KR100194223B1 - Viewer-selective additional information display device and method - Google Patents

Abstract

The disclosed additional information display apparatus and method thereof include superimposing the additional information at the bottom of an image of a television broadcast signal when receiving a character code and a control code from a television receiver and displaying the additional information on a screen according to a viewer's selection. In addition, the additional information is displayed by scrolling and half-tone in the horizontal direction.

The present invention provides a system control unit for controlling the display of additional information according to an operation command of a command input unit; A tuner unit for receiving, demodulating and outputting a television broadcast signal of a selected channel; A video signal processing for outputting an rsb signal after outputting a luminance signal and color processing of the video signal outputted by the tuner unit and outputting a signal of a vertical blanking period; A first attenuator for attenuating the RGB signal output by the image signal processor; An analog / digital converter for converting a signal of the vertical blanking period output by the image processing unit into a digital signal; A sync separator for separating and outputting the vertical sync signal and the horizontal sync signal from the signal of the vertical blanking period output by the image signal processor; When the system control unit commands the display of the additional information, the subtitle control and additional unit detecting unit generates a clock signal synchronized with the color burst signal and generates additional information and subtitle control signals according to the output signal of the analog / digital converter. ; Font ROMs for storing and outputting fonts such as characters such as Korean, English, Chinese and Japanese, and special characters; First and second RAMs for storing and outputting fonts read from the font ROM under the control of the caption controller; A switching unit for selectively outputting an RGB signal output from the image signal processing unit or an output signal of the first attenuating unit according to a switching signal outputted by the subtitle control unit and the additional information detector; A second attenuator for attenuating additional information output by the caption control and additional information detector; A mixing unit mixing the output signals of the switching unit and the second attenuating unit; And a display driver for displaying the output signal of the mixing unit on the cathode ray tube so that the viewer inserts and displays the additional information such as weather forecast or emergency news at the bottom of the image according to the viewer's selection. It is possible to watch clear side information by not only disturbing the viewing of the display but also by scrolling the side information in the horizontal direction and displaying the brightness in halftones.

Description

Viewer-selective additional information display device and method

The present invention relates to a viewer-selective additional information display apparatus and a method thereof.

More specifically, a character code and a control code are transmitted to the television broadcast signal, and the television receiver receives the character code and the control code and displays the additional information on the screen according to the viewer's choice. The present invention relates to a viewer-selective additional information display apparatus and method for superimposing additional information and displaying the additional information in horizontal scroll and halftone.

In the television broadcasting method, the caption broadcasting method is not selected by the viewer, and the caption signal such as urgent news or notifications is superimposed on the active section of the television broadcast signal, that is, the video signal section, according to the broadcaster's selection. Open caption method to display on the screen, and subtitle contents such as character code and control code in non-active section of TV broadcasting signal, that is, horizontal blanking section Closed captioning system which transmits as a signal, receives a television broadcast signal carrying the caption signal from the television receiver, and displays the caption signal on the screen of the television receiver according to the viewer's selection so that the viewer can view it. have.

Among closed captioning methods, closed captioning closed captioning was developed for the hearing impaired without the sign language, and has been implemented since 1978 in the United States. .

US Pat. No. 5,294,982, published in March 1994, discloses a closed caption method of Roman and syllable characters, and specifically describes the closed caption method of Korean.

In US Pat. No. 5,294,982, in order to broadcast Korean in a closed caption method, each Hangul character is divided into phonemes of a consonant, a neutral, and a consonant to transmit an ASCII code corresponding to each phoneme, and the television receiver decodes the ASCII code. It is to display the Hangul characters of the initial, neutral, and final maps after mapping the initial, neutral, and final star to the screen of the television receiver.

In the conventional Korean closed captioning method, at least 2 to 3 bytes must be used to represent one Korean character.

That is, 2 bytes are used to display only Korean and neutral and no final support, and 3 bytes are used to display Korean, which has initial, neutral, and final characteristics.

Therefore, the decoding speed is very complicated because the transmission speed and display speed of the subtitle signal are slow, and the position of one Korean character must be found after converting the 2 to 3 bytes of data received in the decoding process into 3 to 4 bytes. .

The complexity of the decoding process is to increase the production cost of the decoder, which increases the price of the decoder in the television receiver used by many viewers as compared to the encoder required only by the broadcasting station, thereby putting a lot of economic burden on the user.

In addition, simultaneous display of Chinese characters, Korean, and Japanese, and simultaneous display of English, Russian, and Greek were impossible, and display of special symbols was impossible.

In addition, since the control code is required to display the dialogue information in the middle of displaying the supplementary information and display the supplementary information again, there is no independence between the dialogue information and the supplementary information, and a control system for distinguishing the display mode of the dialogue information. Is very complicated in transmission efficiency of the whole system, and if the display mode control code is not received at the time when the receiver starts to operate, the metabolic information cannot be displayed until the next control code is received.

In addition, the above-mentioned US Patent US Pat. No. 5,294,982 was developed based on the transmission environment of US television broadcasting, that is, the geographical environment with a lot of flat land, so in the geographical environment of Korea where the mountain area is 70% or more, the reception status of the receiving device is poor and The quality was poor, and it was not possible to simultaneously display the video, the dialogue subtitles, and additional information of the received television broadcast signal on one screen.

When the additional information is displayed, the additional information is displayed on the entire screen of the cathode ray tube or the screen of the cathode ray tube is divided into two, and the additional information is displayed on the entire screen of the divided one side.

The additional information is, for example, weather forecasts, emergency news, and the like, and this conventional display of such additional information on the entire screen or on one side of the screen has a problem of causing a lot of problems for viewers to watch the image of the television broadcast signal.

Accordingly, an object of the present invention is to superimpose the additional information on the bottom of the image of the television broadcast signal when the additional information is displayed on the screen according to the selection of the viewer, and to display the additional information on the screen and to horizontally scroll the additional information and to adjust the brightness to halftone The present invention provides a viewer-selective additional information display device and a method of adjusting and displaying the same.

In general, the caption information includes a character code consisting of two bytes for designating a plurality of predetermined commercial characters or a control code consisting of one byte for independently performing a caption control function.

Then, the character information or additional character information of the dialogue caption is input together with the control information, and the control information is generated by the control code of 2 bytes by combining the mode control bit and the parity bit, and the character information is combined with the mode control bit and parity bit. Combination occurs as a character code of a Hangul complete code, and the control code or character code is inputted and output as a digitally modulated caption signal, and the caption signal is loaded on a predetermined scan line of every field of the video signal.

The present invention provides a system control unit for controlling the display of additional information according to the operation command of the command input unit; A tuner unit for receiving, demodulating and outputting a television broadcast signal of a selected channel; An image signal processing unit which outputs an RGB signal and outputs a signal of a vertical blanking period after luminance and color processing the image signal output by the tuner; A first attenuator configured to attenuate the RGB signal output by the image signal processor; An analog / digital converter for converting a signal of a vertical blanking period output by the image signal processor; A sync separator for separating and outputting a vertical sync signal and a horizontal sync signal from a signal of a vertical blanking period output by the image signal processor; Subtitle control and addition unit for generating a clock signal synchronized with a color burst signal when the system control unit commands the display of the additional information, and generating additional information and a subtitle control signal according to an output signal of the analog / digital converter. Detector; A font room for storing and outputting fonts such as characters such as Korean, English, Chinese and Japanese, and special characters in advance; First and second RAMs for storing and outputting fonts read from the font room according to the subtitle control; A switching unit for selectively outputting an RGB signal output from the image signal processing unit or an output signal of the first attenuating unit according to a switching signal output by the caption control and additional information detection unit; A second attenuator configured to attenuate additional information output by the caption control and addition unit detectors; A mixing unit mixing the output signals of the switching unit and the second attenuating unit; And a display driving unit for displaying the output signal of the mixing unit on the cathode ray tube so that the viewer inserts and displays the additional information such as weather forecast or emergency news at the bottom of the image according to the viewer's selection. The additional information can be viewed clearly by not only disturbing the viewing of the video, but also by displaying the brightness in halftone while scrolling the additional information horizontally.

1 is a block diagram showing the configuration of a television broadcasting system for viewer-selective caption broadcasting according to the present invention.

2 is a block diagram showing the configuration of a viewer-selective additional information display device of the present invention.

3 is a diagram showing the configuration of a caption signal according to the present invention;

4 is a diagram showing a data packet structure of caption data according to the present invention;

5 is a signal flowchart for explaining a method of displaying additional information of the present invention.

6 is a diagram illustrating a state in which a predetermined image and stock price information is displayed on the screen of the television receiver according to the present invention as an example.

* Explanation of symbols for main parts of the drawings

100: antenna 110: tuner

140: Image signal processing unit 142, 144: First and second attenuator

145 switching unit 150 mixing unit

160: display drive unit 170: cathode ray tube

180: system control unit 190: command input unit

200: subtitle decoding unit 210: analog / digital converter

220: synchronous separator 230: subtitle control and additional information detection unit

240: font ROM 245, 250: first and second RAM

Hereinafter, a viewer-selective additional information display apparatus and method thereof of the present invention will be described in detail with reference to the accompanying drawings.

First, the configuration of the caption information used in the television system for transmitting and receiving the caption broadcast will be described.

In Korea, the NTSC-M system of 525 lines and 60 fields / sec is used as a television broadcast signal, and the vertical blanking period is specified from scan line 10 to scan line 20.

There is no standard set by the Ministry of Information and Communication on the use of signals during the vertical blanking period. References include ITU-R Recommendation Rec 473-2 and FCC Report and Order 83-120 in the United States.

The caption signal may use any one of the scan lines 10 to 20, the scan line 21, or the scan line 262 among the scan lines in the vertical blanking period for the transmission of the caption data. Can also be used.

However, in caption broadcasting, data transmission of the entire field is meaningless and is not considered.

The transmission bit rate of the subtitle data shall be 447,443.125 ± 125 bps, and the maximum change rate of the transmission bit rate shall be within ± 196 (± 0.0125 bps).

The closed caption data signal is used only for transmission of the color television broadcast signal, and the transmission bit rate is set to 1/8 of the color carrier frequency fsc (357,9545 ± 10 Hz), and must be frequency synchronized with the color burst signal.

It is preferable that the color carriers have a continuous phase between the scan line and the scan line, and if the phase of the color carriers is discontinuous due to screen editing or the like, at least phase synchronization should be performed on the color burst of the scan line.

In the data modulation scheme, the one corresponding to the logic value '1' is represented by one period of sinusoidal wave having a phase of 0 degrees and the frequency of fsc / 8 (447.443 KHz), and the one corresponding to the logic value '0' is phased. A digital modulation called BPSK (Binary Phase Shift Keying) or PRK (Phase Reversal Keying), which is 180 degrees and is represented by one cycle of sinusoids with a frequency of fsc / 8, requires a maximum range of phase jitter of ± 10 degrees. do.

The optimal signal waveform will be defined in the future as it may vary depending on the frequency spectrum characteristics of the television channel. However, due to the fundamental band-limiting frequency, the BPSK waveform can be severely distorted where logic transitions occur, so that the phase-corrected waveform is passed after passing through a second Butterworth filter with a cutoff frequency of 3.5 MHz. We will use it for broadcasting.

Here, the impulse response of the Butterworth filter used is as shown in Equation 1 below.

Where fc is 3.5 MHz.

Among the inspection items of radio stations, the inspection method and basis are defined in No. I-7 (television broadcasting station), item 4 (text broadcasting) or item (superposition of data line and amplitude of text signal), and the waveform of subtitle signal is NRZ ( None is not a return to zero, but a pure sine wave, so it is not necessary to apply the above criteria.

However, in areas with more than 70% of mountains, such as Korea, the maximum sine wave is 90 ± 5 IRE to widen the range of reception.

Although the maximum amplitude of the normal data signal is defined, the overshoot may be included due to the filter passband characteristic, so that the absolute value of the overshoot is 5 IRE.

As shown in FIG. 3, the data line of the caption signal is composed of a six-cycle bit clock synchronizing signal 302, a word start number 304, and an 18-bit data string 306. As shown in FIG.

The bit clock synchronizing signal 302 is a 6-period sinusoidal signal that can be used to extract the sinusoidal signal from the subtitle decoding unit to read a bit period of 18-bit data. The frequency of the bit clock synchronizing signal 302 is fsc / 4 (894.886 KHz).

The bit clock synchronizing signal 302 is separated by 9.50 µsec (34 color bursts) from the midpoint OH of the falling edge of the horizontal synchronizing signal when the phase of the color carrier of the scan line is 0 degrees. If the phase of the color carrier of the scan line is 180 degrees, it starts at a point separated by 9.64 secsec (color burst 34.5 cycles) from the midpoint OH of the falling edge of the horizontal synchronization signal.

Since the bit clock synchronizing signal 302 is in frequency synchronization with the color burst of the corresponding line, the bit clock synchronizing signal 302 may be extracted from the color burst.

The word start signal 304 is a sinusoidal signal of one cycle of fsc / 16 (223.722 KHz) and having a phase of 180 degrees, which serves to indicate the start of an 18-bit data packet.

The data string 306 is composed of 18 bits, the bit rate is fsc / 8 (447.443 KHz), and is modulated by the BPSK method.

As shown in FIG. 4, the data packet is composed of three parts: parity (p) in word units, dialogue subtitle / additional information flag (C / T), and code value (c).

Here, D0 to D8 are abbreviated as lower words, and D9 to D17 are abbreviated as upper words.

D17 represents even parity for D0 to D16. The parity bit (p) of this D17 is for first detecting an error in transmission.

D7 and D16 are the metabolism subtitle / additional information flags as 0 for the metabolism subtitle and 1 for the additional information, and the values of D7 and D16 must match. In addition, the subtitle caption / additional information flag is used to maintain the priority in word units.

D0 to D6 and D9 to D15 together represent a code value. The code value is interpreted as a control code if D5, D6, D14 and D15 are all zero, otherwise as a character code.

1 is a block diagram showing the configuration of a television broadcasting system for viewer-selective caption broadcasting according to the present invention.

As shown here, reference numeral 10 denotes a microphone for inputting an audio signal, and reference numeral 20 denotes an image camera for capturing a predetermined subject and outputting an image signal.

The audio signal input through the microphone 10 is mixed and amplified by the audio signal controller 30 and input to the television signal modulator 50, and the video signal output from the video camera 20 is a video signal processor ( 40 is amplified and edited and then input to the television signal modulator 50 through the switching means 78 of the subtitle encoding section 70 described later.

The output signal of the television signal modulator 50 is transmitted to the air wirelessly through the high frequency output unit 60 and through the antenna 80.

Reference numeral 70 denotes a caption encoding unit for mixing predetermined additional information and control information with the output signal of the video signal processor 40 in a closed captioning manner.

The caption encoding unit 70 may include a text information input unit 71 for inputting additional information such as dialogue information, emergency news, and delivery items related to a television screen, and various control information for caption control according to a broadcaster's manipulation. To a control signal input unit 72 for inputting, a character code generation unit 73 for generating a data packet of a character code with respect to an output signal of the character information input unit 71, and an output signal of the control signal input unit 72; A control code generator 74 for generating a data packet of the control code, and a data packet modulator 75 for modulating the data packets generated by the character code generator 73 and the control code generator 74. And a synchronization counter 76 which is reset according to the vertical synchronization signal output from the image signal generator 40 and counts a horizontal synchronization signal, and a window signal according to the count value of the synchronization counter 76. Causing According to the window signal generator 77 and the output signal of the window signal generator 77, the output signals of the video signal processor 40 and the data packet modulator 75 are switched to the television signal modulator ( And switching means 78 for inputting to 60.

The character information input unit 71 includes a keyboard (not shown) for inputting characters or special characters such as Korean, English, Chinese, and Japanese, and converts the inputted character information into a 2-byte Hangul completion code. Outputs (KSC5901).

The control information input unit 72 includes a keypad (not shown) including a mode selection key, a function selection key, and the like. The control information input unit 72 converts the control information according to the input key signal of the keypad into 7-bit binary. Output to code

In the television broadcasting system for the viewer-selective caption broadcasting configured as described above, the predetermined audio signal input through the microphone 10 is mixed and amplified by another predetermined voice myth by the audio signal controller 30 to the television signal modulator 50. Is entered.

Then, the video signal of the subject of the adjustment photographed and output by the video camera 20 is amplified and edited by the video signal processing unit 40 and then the television signal modulator 50 through the switching means 78 of the subtitle encoding unit 70. ) Is entered.

Then, the television signal modulator 50 FM-modulates the audio signal input from the audio signal controller 30, and modulates the video signal input from the video signal processor 40 by AM modulation in a residual sideband method. The signal and the AM modulated signal are frequency-multiplexed and frequency shifted to output a high frequency signal.

As described above, the high frequency signal output from the image signal processor 40 is amplified by the high frequency output unit 60 and then transmitted to the air as a television broadcast signal through the antenna 80.

When the broadcaster manipulates a keyboard provided in the character information input unit 71 of the subtitle encoding unit 70, and inputs character information such as predetermined characters such as Korean, English, Chinese characters, and Japanese or special characters, the character information input unit 71 ) Converts the predetermined character information into a 2-byte Hangul completion code and outputs the converted character information.

When the broadcaster operates the keypad of the control accuracy input unit 72 to input control information such as a mode selection key and a function selection key, the control information input unit 72 converts the predetermined control information into a 7-bit binary code. Convert and output

In this way, the two-byte Hangul completion code according to the predetermined character information output by the character information input unit 71 is inputted to the character code generator 73 and converted into a data packet. By using the Most Signification Bit (MSB) of each byte of the byte Hangul completion code as the subtitle / additional information flag, replace the MSB with '0' for the subtitle and add '1' for the additional information. After replacement, a parity bit is added to each byte to generate a data packet having a total of 18 bits of character code.

The 7-bit binary code output by the control information input unit 72 is input to the control code generator 74 and converted into a data packet of the control code. The control code generator 74 inputs the input 7-bit binary code. Is divided into the upper 4 bits and the lower 3 bits, and then, for the upper 4 bits, 8 bits of 1 bit parity bit, 2 bits of control code identification bit, and 1 bit of subtitle caption / additional information flag are added. An upper byte is generated, and for the lower three bits, one bit of the first parity bit, one bit of the second parity bit, two bits of control code identification bit, and one bit of the subtitle subtitle / additional information flag are added. The lower byte is generated, and a parity bit is added to the generated upper byte and lower byte to generate a data packet having a total of 18 bits of control code.

In this way, the data packet of the total 18 bits of the character code generated by the character code generator 73 and the data packet of the total 18 bits of the control code generated by the control code generator 74 are digitally modulated by the data packet modulator 75. Modulated in such a manner that it is output to the switching unit 78.

The vertical sync signal and the sync signal output by the video signal processor 40 are input to the sync counter 76. The sync catheter 76 is reset according to the input vertical sync signal and counts the horizontal sync signal. And the scan signal is counted and output, and the window signal generator 77 generates the window signal in accordance with the count value of the horizontal synchronization signal output from the synchronization counter 76.

In this way, the switching signal generated by the window signal generator 77 is applied to the switching means 78 as a control signal to control the switching operation of the switching means 78. The switching means 78 is the image signal processor 40. Superimposing a data packet of a character code and a control code according to a caption signal outputted by the data packet modulator 75 on a predetermined specific line of an output signal of the signal; And is transmitted through the high frequency output unit 60 and the antenna 80.

2 is a block diagram showing the configuration of a viewer-selective additional information display device of the present invention.

As shown in the figure, the tuner unit 110 receives, demodulates, and outputs a television broadcast signal of a channel selected from the high frequency signals received through the antenna 100, and the image signal output from the tuner unit 110 includes luminance and After outputting the RGB signal and outputting the RGB signal and outputting the signal of the vertical blanking period, the image signal processing unit 140 and the image signal output from the image signal processing unit 140 attenuate a predetermined level (m / n). A caption decoding unit for detecting and outputting additional information from the first attenuation unit 142 and the vertical sphere erase period signal output from the image signal processing unit 140 and generating a subtitle control signal for displaying the additional information ( 200, a command input unit 190 for inputting an operation command according to a user's operation, and controlling the entire operation of the television receiver according to the operation command input by the command input unit 190; The image signal processing unit 140 and the first attenuating unit according to the system control unit 180 for controlling the decoding unit 200 and the subtitle control signal output from the subtitle decoding unit 200 when displaying additional information. A switching unit 145 for selectively outputting the output signal of 142, a second attenuator 144 for attenuating additional information output by the subtitle decoding unit 200 by a predetermined level (N / M), and the switching unit And a display driver 160 for mixing the output signals of the second and second attenuators 145 and 144 and the output signal of the mixer 150 to the cathode ray tube 170. .

The caption decoding unit 200 may include an analog / digital converter 210 for converting a signal of the vertical blanking period output by the video signal processing unit 140 into a digital signal, and output by the video signal processing unit 140. A synchronous separator 220 for separating and outputting a vertical sync signal and a horizontal sync signal from the signal of the vertical blanking period, and generating a clock signal synchronized with the color burst signal under the control of the system controller 180; Subtitle control and additional information for generating additional information according to an output signal of the analog / digital converter 210 and outputting the second information to the second attenuator 144 and generating a subtitle control signal to control the switching operation of the switching unit 145. The detection unit 230, a font rom 240 for storing and outputting fonts such as characters such as Korean, English, Chinese and Japanese, and special characters in advance, and the fonts read by the font rom 240 Group consists of the first and second ram 245, 250, which alternately stores and outputs according to the control of the subtitle control and the additional information detection section 230.

In the viewer-selectable additional information display device configured as described above, the tuner unit 110 tunes and demodulates a television broadcast signal of a channel selected by the viewer among high-frequency signals received by the antenna 100 to output an image signal.

The image signal output by the tuner 110 is input to the image signal processor 140, the luminance and color are processed, and then the RGB signal is output to the switching unit 145, and the M / N is transmitted from the first attenuator 142. Is attenuated and output to the switching unit 145.

In addition, the signal of the vertical blanking period output by the image signal processor 140 is converted into a digital signal by the analog / digital converter 210 of the caption decoding unit 200 and input to the caption controller 230, and a synchronous separator ( In 220, the vertical synchronizing signal and the horizontal synchronizing signal are separated and input to the caption control and additional information detector 230.

In this state, when the viewer does not command to display the additional information, the subtitle control and additional information detector 230 of the subtitle decoding unit 200 do not output both the subtitle control signal and the additional information.

Then, the video signal output from the video signal processor 140, that is, the RGB signal, is input to the display driver 160 through the switching unit 145 and the mixing unit 150, and received in the cathode ray tube 170. The image of the signal is displayed.

When the viewer manipulates the command input unit 190 to display the additional information on the screen of the cathode ray tube 170, the system controller 180 inputs a display command of the additional information to display the operation mode of the television receiver. The display mode changes to.

When switching to the additional information display mode as described above, the subtitle control and additional information detector 230 of the subtitle decoding unit 200 generates a clock signal synchronized with the color burst signal, and inputs from the analog / digital converter 210. The caption data packet is extracted from the digital signal, and the extracted caption data packet is decoded.

Subtitle processing is controlled in response to the control code decoded the caption data packet, and the character data is read from the font ROM 240 in response to the decoded character code to be alternated with the first and second RAMs 245 and 250. Write and read out.

The character data alternately stored in the first and second RAMs 245 and 250 are converted into an RGB signal and output. The decoded additional information is output to the second attenuator 144 and the switching unit 145. The caption control signal is output.

Then, the additional information output by the caption control and additional information detector 230 is attenuated by N / M by the second attenuator 144 and input to the mixing unit 150, and output by the image signal processor 140. The RGB signal of the video signal attenuated by the first attenuator 142 is mixed through the switching unit 145, and the additional information attenuated by the second attenuator 144 is mixed by the mixing unit 150. Since it is input to the driver 160, the cathode ray tube 170 displays an image of the received television broadcast signal and additional information is displayed in a caption state at the bottom of the image.

5 is a signal flowchart showing a method of displaying additional information according to the present invention.

As shown in the figure, when the viewer operates the command input unit 190 to set the display mode of the additional information, the system controller 180 determines the display mode of the additional information in step S1 and controls the operation of the peripheral system. do.

In the next step S2, the additional information is written in the first RAM 245, and in step S3, the additional information stored in the first RAM 245 is shifted in the horizontal direction and stored in the second RAM 250. In step S4, the character data of the additional information stored in the second RAM 250 is read and output to the second attenuator 144 to be mixed with the image of the received television broadcast signal as described above. (170).

Therefore, as shown in FIG. 6, the cathode ray tube 170 displays a predetermined image of the received television broadcast signal, and additional information is scrolled in the horizontal direction at the bottom of the image displayed on the cathode ray tube 171, thereby reducing the brightness. Displayed in tones.

As described in detail above, the viewer-selectable additional information display device and method thereof may be inserted at the bottom of an image when the additional information such as weather forecast or emergency news is displayed on the screen according to the viewer's selection. It is possible to watch clear additional information by not disturbing the viewing of a predetermined image and by displaying the brightness in halftone while scrolling the additional information horizontally.

Claims (4)

A system controller which controls the display of additional information according to an operation command of the command input unit; A tuner unit for receiving, demodulating and outputting a television broadcast signal of a selected channel; An image signal processing unit which outputs an RGB signal and outputs a signal of a vertical blanking period after luminance and color processing the image signal output by the tuner; A first attenuator configured to attenuate the RGB signal output by the image signal processor; An analog / digital converter for converting a signal of the vertical blanking period output by the image signal processing unit into a digital signal; A sync separator for separating and outputting a vertical sync signal and a horizontal sync signal from a signal of a vertical blanking period output by the video signal processor; When the system controller commands the display of the additional information, the subtitle control mill additional information generates a clock signal synchronized with the color burst signal and generates additional information and a subtitle control signal according to the output signal of the analog / digital converter. Detector; Font ROMs for storing and outputting fonts such as characters such as Korean, English, Chinese and Japanese, and special characters; First and second RAMs for storing and outputting fonts read from the font room under the control of the caption controller; A switching unit for selectively outputting an RGB signal output from the image signal processing unit or an output signal of the first attenuating unit according to a switching signal output by the subtitle control unit and the additional information detector; A second attenuator configured to attenuate additional information output by the subtitle control and additional information detector; A mixing unit which mixes output signals of the switching and second attenuating units; And a display driver configured to display an output signal of the mixing unit on a cathode ray tube. According to claim 1, The first attenuator and the second attenuator; A viewer-selective additional information display device, characterized in that the input signal is attenuated to levels opposite to each other. The method of claim 1, wherein the caption control and additional information detection unit; And additional information stored in the first RAM in the horizontal direction to be written in the second RAM such that the additional information is scrolled in the horizontal direction. A judging step of judging whether the input data for controlling the operation mode of the system is a display command of additional information; A video signal level reduction step of judging whether there is additional information in the received television broadcast signal in the case of the display command of the additional information in the determining step, and attenuating the video signal to a predetermined level or less when there is the additional information; An additional information level reduction step of attenuating a level of the received additional information by a predetermined level or more in the case of the display command of the additional information in the determining step; And the additional information attenuated in the additional information level attenuation step at a lower display position of the video signal attenuated in the video signal level attenuation step.