JP3122445B2 - Communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a communication device for transmitting and receiving an image using a digital communication line as a transmission medium.

<Prior Art> Conventionally, there is a videophone device as such a communication device as shown in FIG.

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 that processes image information and various control information, 25 is an operation unit, and 6 is a display unit. A memory 7, a D / A converter, 8 a display unit for displaying an image in the display memory 6, 9 an imaging unit for capturing an image, 10 an A / D converter, 11 a capture memory, 21 Denotes a digital communication line, and 22 denotes a line terminating device (hereinafter abbreviated as “DSU”).

Next, the operation will be described. An image such as a human image captured 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 in 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 conforming to the transmission speed of the digital communication line and sends the serial data to the line interface unit 1.
The data is transmitted to the partner terminal via the DSU 22 and the digital communication line 21.

Assuming that the partner terminal is a videophone having the same configuration as the present apparatus, the partner terminal receives image data from the DSU 22 at the data transmission unit 23 via the line interface unit 1.
The data transmission unit 23 extracts the image data from the serial data and sends it to the data processing control unit 24. Data processing control unit
At 24, image data is decoded and converted 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.

<Problems to be Solved by the Invention> However, in the above-described conventional videophone device, first, a screen standard of an image to be transmitted between users is negotiated, and after each user starts image communication, each user is transmitting. It was not possible to arbitrarily change the screen standard of the image or the screen standard of the image being received. The present invention has been made in view of such a point, and its purpose is not only to allow a user to arbitrarily change the screen standard of an image being transmitted to a partner user during image communication, but also to be transmitted from the partner user. It is an object of the present invention to provide a videophone device capable of arbitrarily remotely controlling the screen standard of an incoming image.

<Means for Solving the Problems> In order to achieve the above object, according to claim 1 of the present invention, in a communication device for transmitting a digital video signal between a plurality of devices, a digital video signal being transmitted is Means for instructing a change in the number of horizontal and vertical pixels; means for converting an input image into digital video compression information for transmission according to the instructed change in the number of horizontal and vertical pixels; Means for inserting control information indicating the changed number of horizontal and vertical pixels between the moving image frames, when the number of horizontal or vertical pixels of the digital video signal is changed between adjacent moving image frames in the information; Means for transmitting digital video compression information in which control information is inserted, thereby solving the above-mentioned problem.

According to a second aspect of the present invention, in a communication device for transmitting a digital video signal between a plurality of devices, a means for receiving digital video compression information, and a method for transmitting a digital video signal between adjacent video frames in the received digital video compression information. Means for obtaining control information, which is inserted between the moving image frames and indicating the changed number of horizontal and vertical pixels, when the number of horizontal or vertical pixels of the digital video signal is changed, and Means for reproducing information in accordance with the number of horizontal and vertical pixels indicated by the control information.

<Example> Hereinafter, the present invention will be described in detail with reference to an illustrated example.

FIG. 1 is a block diagram showing the circuit configuration of the video telephone of the present embodiment. The control information processor 12 is added to the conventional video telephone shown in FIG. 24, the operation unit 25 is improved.

Here, the control information processing unit 12 functions to issue an instruction to the data processing control unit 4 in accordance with the screen standard selection input input from the operation unit 5 or the control information received via the data transmission unit 4. It has a function of outputting 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 together with the image data to the other user, and to output the control information transmitted from the other user to the control information processing unit 12.

The operation of the videophone device of the present invention will be described. Imaging unit 9
An image such as a human image photographed in the step 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 in 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. The data transmission unit 2 converts the image data or the control information of the screen standard into serial data conforming to the transmission speed of the digital communication line and sends the serial data to the line interface unit 1.
1 to the other terminal.

The partner terminal receives the image data from the DSU 22 at the data transmission unit 2 via the line interface unit 1. The data transmission unit 2 extracts image data from the serial data and sends it to the data processing unit 4. Similarly, it extracts control information of the screen standard and sends it to the control information processing unit 12. The control information processing unit 12 outputs control information of the screen standard to the data processing control unit 4. The data processing control unit 4 performs a decoding process on the image data according to the control information to convert the image data 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, the screen standard of the image to be transmitted is 3
Available in different types. 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.
The standard mode has 256 (H) × 240 (V) pixels, and the high-speed mode has 128 (H) × 120 (V) pixels. The number of gradations is the same for all three modes, and the luminance signal and the color difference signal have 256 gradations. FIG. 2 shows the transmission format of the control information of the screen standard. The control information on the screen is coded in the control information field shown in FIG. 2 and sent to the partner device. FIG. 2 (a) shows a case where only control information is transmitted.
FIG. 2 (b) shows a case where the image data is transmitted together with the image data. When a certain device user changes the screen standard of the 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 an image compression process conforming to the screen standard in the data processing control unit 4 in accordance with an instruction of the control information processing unit 12, converted into image data, and transmitted to the data transmission unit 2. The data transmission unit 2 multiplexes only control information as shown in FIG. 2A or control information of a screen standard on the image data being transmitted as shown in FIG. To be transmitted.

On the other hand, if the user wants to change the screen standard of the image being received from the partner user, a switching signal is input to the control information processing unit 12 by pressing a button on the operation unit 5 and the data is transmitted via the data transmission unit 2 in FIG. The control information alone is multiplexed 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.
The partner user device that has received the control information is the control information processing unit 12
Then, an instruction is issued to the data processing control unit 4 according to the control information. Image compression processing is performed according to the instruction, and the image data is converted into image data. The method of transmitting the image data is the same as the method of transmitting the image data to the above-mentioned user, and thus the description is omitted here.

Next, the data transmission unit will be described. FIG. 3 shows a block diagram of the data transmission unit 2. Here, 31 is a serial interface circuit (hereinafter referred to as “SI / F”) for converting an information channel signal transmitted and received via a digital communication line into parallel data, and conversely, converting parallel data into an information channel signal. ). The SI / F 31 is supplied with a clock signal from the line interface unit 1. 32 is a CPU for controlling the entire data transmission unit. 34 is random access memory (hereinafter "RAM")
, 35 is a read-only memory (hereinafter referred to as “RO
M ”). 36 is a data processing controller 4 and CPU
A parallel interface (hereinafter abbreviated as “PI / F”) for exchanging data with the control 32 is an interface 33 for exchanging control information between the control information processing unit 12 and the CPU 32 (hereinafter referred to as “PI / F”). Then, it is abbreviated as "I / F".)
It is.

Data received 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, the image data from the data processing control unit 4 is PI / F36
Is loaded into the RAM 34 via the. 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 fetched into the RAM 34 are multiplexed, converted into information channel signals via the SI / F 31, sent to the line interface unit 1, and transmitted to the other party's terminal, ie, the videophone device.

In this way, by transmitting and receiving control information of the screen standard of the image between the users during the image communication, not only the user can arbitrarily change the screen standard of the image being transmitted to the other user during the image communication but also the other party. A videophone device capable of arbitrarily changing the screen standard of an image sent from a user can be provided.

<Effect of the Invention> The user can arbitrarily change the number of screen pixels of an image to be transmitted to a partner during image communication according to the type of image to be transmitted, the device of the partner, and the like.

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

Furthermore, since control information is added only to positions where the number of screen pixels changes in continuous moving images, the overall transmission amount is prevented from increasing, and the number of pixels is changed on the receiving side from the immediately preceding frame. The decoding process can be performed without determining whether or not the decoding has been performed, and the processing load at the time of decoding can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a videophone apparatus according to an embodiment of the present invention, FIG. 2 is a diagram for explaining a control signal transmission format in the above embodiment, and FIG. 3 is a data transmission in the above embodiment. FIG. 4 is a block diagram showing a circuit configuration of a unit, and FIG. 4 is a diagram showing a circuit configuration of a conventional videophone device. 1 ... line interface unit, 2 ... data transmission unit, 3
... Phone section, 4 ... Data processing control section, 5 ... Operation section,
21 ... Digital communication line, 22 ... DSU.

Claims (2)

(57) [Claims] 1. A communication device for transmitting a digital video signal between a plurality of devices, comprising: means for instructing a digital video signal being transmitted to change the number of horizontal and vertical pixels; Depending on the number of horizontal and vertical pixels of
Means for converting the input image into digital video compression information for transmission; and when the number of horizontal or vertical pixels of the digital video signal is changed between adjacent video frames in the digital video compression information, A communication apparatus comprising: means for inserting control information indicating the number of horizontal and vertical pixels after the change; and means for transmitting digital video compression information into which the control information has been inserted. 2. A communication device for transmitting a digital video signal between a plurality of devices, comprising: means for receiving digital video compression information; and transmitting a digital video signal between adjacent moving image frames in the received digital video compression information. Means for obtaining, when the number of horizontal or vertical pixels is changed, control information indicating the changed number of horizontal and vertical pixels, which is inserted between the moving image frames; Means for reproducing in accordance with the number of horizontal and vertical pixels indicated by the information.