JPH0222987A - Image transmission equipment - Google Patents

Abstract

PURPOSE:To efficiently perform an encoding processing by eliminating a part related to background out of images obtained by a television camera from transmission data. CONSTITUTION:Picture data obtained by the television camera is supplied to a comparator 7, however, since the picture data of the background obtained by the television camera before transmission is supplied from a memory circuit 8 to the comparator 7, it is possible to recognize whether or not the picture data obtained by the television camera is the one of the background by comparing both picture data. And when it is the picture data of the background, the picture data is encoded to a background identification signal, then, transmitted. A reception side receiving the background identification signal decodes the picture data by taking out the picture data of the background received and stored in advance. Therefore, it is not required to apply the endoing processing on the image of the background. In such a way, the efficiency of a data processing can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image transmission device that transmits image data obtained by a television camera, and particularly to improvements in the content of the image data to be transmitted.

[Background Art] With the recent advances in various communication media and devices, video conference systems and devices that exchange not only audio but also images using communication lines are becoming popular. Such a video conference is a conference method in which conference rooms located at different locations are connected to each other by communication lines, and a plurality of participants participate. According to videoconferencing, efficient meetings can be held between remote locations without the need for mutual travel, such as business trips, and with the same communication of intentions and information as in regular meetings. Furthermore, since facial movements and the like can be ascertained even in one-on-one telephone calls rather than meetings, it is possible to convey intentions and information in a sophisticated manner.

[Problems to be Solved by the Invention] As described above, image transmission devices are used for video conferences, video calls, etc., but they do not take advantage of the characteristic that the background image in such cases hardly changes. However, there was a problem in that the encoding efficiency could not be improved.

This invention was made with the aim of solving the above-mentioned problems, and it identifies a background image from image data obtained by a television camera and encodes it into a background identification signal, thereby improving encoding efficiency. It is an object of the present invention to provide an image transmission device that can be improved.

[Means for Solving the Problems] An image transmission device according to the present invention stores image data about a background obtained by a television camera before transmission in a background memory, and also transmits it to a receiving side in advance to transmit it to a television. The image data obtained by the camera and the image data read from the background memory are supplied to a comparator, where they are compared, and among the input image data, the image data recognized as background by the comparator is It is characterized in that it is encoded into a background identification signal and transmitted.

[Operation] Image data obtained by the television camera is supplied to the comparator. This comparator is also supplied with image data about the background obtained by the television camera before transmission from the background memory. By comparing the two, it is recognized whether the image data obtained by the television camera is related to the background. If the image data is about a background, the image data is encoded into a background identification signal and transmitted. The receiving side that has received the background identification signal decodes it by locating the background image data that has been received and stored in advance.

Therefore, there is no need to encode the background image, so data processing can be made more efficient.

[Embodiment] Next, an image transmission device according to an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the overall configuration of an image transmission device according to an embodiment. In the figure, (1) is a television camera, (2) is a preprocessing circuit, (3) is a background identification insertion circuit,
(4) is an encoding circuit, (5) is a variable length encoding circuit, (6
) is the send buffer. In such a device, signals for images captured by a television camera (1) are supplied to a pre-processing circuit (2). The signal obtained by this television camera (1) is usually an analog video signal. Therefore, the preprocessing circuit (2) performs analog-to-digital conversion or performs predetermined sampling. The signal that has undergone such preprocessing is then supplied to the background identification and insertion circuit (3), where the background image is identified.

Here, the configuration of this background memory circuit (3) will be explained based on FIG. 2. Image data supplied from the preprocessing circuit (2) is first input to a comparator (7). This comparator (7) is for recognizing the ζ background image. That is, background recognition is performed by comparing data about the current image obtained by the television camera (1) inputted from the preprocessing circuit (2) with data about the background supplied from the background memory (8). conduct.

This comparison is performed by comparing data of each of a plurality of pixels constituting the image. That is, if the difference in data between two pixels to be compared falls within a predetermined range, that pixel is considered to be the background.

Here, the background memory circuit (8) must store an image corresponding to the background of the image currently being captured by the television camera (1).

In order to store image data regarding such a background in the background memory circuit (8), the background image may be automatically loaded, for example, when the main power of the image transmission device is turned on and the device is started up. A predetermined switch is provided, and when the switch is pressed, the image data obtained by the television camera (1) at that time is transferred to the background memory circuit (8).
It is also possible to store the information in . Furthermore, the background image data stored in the background memory circuit (8) is transmitted to the receiving side (destination station).

The result of comparison by the comparator (7) in this manner is outputted from the comparator (7) as a background identification signal S.

That is, among the image data obtained in the preprocessing step, data regarding pixels recognized as a background image is replaced with a background identification signal, and is input to the encoding circuit (4) together with the image data.

This encoding circuit (4) is supplied with a background identification signal S obtained by a comparator (7).

Therefore, the encoding circuit (4) can recognize pixels that are identified as the background image, and the encoding process can be omitted for this background image. Therefore, the encoding process in the encoding circuit can be simplified and encoding efficiency can be improved.

Note that an image that is identified as a background image in an encoding process such as interframe DPCM may be set as invalid data that is not a target of the encoding process. In this way, when the output signal from the background identification insertion circuit (3) is directly input to the encoding circuit (4) and the encoding process is performed here, the data regarding the background image is automatically encoded. excluded from the target. Therefore, this method also improves the efficiency of the encoding process. If the image data subjected to such processing is processed by the variable length encoding circuit (5), the image data for the background image can be substantially omitted, and the efficiency of the transmitted image can be improved.

Here, FIG. 3 shows a schematic configuration on the receiving side of this embodiment. That is, (11) is the receiving buffer,
(12) is a variable length decoding circuit, (13) is a decoding circuit,
(14) is a background insertion circuit, (15) is a post-processing circuit, (1
6) is a monitor.

The received image data is first stored in the reception buffer (1
1), from which it is supplied to the variable length decoding circuit (12). The background identification signal decoded in this variable length decoding circuit is sent to a decoding circuit and a background insertion circuit (14).
is supplied to The data subjected to variable length decoding by the variable length decoding circuit is then supplied to the decoding circuit, but in this decoding circuit (13), pixels identified as background by the background identification signal are decoded. excluded from the scope of The decoded image data is then supplied to the background insertion circuit (14). This background insertion circuit inserts a background image sent in advance from the transmitting side as image data into a portion designated by the background identification signal. That is, an insertion background memory (17) is connected to the background insertion circuit, and data regarding pixels identified as background in the variable length decoding circuit (12) is replaced with previously transmitted background image data. . The image data with the background screen inserted in this way is displayed on the monitor (16).

Here, a plurality of types of background images for insertion in the background insertion circuit (14) may be provided, or a predetermined white screen or the like may be provided.

In this embodiment, background identification is performed pixel by pixel.
A similar effect can be obtained by using multiple pixels (blocks).

[Effects of the Invention] As explained above, according to the image transmission device according to the present invention, it is possible to omit the background part of the image obtained by the television camera from the transmission data, thereby improving the efficiency of the encoding process. can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of an image transmission device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a detailed configuration of a background identification insertion circuit (3) in the same embodiment, and FIG. FIG. 2 is a block diagram showing a schematic configuration of the receiving side of the image transmission device in the same embodiment. In the figure, (1) is a television camera, (3) is a background identification insertion circuit, (7) is a comparator, and (8) is a background memory circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] An image transmission device that encodes and then transmits image data obtained by a television camera, comprising: a background memory that stores image data about a background obtained by the television camera as background data before transmission; A comparator which receives both the image data obtained by the television camera and the background data supplied from the background memory and performs background identification by comparing them; means for encoding image data recognized as such into a background identification signal and transmitting it without performing predetermined encoding processing; and means for transmitting background data stored in the background memory in advance, receiving and storing the background data. An image transmitting apparatus comprising: an insertion background memory for detecting the background; and means for receiving the background identification signal and reading and decoding a portion determined to be a background from the insertion background memory.