JPH0244983A - Moving picture transmitter - Google Patents

Abstract

PURPOSE:To display an excellent picture in response to the size of a television monitor screen by giving the priority over picture quality when a large television screen is employed and giving priority over the movement when a small screen is used. CONSTITUTION:A condition of a frame transmission speed (from omission) to decide the quantity of picture data in one frame and its movement which are determinant of picture quality is set by a reception condition setting device 7 and when its own station is provided with a large sized monitor 2a, the reception condition setting device 7a sets the condition of picture quality priority in response to the large sized monitor 2a. Moreover, a reception condition setting device 7b sets the condition giving priority over the movement accordingly since a small sized monitor 2a is provided. Thus, even if the size of the screen of the television monitor differs from its own station and the opposite station, the quality of picture is not deteriorated in any of both the stations.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a moving image transmission device, and particularly to a moving image transmission device configured to compress and efficiently transmit moving image data in videophones, video conferences, etc. It is something.

[Prior Art] In image transmission performed via videophone or video conference,
Although the amount of image information is huge, there is a limit to the line speed during transmission, and there is also a need to reduce transmission costs, so compression encoding is used to reduce the amount of image information to be transmitted. ing.

Figure 2 shows a schematic configuration of a transmission device that performs compression encoding.
In the figure, (1a) is a TV camera on the local station side that takes the transmitted image, (2a) is a large monitor that shows the transmitted image of the other station, and (3a) is the TV camera from the TV camera (1a). an encoder that compresses and encodes transmitted image data by dropping frames, etc., (4a) an image quality setting device that sets image quality, (5a) a decoder that decodes an image signal transmitted from the other station, (6) is a transmission line such as a public line, and a transmission device (100a) is constituted by an encoder (3a), an image quality setting device (4a), and a decoder (5a).

Further, the above-mentioned configuration is similarly provided for the other station, where (1b) is a television camera on the other side, and (2b) is a monitor of the other station, which is, for example, a small monitor. (3b) is an encoder that compresses and encodes the image data of the other station; (4b)
) is an image quality setting device, and (5b) is a decoder that decodes image data transmitted from the local station.

Next, the operation will be explained. Your station's TV camera (1
The image photographed in a) is converted into encoded data by an encoder (3a). In this case, the image data amount for one frame is set by the image quality setting device (4a).

In compression encoding transmission, transmission information is compressed by reducing the number of frames (frame transmission rate) per unit time (second) obtained by the television camera (1a) using a technique called frame dropping.

Therefore, the set amount of image data is set in consideration of the number of frames per unit time after frame dropping, so that the image quality is acceptable on a standard television monitor.

In this way, when compressed encoded data is transmitted from the encoder (3a) to the transmission device (]0Ob) of the other station via the transmission line (6), the encoded data is decoded. The signal is converted into an image signal by the receiver (5b), and a self-portrait photographed by the television camera (1a) of the local station is displayed on the small monitor (2b) of the other station. Similarly, an image of the other party is displayed on the large monitor (2b) on the own side.

[Problem to be solved by the invention] However, in the conventional transmission device, the image quality setting device (4)
Since the settings are fixed, there was a problem that if the TV monitor screen sizes of the local station and the other station were different, the image quality of one of the stations would deteriorate.

In other words, in the conventional example, when the image quality is adjusted to match the screen of a standard TV monitor, or when the other station's small monitor (2
In the case of adjusting to the screen of b), the image quality will be degraded on the large monitor (2a) of the local station. Since the local station transmitting image data does not know the size of the other station's TV monitor screen, the only way to set the image quality is to match the size of the local station's monitor screen. Differences in size cause differences in image quality.

On the other hand, if the image quality is to match the screen of a standard TV monitor, or if it is to match the screen of a large monitor at the local station, the image quality will be higher on the small monitor of the other station, or the transmission equipment that performs compression encoding. This also results in the transmission of useless information. Therefore, in this case, it is preferable to perform image transmission with priority given to motion, and there is a problem that a means for transmitting information according to the size of the television monitor screen should be considered.

This invention has been made to solve this problem, and is capable of transmitting image data according to the size of the television monitor screen provided in each of the local station and the partner station. The purpose is to provide transmission equipment.

[Means for Solving the Problems] A moving image transmission device according to the present invention includes a reception condition setter, (=l adding circuit, decoding circuit, and transmission condition setting device), which has an encoder and a decoder. The reception condition setter sets reception conditions regarding image quality and motion according to the size of the TV screen of the local station, and the reception circuit converts the reception conditions of the reception condition setter into transmission data. The decoding circuit decodes the reception conditions of the other station based on the transmission data transmitted from the other station, and the transmission condition setter encodes the reception conditions of the other station based on the reception conditions of the other station obtained by the decoding circuit. It is characterized by setting the amount of image data for one frame and the frame transmission speed output from the device, so that when the TV screen is large, priority is given to image quality, and when the TV screen is small, priority is given to motion. .

[Operation] According to the above configuration, each station either sets reception conditions according to the size of its own TV monitor, or stations equipped with large monitors set reception conditions that give priority to image quality. For stations equipped with small monitors, set conditions that give priority to movement.

The set reception conditions are then incorporated into the transmission data and sent to the other station, but the other station reads the reception conditions of its own station and, according to these conditions, transmits the one-frame image data required by the encoder. Transmission conditions regarding the amount and frame transmission rate will be set.

Therefore, the other station will transmit encoded image data that corresponds to the size of its own TV monitor. In this case, the own station can receive data that gives priority to motion, and it becomes possible to obtain a good image according to the size of the TV monitor screen.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a circuit configuration of a moving image transmission device according to the present invention, and a case where information is transmitted between two stations will be described. In the figure, except for (4), circuits (1) to (6) are the same as the conventional circuits, and (7a),
(7b) is a reception condition setter for setting reception conditions regarding image quality and motion; (8a) and (8b) are additional circuits for adding reception conditions to data sent from the encoder (3); 9a) and (9b) are decoding circuits that decode the reception conditions from the transmission pigs transmitted from other stations;
(10a) and (10b) are transmission condition setters that set transmission conditions to match the reception conditions of other stations decoded by the decoding circuit (9).

The reception condition setting device (7) is a device for determining image quality.
Conditions for frame transmission speed (shaving) are set to determine the amount and movement of image data in a frame, and if your station is equipped with a large monitor (2a), use the reception condition setting device (7a). Now, conditions for prioritizing image quality are set according to the large monitor (2a). For example, if the frame transmission rate on a standard TV monitor is about 10 frames/see,
Set the frame transmission rate to about 6 frames/see, and
The amount of image data in a frame is increased according to the reduced transmission speed. Furthermore, since the reception condition setter (7b) of the partner station is equipped with a small monitor (2a), conditions for giving priority to movement are set accordingly.

For example, the frame transmission rate is set to about 14 images/see, and the amount of image data in one frame is reduced in accordance with the increased transmission rate.

These reception conditions are set at the own station according to the size of the own station's TV monitor, so it can be done without any problems even when communicating with an unspecified partner station using a public digital line. .

The embodiment consists of the following two configurations, and their functions will be explained below.

First, in the case of a videophone call, the image data of the self-portrait taken with the TV camera (1a) is transmitted to the transmission device (
100a), and the image data is converted into compressed encoded data by an encoder (3a).

Then, in the reception condition setting device (7a), the large monitor (2
According to a), a reception condition is set in which the transmission rate is about 6 images/see and the amount of image data for one frame is large, and this reception condition is applied to the transmission data output from the encoder (3a). Added.

The data sent from the transmission device (100a) of the local station is sent to the transmission device (100b) of the other station via the transmission line (6).
), the decoding circuit (9b) separates and decodes the reception conditions of the local station, and the reception conditions are supplied to the transmission condition setter (10b). In this transmission condition setter (10b), based on the reception condition, the transmission condition is set to increase the transmission rate by about 6 images/sec and the amount of image data for one frame. The encoder (3b) outputs encoded image data suitable for the large monitor (2a) to its own station.

Therefore, since the transmission device (100a) on the local side receives the encoded image data and decodes it using the decoder (5a), the large monitor (2a) can see the movement, although the movement is gradual. A high-quality image will be displayed.

On the other hand, the reception condition setter (7b) of the other station uses a transmission rate of about 14 frames/see, depending on the small monitor (2b).
A reception condition that reduces the amount of image data for one frame is set, and this reception condition is added to the transmission data output from the encoder (3b).

Then, in the same operation as in the above case, the transmission condition setter (10a) on the local station side sets the transmission rate to 14 frames/sec.
At about e, a condition is set in which the amount of image overlap in one frame is reduced, and only image data giving priority to motion is transmitted. Therefore, an image of good quality and movement is displayed on the small monitor (2b) of the partner station.

[Effects of the Invention] As explained above, according to the present invention, by setting the reception conditions at the own station according to the size of the TV monitor screen of the own station, the conditions for transmitting image data at the other station can be determined. As a result, encoded image data can be transmitted according to the TV monitors equipped at each station, and images with good quality can be transmitted on large monitors, and images with good quality and movement can be transmitted on small monitors. It is possible to obtain it.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing the configuration of a moving image transmission device according to the present invention, and FIG. 2 is a circuit block diagram showing the configuration of a conventional transmission device. In the figure, (1) is a television camera, (3) is an encoder, (5) is a decoder, (6) is a transmission line, (7) is a reception condition setting device, (8) is an additional circuit, ( 9) is the decoding circuit, (
10) is a transmission condition setting device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent: Masuo Oiwa, patent attorney (and 2 others)

Claims (1)

[Claims] It has an encoder that encodes image information from the local station and sends it to the other station, and a decoder that decodes the received coded image data of the other station, and uses a digital line to generate video. A video transmission device that transmits images includes a reception condition setter that sets reception conditions regarding image quality and motion according to the size of the own station's TV screen, and a reception condition setting device that converts the reception conditions of this reception condition setting device into transmission data. an additional circuit for adding data, a decoding circuit that decodes the reception conditions of the other station based on the transmission data transmitted from the other station, and an encoder on the local station side based on the reception conditions of the other station obtained by this decoding circuit. A transmission condition setting device is provided to set the amount of image data for one frame and the frame transmission speed output from the system, so that when the TV screen is large, priority is given to image quality, and when the TV screen is small, priority is given to motion. A moving image transmission device characterized by: