JPH09261606A - Image transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously and clearly display images and characters by judging the start position and form of the character to be inserted on a screen, superimposing the start position and an input character code, transmitting them to an opposite party terminal equipment and separating font data corresponding to the input character code from image data there. SOLUTION: A controller 10 reads character font data stored in a ROM 11 based on the inputted character code and position code, judges the form and position of the character to be displayed and writes the data to a RAM 8. Simultaneously, the character code and an input start position code are outputted to a character encoder 12 and they are encoded together. Encoded character signals and encoded image signals outputted from the character encoder 12 and an image encoder 9 are multiplexed by a multiplex circuit 14 and sent out from an ISDN interface part 19 to an ISDN circuit network. In the meantime, on a reception side, signals from a transmission side are received in the ISDN interface part 19 and separated into the encoded image signals and the encoded character signals by a demultiplex circuit 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for encoding and transmitting an image signal, and more particularly to an image transmission system for simultaneously transmitting image information and character information.

[0002]

2. Description of the Related Art Conventionally, in this type of image transmission apparatus, when transmitting character information or the like and displaying it on the other side, the character information is superimposed on the image display screen. At this time, the image is coded uniformly regardless of whether or not the character is displayed, and the part that cannot be seen on the receiving side because the character is superimposed is also coded and transmitted.

[0003]

However, in the prior art, when the image signal is first converted into an analog signal and then the superimposing is performed, a special circuit for superimposing is required, and in the analog manner. Since the signals are combined, deterioration of the signals cannot be avoided, and it is difficult to obtain a clear combined image. On the other hand, when performing superimposing with a digital signal, prepare another storage device for storing character data in addition to the storage device for storing image data,
Furthermore, a circuit for synthesizing the data stored in these separate storage devices is required. In addition, since the sending side encodes and sends the image area that cannot be seen on the receiving side due to the superimposed characters, useless information must be sent at a limited sending rate. And the efficiency is getting worse.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and in an image transmission device for transmitting image data and the like to a partner terminal device via an ISDN line, a character to be inserted on the screen. The start position and the character format of the input character code are determined, the start position and the input character code are superimposed and transmitted to the other terminal device, and the other terminal device separates the font data and the image data corresponding to the input character code and is the same. And an image transmission device stored in the memory of the same.

[0005]

With the above-described structure, the transmission side and the clear character can be displayed on the same screen on the receiving side with a simple circuit structure, and even the partial image hidden by the displayed character can be displayed on the transmitting side. Since it is not necessary to perform coded transmission, it is possible to transmit information efficiently. Also, since the screen in which this image and characters are combined is stored once in the memory, if this stored signal is digitally recorded in a storage medium such as a hard disk, the combined information can be stored without deterioration of the signal. Is possible.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, on the image transmission side, an image is input from a television camera 1 and an A / D converter 7 outputs A / D (An
RAM (Random Access M)
stored in 8. The operator uses the mouse 2 to specify a character input start position on the screen, inputs a desired character using the keyboard 3, and inputs the character code to the control device 10 as a character code position code. The control device 10 reads the character font data stored in the ROM 11 based on the input character code and position code, determines the shape and position of the corresponding character to be actually displayed, and stores the data in the RAM 8 Export to. This allows the operator to input characters while confirming the characters he is inputting and the input position on the screen. The control device 10 also outputs the character code and the input start position code to the character encoder 12, and the encoder 12 encodes them together. Further, the control device 10 refers to the character font data stored in the ROM 11 to determine the size information of the character to be actually displayed corresponding to the input character, and matches it with the input position of the input character. By doing so, the area where characters are displayed on the screen is calculated, and the result is input to the image encoder 9. In the image encoder 9, the image stored in the RAM 8 is encoded by an encoding method that divides the screen into a plurality of small blocks and encodes each block as in ITU-T Recommendation H.261. To be done. For example, in the case of the H.261 recommendation, one image in CIF format is divided into multiple vertical 16
The pixel is divided into 392 macroblocks each having 16 pixels in the horizontal direction, and the encoding process is sequentially performed for each macroblock. Here, the image encoder 9 does not encode the image for the small blocks included in the character display area calculated by the control device 10 earlier, but only the other small blocks. The coded character signal and the coded image signal output from the character encoder 12 and the image encoder 9 are multiplexed by the multiplexing circuit 14.
ISDN from ISDN interface section 19
It is sent to the network. On the other hand, on the receiving side, the ISDN interface unit 19 receives the signal transmitted by the transmitting side from the network,
The separation circuit 15 separates the encoded image signal and the encoded character signal. The image decoder 18 decodes the coded image signal and stores the decoded image signal in the RAM 17. The encoded character signal is decoded by the character decoder 13 into a character code and an input start position code, and the control device 1
Input to 0. The control device 10 displays the character code at the position on the RAM 17 corresponding to the character input start position on the image.
While referring to the character font data stored in the ROM 11, the corresponding characters to be actually displayed are stored. The D / A converter 7 that combines the image signal and the character signal stored in the RAM 17 causes the D / A (Digital / Anal)
og) converted and displayed on the display 5. FIG. 2 shows how the image is actually displayed on the screen. The shaded area in the figure is 1
It is one small block. In this example, the operator on the sending side specifies the vicinity of the lower center of the screen as the character input start position and
I'm typing the word "Office."
The small block area of the column is used for character display. According to the second aspect of the present invention, the composite signal of the image signal and the character signal stored in the RAM 17 can be recorded in the hard disk device or output to the printer according to the instruction of the operator.

[0007]

As described above, according to the present invention, an image and a character can be clearly displayed on a display at the same time with a simple circuit configuration in an image transmission device. Further, by providing the character display position information to the image encoder, it is not necessary to encode the image of the portion hidden by the character, so that efficient image encoding transmission is possible.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a screen display example when the present invention is implemented.

[Explanation of symbols]

 1 TV camera 2 keyboard 3 mouse 4 hard disk 5 printer 6 display 7 A / D (Analog / Digital) converter 8 RAM (Random Access Memory) 9 image encoder 10 controller 11 ROM (Read Only Memory) 12 character encoder 13 Character Decoder 14 Multiplexing Circuit 15 Separation Circuit 16 D / A (Digital / Analog) Converter 17 RAM (Random Access Memory) 18 Image Decoder 19 ISDN Interface Section

Claims (1)

[Claims] 1. An image transmission device for transmitting image data and the like to a partner terminal device via an ISDN line, determines the start position and character format of a character to be inserted on the screen, and determines the start position, input character code and image. An image transmitting apparatus, wherein data is superimposed and transmitted to a partner terminal device, and font data and image data corresponding to the input character code are separated and stored in the same memory in the partner terminal device.