KR100617201B1 - Apparatus and Method for Displaying Image Using Signal Synchronization - Google Patents

Abstract

The present invention provides an image output apparatus and method capable of synchronizing signals in a process of mixing digital signals in accordance with a synchronization signal, wherein the first and second synchronization signals are generated and output at regular intervals, and the first and second synchronization signals are synchronized with each other. A video decoder for converting an analog composite video signal input from an external source into a digital signal according to a signal generation period and outputting the digital signal; A caption unit for separating a caption signal from an analog composite video signal input from the outside according to the first synchronization signal; An A / D converter for converting a caption signal output from the caption unit into a digital signal according to the first synchronization signal; And a mixing unit for mixing the digital signals output from the video decoder and the A / D converter according to the first and second synchronization signals and outputting the mixed digital signals on the screen.

Signal, sync, video, clock, digital

Description

Apparatus and Method for Displaying Image Using Signal Synchronization

1 is a block diagram of a conventional video output device applied to a television or a computer.

2 is a block diagram of an image output apparatus using signal synchronization according to an embodiment of the present invention.

3 is a flowchart illustrating an image output method using signal synchronization according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

210: video decoder 221: crystal oscillator

220: caption portion 230: A / D converter

240: mixing unit

The present invention relates to a video output device and method applied to a television (TV) for receiving a composite video signal and outputting it to a display device such as a monitor or a CRT, and in particular, an image output capable of mixing digital signals using signal synchronization. It relates to a device and a method.

In general, a television receives a radio frequency (RF) signal transmitted to a broadcasting station, converts the received radio frequency signal into a digital composite video signal through a tuner, and outputs the same to a monitor, that is, a CRT. Like a television, a computer also converts a radio frequency signal transmitted from a broadcasting station into a digital composite video signal and outputs it to a monitor.

Recently, thanks to the development of information and communication technology, mobile communication terminals, which are provided with wireless communication services, also convert radio frequency signals transmitted from broadcasting stations into digital composite video signals and output them to liquid crystal display (LCD). Providing.

As described above, various techniques for displaying video signals have been proposed and commonly used. Among these technologies, a conventional video output apparatus applied to a computer capable of inputting a computer and a video AV signal will be described with reference to FIG. 1. .

Referring to FIG. 1, a conventional video projection apparatus includes an A / D converter 110 for converting an R, G, B analog input signal into a digital signal by inputting a horizontal synchronization signal (H-sync), and a video AV. A video decoder 120 for receiving and decoding a signal, a video processor 130 for scaling and signal processing a received AV signal and a digital signal converted by the A / D converter 110; The display unit 140 receives and displays the processed signal from the video processor 130, and the controller 150 controls the video processor 130 and the display unit 140.

The display unit 140 adjusts the drive current of the backlight lamp according to a control command input from the controller 150, and a lamp driven at a luminance corresponding to the drive current output from the inverter 141. 142 and 143, and an LCD panel 144 for displaying an image signal input from the video processor 130.

The controller 150 includes a microprocessor 151 that controls the video processor 130 and controls screen brightness through the inverter 141, and a memory (EEPROM) 152 that stores data necessary for control.

The A / D converter 110 converts the input R, G and B signals and the horizontal synchronization signal (H-Sync) into digital signals, and the converted digital R, G and B signals are input to the digital video processor 130. do.

The video decoder 120 decodes the input video signal and inputs it to the digital video processor 130.

The digital video processor 130 converts the digital R, G, and B signals converted from the A / D converter 110 into digital signals and outputs the AV signals output from the video decoder 120 to the LCD panel 144. Processing to output to the display unit 140.

In the conventional video output apparatus as described above, a signal is mixed to display a caption signal on a monitor. In this process, an analog signal is mixed. However, when the analog signal is mixed, the R, G, B light is delayed when mixing due to the characteristics of the analog signal, causing a problem of deterioration in image quality.

In order to solve this problem, an RGB mixing chip has been used, but there is still a problem that a large manufacturing cost is required because the RGB mixing chip corresponds to expensive equipment.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an image output apparatus and method capable of synchronizing signals in a process of mixing digital signals according to simultaneous signals.

Another object of the present invention is to provide an image output apparatus and method capable of preventing a signal delay generated during a mixing process by mixing a digital signal by synchronizing a signal according to a synchronization signal generated at a predetermined period.

Another object of the present invention is to provide an image output apparatus and method capable of clearly improving image quality of a screen by mixing digital signals without signal delay through synchronization of signals in the process of outputting a composite image signal.

Provided is an image output apparatus and method capable of mixing digital signals at a relatively low cost by simply performing another digital video signal mixing process through signal synchronization.

In order to achieve the above object, the present invention provides a device for converting a composite video signal input from the outside into a digital signal and outputting it to a screen, wherein the first and second synchronization signals for synchronizing the signals are generated at regular intervals. A video decoder configured to output an analog composite video signal inputted from the outside into a digital signal according to a generation period of the first and second synchronization signals; A caption unit for separating a caption signal from an analog composite video signal input from the outside according to the first synchronization signal output from the video decoder; An A / D converter for converting a caption signal output from the caption unit into a digital signal according to the first synchronization signal output from the video decoder; And a mixing unit configured to mix the digital signals output from the video decoder and the A / D converter according to the first and second synchronization signals output from the video decoder, and output a mixed digital signal to the screen.

According to an aspect of the present invention, there is provided a method of converting a composite video signal input from an external source into a digital signal and outputting the same to a screen, the method comprising: a first step of generating a high section of a first clock signal for synchronizing signals; A second step of separating the analog caption signal from the first analog composite video signal input from the outside during the high period of the first clock signal and converting the analog caption signal into a first digital signal; Generating a high period of the second clock signal for synchronizing the signals in the high period of the first clock signal, and converting a second analog composite video signal input from the outside into a second digital signal; And a fourth step of mixing the first and second digital signals in the high section of the first and second clock signals and outputting the mixed digital signals on the screen.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a block diagram of an image output apparatus using signal synchronization according to an embodiment of the present invention.

Referring to FIG. 2, the image output apparatus of the present invention generates and outputs the first and second clock signals CLK1 and CLK2 for synchronizing the signals at predetermined periods, and outputs the first and second clock signals CLK1 and CLK2. Video that generates and outputs vertical sync signal (V-Sych) and horizontal sync signal (H-Synch) according to the generation cycle of) and converts analog composite video signal input from outside into digital signal (Y, UV) A caption unit 220 for separating a caption signal from an analog composite video signal input from the outside according to a decoder 210 and a first clock signal CLK1 output from the video decoder 210. And an A / D converter 230 for converting the caption signal output from the caption unit 220 into digital signals Y and UV according to the first clock signal CLK1 output from the video decoder 210. First and second clocks output from video decoder 210 According to the calls CLK1 and CLK2, the digital signals Y and UV output from the video decoder 210 and the A / D converter 230 are mixed to monitor the mixing signals Y and UV (not shown). And a mixing unit 240 for outputting the same.

The video decoder 210 includes a crystal oscillator 211 that generates a trigger signal at a predetermined period, and includes a first signal for synchronizing signals in a mixing process of digital signals according to a trigger signal oscillated from the crystal oscillator 211. And generating the second clock signals CLK1 and CLK2 at regular intervals, and outputting the first clock signal CLK1 to the caption unit 220, the A / D converter 230, and the mixing unit 240. The signal CLK2 is output to the mixing unit 240. At this time, the video decoder 210 generates a vertical synchronization signal and a horizontal synchronization signal for vertical and horizontal synchronization of the signal according to the generation periods of the first and second clock signals CLK1 and CLK2 and the caption unit 220. It outputs to the mixing unit 240, and outputs only the horizontal synchronization signal to the A / D converter 230.

In addition, the video decoder 210 converts an analog composite video signal input externally according to a generation period of the first and second clock signals CLK1 and CLK2 into a digital signal, that is, a luminance signal Y and a color difference signal UV. The conversion is output to the mixing unit 240. Here, the video decoder 210 outputs a signal of 16 bits in total, and outputs an 8-bit luminance signal Y and an 8-bit color difference signal UV.

Meanwhile, in the present invention, the video decoder 210 generates a clock signal in order to synchronize the signal in the mixing process of the digital signal. However, the present invention is not limited thereto, and signals other than the clock signal may be used as the synchronization signal. will be. That is, the technical idea of the present invention is to prevent delay of a signal by synchronizing the signal when converting and mixing an analog composite video signal into a digital signal, and not simply to use a clock signal.

The caption unit 220 separates the caption signal, that is, the R, G, and B signals from the analog composite video signal input from the outside according to the first clock signal CLK1 generated from the video decoder 210, thereby converting the A / D converter ( 230).

When the high section of the first clock signal CLK1 is input to the caption unit 220 as described above, the high section High of the first clock signal CLK1 is also input to the A / D converter 230 at the same time. The D converter 230 is also driven. At this time, the high section of the first clock signal CLK1 is input to the mixing unit 240, but the mixing section 240 is not driven because the low section Low of the second clock signal CLK2 is input.

When the caption unit 220 separates the caption signal from the composite video signal according to the first clock signal CLK1, the caption unit 220 is input from the outside according to the horizontal synchronization signal and the vertical synchronization signal generated from the video decoder 210. The horizontal and vertical synchronization of the image signal and the caption signal are matched, and the test blanking signal FB is output to the mixing unit 240. The test blanking signal is a mixed signal, that is, the mixing unit 240. The luminance signal (Y) and the color difference signal (UV) that are output from the (i.

The A / D converter 230 converts the analog caption signals R, G, and B signals output from the caption unit 220 according to the first clock signal CLK1 generated from the video decoder 210 into digital signals and luminance. The signal Y is converted into a color difference signal UV and output to the mixing unit 240. At this time, the A / D converter 230 outputs a signal of 16 bits in total, and outputs an 8-bit luminance signal Y through the G port and an 8-bit color difference signal UV through the R port. .

When the A / D converter 230 converts the analog caption signal into a digital signal according to the first clock signal CLK1, the A / D converter 230 may convert the analog caption signal and the digital signal according to the horizontal synchronization signal generated from the video decoder 210. Match horizontal sync.

Since the A / D converter 230 operates simultaneously with the caption unit 220 according to the first clock signal CLK1 as described above, the analog caption signal separated by the caption unit 220 is converted into a digital signal. The signal delay is never generated in the process of being delivered to the mixing unit 240.

The mixing unit 240 simultaneously inputs the digital signals Y, which are simultaneously input from the video decoder 210 and the A / D converter 230 according to the first and second clock signals CLK1 and CLK2 generated from the video decoder 210. UV) is mixed to output the mixed signal, that is, the luminance signal Y and the color difference signal UV simultaneously. Here, the video decoder 210 outputs the digital signal (Y, UV) from the A / D converter 230 and generates a high section of the second clock signal (CLK2) to output to the mixing unit 240, and The analog composite video signal input from the outside is converted to a digital signal (Y, UV) and output to the mixing unit 240, which is a digital signal (Y) converted by the video decoder 210 and the A / D converter 230 , UV) is synchronized to be mixed by the mixing unit 240.

The digital signals (Y, UV) converted by the video decoder 210 and the A / D converter 230 are synchronized and input to the mixing unit 240, and at the same time, the high section of the first and second clock signals CLK2 are provided. Since it is input to the mixing unit 240, no signal delay occurs in the process until the analog composite video signals inputted from the outside are converted into digital signals and mixed.

The mixing unit 240 outputs the luminance signal Y and the color difference signal UV mixed at a position on the screen designated by the test blanking signal output from the caption unit 220. Aligns the horizontal and vertical synchronization of the luminance signal Y and the color difference signal UV, which are mixed according to the horizontal and vertical synchronization signals generated from the video decoder 210.

If the signals are not synchronized for the mixing of the digital signals as described above, a signal delay is generated during signal conversion and mixing, so that shaking may occur on the screen. However, the present invention may occur at regular intervals from the video decoder 210. By synchronizing the signals by the first and second clock signals CLK1 and CLK2, the signal delay can be prevented. Therefore, the digital signal is mixed without the use of an expensive RGB mixing chip. It can be provided.

A process of mixing the digital signal by the image output apparatus of the present invention having the configuration and function as described above will be described in more detail with reference to FIG. 3.

Referring to FIG. 3, when the crystal oscillator 211 oscillates a trigger signal at a predetermined period (S301), the video decoder 210 captures a high section of the first clock signal CLK1 in response to the trigger signal. Outputs to the A / D converter 230 and the mixing unit 240, generates a vertical synchronizing signal and a horizontal synchronizing signal at the same time and outputs to the caption unit 220 and the mixing unit 240, the A / D converter 230 Output only the horizontal synchronization signal (S302).

In the high section of the first clock signal CLK1, the caption unit 220 separates the caption signals R, G, and B from the analog composite video signal input from the outside and outputs them to the A / D converter 230. In operation S303, the A / D converter 230 converts the input analog caption signal into digital signals Y and UV and outputs the converted analog caption signal to the mixing unit 240 (S304).

In the signal separation process (S303), the caption unit 220 matches the horizontal and vertical synchronization of the composite image signal and the caption signal input from the outside according to the horizontal synchronization signal and the vertical synchronization signal generated from the video decoder 210 Also, the test blanking signal FB is output to the mixing unit 240.

In the signal conversion process (S304), the A / D converter 230 converts the analog caption signal and the horizontal signal from the digital signal according to the horizontal synchronization signal generated from the video decoder 210 when converting the analog caption signal into a digital signal. Match.

As described above, in the state where the high section of the first clock signal CLK1 is maintained, the video decoder 210 outputs the digital signals Y and UV from the A / D converter 230 and according to the trigger signal. A high section of the two clock signals CLK2 is generated and output to the mixing unit 240, and an analog composite video signal input from the outside is converted to digital signals Y and UV and output to the mixing unit 240 ( S305).

In the high section of the first and second clock signals CLK1 and CLK2, the digital signals Y and UV converted by the video decoder 210 and the A / D converter 230 are synchronized to the mixing unit 240. When input, the mixing unit 240 mixes the luminance signal Y and the color difference signal UV which are mixed by mixing the digital signals Y and UV which are simultaneously input from the video decoder 210 and the A / D converter 230. Simultaneously output to the screen (S306).

In the mixing process S306, the mixing unit 240 outputs the luminance signal Y and the color difference signal UV mixed at a position on the screen designated by the test blanking signal output from the caption unit 220. The horizontal and vertical syncs of the luminance signal Y and the color difference signal UV, which are mixed according to the horizontal and vertical sync signals generated from the video decoder 210, are matched.

Although the technical spirit of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, according to the present invention, by synchronizing the signals in the mixing process of the digital signals according to the clock signal, the digital signals can be easily mixed without using expensive equipment such as an RGB mixing chip, and even if the digital signals are mixed, Clear picture quality can be provided, which reduces manufacturing costs.

Claims (19)

In the device for converting a composite video signal input from the outside into a digital signal and output to the screen, A video for generating and outputting the first and second synchronization signals for synchronizing the signals at predetermined periods, and converting and outputting the analog composite video signals inputted from the outside into digital signals in accordance with the generation periods of the first and second synchronization signals. Decoder; A caption unit for separating a caption signal from an analog composite video signal input from the outside according to the first synchronization signal output from the video decoder; An A / D converter for converting a caption signal output from the caption unit into a digital signal according to the first synchronization signal output from the video decoder; And A mixing unit for mixing the digital signals output from the video decoder and the A / D converter according to the first and second synchronization signals output from the video decoder and outputting the mixed digital signals to the screen Image output device comprising a. The method of claim 1, The video decoder, Crystal Oscillator Generates Trigger Signal at Period Image output device comprising a. The method of claim 2, And the video decoder generates the first and second synchronization signals at regular intervals for signal synchronization in a mixing process of digital signals according to a trigger signal oscillated from the crystal oscillator. The method of claim 1, And the video decoder generates and outputs a vertical synchronizing signal and a horizontal synchronizing signal for vertical and horizontal synchronizing of signals according to the generation periods of the first and second synchronizing signals. The method of claim 4, wherein The caption unit is a video output device, characterized in that to match the horizontal synchronization and the vertical synchronization of the composite image signal and the caption signal input from the outside in accordance with the horizontal synchronization signal and the vertical synchronization signal generated from the video decoder. The method of claim 1, And the caption unit outputs, to the mixing unit, a test blanking signal for designating a position at which the digital signal output from the mixing unit is displayed on the screen according to the first synchronization signal. The method of claim 4, wherein The A / D converter is characterized in that the horizontal synchronization of the analog caption signal and the digital signal in accordance with the horizontal synchronization signal generated from the video decoder. The method of claim 1, And the video decoder simultaneously outputs a high section of the first synchronization signal to the caption unit, the A / D converter, and the mixing unit. The method of claim 4, wherein And the mixing unit matches horizontal and vertical synchronization of a digital signal mixed according to a horizontal synchronization signal and a vertical synchronization signal generated from the video decoder. The method of claim 6, And the mixing unit outputs a digital signal mixed at a position on the screen designated by a test blanking signal output from the caption unit. The method of claim 1, The mixing unit is driven when the high section of the first and second synchronization signal is input. The method according to any one of claims 1 to 11, And the first and second synchronizing signals are clocks. In the method for converting a composite video signal input from the outside into a digital signal and output to the screen, Generating a high section of the first clock signal for synchronizing the signals; A second step of separating the analog caption signal from the first analog composite video signal input from the outside during the high period of the first clock signal and converting the analog caption signal into a first digital signal; Generating a high period of the second clock signal for synchronizing the signals in the high period of the first clock signal, and converting a second analog composite video signal input from the outside into a second digital signal; And A fourth step of mixing the first and second digital signals in a high section of the first and second clock signals to output a mixed digital signal on the screen; Image output method comprising a. The method of claim 13, A fifth step of generating a horizontal synchronization signal and a vertical synchronization signal for vertical and horizontal synchronization of the signal according to the first and second clock signals; Image output method further comprising. The method of claim 14, And the horizontal synchronizing signal and the horizontal synchronizing of the first composite video signal and the caption signal input from the outside according to the horizontal synchronizing signal and the vertical synchronizing signal in the second step. The method of claim 14, In the second step, the image output method, characterized in that to match the horizontal synchronization of the analog caption signal and the first digital signal in accordance with the horizontal synchronization signal. The method of claim 14, And in the fourth step, matching the horizontal synchronization and the vertical synchronization of the mixed digital signal according to the horizontal synchronization signal and the vertical synchronization signal. The method according to any one of claims 13 to 17, A sixth step of generating a test blanking signal for designating a position at which the mixed digital signal is to be displayed on the screen according to the first clock signal; Image output method further comprising. The method of claim 18, And in the fourth step, outputting the mixed digital signal to a position on the screen designated by the test blanking signal.

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