JP2000059650A - Horizontal contour correction device - Google Patents

Abstract

(57) Abstract: Provided is a horizontal contour correction device capable of enhancing the effect of horizontal contour correction of a video without increasing the gains of a video signal correction circuit and a speed modulation circuit. SOLUTION: A video signal correction circuit 1 performs an outline correction in which a black portion is thick and a white portion is thin at a contrast boundary of an original horizontal luminance signal (a) of an input video. The speed modulation circuit 2 receives the corrected signal (h) output from the video signal correction circuit 1, and receives a second-order differentiated speed modulation signal (i).
Generate By controlling the drive of the speed modulation coil 3 based on the speed modulation signal (i), the CRT
5, it is possible to reproduce an image in which the white portion is thinner and tighter than in the related art.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal contour correcting apparatus, and more particularly to a horizontal contour correcting apparatus used in an apparatus for projecting an image by scanning an electron beam on a picture tube such as a television receiver. The present invention relates to a horizontal contour correction device that performs a process of correcting a contour.

[0002]

2. Description of the Related Art Conventionally, a method of correcting a horizontal contour (hereinafter, abbreviated as a horizontal contour) of an image in a television receiver or the like includes a method of correcting an image signal and a method of correcting the image signal using a speed modulation device. There are two ways to do this.

First, a method of correcting a video signal is a method of directly processing and correcting a horizontal luminance signal itself of a video by a video signal correction circuit or the like, and there are the following two methods. One of them is a correction method for adding a preshoot and an overshoot to an edge portion of a horizontal luminance signal as shown in FIG. 6A (hereinafter, referred to as a first correction). The other is a correction method in which black portions are thick and white portions are thin at the contrast boundary of the horizontal luminance signal as shown in FIG. 6B (hereinafter, referred to as second correction). By performing the first or second correction, the rise and fall of the horizontal luminance signal become steep, and the horizontal contour of an image having a contrast difference can be made clear.

On the other hand, the method of correcting using a speed modulation device is a method of correcting by controlling scanning of an electron beam on a picture tube (CRT) using a speed modulation device (hereinafter, a third method). Correction). This velocity modulation device is a technique already known to those skilled in the art, and the description thereof will be omitted. However, the effect of the third correction is the same as that obtained by performing the first and second corrections simultaneously. The effect of can be obtained.

[0005] In general, in a conventional television receiver, a horizontal contour correction device that combines either the first or second correction with the third correction is used to provide a horizontal contour with a higher effect. Correction has been performed. FIG. 7 is a block diagram showing a part of the configuration of a television receiver using a conventional horizontal contour correction device in which the second correction and the third correction are combined.

[0006]

Here, in the above-mentioned conventional horizontal contour correction device shown in FIG. 7, when the horizontal contour correction with a higher effect is to be performed, the video signal correction circuit 1 and the speed modulation circuit 2 need not be used. The only option is to increase the gain.

However, if the gain is excessively increased in the video signal correction circuit 1, a portion that does not need to be corrected is also corrected, and the portion appears as noise on the video. Further, in the speed modulation circuit 2, due to problems such as ringing and dynamic range due to its configuration, there is a limit to increasing the gain to increase the effect of correction.

Therefore, it is an object of the present invention to increase the gains of the video signal correction circuit 1 and the speed modulation circuit 2 without increasing the gain.
An object of the present invention is to provide a horizontal contour correction device that can enhance the effect of horizontal contour correction of an image.

[0009]

Means for Solving the Problems and Effects of the Invention The first invention is used in a device for projecting an image by scanning an electron beam on a picture tube, and a horizontal direction signal for an original horizontal luminance signal of an input image is used. A horizontal contour correction device for performing a process of correcting a contour, a signal correction unit that receives an original horizontal luminance signal and outputs a corrected horizontal luminance signal obtained by performing a predetermined correction on the original horizontal luminance signal, Speed correction means for receiving the corrected horizontal luminance signal output from the signal correction means and outputting a modulation signal for controlling the speed modulation of the picture tube based on the corrected horizontal luminance signal.

As described above, according to the first aspect, the corrected horizontal luminance signal output from the signal correction means is used as an input signal to the speed modulation means. As a result, the modulation signal output from the speed modulation unit is a signal obtained by superimposing the correction of the speed modulation unit on the correction of the signal correction unit. Therefore, a high contour correction effect can be obtained without increasing the gains of the signal correction unit and the speed modulation unit.

According to a second aspect of the present invention, in the first aspect, the predetermined correction to be performed by the signal correction means is a correction to make a black portion thick and a white portion thin at a contrast boundary of the original horizontal luminance signal. It is characterized by.

As described above, according to the second aspect, the first aspect
The predetermined correction according to the invention is a correction in which a black portion is made thicker and a white portion is made thinner at a contrast boundary of an original horizontal luminance signal. By performing this correction, a higher contour correction effect can be obtained.

According to a third aspect of the present invention, in the second aspect, a switch means for selectively switching either the original horizontal luminance signal or the corrected horizontal luminance signal is provided as an input to the velocity modulation means. Features.

As described above, according to the third aspect, the second aspect
In the invention of the fifth aspect, switch means for switching whether the input of the speed modulation means is an original horizontal luminance signal or a corrected horizontal luminance signal is provided. As a result, it is possible to always obtain the optimal contour correction effect selectively.

According to a fourth aspect, in the third aspect, the switching of the switch means is controlled based on a microcomputer output.

As described above, according to the fourth aspect, the third aspect
The switching of the switch means in the invention according to the invention can be externally controlled. As a result, the user can easily select the contour correction level, so that usability is improved.

A fifth invention is a television receiver for projecting an image on a picture tube after correcting an outline in a horizontal direction with respect to an original horizontal luminance signal of an input image, wherein the original horizontal luminance signal is inputted. A signal correction unit that outputs a corrected horizontal luminance signal obtained by performing a predetermined correction on the original horizontal luminance signal, and a corrected horizontal luminance signal output by the signal correction unit, and based on the corrected horizontal luminance signal. Speed modulation means for outputting a modulation signal for controlling the speed modulation of the picture tube;

As described above, according to the fifth aspect, the corrected horizontal luminance signal output from the signal correction means is used as an input signal to the speed modulation means. As a result, the modulation signal output from the speed modulation unit is a signal obtained by superimposing the correction of the speed modulation unit on the correction of the signal correction unit. Therefore, a high contour correction effect can be obtained without increasing the gains of the signal correction unit and the speed modulation unit.

A sixth aspect of the present invention is characterized in that the predetermined correction applied by the signal correction means is a correction for making the black portion thick and the white portion thin at the contrast boundary of the original horizontal luminance signal.

As described above, according to the sixth aspect, the fifth aspect
The predetermined correction according to the invention is a correction in which a black portion is made thicker and a white portion is made thinner at a contrast boundary of an original horizontal luminance signal. By performing this correction, a higher contour correction effect can be obtained.

According to a seventh aspect of the present invention, there is further provided a switch as an input to the speed modulator, which can selectively switch either the original horizontal luminance signal or the corrected horizontal luminance signal.

As described above, according to the seventh aspect, the sixth aspect
In the invention of the fifth aspect, switch means for switching whether the input of the speed modulation means is an original horizontal luminance signal or a corrected horizontal luminance signal is provided. As a result, it is possible to always obtain the optimal contour correction effect selectively.

The eighth invention is characterized in that the switching of the switch means is controlled based on the microcomputer output.

As described above, according to the eighth aspect, the seventh aspect
The switching of the switch means in the invention according to the invention can be externally controlled. As a result, the user can easily select the contour correction level, so that usability is improved.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The horizontal contour correcting apparatus of the present invention can be used for an apparatus which projects an image on a picture tube (CRT) by scanning with an electron beam. In the following embodiments, a television receiver will be described. The case where it is used is described.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
It is a block diagram which shows a part of structure of the television receiver using the horizontal contour correction apparatus which concerns on 1st Embodiment. In FIG. 1, the horizontal contour correction device according to the first embodiment includes a video signal correction circuit 1 and a speed modulation circuit 2.

The video signal correction circuit 1 performs the above-described second correction on the horizontal luminance signal of the input video and outputs the result. The speed modulation circuit 2 receives the corrected signal output from the video signal correction circuit 1 and expresses a predetermined speed modulation correction effect on the CRT 5 by controlling the speed modulation coil 3. The video signal processing circuit 4 inputs the horizontal luminance signal output from the video signal correction circuit 1 and the color signal output from another circuit (not shown), performs predetermined processing, and then outputs the processed signal to the CRT 5. Output. The CRT 5 scans an electron beam under control of a deflection coil (not shown) and a modulation coil based on an input signal.

Hereinafter, with further reference to FIGS. 2 and 3,
The operation of the horizontal contour correction device according to the first embodiment will be described. FIG. 2 is a block diagram showing a more detailed configuration of the video signal correction circuit 1 of FIG. FIG. 3 is a diagram showing signal waveforms at various points in FIG. In addition, (a) of FIG.
(H) corresponds to each symbol in FIG.

First, with reference to FIGS. 2 and 3, a description will be given of a second correction performed by the video signal correction circuit 1, that is, a correction method in which black portions are thick and white portions are thin at the contrast boundary of the original horizontal luminance signal. I do. 2, the video signal correction circuit 1 includes differentiating units 11 and 12 and a full-wave rectifying unit 1.
3; an adder 14; a minimum value detector 15; a shoot remover 16;

The original horizontal luminance signal (a) is input to the differentiator 11. The differentiating unit 11 outputs a first differentiated signal (b) obtained by differentiating the input original horizontal luminance signal (a). The differentiator 12 receives the first differential signal (b),
Further, a second differential signal (c) subjected to the differential processing is output. On the other hand, the full-wave rectifier 13 receives the first differential signal (b) and outputs a full-wave rectified signal (d). The adder 14 receives the second differential signal (c) and the full-wave rectified signal (d), and outputs an addition signal (e) obtained by adding both. The minimum value detection unit 15 receives the full-wave rectified signal (d) and the addition signal (e), detects the minimum value of both signals at each signal point, and sets it as the minimum value signal (f). Output. The shoot removing unit 16 outputs the minimum value signal (f).
And outputs a correction signal (g) from which the white-side shot waveform has been removed. Then, the subtractor 17 subtracts the correction signal (g) from the original signal (a) and outputs a corrected horizontal luminance signal (h) subjected to the second correction.

Next, referring to FIGS. 1 and 3, the corrected horizontal luminance signal (h) is input to the speed modulation circuit 2 as described above. The speed modulation circuit 2 performs a predetermined process on the corrected horizontal luminance signal (h) and outputs a speed modulation signal (i) for controlling the driving of the speed modulation coil 3. On the other hand, the corrected horizontal luminance signal (h) is output to the CRT 5 via the video signal processing circuit 4.

As described above, the television receiver using the horizontal contour correcting device according to the first embodiment applies velocity modulation to the corrected horizontal luminance signal (h) based on the velocity modulation signal (i). Thus, a visual effect as shown in FIG. 4K can be obtained. FIG. 4 shows signal waveforms of a television receiver using the horizontal contour correction device according to the first embodiment shown in FIG. 1 and a television receiver using the conventional horizontal contour correction device shown in FIG. It is a figure which shows the difference of an effect. In addition, (a) of FIG. 4, (h), (i),
(I '), (k) and (k') correspond to the respective portions in FIGS. 1 and 7, respectively.

As described above, the horizontal contour correction device according to the first embodiment of the present invention uses the signal subjected to the second correction by the video signal correction circuit 1 as the input signal to the speed modulation circuit 2. Therefore, the speed modulation signal (i) for controlling the driving of the speed modulation coil 3 is two times the original horizontal luminance signal (a).
The signal is the second derivative. Thereby, in the television receiver using the horizontal contour correction device according to the first embodiment, the effect of the horizontal contour correction of the video can be enhanced without increasing the gain in the video signal correction circuit 1 and the speed modulation circuit 2. it can.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
It is a block diagram which shows a part of structure of the television receiver using the horizontal contour correction apparatus which concerns on 1st Embodiment. 5, the horizontal contour correction device according to the second embodiment includes a video signal correction circuit 1, a speed modulation circuit 2, and a changeover switch 6.

As shown in FIG. 5, the horizontal contour correcting device according to the second embodiment is obtained by further adding a changeover switch 6 to the configuration of the horizontal contour correcting device according to the first embodiment. The other configuration of the horizontal contour correction device according to the second embodiment is the same as the configuration of the horizontal contour correction device according to the first embodiment.

The changeover switch 6 is a switch for selectively switching either the original horizontal luminance signal (a) or the corrected horizontal luminance signal (h) after the second correction as an input signal to the speed modulation circuit 2. When the corrected horizontal luminance signal (h) is selected as the input signal of the speed modulation circuit 2, the first
This is equivalent to the horizontal contour correction device according to the first embodiment, and the effect of the horizontal contour correction described in the first embodiment can be enhanced. On the other hand, as an input signal of the speed modulation circuit 2,
When the original horizontal luminance signal (a) is selected, it becomes equivalent to the horizontal contour correction device according to the above-described conventional embodiment, and the effect of the conventional level of horizontal contour correction can be obtained.

As described above, the horizontal contour correction apparatus according to the second embodiment of the present invention uses the original horizontal luminance signal (a) or the corrected horizontal Any of the luminance signals (h) can be selectively used. Thereby, in the television receiver using the horizontal contour correction device according to the second embodiment, the level of the horizontal contour correction can be selectively switched according to the state of the input video signal or the preference of the user or the like. .

The changeover switch 6 of the horizontal contour correcting device according to the second embodiment can be switched from the outside by an instruction of a remote controller or the like using a microcomputer or the like included in a television receiver. it can. In this case, the user or the like can easily select the horizontal contour correction level of the video.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a part of a configuration of a television receiver using a horizontal contour correction device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a more detailed configuration of the video signal correction circuit 1 of FIG.

FIG. 3 is a diagram showing signal waveforms at various points in FIG. 2;

FIG. 4 is a diagram showing signal waveforms of a television receiver using the horizontal contour correction device according to the first embodiment shown in FIG. 1 and a television receiver using the conventional horizontal contour correction device shown in FIG. It is a figure which shows the difference of an effect.

FIG. 5 is a block diagram illustrating a part of a configuration of a television receiver using a horizontal contour correction device according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a method of processing a horizontal luminance signal performed by a video signal correction circuit.

FIG. 7 is a block diagram illustrating a part of a configuration of a television receiver using a conventional horizontal contour correction device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Video signal correction circuit 2 ... Speed modulation circuit 3 ... Speed modulation coil 4 ... Video signal processing circuit 5 ... CRT 6 ... Changeover switch 11, 12 ... Differentiator 13 ... Full-wave rectifier 14 ... Adder 15 ... Minimum value detection Unit 16: Shoot removal unit 17: Subtraction unit

Claims (8)

[Claims] 1. A horizontal contour correction device used in a device for projecting an image by scanning an electron beam on a picture tube and performing a process of correcting a horizontal contour of an original horizontal luminance signal of an input image. A signal correcting unit that receives the original horizontal luminance signal, outputs a corrected horizontal luminance signal obtained by performing a predetermined correction on the original horizontal luminance signal, and outputs the corrected horizontal luminance signal output by the signal correcting unit. A speed modulation means for inputting and outputting a modulation signal for controlling the speed modulation of the picture tube based on the corrected horizontal luminance signal. 2. The method according to claim 1, wherein the predetermined correction performed by the signal correction unit is a correction that makes a black part thick and a white part thin at a contrast boundary of the original horizontal luminance signal. 5. The horizontal contour correction device according to 1. 3. The apparatus according to claim 2, further comprising a switch as an input to said speed modulation means, said switch means being capable of selectively switching either said original horizontal luminance signal or said corrected horizontal luminance signal. 5. The horizontal contour correction device according to 1. 4. The horizontal contour correcting device according to claim 3, wherein switching of said switch means is controlled based on a microcomputer output. 5. An original horizontal luminance signal of an input video,
A television receiver for displaying an image on a picture tube after correcting a contour in a horizontal direction, wherein the corrected horizontal luminance is obtained by inputting the original horizontal luminance signal and performing a predetermined correction on the original horizontal luminance signal. Signal correction means for outputting a signal; and a speed at which the corrected horizontal luminance signal output from the signal correction means is input and a modulation signal for controlling speed modulation of the picture tube is output based on the corrected horizontal luminance signal. A television receiver comprising at least modulation means. 6. The predetermined correction performed by the signal correction means is a correction for making a black part thick and a white part thin at a contrast boundary of the original horizontal luminance signal. 3. The television receiver according to item 1. 7. The apparatus according to claim 6, further comprising a switch as an input of said velocity modulation means, capable of selectively switching either said original horizontal luminance signal or said corrected horizontal luminance signal. 3. The television receiver according to item 1. 8. The television receiver according to claim 7, wherein switching of said switch means is controlled based on a microcomputer output.