JP2000209464A - Television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain optimum image quality in response to a noise quantity of a video signal by optimally controlling a gain and a coring amount of an image quality improvement circuit in response to the noise amount of a received video signal and providing a field cyclic type noise reduction circuit to a post- stage of the image quality improvement circuit so as to optimally control its cyclic coefficient depending on the noise amount. SOLUTION: Afield cyclic noise reduction circuit 101 detects a noise amount of a video signal from the A/D converted video signal and the detected noise amount is fed to a microcomputer 106 via an IIC bus 10. The field cyclic noise reduction circuit 101 uses a field memory 102 to detect a motion of each pixel of the video signal. The microcomputer 106 controls the cyclic coefficient of the noise reduction circuit in response to a degree of a motion of each pixel and the noise amount obtained through the IIC bus 10 to be an optimum noise reduction amount through the IIC bus. The video signal whose noise is optimally reduced is given to a plurality of circuits, where the image quality is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver having a horizontal contour correction circuit, a peaking circuit, a vertical contour correction circuit, and a speed modulation signal generation circuit as an image quality improvement circuit disposed downstream of a field cyclic noise reduction circuit. Optimally controls the gain and coring amount of the image quality improvement block according to the amount of noise of the video signal input in
The present invention relates to a television receiver that provides optimal image quality according to the amount of noise.

[0002]

2. Description of the Related Art As a conventional technique, Japanese Utility Model Laid-Open No. 5-155 is used.
As described in Japanese Patent Application Publication No. 72-72, a contour enhancement effect variable circuit applies a contour enhancement effect to a video signal that has passed through a noise reduction circuit with a contour enhancement effect that is opposite to the noise reduction effect of the noise reduction circuit. When the noise reduction effect of the noise reduction circuit is set to a large value, the outline enhancement is suppressed. Conversely, when the noise reduction effect of the noise reduction circuit is set to a small value, the degree of the outline enhancement is increased to improve the image quality. There is an image processing apparatus in which an appropriate image quality is improved by a synergistic effect of noise reduction and edge enhancement.

Further, as described in Japanese Patent Application Laid-Open No. 8-98058, a subtraction process is performed between the same signal waveforms periodically arranged in a video signal to obtain a difference signal, and the original value becomes zero. A noise measuring circuit for measuring an additional noise component of a transmission system appearing in a power signal period, and a contour adjusting circuit for adjusting a degree of contour emphasis of a signal corresponding to a video signal based on an output of the noise measuring circuit. there were.

[0004]

However, the above-mentioned conventional technique does not apply to a signal after noise reduction processing.
A / D conversion is performed and the effect level is controlled by the information from the contour emphasis effect variable circuit by the contour emphasis circuit. However, only the vertical contour correction circuit is used as the contour emphasis circuit, and the horizontal contour correction circuit is used. The peaking circuit and the speed modulation signal generating circuit have not been controlled according to the amount of noise reduction. In addition, there is no field recursive noise reduction circuit in front of the image quality improvement circuit, and the overall image quality is linked by linking the cyclic coefficient of the field recursive noise reduction circuit with the gain and coring amount of the image quality improvement circuit. There was no one that improved.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides not only a vertical contour correction circuit but also a horizontal contour correction circuit, a peaking circuit, and a speed modulation signal generation circuit according to the amount of noise in an input video signal. By optimally controlling the gain and coring amount of the circuit, and having a field recursive noise reduction circuit arranged downstream of the image quality improving circuit, the cyclic coefficient is optimally controlled according to the noise amount. Optimal image quality can be provided according to the amount of noise in the video signal.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first invention of the present invention is as follows.
Noise reduction of an input video signal in a television receiver having a horizontal contour correction circuit, a peaking circuit, a vertical contour correction circuit, and a speed modulation signal generation circuit after subjecting the A / D converted video signal to noise reduction processing A television receiver characterized by achieving both noise reduction and image quality improvement by optimally controlling the gain and coring amount of these circuits according to the Optimum image quality can be provided according to the situation.

Further, according to a second aspect of the present invention, the gain and coring amount of the horizontal contour correction circuit, peaking circuit, vertical contour correction circuit, and velocity modulation signal generation circuit of the image quality improvement block are
It can be controlled by the IIC bus, and automatically corrects the gain and coring amount of the image quality improvement block via a microcomputer according to the amount of noise detected by the noise detection circuit.
This is a television receiver characterized by performing optimal control through the C bus, and can provide an optimal image quality according to the amount of noise of a video signal. Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

(Embodiment 1) FIG. 1 is a system configuration diagram of an image quality improving method according to a noise amount in one embodiment of the present invention. In FIG. 1, reference numeral 101 denotes a field recursive noise reduction circuit, 102 denotes a field memory for the field recursive noise reduction circuit, 103 denotes an image quality improvement circuit, 104 denotes an RGB processing circuit, 105 denotes a CRT, and 106 denotes a microcomputer. The operation of the image quality improving method according to the noise amount configured as described above will be described below.

In FIG. 1, an A / D-converted video signal is subjected to a field recursive noise reduction circuit 101 to detect the amount of noise in the video signal. The detected noise amount is II
It is transmitted to the microcomputer 106 through the C bus 10. The field recursive noise reduction circuit 101 uses the field memory 102 to perform motion detection on each pixel of the video signal. The microcomputer 106 controls the cyclic coefficient of the noise reduction circuit through the IIC bus 11 so that the optimal noise reduction amount is obtained according to the noise amount obtained through the IIC bus 10 and the degree of motion of each pixel.

The video signal whose noise has been optimally reduced is subjected to a horizontal contour correction circuit, a peaking circuit,
Image quality improvement processing is performed by a vertical contour correction circuit and a speed modulation signal generation circuit. Further, the amount of noise during the vertical blanking period of the video signal is detected.
It is transmitted to the microcomputer 106 through the IIC bus 12. The microcomputer 106 calculates the horizontal contour correction circuit, the peaking circuit, the vertical contour correction circuit, and the like according to a constant calculation formula programmed internally according to the amount of noise transmitted from the IIC bus 12.
Each gain and coring amount of the speed modulation signal generation circuit are calculated.

The calculated gain and coring amount of each circuit are transmitted to the image quality improvement circuit 103 through the IIC bus 13 and are subjected to optimal image quality control according to the amount of noise. Further, the video signal is D / A converted by the image quality improvement circuit 103.
The signal is converted to an RGB primary color signal by the RGB
Displayed on the CRT at 05. The speed modulation signal generated by the speed modulation signal generation circuit is processed by the image quality improvement circuit 103.
The D / A conversion is performed and transmitted to the speed modulation coil of the CRT 105 to obtain an optimum speed modulation effect according to the noise amount.

(Embodiment 2) An embodiment of a block configuration and a control flow in an image quality improvement circuit block according to the present invention will be described with reference to FIG.

In FIG. 2, an image quality improving circuit includes a vertical contour correcting circuit 21, line memories 201 and 202 for obtaining a vertical contour correcting signal, a horizontal contour correcting circuit 21, a peaking circuit 22, a speed modulation signal generating circuit 23, and a D / A. It comprises converters 213 and 214 and a noise detection circuit 24.

From the video signal input to the image quality improving circuit, only the high frequency component of the video signal is extracted by the noise detection circuit 24 by the high-pass filter 218, and the noise amount is measured by the vertical blanking period noise detection circuit 219. The measured noise amount is transmitted to the microcomputer via the IIC bus 25. Separately, the video signal is supplied to a vertical contour correction circuit 20.
The line memories 201 and 202 are used to apply low-pass filters 203, 204, and 205 to each line, to extract only low-frequency components, and to add them to perform coring processing 206.

The video signal that has passed through the vertical contour correction circuit is
First-order differentiation is performed by the first-order differentiating circuit 207 in the horizontal contour correction circuit 21, and the coring circuit 208 and the gain adjusting circuit 20 are used.
9 are performed. The peaking circuit 22 is secondarily differentiated by the second differentiating circuit 210, subjected to the processing of the coring circuit 211 and the gain adjusting circuit 212, added by the adder, and further added to the video signal to obtain a signal whose outline is emphasized.
The signal is converted into an analog signal by the D / A converter 213. The signal that has passed through the horizontal contour correction circuit and the peaking circuit is first-order differentiated by a first-order differentiation circuit 214 by a velocity modulation signal generation circuit 23, and gain and coring amount are corrected by a gain adjustment circuit 215 and a coring circuit 216. The signal is converted into an analog signal by the D / A converter 217.

The coring circuit 2 of the vertical contour correction circuit 23
06 and coring circuit 20 of horizontal contour correction circuit 21
8, the coring circuit 211 of the gain adjustment circuit 20 and the peaking circuit 22, the gain adjustment circuit 212, the gain adjustment circuit 215 of the speed modulation signal generation circuit, and the coring circuit 216 are controlled by the microcomputer via the IIC bus 26.

(Embodiment 3) An embodiment of a control method according to the noise amount of each coring circuit and gain adjustment circuit of the image quality improvement circuit according to the present invention will be described with reference to FIG. In FIG. 3, NOI is data of the amount of noise transmitted from the noise detection circuit of the image quality improvement circuit via the IIC bus.

The control of the coring amount of each circuit is calculated by a control formula Fk as shown in FIG. Parameters in control expressions
A, B, and C can be set independently for each circuit. If the noise level of the input signal is very good,
Since NOI becomes zero, the value of C in the calculation formula is transmitted to each circuit as a coring amount. When the noise level of the input signal gradually deteriorates, the value of NOI increases, and a value obtained by adding C to a value obtained by multiplying NO / B / A is transmitted to each circuit as a coring amount. This makes it possible to suppress noise enhancement by continuously changing the coring amount according to the noise amount of the input signal.

Next, the gain control of each circuit is calculated by the control formula Fg as shown in FIG. Parameters A, B, C, and D in the control formula can be set independently for each circuit. However, when the NOI is zero, the value of the control formula Fg becomes infinite, so the NOI is set to 1 at this time. As the noise level of the input signal gradually deteriorates, the value of the denominator of the control formula Fg increases, and the gain amount continuously decreases as the noise increases. By continuously changing the coring amount and the gain amount according to the noise amount of the input video signal, it is possible to always optimally control the noise.

[0020]

As described above, according to the image quality improving method of the television receiver of the present invention, it is possible to provide the optimum image quality according to the noise amount of the input video signal.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an image quality improvement method according to a noise amount according to an embodiment of the present invention.

FIG. 2 is a block diagram of an image quality improvement circuit block according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a control method according to a noise amount of each coring circuit and a gain adjustment circuit of the image quality improvement circuit according to the present invention.

[Explanation of symbols]

10, 11, 12, 13 IIC bus 101 Field cyclic noise reduction circuit 102 Field memory 103 Image quality improvement circuit 104 RGB processing circuit 105 CRT 106 Microcomputer 20 Vertical contour correction circuit 21 Horizontal contour correction circuit 22 Peaking circuit 23 Speed modulation signal generation circuit Reference Signs List 24 Noise detection circuit 25, 26 IIC bus 201 Line memory 202 Line memory 203, 204, 205 Low pass filter 206 Coring circuit of vertical contour correction circuit 207 First derivative circuit of horizontal contour correction circuit 208 Coring circuit of horizontal contour correction circuit 209 Gain adjustment circuit of horizontal contour correction circuit 210 Secondary differentiation circuit of peaking circuit 211 Coring circuit of peaking circuit 212 Gain adjustment circuit of peaking circuit 213 D / A converter for video signal 214 Speed change Primary differentiation circuit of signal generation circuit 215 Gain adjustment circuit of speed modulation signal generation circuit 216 Coring circuit of speed modulation signal generation circuit 217 D / A converter for speed modulation signal generation circuit 218 High-pass filter of noise detection circuit 219 Noise detection circuit Vertical blanking period noise detection circuit

Claims (5)

[Claims] 1. A television receiver having an image quality improvement circuit after a noise reduction circuit, wherein the gain and coring amount of these circuits are optimally controlled. 2. A horizontal contour correction circuit, a peaking circuit, after performing a noise reduction process on an A / D converted video signal.
In a television receiver having a vertical contour correction circuit and a velocity modulation signal generation circuit, noise reduction and noise reduction can be achieved by optimally controlling the gain and coring amount of these circuits in accordance with the amount of noise in the input video signal. A television receiver characterized by improving image quality. 3. A noise reduction circuit having a field recursive noise reduction circuit preceding the image quality improvement circuit for an input video signal, wherein a recursive coefficient is optimally controlled according to the amount of noise to achieve optimal noise reduction. Television receiver. 4. A noise detecting circuit for detecting an amount of noise in a vertical blanking period as means for detecting an amount of noise in an image quality improving circuit of an input video signal, wherein the amount of noise is detected.
A television receiver having a circuit for inputting data to a microcomputer through an IIC bus. 5. A horizontal contour correction circuit for an image quality improvement block,
The gain and coring amount of the peaking circuit, vertical contour correction circuit, and velocity modulation signal generation circuit can be controlled by the IIC bus. The gain and the quality of the image quality improvement block are controlled via the microcomputer according to the noise amount detected by the noise detection circuit. A television receiver characterized by automatically correcting the coring amount and performing optimal control over the IIC bus.