KR19990056559A - Noise reduction method and device - Google Patents

Abstract

Detects an arbitrary luminance signal for detecting a noise level among the luminance signals included in the vertical blanking period, detects a level of a noise component incorporated into an arbitrary luminance signal, and sets a predetermined sharpness level corresponding to the level of the noise component. Is detected, and the video signal of the preset frame amount is adjusted to the detected sharpness level. Therefore, the optimized screen corresponding to the received video signal can be viewed.

Description

Noise reduction method and device

The present invention relates to a noise reduction method and an apparatus thereof, and more particularly, to detect a level of a noise component included in an input video signal and to detect the noise component at a level higher than or equal to a reference value. The present invention relates to a noise reduction method and apparatus for automatically reducing the level to a predetermined level.

In general, a video reduction apparatus employs a noise reduction circuit for reducing a noise component included in an input video signal to a constant level and outputting a stable screen. That is, in the conventional noise reduction circuit, when a noise is mixed into a video signal and a normal image is not displayed on the screen, as the user drives the noise reduction circuit, a predetermined value of sharpness is set regardless of the amount of change in the noise component. To decrease.

However, such a conventional noise reduction circuit causes the following problems.

That is, the level of noise component included in the video signal input from the outside changes from time to time. As the noise reduction circuit is operated, the sharpness is always reduced to a predetermined level. This results in a decrease in the clarity of the entire screen, which cannot be responded to according to the amount of change in the noise component. Therefore, even in the case of a video signal including a low level noise component, it is inevitable to watch the reduced clarity of the screen.

Accordingly, the present invention has been made to solve such a problem, and a first object of the present invention is to provide a noise reduction method which enables to automatically adjust the sharpness of an image in response to an amount of change in a noise component.

In addition, a second object of the present invention is to provide an apparatus for achieving the above first object.

1 is a schematic block diagram of a noise reduction apparatus according to the present invention;

2 is an operation flowchart showing a process of performing a noise reduction method according to the present invention;

3A is a state diagram of various pulses included in the vertical retrace period;

3b is a waveform diagram of a pseudo vertical synchronization pulse,

3C is a waveform diagram of a noise detection pulse.

<Description of the code | symbol about the principal part of drawing>

1: Chroma Signal Processing Unit 4: Image Control Unit

5: noise measurement unit 6: analog-to-digital converter

7: microcomputer

A first aspect of the present invention for achieving the above object is to detect any luminance signal for detecting the noise level of the luminance signal included in the vertical blanking period, and the level of the noise component incorporated in the arbitrary luminance signal. Is detected, the predetermined sharpness level corresponding to the level of the noise component is detected, and the video signal of the preset frame amount is adjusted to the detected sharpness level.

In the first aspect of the present invention, it is preferable that the luminance signal detecting step detects the luminance signal with respect to any one of the horizontal synchronization signals among the plurality of horizontal synchronization signals included in the vertical blanking period.

In addition, it is preferable that the sharpness levels divided by the stages of each sharpness level detection step are stored in a table, and the sharpness level corresponding to the detected noise level is detected.

In addition, the preset frame amount is preferably set to one frame.

On the other hand, the second aspect of the present invention, the chroma signal processing unit for separating and processing the image signal received from the outside into the luminance and color signal, and the brightness control signal and the brightness and gradation input from the chroma signal processor separated from the outside Noise to detect the level of noise component mixed in the horizontal control signal included within the vertical retrace period applied by the image control unit and the image control unit correcting the sharpness, brightness, and gradation value according to the control signal and outputting it to the chroma signal processing unit. A measuring unit, an analog / digital converter for converting the level value of the analogue noise component detected by the noise measuring unit into a digital form, and a sharpness level corresponding to the level data of the noise component applied from the analogue / digital converter; Outputting a sharpness control signal corresponding to the detected sharpness level to the image controller; The point is to include a microcomputer.

At this time, the image control unit generates a pseudo-vertical synchronization pulse which is inverted to a logic "high" state in synchronization with the start point of the vertical synchronization pulse among the luminance signals separated by the chroma signal processing unit, and outputs the pseudo-vertical synchronization pulse to the microcomputer. Counting is started from the pulses to generate a noise detection pulse synchronized with any one of the plurality of horizontal synchronization pulses included in the blanking period, and output to the noise measurement unit. The noise measurement unit is mixed with the horizontal synchronization pulse synchronized with the noise detection pulse. It is preferable to detect the level of the noise component.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the elements of each drawing, it should be noted that the same elements are denoted by the same reference numerals as much as possible even if they are displayed on different drawings. In addition, in the following description there are shown a number of specific details, such as components of the specific circuit, which are provided only to help a more general understanding of the present invention that the present invention may be practiced without these specific details. It is self-evident to those of ordinary knowledge in Esau. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a schematic block diagram of a noise reduction apparatus according to the present invention.

Referring to FIG. 1, the chroma signal processor 1 separates and processes a broadcast signal received through a tuner into a luminance and color signal, and outputs the processed signal to the RGB matrix 2. The RGB matrix 2 is separated into respective RGB color signals using the luminance and color signals signaled by the chroma signal processing unit 1, and then output to the electron gun of the cathode ray tube 3. Thus, an image corresponding to the received broadcast signal is displayed on the screen.

The image controller 4 adjusts the luminance and color signals separated by the chroma signal processor 1 according to various control signals (control signals such as sharpness, brightness, gradation, etc.) operated from the outside, and then returns to the chroma signal processor 1 again. Output The noise measuring unit 5 detects the level of the noise component included in the luminance signal detected by the image control unit 4 and outputs the detected noise level to the analog / digital converter 6. The analog / digital converter 6 converts the noise level measured by the noise measuring unit 5 into a digital form and outputs it to the microcomputer 7. The microcomputer 7 outputs a sharpness control signal for adjusting the level of sharpness corrected by the image controller 4 according to the digital noise level data output from the analog / digital converter 6.

An operation of the present invention having such a configuration will be described below with reference to FIGS. 2 and 3.

First, the microcomputer 7 detects the luminance signal within the vertical blanking period from the image control section 4. Typically, the luminance signal within the vertical blanking period is equalized with three equalizing pulses and three periods of vertical synchronous pulses (V-sync) after one frame of video signal is terminated, as shown in FIG. It includes three periods of equalization pulse and a plurality of horizontal synchronization pulses. Here, each cycle refers to one line of video signal included in one frame of video signal. That is, the period includes one line of video signal and the horizontal blanking period.

Meanwhile, in order to match the luminance signal level of the previous frame with the luminance signal level of the current frame, the luminance signal level included in the equalization pulse of the previous frame is detected and the luminance signal level included in the equalization pulse of the current frame is detected. The luminance signal level of the current frame is compensated by a value corresponding to the luminance signal level of the previous frame.

The vertical synchronization pulse is detected to match the vertical synchronization with respect to the video signal of the current frame. In this case, the reason why the 3 cycles of vertical synchronization pulses are continuously loaded is to compensate for an error that the image of the frame is not displayed on the screen when one vertical synchronization pulse included in the image signal of the frame is not detected. .

Each of these pulses is included in the vertical blanking period. This pulse is included in the vertical blanking period, which cannot be visually confirmed by the user. Since the vertical blanking period does not include a video signal, various additional signals are generated. This can be mixed.

The image controller 4 detects a vertical synchronous pulse (V-sync) among the pulses included in the vertical blanking period and is inverted to a logic " high " in synchronism with the time when the vertical synchronous signal is generated. A synchronous pulse (pseudo V-sync) (see FIG. 3B) is generated and output to the microcomputer 7. The microcomputer 7 counts a predetermined period, starting at the time when the pseudo vertical synchronization signal (pseudo V-sync) transmitted from the image control unit 4 is inverted to logic "high" (S1). That is, since the equalization pulse is detected at the time of three cycles from the time when the pseudo vertical synchronous signal (pseudo V-sync) is generated, and the horizontal synchronous signal is detected at the time of three cycles from the time of the detection of the equalization pulse, The microcomputer 7 generates a noise detection pulse (see FIG. 3C) that is synchronized with the horizontal synchronization signal at a point in time at which the horizontal synchronization signal is detected, that is, a period further delayed by 6 or more cycles (S2). Output to (5). At this time, the generation position of the noise detection pulse is set to be synchronized with any one of the plurality of horizontal synchronization signals detected from within the time point from which the horizontal synchronization signal is generated until the next frame amount of video signal is detected.

The noise measuring unit 5 detects the level of the noise component mixed in the horizontal synchronous signal corresponding to the noise detection pulse in accordance with the noise detection pulse output from the microcomputer 7 (S3). The detected level value of the noise component is converted into digital data by the analog-to-digital converter 6, and the digital data is transferred to the microcomputer 7. The microcomputer 7 detects a sharpness control value corresponding to the data transmitted from the analog-digital converter 6 (S4), and outputs a control signal corresponding to the detected sharpness control value to the image control unit 4. Here, the microcomputer 7 stores the sharpness control values corresponding to the level values of the noise components incorporated in the luminance signal in a table, and stores the sharpness control values corresponding to the level data applied from the analog / digital converter 6. It is preferable to vary the sharpness control signal output to the image control section 4 according to the searched result.

The image controller 4 reduces the sharpness level of the image data of one frame by the above sharpness control value according to the sharpness control signal applied from the microcomputer 7 and outputs the sharpness control value to the chroma signal processor 1 (S5). . Thereafter, it is checked whether the pseudo vertical sync signal is inverted to the logic "low" state (S6), and if it is inverted to the logic "low" state, all the processes are finished until the pseudo vertical sync signal of the next frame is detected.

At this time, the pseudo vertical synchronization signal is set to be inverted to a logic "high" state at the time of detection of the vertical synchronization signal included in the vertical blanking period, and to be inverted to a logic "low" state at the start of the image signal of the next frame. It is preferable.

In addition, the period in which the sharpness is automatically reduced by detecting the noise component may be set in one frame unit or within a minimum frame unit that can be recognized by the user.

Therefore, the noise reduction device is automatically operated in units of frames in response to the changing video signal without the user having to separately operate the noise reduction device.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As a result, the noise reduction method and the apparatus according to the present invention have the following advantages.

That is, by detecting the noise level of the horizontal sync pulse included in the vertical retrace period among the input image signals, and automatically changing the sharpness value of the video signal to a preset value corresponding to the noise level according to the detected noise level. The optimized screen corresponding to the video signal can be viewed.

Claims (8)

Detecting an arbitrary luminance signal for detecting a noise level among the luminance signals included in the vertical blanking period; Detecting a level of a noise component incorporated in the arbitrary luminance signal; Detecting a predetermined sharpness level corresponding to the level of the noise component; And And adjusting the video signal of a preset frame amount to the detected sharpness level. The method of claim 1, wherein the detecting of the luminance signal comprises: And a luminance signal is detected with respect to any one of a plurality of horizontal synchronization signals included in the vertical blanking period. The method of claim 1, wherein the sharpness level detection step, And classifying and storing the sharpness levels classified for each step, and detecting the sharpness level corresponding to the detected noise level. The method of claim 1, wherein the preset frame amount is Noise reduction circuit, characterized in that set to one frame. A chroma signal processor for separating and processing the image signal received from the outside into a luminance and a color signal; An image control unit for correcting the clarity, brightness, and gradation values according to a sharpness control signal and a brightness and gradation control signal input from the chroma signal processor, and outputting the luminance signal to the chroma signal processor; A noise measuring unit for detecting a level of a noise component mixed in a horizontal synchronous signal included in the vertical retrace period applied by the image control unit; An analog / digital converter for converting the level value of the noise component in analog form detected by the noise measuring unit into a digital form; And And a microcomputer detecting a sharpness level corresponding to the level data of the noise component applied from the analog / digital converter, and outputting the sharpness control signal corresponding to the detected sharpness level to the image controller. The method of claim 5, The image control unit generates a pseudo-vertical synchronizing pulse which is inverted to a logic " high " state in synchronization with the start point of the vertical synchronizing pulse among the luminance signals separated by the chroma signal processing unit, and outputs the pseudo vertical synchronizing pulse to the microcomputer. Start counting from the pseudo-vertical synchronous pulses, generate a noise detection pulse synchronized with any one of the plurality of horizontal synchronous pulses included in the blanking period, and output the noise detection pulse to the noise measuring unit, wherein the noise measuring unit outputs to the noise detection pulse. And a level of the noise component incorporated in the synchronized horizontal synchronization pulses. The method of claim 5, wherein the microcomputer, The sharpness level divided by each step is tabled and stored, the sharpness level corresponding to the detected level of the noise component is detected, and the sharpness control signal according to the detected sharpness level is output to the image controller. Noise reduction method characterized in that. The method of claim 7, wherein the sharpness control signal, Noise reduction method characterized in that the same clarity is applied to one frame of the video signal.