communication service using moving images and still images. Video conferences use high-efficiency encoding technology to transmit video or still image data to each other over regular audio lines or high-speed dedicated lines, and it is possible to display the other party's image on a display device. It is said that Furthermore, in video conferences connecting multiple points, multiple display devices are used to display images from multiple points.

It is common practice to switch and display screens on a single display device.

Furthermore, in order to simultaneously display images of a plurality of points on a single display device, images a, b, c, -d of the terminal device 50 of each point are displayed as shown in FIG. 5(a).

e on the exchange 51, reduced in the image processing device 52, and synthesized into a plurality of divided screens as shown in FIG. A split-screen method has been proposed that displays images in advance. In addition,
FIG. 5(b) shows the screen of the terminal device whose image is a.

[Problem that the invention seeks to solve]

However, in conventional image transmission methods, one entire screen is transmitted as image data, so only a single image can be viewed on a single display device, and multiple images are used to simultaneously view the material and the other party. Conversation had the disadvantage of requiring complex equipment as described above.

In addition, if multiple display devices are required for video conferences connecting multiple points, or if a single display device is used,
There was a problem in that it was not possible to view images from all locations at the same time. In order to solve this problem, even if a screen splitting method as described in FIG. 5 is used, the image must be displayed in a reduced size, resulting in a reduction in resolution.

An object of the present invention is to provide an image transmission method that allows a plurality of moving images and/or still images to be simultaneously transmitted and displayed on a single display device.

[Means for solving problems]

The present invention provides an image transmission method for transmitting and receiving image data of a plurality of moving images and/or still images between image memories.
Regarding multiple rectangular areas of arbitrary size that do not overlap with each other on the screen, the transmitting side transmits the image data within the multiple rectangular areas to be transmitted within a frame period of the transmitting side's image memory, and the receiving side The present invention is characterized in that a plurality of images are transmitted by reading and holding the transmitted image data within a rectangular area of the image memory on the receiving side within a frame cycle of the receiving memory on the receiving side.

[Effect]

An image memory that stores images samples a video signal from an image input device such as a camera or a video disk at a sampling frequency, and stores it as image data. Image data is always read out at the timing of the sampling frequency, reproduced into a video signal and sent to a display device, and in the case of a moving image, the image data of the next frame is written and the screen is updated.

In the case of still images, the image data is retained by being written back to the image memory.

In the image transmission method of the present invention, image data within a rectangular area of any size at any position on the image memory is transmitted to the buffer memory on the receiving side within the frame period of the image memory on the sending side, and On the side, image transmission in a rectangular area is realized by repeating the process of reading out the transmitted image data from this Banofa memory into a rectangular area within the frame period of the image memory on the receiving side for each frame period. At this time, the transmission and reception processes can be performed in parallel, so by implementing multiple image data transmission circuits to realize the transmission process and image data reception circuits to realize the reception process, mutual transmission and reception can be performed for multiple rectangular areas. This makes it possible to display multiple images on a single display device.

Further, since the size and position of the rectangular area are variable, it can be dynamically enlarged or reduced as necessary.

〔Example〕

FIG. 1 shows an example of a terminal device used to implement the image transmission method of the present invention. This terminal device shows an example having one image data transmitting circuit and one image data receiving circuit. 16 is an image memory for storing image data;
It is always refreshed at a constant frame rate. 10a
, 10b is a position detection means, which detects whether the image data on the image memory 16 is within the set rectangular area when the position and size of the rectangular area is set, and turns on if it is within the rectangular area. Otherwise, it outputs the off state. Reference numeral 11 denotes a transmitting buffer, and 12 denotes a receiving buffer, which is a buffer memory between the communication line and a first-in first-out type memory (FIFO).

A writing device 13 writes the image data on the image memory 16 to the transmission buffer 11 as transmission data.

Reference numeral 14 denotes a reader that reads received data from the reception buffer 12 as image data. Reference numeral 15 denotes a selector, which outputs image data from an image input device (not shown) and the reader 14.
Of the image data of and the image data of image memory 16,
When the position detecting means 10a is on, the image data of the image input device is selected, when the position detecting means 10b is on, the image data of the reader 14 is selected, and at other times, the image data of the image memory 16 is selected. is selected and written to the image memory 16.

Position detection means 10a, transmission buffer 11. One image data transmitting circuit is connected to the writing device 13, and the position detecting means 1
0b, receive buffer 12. Together with the reader 14, one image data receiving circuit is configured.

The present embodiment will be described assuming that such terminal devices are connected via a communication line. In the following description, it is assumed that the frame cycles of the image memories on the transmitting side and the receiving side are the same.

In this embodiment, on the transmitting side, as shown in FIG.
, p within the rectangular area to be transmitted.

(Xo, Yo), Po' (Xo+Δxo, yo
+ΔYo) is sent to the buffer memory on the receiving side within the frame period of the image memory on the sending side, and on the receiving side, the transmitted image data is transferred from the buffer memory to the image memory on the receiving side within the frame period. Image transmission in a rectangular area is realized by repeating reading into a rectangular area every frame period. Furthermore, on the transmitting side, a rectangular area (ΔXI
, ΔY1) from an arbitrary position (X+, Y+), within the rectangular area P+ (X+, Y+), P
It is assumed that image data of +' (X+ +ΔX,, y, +ΔY+) is received.

In the terminal device shown in FIG. 1, when transmitting, first, as a rectangular area, the parameters x, , yo l ΔXo, ΔYo for setting the rectangular area shown in FIG. memory 16
Each time the image data is refreshed, the position detecting means 10a detects the read position from the image memory 16 in a rectangular manner using the basic clock CLK which is the same as the sampling frequency indicating the image data read timing and the horizontal synchronization signal H indicating each line signal in the X direction. When the area is within the rectangular area, an on state is output, and when outside the rectangular area, an off state is output. In the on state, the selector 15 writes image data from the image input device into the image memory 16. The written image data is sent to the display device, and at the same time, it passes through the writer 13 and is written into the transmission buffer 11 when the output of the position detection means 10a is in the ON state. As a result, the image input data is written within the set rectangular area of the image memory 16, and at the same time, the image input data is also written to the transmission buffer 11. The contents of the transmission buffer 11 are sequentially transmitted via the communication line.

Next, the reception operation will be explained. To receive the image, first set the rectangular area using parameters XI, Yl +
ΔX plate and ΔY1 are set in the position detection means lOb based on communication with the transmitting side. Image data received via the communication line is stored in the reception buffer 12. Reading the image data from the reception buffer 12 to the image memory 16 is performed in exactly the same manner as the operation of writing the image data from the image input device to the rectangular area described above. That is, the position detecting means 10b outputs an ON state when the image data written from the receiving buffer 12 to the image memory 16 falls within a rectangular area based on the CLK signal and the horizontal synchronizing signal H, and outputs an OFF state when outside the rectangular area. When the output of the position detection means 10b turns on, the reader 14 reads the received data from the reception buffer 12 as image data,
The selector 15 writes the image data from the reader 14 into the image memory 16. The written image data is sent to a display device.

When both position detection means 10a and 10b are in the off state, the selector 15 writes the read contents of the image memory 16a as they are into the image memory 16a, and the contents of the image memory are retained and are displayed only in the transmission/reception area on the screen. It will be updated.

Through the above-described transmission and reception operations, if the data sent on the receiving side can be read within the frame period, images can be continuously sent.

Furthermore, as is clear from the above explanation, since the image data transmitting circuit and the image data receiving circuit can operate in parallel, two rectangular windows can be opened on one screen as shown in Fig. 2, and each can be operated separately. It is possible to receive and display one image.

In addition, even if the transmission speed of the communication line is slow, the reception buffer 12 is configured with two sets of buffers of the size of the image memory, and the buffer that has finished receiving the image data of one rectangular area transfers the image data to the image memory. The frames are automatically thinned out by supplying the first image data and storing the next image data on the other side, so that even a line with a slow transmission speed can be used for image transmission according to the present invention.

FIG. 3 shows an example of a terminal device used in an embodiment of a transmission method for displaying images from multiple points on a single screen. This terminal device corresponds to a case where it has two image data transmitting circuits and two image data receiving circuits. In the figure, 30a
, 30b, 30c, 30d are position detection means, 31a
, 31b are sending buffers, 32a, 32b are receiving buffers, 33a, 33b are writers, 34a1
34b is a reader, 35 is a selector, and 36 is an image memory. If the communication line has a broadcast function between at least three parties,
One of the image data transmission circuits sends the image of the own terminal device,
By receiving images from two points with two image data receiving circuits, images A, B, and C of three points A terminal device, B terminal device, and C terminal device are divided into respective rectangular areas as shown in Fig. 4. They can now be displayed simultaneously, making it possible to conduct multipoint video conferences on a single screen.

Although the above explanation does not mention image band compression, image band compression is performed by adding an encoder to the image data transmitting circuit and a decoder to the image data receiving circuit. Of course, transmission is also possible.

This embodiment deals with the case of moving images, but it can also be used for still images by transmitting and receiving them frame by frame using a pair of image data transmitting and receiving circuits, and by sequentially transmitting and receiving data for multiple areas. I can handle it.

〔Effect of the invention〕

By using the image transmission method of the present invention, it is possible to display multiple images simultaneously on a single display device, which enables services using multiple videos, services that mix still images and videos, and multi-point services. This makes it possible to implement conference services between

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating an embodiment of the image transmission method of the present invention, FIG. 2 is a diagram showing a rectangular area on the screen in the embodiment of FIG. 1, and FIG. 3 is another embodiment of the present invention. 4 is a diagram showing a rectangular area on the screen of each terminal device in the embodiment of FIG. 3, and FIG. 5 is a diagram illustrating a conventional image transmission method.
) is an overall configuration diagram, and (b) is a diagram showing an image displayed on a terminal device. 10a, 10b... position detection means 11...
...Send buffer 12...Receive (t buffer 13...
・ ・ ・ ・ ・Exporter 14・・・・・・・・・
Reader 15...Selector

Claims (1)

[Claims] (1) In an image transmission method that transmits and receives image data of multiple moving images and/or still images between image memories, the transmitting side transmits multiple rectangular areas of any size that do not overlap with each other on the screen. The image data within the rectangular area to be sent is sent within the frame period of the image memory on the sending side, and the image data that has been sent is sent to the image memory on the receiving side within the frame period of the receiving memory on the receiving side. An image transmission method characterized by transmitting a plurality of images by reading and holding them within a rectangular area.