KR20010064715A - Method for controlling vertical slice level - Google Patents

Abstract

PURPOSE: A vertical slice level control method is provided to perform a separation of synchronous signal stably by counting line of an irregular field in case an inputted signal has much noise and judging whether the counted line is a normal signal or an abnormal signal and controlling a synchronous slice according to the judgment signal. CONSTITUTION: A first process detects a level of noise included in a digital image signal. A second process compares the detected noise level of each line with a specific value set up in a little less value than a noise level value in which a synchronous detection error is generated. A third process maintains a slice level in a constant level(50%) in case the noise level of each line is over the specific value in result of the comparison. A fourth process sets up the slice level most stable in case the noise level of each line is under the specific value in result of the comparison.

Description

Method for controlling vertical slice level}

According to the present invention, the sync slice level is stably operated to increase the winter stability to prevent the shaking of the video signal caused by the irrational setting of the sync slice level when playing a noisy VCR tape or receiving a weak electric field signal. It relates to a vertical slice level control method.

As shown in FIG. 1, a conventional slice receiver of a TV receiver includes a tuner / IF amplifier 1 for tuning a broadcast signal received by an antenna and amplifying and outputting the tuned broadcast signal by intermediate frequency processing. The image detector 2 for detecting the amplified output image signal from the / IF amplification unit 1 and outputting the composite image signal, and receiving the composite image signal detected by the image detector 2 as a digital signal. A / D conversion and image processing unit 3 for converting and processing an image, and a sync slice and a separation unit 4 for receiving a composite video signal output from the image detector 2 and separating vertical and horizontal synchronization signals. And a vertical oscillator 5 for triggering and oscillating the vertical synchronous signal separated by the synchronous separator 4, and a vertical output stage for controlling the current flowing through the deflection coil by receiving the signal oscillated from the vertical oscillator 5; 6) and the synchronization separator ( The horizontal oscillation unit 7 for triggering and oscillating the horizontal synchronization signal separated in 5) and the horizontal output stage 8 for receiving the oscillated signal and controlling the current flowing through the deflection coil.

As shown in FIG. 1, the vertical slice level control apparatus of the conventional TV receiver configured as described above has a signal received through an antenna applied to the tuner / IF amplifier 1 so that the broadcast signal is tuned and then tuned to the broadcast signal. The amplified output is processed by the intermediate frequency and then applied to the image detector 2 to output a composite video signal.

At this time, the composite image signal output from the image detector 2 is applied to the A / D conversion and image processor 3 for image processing, and is simultaneously applied to the sync slice and the sync separator 4 while the image processing is performed. The sync slice and sync separator 4 separates the vertical and horizontal sync signals of the input composite video signal.

The vertical and horizontal synchronization signals separated in this way are applied to the vertical oscillator 5 and the horizontal oscillator 7, respectively, to trigger the synchronization signal, and then to the vertical output terminal 6 and the horizontal output terminal 8 so that image information is displayed on the screen. To be printed.

That is, the synchronous signal separated by the synchronous slice and the synchronous separator 4 is applied to the vertical oscillator 5 and the horizontal oscillator 7, respectively, to be triggered and output from the vertical oscillator 5 and the horizontal oscillator 7, respectively. The signal is converted into a signal that can be processed by the vertical output section 6 and the horizontal output section 8 so that the vertical output section 6 and the horizontal output section 8 are connected to the vertical oscillation section 5 and the horizontal oscillation section 7. Since the current flowing through the deflection coil is controlled by the output signal, accurate image information can be received through the screen through deflection of the electron beam.

The synchronous slice and the synchronous separator 4 must receive the image information of all conditions to have absolute stability and reliability of the operation so as to accurately transfer the image information through the CRT and other display devices.

However, the vertical slice level control apparatus of the conventional TV set cannot accurately receive image information when a noisy signal is input.

That is, there is a problem that vertical synchronization becomes unstable when synchronous detection is unstable because the state of the image information is not accurate when playing a tape with a lot of noise.

In order to solve the conventional problem, the present invention counts the lines of irregular fields when a noisy signal is input, and then determines whether the counted lines are normal or abnormal signals, and generates a synchronous slice according to the determined signal. By controlling the control to separate the synchronous signal, the configuration and operation of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram showing a vertical slice level control apparatus of a conventional TV receiver.

Figure 2 is a block diagram showing a vertical slice level control apparatus of the present invention TV receiver.

3 is a diagram illustrating a case where a synchronization detection error occurs when the vertical slice level of the present invention is constant.

Figure 4 is a flow chart showing a vertical slice level control method of the present invention.

First, as shown in FIG. 2, the vertical slice level control apparatus of the present invention includes an image detector 11 for receiving an intermediate frequency processed image signal and detecting and outputting a composite image signal, and the image detector. A / D conversion and image processing unit 12 for converting the composite video signal detected in step 11 into a digital signal for image processing and inputting the digital image signal processed in the A / D conversion and image processing unit 12. A noise detector 13 for detecting the number of noise signals above a specific level per line, and a microcomputer 14 for controlling the synchronous slice controller 15 to recognize noise as a slice level according to the detected noise level. ), A synchronous slice controller 15 for receiving a composite image signal detected by the image detector 11 to determine a synchronous slice level, and the determined slice level. A synchronization separator 16 for separating the vertical and horizontal synchronization signals of the composite video signal and a synchronization signal separated from the synchronization separator 16 are triggered to be processed by the vertical / horizontal output terminals 19 and 20. The vertical / horizontal oscillation unit 17 and 18 converting and outputting the signal into a form of signal and the signal converted from the vertical / horizontal oscillation unit 17 and 18 are inputted to control the current flowing through the deflection coil to thereby deflect the electron beam. Through the vertical / horizontal output stage 19, 20 for outputting the correct image information on the screen.

4 is a flowchart illustrating a vertical slice level control method according to the present invention, comprising: detecting a noise level included in a digital video signal, and comparing the detected noise level per line with a noise level value generated by a synchronization detection error. Comparing the specified value with a slightly smaller value, maintaining the slice level at a predetermined level (50%) when the noise level per line is equal to or greater than the specified value, and specifying the noise level per line as a result of the comparison. If it is less than the value, the slice level is set to the best level (70%) to proceed to the step of performing the synchronous separation stably.

The effects of the present invention configured as described above will be described with reference to FIGS. 2 and 4.

When the user wants to play back the image recorded on the VCR tape, the image detector 11 detects the reproduced image and applies the composite image signal to the A / D conversion and image processing unit 12 and the synchronous slice controller 15. do.

Therefore, the A / D conversion and image processing unit 12 converts the input composite video signal into a digital signal, and then processes the image and applies it to the noise detection unit 13.

At this time, the noise detector 13 receives the input digital image processed information and reads the number of noise signals of a certain level or more per line to the microcomputer 14.

In general, the noise is composed of a signal exceeding the white level of the video signal, it is easy to distinguish whether the signal is a signal containing the noise or a normal white signal.

Accordingly, the microcomputer 14 controls the synchronous slice controller 15 at a slice level that does not recognize noise synchronously as shown in FIG. 3 according to the noise level detected by the noise detector 13.

That is, as shown in FIG. 3, in the signal with a lot of noise, an error of recognizing the noise as a synchronous is made, so that the synchronous is not stabilized and the synchronous flows. Therefore, the microcomputer 14 is a noise detector ( The synchronous slice control unit 15 is controlled according to the result detected by the 13).

Accordingly, the synchronous slice controller 15 moves the slice level to a range where a synchronous detection error does not occur according to the control signal of the microcomputer 14 when the composite video signal detected by the image detector 11 is input. If the slice level is too low, a synchronization detection error will occur.

Experimentally, since the slice level is most stable to maintain a certain level (50%), the microcomputer 14 determines whether the noise level that is input first is a specific value or more.

The specified value is set to a value slightly smaller than the noise level value at which the synchronous detection error occurs to have a margin.

As described above, the microcomputer 14 receiving the signal detected by the noise detector 13 determines whether the input noise detection level is higher or lower than a specific value.

As a result of the determination, when the noise level input to the microcomputer 14 is higher than a specific value, the slice level control unit 15 sets the synchronous slice level at a predetermined level (70%) by the control signal of the microcomputer 14 at a predetermined level ( The synchronous slice level is lowered by 50%), and the state is maintained until the noise level is lower than or equal to a specific value.

On the other hand, when the microcomputer 14 determines that the noise level is lower than the specified value, the sync slice level is set to the most stable level (70%) to perform sync separation.

As described above, the sync slice controller 15 changes the sync slice level of the composite video signal input by the control signal of the microcomputer 14, so that the sync separator 16 stably inputs the vertical / horizontal sync of the composite video signal. It will separate the signal.

Subsequently, the stable vertical / horizontal synchronization signal is separated from the synchronization separator 16 and applied to the vertical / horizontal oscillator 17,18 to convert the signal into a signal that can be processed by the vertical / horizontal output terminals 19,20. Is triggered.

Therefore, the vertical / horizontal output stages 19 and 20 control the current flowing through the deflection coil by receiving the signal converted and triggered by the vertical / horizontal oscillator 17 and 18 to display accurate image information through the deflection of the electron beam. Is received via.

As described above, when the complex video signal containing noise is input, the noise detection unit compares the noise detection amount with the value at which the synchronous detection error occurs in the microcomputer and applies it to the synchronous slice level control unit so that the noise is not affected by the noise. By moving the sync slice level so that the sync can be stably detected, an accurate image is displayed on the screen.

Claims (2)

In the TV receiver that the image is displayed, An image detector for detecting a noise-containing image and applying the same to a synchronous slice controller and an A / D converter and an image processor, and an A / D converter for receiving a composite image signal detected by the image detector and processing a digital image; An image processor, a noise detector which detects the number of noise signals above a certain level per line by receiving the digital image-processed signal from the A / D converter and the image processor, and a stable that is not affected by noise by receiving the detected noise level. The microcomputer controls the synchronous slice control unit to compare the slice level with a specific value, and the control signal of the microcomputer moves the noise level of the composite video scene to a stable synchronous slice level so that the vertical / horizontal sync signal can be stably separated from the synchronous separator. A synchronous slice controller for controlling the signal and a signal output from the synchronous slice controller A synchronization separator for separating the vertical / horizontal synchronization signal of the image signal, a vertical / horizontal oscillator for receiving the synchronization signal separated by the synchronization separator and converting the signal into a signal of a type that can be processed by the vertical / horizontal output terminal; And a vertical / horizontal output stage configured to control the current flowing through the deflection coil by receiving the signal output from the vertical / horizontal oscillator and outputting accurate image information to the screen through deflection of the electron beam. Detecting a noise level included in the digital image signal, comparing the detected noise level per line with a specific value set to a value slightly smaller than a noise level value generated by a synchronous detection error, and as a result of the comparison, the line Maintaining the slice level at a certain level (50%) when the noise level is above a certain value, and setting the slice level at the highest level (70%) when the noise level per line is less than the specified value. A vertical slice level control method comprising the step of performing a synchronous separation stably.