JP3618741B2 - Communication device - Google Patents

Description

  The present invention relates to a communication apparatus that transmits and receives an image using a communication line as a transmission medium.

  Conventionally, there is a videophone apparatus as shown in FIG. 4 as such a communication apparatus.

  1 is a line interface unit for connecting to a digital communication line, 23 is a data transmission unit, 3 is a telephone unit, 24 is a data processing control unit for processing image information and various control information, 25 is an operation unit, and 6 is for display Memory, 7 is a D / A converter, 8 is a display unit for displaying an image of the display memory 6, 9 is an imaging unit for capturing an image, 10 is an A / D converter, 11 is a memory for capture, 21 Is a digital communication line, and 22 is a line terminator (hereinafter abbreviated as “DSU”).

  Next, the operation will be described. An image such as a human image taken by the imaging unit 9 is converted into a digital video signal by the A / D converter 10 and stored in the capture memory 11. The digital video signal stored in the capture memory 11 is subjected to image compression processing by the data processing control unit 24, converted into image data, and sent to the data transmission unit 23. The data transmission unit 23 converts the image data into serial data that matches the transmission speed of the digital communication line, sends it to the line interface unit 1, and sends it to the partner terminal via the DSU 22 and the digital communication line 21.

  If the partner terminal is a videophone having the same configuration as this apparatus, the partner terminal receives the image data from the DSU 22 by the data transmission unit 23 via the line interface unit 1. The data transmission unit 23 extracts image data from the serial data and sends it to the data processing control unit 24. The data processing control unit 24 decodes the image data and converts it into a digital video signal. This digital video signal is stored in the display memory 6, converted into an analog video signal by the D / A converter 7, and displayed on the display unit 8.

  However, in the above-described conventional apparatus, first, after determining the screen standard of images transmitted between users and starting image communication, the screen standard of the image being transmitted by each user or the screen of the image being received by each user. The standard could not be changed arbitrarily.

  The present invention has been made in view of such a point, and the object thereof is not only that the user arbitrarily changes the screen standard of the image being transmitted to the other user during image communication, but also that the user sends the image to the other user. An object of the present invention is to provide a videophone device capable of arbitrarily remotely controlling the screen standard of incoming images.

  The communication device according to the present invention is a communication device for transmitting digital video signals between a plurality of devices, interface means for receiving the transmitted digital video signals, and control information indicating the number of horizontal and vertical pixels of the screen, Means for obtaining from the control information field not including image data of the received digital video signal; a data processing control unit for decoding the received digital video signal using the obtained control information; A memory for storing a video signal; and when the control information is changed, the data processing control unit decodes the digital video signal according to the changed control information received separately from the image data. Features.

  Since the communication apparatus of the present invention is configured as described above, the user can arbitrarily change the number of screen pixels of an image transmitted to the other party during image communication according to the type of image to be transmitted, the other party's apparatus, and the like. .

  In addition, it is possible to capture the number of screen pixels of images that are transmitted to each other on the transmission side and the reception side, and after exchanging control information, there is no need to transmit data. Therefore, data can be transmitted without waiting for a response on the receiving side in the control of broadcasting that is one-to-many transmission.

  In addition, control information is added only to the position where the number of screen pixels is variable in successive moving images, preventing an increase in the total transmission amount and changing the number of pixels from the previous frame on the receiving side. It is possible to perform a decoding process without determining whether or not it has been performed, and it is possible to reduce the processing load during decoding.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a block diagram showing the circuit configuration of the videophone apparatus of this embodiment. A control information processing unit 12 is added to the conventional videophone apparatus shown in FIG. 4, and a data transmission unit 23, a data processing control unit 24, The operation unit 25 is improved.

  Here, the control information processing unit 12 outputs an instruction to the data processing control unit 4 according to the screen standard selection input input from the operation unit 5 or the control information received through the data transmission unit 2, and from the operation unit 5 It functions to output control information according to the input screen standard selection input to the data transmission unit 2.

  The data transmission unit 2 functions to transmit the control information input from the control information processing unit 12 to the counterpart user together with the image data, or to output the control information transmitted from the counterpart user to the control information processing unit 12.

  The operation of the apparatus of the present invention will be described. An image such as a human image taken by the imaging unit 9 is converted into a digital video signal by the A / D converter 10 and stored in the capture memory 11. The digital video signal stored in the capture memory 11 is subjected to image compression processing by the data processing control unit 4 according to an instruction from the control information processing unit 12, converted into image data, and sent to the data transmission unit 2.

  The data transmission unit 2 converts image data or screen standard control information into serial data that matches the transmission speed of the digital communication line, sends it to the line interface unit 1, and sends it to the partner terminal via the DSU 22 and the digital communication line 21. .

  The counterpart terminal receives the image data from the DSU 22 at the data transmission unit 2 via the line interface unit 1. In the data transmission unit 2, image data is extracted from the serial data and sent to the data processing unit 4. Similarly, the screen standard control information is extracted and sent to the control information processing unit 12. The control information processing unit 12 outputs screen standard control information to the data processing control unit 4.

  The data processing control unit 4 decodes the image data in accordance with the control information and converts it into a digital video signal. This digital video signal is stored in the display memory 6, converted into an analog video signal by the D / A converter 7, and displayed on the display unit 8.

  In one embodiment of the present invention, three types of screen standards for images to be transmitted are prepared. The number of pixels in the horizontal direction (hereinafter abbreviated as “H”) and vertical direction (hereinafter abbreviated as “V”) of each screen standard is 512 (H) × 480 (V) pixels in the high resolution mode, and 256 (in the standard mode). H) × 240 (V) pixels, and in the high-speed mode, 128 (H) × 120 (V) pixels. The number of gradations is the same in all three modes, and both the luminance signal and the color difference signal have 256 gradations.

  A transmission format of the control information of the screen standard is shown in FIG. The control information on the screen is coded in the control information field shown in FIG. 2 and sent to the partner apparatus. FIG. 2A shows a case where only control information is transmitted, and FIG. 2B shows a case where the control information is transmitted together with image data.

  When a screen user changes the screen standard of an image being transmitted, a switching signal is input to the control information processing unit 12 by pressing a button on the operation unit 5. The video signal to be transmitted is subjected to image compression according to the screen standard by the data processing control unit 4 in accordance with an instruction from the control information processing unit 12, converted into image data, and sent to the data transmission unit 2.

  In the data transmission unit 2, only the control information as shown in FIG. 2A or the control information of the screen standard is multiplexed with the image data being transmitted as shown in FIG. To do.

  On the other hand, when it is desired to change the screen standard of the image being received from the other user, a switching signal is input to the control information processing unit 12 by pressing a button on the operation unit 5, and FIG. Only the control information as shown in a) or the control information of the screen standard is multiplexed with the image data being transmitted as shown in FIG.

  The counterpart user apparatus that has received the control information issues an instruction from the control information processing unit 12 to the data processing control unit 4 according to the control information. In accordance with the instruction, image compression processing is performed and converted into image data. The method for sending image data is the same as that for sending image data to the other user, and is omitted here.

  Next, the data transmission unit will be described. FIG. 3 shows a block diagram of the data transmission unit 2. Reference numeral 31 denotes a serial interface circuit (hereinafter referred to as “SI / F”) for converting information channel signals transmitted / received via a digital communication line into parallel data, or conversely converting parallel data into information channel signals. Abbreviated). A clock signal is given to the SI / F 31 from the line interface unit 1.

  Reference numeral 32 denotes a CPU for controlling the entire data transmission unit. Reference numeral 34 denotes a random access memory (hereinafter abbreviated as “RAM”), and reference numeral 35 denotes a read-only memory (hereinafter abbreviated as “ROM”). Reference numeral 36 denotes a parallel interface (hereinafter abbreviated as “PI / F”) for exchanging data between the data processing control unit 4 and the CPU 32, and 33 denotes control information between the control information processing unit 12 and the CPU 32. Is an interface (hereinafter abbreviated as “I / F”).

  Received data from the videophone device as the partner terminal is received by the SI / F 31 from the line interface unit 1 and temporarily stored in the RAM 34 by the CPU 32. Among the data stored in the RAM 34, the image data is sent to the data control unit 4 via the PI / F 36, and the control information is sent to the data control unit 4 via the I / F 36.

  On the other hand, image data from the data processing control unit 4 is taken into the RAM 34 via the PI / F 36. Further, the control information is taken into the RAM 34 from the control information processing unit 12 via the I / F 33. The image data and control information captured in the RAM 34 are multiplexed, converted into information channel signals via the SI / F 31, and sent to the line interface unit 1, where they are transmitted to the videophone device that is the counterpart terminal.

  In this way, the user can not only arbitrarily change the screen standard of the image being transmitted to the other user during the image communication by transmitting and receiving the control information of the screen standard between the users during the image communication. It is possible to provide an apparatus that can arbitrarily change the screen standard of an image sent from a partner user.

It is a block diagram which shows the circuit structure of the video telephone apparatus of one Example of this invention. It is explanatory drawing of the transmission format of the control signal in one Example of this invention. It is a block diagram which shows the circuit structure of the data transmission part in one Example of this invention. It is a figure which shows the circuit structure of the conventional videophone apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Line interface part 2 Data transmission part 3 Telephone part 4 Data processing control part 5 Operation part 21 Digital communication line 22 DSU

Claims (1)

In a communication device that transmits digital video signals between a plurality of devices,
Interface means for receiving the transmitted digital video signal;
Means for obtaining control information indicating the number of horizontal and vertical pixels of the screen from a control information field not including image data of the received digital video signal;
A data processing control unit for decoding the received digital video signal using the obtained control information;
A memory for storing the decoded digital video signal;
With
The data processing control unit, when the control information is changed, decodes a digital video signal according to the changed control information received separately from the image data.

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