JPS60199273A - Profile correcting device of video signal - Google Patents

Abstract

PURPOSE:To avoid an unpleasant pattern even when an integrated value of a profile correction signal per one vertical synchronizing period is comparatively larger by providing an integrating means receiving the profile correction signal and integrating it, an amplitude change means changing the amplitude of the profile correction signal in response to an output of the integrating means and a synthesizing means synthesizing an output of the amplitude change means into a video signal. CONSTITUTION:A voltage controlled gain variable circuit 9 has an input terminal 8a connected to a profile correction signal generating circuit 6, an output terminal 8b connected to an adder circuit 3 and a control terminal 8c. An output V1 of an integration circuit 12 is shown in Fig. H. The output V1 responds to a reset pulse P2 and reset to zero as shown in Fig. E. An output V2 of a sample-and-hold circuit 16 is shown in Fig. I. The output V2 responds to the sampling pulse P3 and samples the output V1 of the integration circuit 12. Further, the profile correction signal E1 shown in Fig. B is given to the voltage controlled gain variable circuit 9, the amplitude is changed and the signal is outputted as an output signal E2 as shown in Fig. J. Moreover, the gain A of the voltage controlled gain variable circuit 9 is controlled by an output voltage V2 of a control signal generating circuit 10.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an improvement in a contour correction device for a video signal.

[Prior art@] FIG. 1 shows a conventional image signal contour correction device. In the figure, an original video signal S1 from a video signal w1 is applied to one input of an adder circuit 3 via an amplifier circuit 2 as required. This original video signal S1 is also given to the contour correction signal generation circuit 6.

The contour correction signal generation circuit 6 consists of two differentiating circuits 4 and 5 connected in series. The differentiating circuit 4 receives the original video signal S
The differentiating circuit 5 differentiates the components during one video period, and the differentiating circuit 5 differentiates the output again. Therefore, the contour correction signal E1, which is the output of the contour correction signal generation circuit 6, is two or more components of the original video signal S1 during the video period. Contour corrected image @E1
is applied to the other input of the adder circuit 3, and is combined with the original 12-image signal S1 applied from the other input. In this way, from the adding circuit 3, the contour-corrected video signal @S
2 is output.

Next, the operation of the conventional @- shown in FIG. 1 will be explained with reference to the waveform diagram in FIG. Now, the original video signal S1 from the video signal source 1 is as shown in FIG. 2A, for example.
It is assumed that a pulse wave is obtained in each horizontal synchronization section. In this case, the contour correction signal E1 obtained from the contour correction signal generation circuit 6 is obtained as two-several waves at the rising and falling positions of the cool taste image signal @S1, which is a pulse wave, as shown in FIG. 2B. It will be done. The original video signal S1 (waveform A) and the contour correction signal El (waveform B) are combined in an adder circuit 3 to obtain a contour-corrected video signal S2 having a waveform as shown in FIG. 2C. Figure 2C
As is clear from this, the contour-corrected video signal S2
is a combination of two or more signals at the rising and falling positions of the original video signal S1, which is a pulse wave.

If an image is obtained on a display device (not shown) using the contour-corrected video signal S2 obtained in this way, the contour of the image can be changed by using the original video signal S1 as it is. The result is clearer than the case where

However, in such conventional devices, the original video signal S
Depending on the contents of item 1, performing contour correction may actually make the screen harder to see.

This is particularly noticeable when the number of pulsed waves of positive or negative polarity (hereinafter simply referred to as pulses) included in the multiplexing of two or more machines per vertical synchronization period is relatively large. In that case, the screen on the display device obtained using the contour-corrected video signal S2 becomes so-called "stirly" and becomes difficult to see.

[Summary of the invention]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a video signal contour correction device that eliminates the drawbacks of the conventional devices as described above and does not make the screen difficult to view due to contour correction.

The apparatus for correcting the contour of a video signal according to the present invention includes contour correction signal generating means for receiving the video signal and generating a contour correction signal for correcting the contour of the video signal. The contour correction signal generated by the contour correction signal generating means is integrated, and the amplitude of the contour correction signal is changed in response to the integrated signal. The amplitude-changed signal is combined with the video signal, thereby obtaining the contour-corrected video signal according to the invention.

[Embodiment of the Invention] FIG. 3 is a block diagram showing a preferred embodiment of a video signal contour correction apparatus according to the present invention.

The same parts as in FIG. 1 are given the same reference numerals and their explanations will be omitted. The conventional device shown in Fig. 1 and its development,
The image signal contour correction apparatus according to the present invention has a voltage IJ11p type variable gain circuit 9 between the contour correction signal generation circuit 6 and the addition circuit 3. The voltage-controlled variable gain circuit 9 has an input terminal 8a connected to the contour correction signal generation circuit 6, an output terminal 8b connected to the adder circuit 3, and a control terminal 8.
It has C. Contour correction signal generation circuit 6 and IIJIIl
IIIIIIJ! which receives the contour correction signal E1 and provides an output signal v2 for controlling the voltage-controlled variable gain circuit 9 is connected to the terminal 8C! A generating circuit 10 is connected.

The control signal generation circuit 10 is configured as follows.

That is, the contour correction signal E1, which is a secondary image branch of the original video signal S1, is given to the detection circuit 11, and among the pulses included in the contour correction signal E1, for example, only positive polarity pulses are detected. Ru. The pulse P1 detected by the detection circuit 11 is given to the integration circuit 12 and integrated.
It is output as output voltage ■1. The integrating circuit 12 receives the reset pulse P2 from the reset pulse generating circuit 13.
will be reset to zero. Output voltage v1 is given to sample and hold circuit 16.

The sample hold circuit 16 samples the voltage v1 at the time when the sampling pulse P3 from the sampling pulse generation circuit 17 is input, and continues to output the voltage value v2 until the next sampling pulse P3 is input. The reset pulse generation circuit 13 and the sampling pulse generation circuit 17 receive the vertical synchronization pulse P4, so that the reset pulse P2 and the sampling pulse P3 are synchronized with the vertical synchronization pulse P4. The vertical synchronization pulse P4 is given from a vertical synchronization pulse generation circuit 14 provided separately from the control signal generation circuit 1o. The vertical synchronization pulse generation circuit 14 receives the original video signal S1
A vertical synchronization pulse P4 synchronized with the vertical synchronization of is applied. The output v2 of the sample hold circuit 16 (that is, the output of the control signal generation circuit 10) is applied to the IllJw terminal 8C of the voltage controlled variable gain circuit 9.

FIG. 4 is a waveform diagram for explaining the operation of the video signal contour correction apparatus shown in FIG. 3, which is a preferred embodiment of the present invention. The operation of the embodiment shown in FIGS. 11 and 13 will be described below with reference to FIG. For the sake of explanation, as shown in FIG. 4, attention will be paid to one vertical synchronization period of the original video signal S1 obtained from the video signal source 1, and further attention will be paid to one horizontal synchronization period within this vertical synchronization period.

As shown in FIG. 4A, if the cool taste detection signal 81 includes N pulses in one horizontal opening period, the contour correction signal @E1 obtained by the contour correction signal generation circuit 6 is as shown in FIG. 4B. As shown, the horizontal synchronization period includes a set of 2N pulses of positive polarity and negative polarity. This contour correction signal E1 is l! llJ control signal generation signal generation circuit 10 inner path 1
1, the detection circuit 11 outputs 2N positive pulses P1 in the horizontal synchronization period, as shown in FIG. 4C.

From the vertical synchronization pulse generation circuit 14, as shown in the fourth figure, the ! ! A pulse P4 of negative polarity synchronized with direct synchronization is output.

This pulse P4 is applied to the reset pulse generation circuit 13 and the sampling pulse generation circuit 17, and in response, the reset pulse P2 and the sampling pulse P3 shown in FIG. 4 Et3 and Et3 are output, respectively. Three pulses P2, P3. And the timing of P4 is t 1. in FIG. 4G. t2. t 3
．． t4. t 5. and t6, and their relationship is as shown in the following equation.

t 1 < t 2 < t 3 < t 4 < t 5 < t 5th
FIG. H shows the output v1 of the integrating circuit 12.

It can be seen that this output (1) is reset to zero in response to the reset pulse P2 shown in FIG. 4E. FIG. 4I shows the output v2 of the sample and hold circuit 16. This output ■2 is the sampling pulse P
It can be seen that the output v1 of the integrating circuit 12 is sampled in response to 3.

The contour correction signal E1 shown in FIG. 4B has a voltage of 11JI
It is applied to the II type variable profit circuit 9 and the amplitude is changed.
It is output as an output signal @E2 as shown in Figure J. When the amplitude of the contour correction signal E1 is VEl and the amplitude of the output signal E2 of the voltage controlled variable gain circuit 9 is VF6, the voltage 1
The gain #RA of the 11JIII type variable gain circuit 9 is expressed as A-V E 2 ,/V E 1 .

The gain IA of the voltage controlled variable gain circuit 9 is controlled by the output voltage 2 of the control signal generating circuit 10.

FIG. 145 is a graph showing a preferable relationship between the output voltage v2 of the control signal generation circuit 10 and the gain of the voltage 11JIII type variable gain circuit 9. As shown in FIG. 5, the gain 41A of the voltage 11i'1lll type variable gain circuit 9 is configured to decrease as the output voltage v2 of the control signal generation circuit 10 increases. In Figure 15, $J
Although the relationship between gain A and voltage v2 is shown as being inversely proportional, this relationship may be changed as appropriate to obtain desired characteristics.

j! ! 4 bad J signal E21. t, 210 is combined with the original video signal S1 in the arithmetic circuit 3, and the adder circuit 3 outputs the contour-corrected video signal J! as shown in FIG. 4K. S
2 is output.

According to the above operation, as the number of pulses P1 per vertical synchronization period shown in FIG. 4C increases, the clip width EC also increases in proportion. On the contrary,
1 of pulse P1! l! ii If the number per synchronization section becomes smaller, the clip width EC also becomes smaller in proportion to it.

In this way, since the clip width EC changes in proportion to the number per vertical synchronization period of the pulse P1, the contour correction signal (signal@E2) of the clipping center is independent of the contour correction signal E1 before clipping. The signal is almost constant. Therefore, the 41st! It will be understood that the video signal S2 shown in IIK subjected to the contour correction according to the present invention always undergoes appropriate contour correction.

In the above-described embodiment, the output of the contour correction signal generation circuit 6 is directly given to the detection circuit 11, but a clip circuit or an amplitude discrimination circuit is provided between the two, so that only pulses having a certain amplitude or more are sent to the detection circuit 11. 11. In this case as well, the same effects as in the above embodiment can be achieved.

Further, a delay circuit may be inserted between the amplifier circuit 2 and the adder circuit 3, thereby making it possible to perform more appropriate contour correction. The delay may be, for example, one vertical synchronization period.

[Effects of the Invention] As described above, according to the present invention, even when the number of contour correction signals per vertical synchronization section is relatively large,
The advantage is that the screen obtained by the contour-corrected video signal does not become difficult to view.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional image signal contour correction device, FIG. 2 is a waveform diagram for explaining the operation of the conventional device shown in FIG. 1, and FIG. 3 is a preferred embodiment of the present invention. Block diagram illustrating an example of a video signal contour correction device, No. 4
The figure is a waveform diagram for explaining the operation of a preferred embodiment of the present invention shown in FIG. 3, and FIG.
7 is a graph showing the gain characteristics of the variable gain circuit 9. FIG. In the figure, 1 is a video signal source, 2 is an amplifier circuit, 3 is an adder circuit, 4 and 5 are differentiating circuits, 6 is a contour correction signal generation circuit, 9 is a voltage 11 type gain variable circuit, 1o is Ijllll
The signal generation circuit and 14 indicate a vertical synchronization pulse generation circuit, respectively. Agent Masuo Daimyo Figure 1 Figure 2; 1: : Figure 4 Figure 5 Procedural amendment (voluntary) 21 Name of invention Video signal contour correction device 3, person making the correction Representative Hitoshi Katayama Department 5. Claims column of the specification to be amended and Detailed description of the invention column 6, Contents of amendment (1) The claims of the specification are amended as shown in the attached sheet. (2) Correct the "number" in the second line of the 6th section of the specification and the 13th line of the 13th section to the "integral value J." becomes larger...and becomes larger again. j is corrected so that "as the integral value becomes larger, the gain A of the voltage-controlled gain variable circuit Wi9 becomes smaller in inverse proportion to the integral!!". (4) On page 12 of the specification, lines 11 to 17, [the number is small... Therefore, J is defined as "If the integral value becomes small, the profit l!A increases in inverse proportion to the integral value. In this way, the gain A changes in inverse proportion to the integral value per 1!! series synchronization section of the pulse P1, so it is corrected to ``. 2. Claims (1) An apparatus for performing contour correction of a video signal, comprising: contour correction signal generating means for receiving the video signal and generating a contour correction signal for contour correction; integrating means for receiving and integrating the correction signal; amplitude changing means for receiving the contour correction signal and changing the amplitude of the contour correction signal in response to the output of the integrating means; A video signal contour correction device l, comprising a combining means for combining with the video signal. (2) The contour correction device for a video signal according to claim 1, wherein the amplitude changing means decreases the amplitude of the contour correction signal as the output of the integrating means increases. (3) The video signal contour correction device according to claim 1, wherein the integrating means integrates the video signal by 1 for each vertical synchronization section of the video signal. (4) The contour correction of a video signal according to claim 1, wherein the contour correction signal generating means includes a differentiating circuit that differentiates the video signal. (5) 1! as set forth in claim 4, wherein the differentiating circuit includes two-several circuits. Contour correction side L of image signal (6) The output of the differentiation circuit described in ItJ includes pulses of positive and negative polarity, and the integrating means is configured to integrate only one polarity of the pulses of positive and negative polarity. Contour correction of a video signal according to claim 4, which is performed as follows. (7) The video signal according to claim 6, wherein the integrating means configured to integrate only the impulse-like pulses includes a detection circuit for selecting the impulse-like pulses. contour correction device. (8) The video signal contour correction apparatus according to claim 11, wherein the integrating means is configured to integrate only those of the contour correction signal having a predetermined amplitude or more. (9) Claim 8, wherein the integrating means configured to integrate only the contour correction signal having a predetermined amplitude or more includes an amplitude discrimination circuit for discriminating the amplitude of the contour correction signal. The video signal contour correction device described above. (10) Claim 1, wherein the synthesizing means includes a delay means for delaying the combined signal, and the output of the amplitude changing means is synthesized with the 91 signal delayed by the delay means. The video signal contour correction device described above.

Claims (10)

[Claims] (1) An apparatus for performing contour correction of a video signal, comprising: contour correction signal generating means for receiving the video signal and generating a contour correction signal for contour correction; and a contour correction signal generating means for receiving the contour correction signal. integrating means for integrating the contour correction signal; amplitude changing means for receiving the contour correction signal and changing the width of the contour correction signal in response to the output of the integrating means; and combining the output of the amplitude changing means into the 1111 signal. A contour correction device for a video signal, comprising a synthesizing means. (2) The contour correction side L of the video signal according to claim 1, wherein the amplitude changing means is configured to reduce the amplitude of the contour correction signal when the output of the integrating means becomes large. (3) The integration means includes the previous IC! 2. A contour correction device for a video signal according to claim 1, wherein the video signal is integrated for each vertical synchronization section of the video signal. (4) III! according to claim 1, wherein the contour correction @ number generation means includes a differentiating circuit that differentiates the video signal. 11 (!! Contour correction device. (5) The contour correction @It of a video signal according to claim 4, wherein the differentiating circuit includes a secondary image dividing circuit. (6) The output of the differentiating circuit combines pulses of positive and negative polarity, and the integrating means is configured to integrate one of the pulses of positive and PI polarity.
A video signal contour correction device according to claim 4. (7) The contour correction of the video signal according to claim 6, wherein the integrating means configured to integrate only the pulses of one polarity includes a detection circuit for selecting the pulses of one polarity. Device. (8) The contour correction side L of the video signal according to claim 1, wherein the integrating means integrates only those of the contour correction signal that are equal to or larger than a predetermined constant amplitude. (9) Claim 8, wherein the integrating means configured to integrate only the contour correction signal having a predetermined amplitude or more includes an amplitude discrimination circuit for discriminating the amplitude of the contour correction signal. The video signal contour correction device described above. (10) The synthesizing means includes a delay means for delaying the contour correction signal, and the output of the flea width changing means is synthesized with the contour correction signal delayed by the delay means. Contour correction of the video signal described in item 1 1ull.