JPS6248178A - Vertical outline compensating circuit of television receiver - Google Patents

Abstract

PURPOSE:To obtain a clear picture in a vertical outline part by differentiating a vertical direction of a picture by the use of a 1H delay element, auxiliarily operating a vertical magnetic field of a cathode ray tube by an obtained control signal and compensating an outline on a vertical outline part of the picture. CONSTITUTION:To a video input terminal 101, a video signal (a) having a slow leading outline part in a vertical direction of a picture is added, a video signal (b) delayed by one horizontal period is obtained by a 1H delay element 102, and further, a video signal (c) delayed by another one horizontal period is obtained by a 1H delay element 103. Then, they are made signals multiplied by prescribed coefficients, respectively in coefficient circuits 104-106. Thereafter, a compensating signal of a luminance changing in the outline part is obtained in an adder 107, amplified in an output drive circuit 108, impressed to a vertical deflecting main coil 110 through an output circuit 109, a main magnetic field generated by the vertical deflecting main coil 11 in an auxiliary magnetic field through an auxiliary deflecting current is compensated to change a vertical scanning speed of an electronic beam. Thereby the vertical outline part becomes steep and a clear picture of the vertical outline part can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a general television receiver, and particularly to a vertical contour compensation circuit suitable for making vertical contours clear.

[Background of the invention]

A conventional device is described in Japanese Utility Model Publication No. 58-23171, and will be explained below with reference to the drawings.

FIG. 8 is an example of a conventional contour compensation device, and is a block diagram showing a horizontal scanning speed modulation circuit of a television receiver. In the figure, 801 is a video signal input terminal;
2 is a chroma circuit and a delay circuit for compensating the signal delay of the luminance circuit; 803 and 805 are differentiating circuits;
04 can width circuit, 806 is output drive and output circuit,
807 is an auxiliary deflection coil, 808 is a main coil for horizontal deflection, and 112 is a cathode ray tube. The operation of Fig. 8 will be explained using the waveform diagram of Fig. 9. First, the video signal input terminal 80
Add to 1 a movie with a slow rise and fall part as shown in Figure 9 (G).

This video signal) is delayed by a delay circuit 802 and then differentiated by a first differentiating circuit 803, and the -
Obtain the second derivative signal. This -order differential signal (I3) is a signal that detects the contour part of the video signal (5), but here it does not have a perfect differential waveform due to the influence of the circuit time constant and stray capacitance, and the triangular It is approximated by The first-order differential signal (B) thus obtained is amplified by an amplifier circuit 804 and then applied to a second differential circuit 805 to obtain a second-order differential signal shown in FIG. 90. Here again, as mentioned above, the waveform is approximated by a triangular wave. The second-order differential signal (0) thus obtained is amplified by an output circuit 806 and then applied to an auxiliary deflection coil 807 provided at the neck of the cathode ray tube 1112, and its auxiliary deflection current scans the shimiko beam. Vary the speed.

At this time, if the second-order differential signal (Q) is applied to the auxiliary deflection coil 807, the flow will be an integrated waveform as shown in FIG. % of such auxiliary deflection coil 807
The equal-single deflection current corresponding to the total deflection magnetic field obtained by adding the auxiliary deflection magnetic field due to the current 0 to the main deflection magnetic field due to the main deflection coil 80B is as shown in FIG.

Therefore, during the tl and t4 periods of this equivalent deflection flow (2), the scanning speed is accelerated and the brightness on the screen becomes dark.
2. During the t3 period, the scanning speed is reduced and the brightness becomes brighter. Therefore, on the screen, as shown in FIG. 90, the scanning speed at the rising and falling parts of the video signal (8) is 1ll
tlJ thank you, in the rising part, the latter part 2
The brightness suddenly becomes brighter in the area 1, and the brightness becomes darker in the other part 1.

In addition, in the falling part, the brightness suddenly becomes brighter in the creation part 6, and becomes clearer in the other parts 4. As a result, the brightness change becomes steeper in the brightness change part such as the outline part of the image. Because of this, it is possible to improve the painting resources for a section in the horizontal direction.

However, in the conventional example mentioned above, although the horizontal contour is compensated, no consideration is given to the vertical contour, and only one-dimensional processing is performed, contrary to the two-dimensional nature of the image. Therefore, there is a problem that the best image quality cannot necessarily be obtained.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that also performs scanning speed modulation in the vertical direction of a television receiver and can obtain clear images of vertical contours.

[Summary of the invention]

The present invention uses a 1H delay element to replace the image differentiation circuit for horizontal contour compensation in the conventional example, and uses a control signal obtained by performing vertical differentiation of the image to supplement the vertical magnetic field of the cathode ray tube. By performing this operation, contour compensation is also performed on the vertical contour portion of the image, resulting in more natural contour compensation.

[Embodiments of the invention]

A first embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 101 is a video signal input terminal, 102
and 103 is a 1H delay element, 104 and 106 are i
Coefficient circuit, 105 is 11 coefficient circuit 107 is adder, 10
8 is an output drive circuit, 109 is an output circuit, 110 is an auxiliary coil for vertical deflection provided at the neck of the cathode ray tube, 111 is a main coil for vertical deflection, and 112 is the cathode ray tube.

The operation of path (b) in FIG. 1 will be explained with reference to the waveform diagram in FIG. 2.

A video signal (α) having a slowly rising edge in the vertical direction of the image as shown in FIG. 2 (α) is applied to the video input terminal 101 in FIG. α) is applied to the 1H delay element 102 to obtain a video signal (b) delayed by −1,000 periods. Further, this 1H delayed video signal (b) is passed through a 1H delay element 103 having the same characteristics as the 1H delay element 102, and becomes a video signal (C) delayed by one more horizontal period. As a delay element,
Analog delay elements such as charge-coupled devices (CODs) and
Use digital memory such as H memory or RAM.

Video signals (α) and (b) obtained in this way.

(C) are respectively input to coefficient circuits 104, 105, and 106 and output as signals multiplied by a predetermined coefficient, and then an adder 107 obtains a compensation signal (d) for the brightness change in the contour portion of the video signal.

This compensation signal (d) is amplified by the output drive circuit 108 and input to the output circuit 109 that generates a coil drive current, and then applied to the vertical deflection auxiliary coil 110 provided at the neck of the cathode ray tube 112. The auxiliary magnetic field generated by the auxiliary deflection current compensates for the main magnetic field generated by the vertical deflection main coil 111, and changes the vertical scanning speed of the electron beam.

The current waveform flowing through the auxiliary coil 110 at this time is shown in Figure 2 (
e).

The auxiliary deflection magnetic field created by the auxiliary deflection current (e) #t is applied to the auxiliary deflection coil 110 as shown in FIG.
In addition to the main deflection magnetic field due to 11, when the ``separate beam'' is deflected, the equivalent deflection of the deflection system corresponding to the total deflection magnetic field ``#L flow is shown in Figure 2 (f). In the same figure, the vertical axis is the equivalent deflection. '1 flow value, the horizontal axis is the vertical scanning time, and the period from one end of the solid line to the other is one vertical scanning period.

Therefore, in the 0 portion of the equivalent deflection current (f), the scanning line scans slightly below the normal scanning position on the TV screen, and in the ■ portion, it scans slightly above the normal scanning position, so that the image The vertical contours become bright and dark, making it possible to correct the vertical contours.

Here, the main deflection magnetic field of this embodiment is generated in synchronization with the 1H-delayed video signal (in FIG. 2), and the television image is displayed as the video signal (in FIG. 2).

A diagram explaining the above operation is FIG. 6, in which the horizontal axis is the vertical scanning direction, the vertical axis is the brightness level, and the direction perpendicular to the drawing is the horizontal scanning direction. Circle mark A-
E corresponds to the image portion A-E in FIG. 2(b), and is modulated in vertical scanning velocity by the auxiliary deflection current in FIG. 2(e).

As a result, the circles A and Bij in Figure 3 are A'B', respectively.
Since the vertical contour is scanned, the vertical contour becomes steep, and a sharp and clear image of the vertical contour can be obtained.

Next, a second embodiment will be described. FIG. 4 is a circuit block diagram showing the second embodiment, in which 401 is a subtracter;
02 is an output drive circuit for the vertical deflection main coil 111;
403 is a subtraction circuit, 404 is a vertical output circuit for the main coil 111, and the same numbers as in FIG. 1 indicate the same functions. 5 is a waveform diagram for explaining the operation of FIG. 4, and using this diagram, the operation of the second embodiment will be explained.

The video signal shown in FIG. 5(5) is inputted to the video input terminal 101, and passes through the IH:M extension element 102 to obtain the hacksaw signal shown in FIG. 5(13) with a delay of one minute. The difference between this signal 0 and the original video signal is outputted by the subtracter 401, and becomes a vertical contour compensation signal 0.

This signal is amplified by the next stage output drive circuit 108 and input to the subtraction circuit 403 or
3.Other inputs are the conventional drip r1! This is a vertical deflection sawtooth wave signal output from the output drive circuit 402 of the deflection main coil. Due to the above operation, the subtraction circuit 403 outputs the fifth
As shown in Figure (F), a signal compensated for the vertical contour of the same image is obtained, and when this is input to the output circuit 404, a deflection current is applied to the main coil 111 at the neck of the cathode ray tube 112.
flows, and a deflection magnetic field is created. Here, the signal in FIG. 5(d) is a sawtooth wave signal having a period of one period, and the vertical contour portion is shown in an enlarged manner.

FIG. 6 is a conceptual diagram showing how vertical contour compensation can be performed by the embodiment shown in FIG. -E, and when normal contour compensation cannot be performed, it becomes a solid line A-E. Now, at this time, no matter what the vertical contour detection is done by the circuit in Figure 4, the vertical scanning speed is reduced at points ■ to ■ in Figure 5(d), and the circles B to E in Figure 6 are respectively circled. Marks B'-E/
move to. Therefore, since the slope becomes steeper in the vertical contour portion, a contour compensation effect can be obtained.

Further, FIG. 7 is a block diagram showing the fifth embodiment, in which the 1H delay type in FIG. and the fourth
The same reference numerals as in the figure indicate the same functions. The operation from the video input terminal 101 to the output drive circuit 108 in FIG. 7 is the same as that in FIG. 1, and the output drive circuit 108 produces the contour compensation signal shown in FIG. 2(e).

This compensation signal is input to the adder circuit 701 and added to the drive pulse (usually a sawtooth wave with a period of vertical period and includes a synchronization signal) that drives the king coil 111, and is This is the signal that indicates. Furthermore, this signal is converted in the output circuit 404 into a deflection current for generating a vertical deflection field in the main coil 111. Here, since the deflection current is compensated at the vertical contour, the vertical magnetic field applied to the electron beam scanning in the cathode ray tube 112 is the same as in the case of FIG. 1, and therefore the vertical contour compensation effect is also the same.

As described above, according to this embodiment, the delay is 1H.

By using a spreading element, an adder, and a subtracter, vertical scanning speed modulation is applied and contour correction of the vertical contour portion of the image is performed, thereby obtaining an image with a clear vertical contour. Furthermore, if it is combined with the conventional horizontal scanning velocity modulation method, a good image with a clear two-dimensional outline can be obtained, making it possible to improve the image quality.

〔Effect of the invention〕

According to the present invention, when one or two 1H delay elements and a subtracter or an adder are used, the first generates an auxiliary magnetic field by a deflection auxiliary coil provided at the neck of the cathode ray tube, and the second This is a case where the deflection current flowing through the main coil is controlled by adding a simple signal addition circuit without using an auxiliary coil. Since it is possible to perform contour correction in the vertical direction, it has the effect of improving image quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first vertical scanning velocity modulation circuit according to an embodiment of the present invention, FIG. 2 is a waveform diagram explaining the operation of FIG. 1, and FIG. 3 is an explanation of the effect of FIG. 1. conceptual diagram,
FIG. 4 is a block diagram showing a second vertical scanning speed modulation circuit according to the present invention, FIG. 5 is a waveform diagram explaining the operation of FIG. 4, and FIG. 6 is a conceptual diagram explaining the effect of FIG. 4. FIG. 7 is a block diagram showing a third vertical scanning speed modulation circuit according to the present invention, FIG. 8 is a block diagram showing a conventional horizontal scanning speed modulation circuit, and FIG. 9 is a waveform diagram explaining the operation of FIG. 8. It is. 102 and 103...1H delay elements 104 and 106...1 coefficient unit 105...-
1 coefficient unit 107... Adder 108... Output drive circuit 109... Output circuit 110... Vertical deflection auxiliary coil 111...
. . . Main coil for deflection 112 . . . Braun tube 401 . . . Subtractor 402 . . . Output drive circuit for vertical deflection 406
... Addition circuit 404 ... Output circuit

Claims (1)

[Claims] 1. A cathode ray tube including a vertical scanning line deflection means, a means for detecting a vertical contour position of an image from a luminance signal of the image, a means for generating a contour compensation signal from the detection means, and applying the generation means to the deflection means. A vertical contour compensation circuit for a television receiver, comprising means.