JPH05292523A - Contour correcting device - Google Patents

Abstract

PURPOSE:To provide a contour correcting device which sharpens the boundary part of a color signal in the case of any input signal having a short amplitude. CONSTITUTION:A video signal is separated into a color signal and a luminance signal by a separating circuit 12, and the color signal is demodulated to a color difference signal by a color demodulating circuit 13, and the quick change part of this color difference signal is emphasized by emphasis signal extracting circuits 15 and 18, and the output signal is amplified by an amplifying circuit 26. Thereafter, this signal and the color difference signal are added by an adding circuit 27, and the inclination of the quick change part of the output is sharpened by contour emphasis circuits 16 and 19, and the output is modulated to the color signal by a color modulating circuit 14. Thus, contour correction of all signals is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly enhances a small vibration signal by providing an emphasis signal extraction circuit in the preceding stage of the contour emphasis circuit when performing image signal processing of a color television receiver or a video tape recorder. By doing so, the present invention relates to a contour correction device capable of performing a proper contour correction for any small signal.

[0002]

2. Description of the Related Art FIG. 10 shows, for example, JP-A-63-292.
It is a block diagram which shows an example of the conventional contour correction apparatus disclosed by 776 publication. In FIG. 10, the color signal input from the input terminal 1 is delayed by the first delay circuit 2 for the predetermined time D, and further delayed by the second delay circuit 3 for the predetermined time D. As a result, the color signal at the current time and the three color signals at the time D and the time 2D before are simultaneously input to the three input terminals a, b, and c of the changeover switch 9.

Now, the output signal of the first delay circuit 2 is f
(T), the current color signal f (t−D) becomes the second color signal.
The output signal of the delay circuit 3 is represented by f (t + D).
FIG. 11 shows the positional relationship between them, and FIG.
Is the output signal f (t + D), and FIG. 11 (b) is the output signal f
11 (c) and FIG. 11 (c) show the output signal f (t-D), respectively. Hereinafter, these output signals will be simply referred to as signals.

Here, the description returns to FIG. Figure 10
The subtractor 4 in [signal f (t) -amplitude]-[signal f
Amplitude of (t−D)] (hereinafter, “f (t) −f (t−
D) ”) is calculated every time, and the absolute value circuit 6 outputs the absolute value A of the subtraction result. Similarly, the subtractor 5 is
(T) -f (t + D) is calculated every time, and the absolute value circuit 7 outputs the absolute value B of the subtraction result.

The comparator 8 has an absolute value A shown in FIG.
The absolute value B shown in FIG. 11 (e) is compared, and during the period of A <B, the changeover switch 9 is switched to the input terminal a, and the signal f (t−D) is changed as shown in FIG. 11 (f). , Output terminal 10 and when A = B, switch to input terminal b and output signal f (t) to output terminal 10 as shown in FIG. , The input terminal c, and the signal f as shown in FIG.
(T + D) is output to the output terminal 10.

As a result, from the output terminal 10 to FIG.
The signal g (t) shown in is output. The waveform of the signal g (t) is a signal in which a color signal having a slow rise time is corrected to a signal waveform having a fast rise time, whereby the rise time is shortened in the rise period of the color signal, and In the fall period, the fall time becomes short.

[0007]

Since the conventional contour correcting device is configured as described above, the input terminal 1 is provided with the configuration shown in FIG.
When a signal as shown in (a) is input, the signal f delayed by each of the first delay circuit 2 and the second delay circuit 3 is inputted.
(T), f (t + D) are created, and by the subtracters 4 and 5,
{F (t) -f (t-D)} and {f (t), respectively
-F (t + D)} is calculated every time, absolute values circuits 6 and 7 compare respective absolute values A and B of the subtraction result with a comparator 8, and the changeover switch 9 is input during the period of A <B. Switching to the terminal a and outputting the signal f (t−D), when A = B, the changeover switch 9 is switched to the input terminal b and outputting the signal f (t), and in the period of A> B. , The selector switch 9 is switched to the input terminal c so that the signal f (t + D) is output.

Therefore, in the contour correcting apparatus having the above-mentioned structure, there is no problem when the amplitude of the input signal is large, but when the amplitude is lower than the threshold voltage of the comparator 8 or the changeover switch 9, To cause a malfunction,
At present, the contour correction device performs a normal operation only in some limited cases and does not function sufficiently.

Further, in the contour correction device having the above-mentioned structure, there is a problem in that the inclination of the edge portion of the signal cannot be changed because the signal is selected by switching and the waveform is generated due to its structure. there were.

The present invention has been made to solve the above-mentioned problems, and it works properly even when a signal of any small amplitude is input, and the effect of contour correction is applied to all amplitude signals. It is an object of the present invention to obtain a contour correction device that can obtain the above-mentioned, and an object of the present invention is to obtain a contour correction device that can reduce the unnatural feeling at the time of large amplitude.

[0011]

SUMMARY OF THE INVENTION A contour correction device according to the present invention includes an emphasis signal extraction circuit for extracting etching of a sharp change portion of a color difference signal and a sharp change portion of an output signal of the emphasis signal extraction circuit. A contour emphasis circuit for making the inclination steep is provided.

Further, an emphasis signal extraction circuit for extracting the edge of the abrupt change portion of the color difference signal, a contour emphasis circuit for making the inclination of the abrupt change portion of the output signal of the emphasis signal extraction circuit steep, and an emphasis signal extraction And an amplitude limiting circuit for limiting the amplitude of the output signal of the circuit.

[0013]

The emphasizing signal extraction circuit according to the present invention extracts a portion where the demodulated color difference signals change abruptly, and the contour emphasis circuit further steers the inclination of the abruptly changing portion of the extracted color difference signals. By doing so, contour correction is performed.

Further, according to the present invention, the emphasis signal extraction circuit extracts a portion where each demodulated color difference signal changes abruptly, and the amplitude of the extracted signal is limited by the amplitude limiting circuit. The gradient of the portion where the output signal of the emphasized signal extraction circuit changes rapidly is made steeper, and the inclination of the portion where the color difference signal changes abruptly can be freely changed.

[0015]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment, and shows the configuration of an embodiment corresponding to the invention of claim 1. In FIG. In FIG. 1, reference numeral 11 denotes the entire contour correction apparatus, and 12 is a separation circuit for separating a video signal input from the input terminal 1 into a color signal and a luminance signal.

The color signals separated by the separation circuit 12 are demodulated by a color demodulation circuit 13 into color difference signals of (RY) and (BY) (FIG. 2A). The emphasis signal extraction circuits 15 and 18 extract portions where the color difference signals demodulated by the color demodulation circuit 13 change abruptly. The emphasis signal extraction circuits 15 and 18
The edge of the output signal extracted by the edge enhancement circuit 16, 1
It is designed to stand at 9.

Further, the gain control circuit 17 adjusts the boost amount of the emphasized signals extracted by the emphasized signal extraction circuits 15 and 18 according to the input DC level. Further, the color difference signal emphasized by the contour emphasizing circuit 19 is modulated by the color modulating circuit 14 into a color signal.

Of the two emphasized signal extracting circuits 15 and 18, one emphasized signal extracting circuit 15 is a color difference signal (R-
Y) is to extract the emphasized signal to be added to the abruptly changing portion, and the other emphasized signal extraction circuit 18 is an emphasized signal to be added to the abruptly changed portion of the color difference signal (BY). Is to be extracted.

Further, the contour emphasizing circuit 16 emphasizes the edge of the portion of the output signal of the emphasizing signal extracting circuit 15 which changes abruptly, and the contour emphasizing circuit 19 abruptly changes the output signal of the emphasis signal extracting circuit 18. The edge of the part to be emphasized is emphasized.

The emphasized signal extraction circuits 15 and 18 have the same structure, and the emphasized signal extraction circuit 15 will be described as a representative.
In the emphasized signal extraction circuit 15, reference numeral 21 is a delay circuit that delays the color difference signal demodulated by the color demodulation circuit 13 (FIG. 2A) by a certain time t.
The signal delayed by 1 is delayed by the delay circuit 22 again by the same time t.

The signal passed through the delay circuit 21 is subtracted by the subtraction circuit 23.
And subtracts the color difference signal (RY) from the signal which has passed through the delay circuit 21, and subtracts the signal which has passed through the delay circuit 22 by the subtraction circuit 24. The output signals of the subtraction circuits 23 and 24 are added by the addition circuit 25. The emphasized signal calculated by the adder circuit 25 is amplified by the amplifier circuit 26.

The emphasized signal amplified by the amplifier circuit 26 and the color difference signal delayed by the time t by the delay circuit 21 are added by the adder circuit 27, and the result of the addition is added to the emphasized signal extraction circuit 15 as described above. Is output to the contour emphasis circuit 16.

Further, the contour emphasizing circuits 16 and 19 have the same structure, and the internal structure is shown as a representative of the contour emphasizing circuit 16. Therefore, the contour emphasis circuit 16 will be described as a representative. The contour emphasis circuit 16 includes delay circuits 31 and 3.
2. The subtraction circuits 33 and 34 have the same configuration as that of the emphasized signal extraction circuit 15, and the functions are as described above.

The absolute value circuits 35 and 36 are the subtraction circuit 3
Taking the absolute value of the signal calculated in 3, 34,
The data is output to the comparison circuit 37. The comparison circuit 37 compares the magnitudes of the signals that have passed through the absolute value circuits 35 and 36 to generate the timing for switching the changeover switch 38. The emphasis signal extraction circuit 18,
The contour enhancement circuit 19 has the same configuration as the enhancement signal extraction circuit 15 and the contour enhancement circuit 16 as described above, and therefore the description thereof will be omitted.

Next, the operation will be described. First, the video signal input from the input terminal 1 is separated into a color signal and a luminance signal by the separation circuit 12, and the color signal is further separated by the color demodulation circuit 13 into (RY), (B).
-Y) color difference signal a is demodulated. This color difference signal a is, for example, a signal as shown in FIG.
The delay circuit 21 delays for a predetermined time t,
The waveform of the delayed signal as shown in FIG. 2B is further delayed by the delay circuit 22, and the waveform of the delayed signal as shown in FIG. 2C is obtained.

The signal b delayed by the delay circuit 21 (see FIG.
The signal obtained by subtracting the original color difference signal a (FIG. 2A) from (b)) by the subtraction circuit 23 and the signal b delayed by the delay circuit 21.
The signal c (FIG. 2 (c)) delayed by the delay circuit 22 is subtracted by the subtraction circuit 24 and amplified by the amplifier 26. At the output terminal of the amplifier 26, as shown in FIG. The enhancement signal d is output to the adding circuit 27. This adder circuit 27
Is the emphasized signal d output from the amplifier circuit 26 and the delay circuit 2
The signal e obtained by adding the signal b output from 1 (see FIG.
(E)) is output to the contour emphasis circuit 16.

In the contour emphasizing circuits 16 and 19, the signal e is input and an output signal f (FIG. 2 (f)) delayed by the delay circuit 31 is output, and the output signal f is delayed by the delay circuit 32. Further delay by, in the subtraction circuit 33,
The output signal e of the adder circuit 27 is subtracted from the output signal f of the delay circuit 31 (fe), and the output signal (fe) is input to the absolute value circuit 35. As a result, the absolute value circuit 35 outputs the absolute value A of the subtraction result of the subtraction circuit 33 and outputs it to the comparison circuit 37.

In the subtraction circuit 34, the output signal f of the delay circuit 31 is subtracted from the output signal g of the delay circuit 32 (FIG. 2 (g)), and the subtraction result (b-g) is input to the absolute value circuit 36. To do. The absolute value circuit 36 takes the absolute value B of the calculation result (b−g) of the subtraction circuit 34 and outputs it to the comparison circuit 37.

In the comparison circuit 37, these absolute values A, B
The comparison circuit 37 switches to the input terminal a side of the changeover switch 38 by the comparison circuit 37 and outputs the output signal e of the addition circuit 27 during the period of A <B.
When A = B, the changeover switch 38 is switched to the input terminal b side by the output signal of the comparison circuit 37, and the output signal f of the delay circuit 31 is output. Further, in the period of A> B, the changeover switch 38 is switched to the input terminal c side by the output signal of the comparison circuit 37, and the delay circuit 32
To output the output signal g. As a result, the changeover switch 38
Will output an output signal as shown in FIG.

This output signal h, that is, the contour emphasis circuit 1
The output signal h of 6 is modulated into a color signal by the color modulation circuit 14.

Example 2. Next, a second embodiment corresponding to the invention of claim 1 will be described with reference to FIG. In FIG. 3, the same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. In FIG. 3, the delay circuit 21 in the emphasized signal extraction circuit 15 has a color difference signal a (FIG. 4A).
Is delayed by a predetermined time t and its output is output to the subtraction circuit 39.

Further, the color difference signal a is converted into
The second differentiation is performed, and the output of the second differentiation circuit 28 is output to the amplification circuit 26. The amplification circuit 26 varies the amplification of the signal secondarily differentiated by the second differentiation circuit 28, and the output signal of the amplification circuit 26 is output to the subtraction circuit 39.

The subtracting circuit 39 subtracts the color difference signal delayed by the delay circuit 21 and the signal amplified by the amplifying circuit 26, and outputs the subtraction result to the contour emphasizing circuit 16. The enhancement signal extraction circuit 18 has the same configuration as the enhancement signal extraction circuit 15 and the contour enhancement circuit 19 has the same configuration as the contour enhancement circuit 16, and detailed description thereof will be omitted.

Next, the operation of the embodiment shown in FIG. 3 will be described with reference to FIG.
This will be described with reference to the waveform diagram of FIG. FIG. 4 shows the waveform of each part of FIG. First, the video signal input from the input terminal 1 is separated into a color signal and a luminance signal by the separation circuit 12, and the color signal is further separated by the color demodulation circuit 13 into color difference signals a of (RY) and (BY). Demodulated to. For example, when the color difference signal a is a signal as shown in FIG. 4A, the color difference signal a is secondarily differentiated by the second-order differentiation circuit 28 and has a waveform of the second-order differential signal b as shown in FIG. 4B. The waveform of the secondary differential signal b is amplified at the same level by the amplifier circuit 26 according to the DC level given from the gain control circuit 17. The subtraction circuit 39 subtracts the amplified signal and the color difference signal delayed by the delay circuit 21, and the result of the subtraction is output to the contour emphasis circuit 16 as an output signal c (FIG. 4C).

In the contour emphasizing circuits 16 and 19, the current signal is c, the output signal of the delay circuit 31 is d (FIG. 4 (d)), and the output signal of the delay circuit 32 is e (FIG. 4).
(E)), the subtraction circuit 33 calculates the subtraction (dc) of the output signal c of the subtraction circuit 39 from the output signal d of the delay circuit 31 every time, and the absolute value circuit 35 outputs the subtraction result ( The absolute value A of dc) is output to the comparison circuit 37.

In the same way, the subtraction circuit 34 includes the delay circuit 3
The output signal e of the delay circuit 32 is subtracted from the output signal d of 1 and the subtraction result (d−e) is output to the absolute value circuit 36. The absolute value circuit 36 subtracts the subtraction result (d−
The absolute value B of e) is output to the comparison circuit 37.

The comparison circuit 37 compares the absolute values A and B. As a result of the comparison, during the period of A <B, the changeover switch 38 is switched to the input terminal a by the output of the comparison circuit 37, and the subtraction circuit The output signal c of 39 is output, and A = B
In the case of, the changeover switch 38 is switched to the input terminal b by the output signal of the comparison circuit 37, and the output signal d of the delay circuit 31 is output. In the period of A> B, the changeover switch 38 is changed by the output signal of the comparison circuit 37. Switch 38 to input terminal c
The output signal e of the delay circuit 32 is output by switching to the side. As a result, the signal f as shown in FIG.
The color modulation circuit 14 modulates the signal f into a color signal.

Example 3. Next, a third embodiment corresponding to the invention of claim 2 will be described. FIG. 5 is a block diagram showing the configuration of the third embodiment. Since the third embodiment is equivalent to the first embodiment (embodiment of FIG. 1) corresponding to the invention of claim 1, detailed description thereof will be omitted, and only the difference from the invention of claim 1 will be omitted. I will explain. In the third embodiment, in the emphasis signal extraction circuits 15 and 18, an amplitude limiting circuit 29 for limiting the amplitude of the emphasis signal.
Is inserted between the amplifier circuit 26 and the adder circuit 27.

Next, the operation of the third embodiment shown in FIG. 5 will be described with reference to the waveform chart of FIG. This FIG. 6 is shown in FIG.
The waveform of the signal of each part of is shown. First, the video signal input from the input terminal 1 is separated into a color signal and a luminance signal by the separation circuit 12, and the color signal is further separated by the color demodulation circuit 13 into (R−Y) and (B−Y) color differences. The signal a is demodulated. When the color difference signal a is, for example, a signal as shown in FIG. 6A, the color difference signal a is delayed by the delay circuit 21 for a predetermined time t, and then delayed as shown in FIG. 6B. It becomes the waveform of the signal b. This delay signal b is further delayed by the delay circuit 22, and becomes a delay signal c having a waveform as shown in FIG.

Further, the subtraction circuit 23 subtracts the delayed signal b output from the delay circuit 21 and the color difference signal a, and outputs the subtraction result (ba) to the addition circuit 25. Similarly, the subtraction circuit 24 subtracts the delay signal b output from the delay circuit 21 and the delay signal c output from the delay circuit 22, and outputs the subtraction result (bc) to the addition circuit 25. .. The adder circuit 25 adds the subtraction results of both the subtraction circuits 23 and 24, amplifies the output signal thereof by the amplifier circuit 26, limits the amplitude by the amplitude limiter circuit 29, and outputs the output signal d as shown in FIG. 6D. Output to the adder circuit 27.

The adder circuit 27 adds the output signal d of the amplitude limiting circuit 29 and the delay signal b output from the delay circuit 21, and the output signal e of the addition result (FIG. 6 (e)).
Is output to the contour emphasis circuit 16. This contour enhancement circuit 1
6 and 19, the input signal is e, the output signal of the delay circuit 31 is f (FIG. 6 (f)), and the output signal of the delay circuit 32 is g.
(FIG. 6 (g)) In the subtraction circuit 33, the output signal f of the delay circuit 31 is changed to the output signal e of the addition circuit 27.
Is subtracted every time, and the subtraction result (fe) is output to the absolute value circuit 35. The absolute value circuit 35 outputs the absolute value A of the subtraction result (fe) to the comparison circuit 37.

Similarly, the subtraction circuit 34 is the delay circuit 31.
The output signal g of the output signal f is subtracted from the output signal g of the delay circuit 32, and the subtraction result (f−g) is output to the absolute value circuit 36.
The absolute value circuit 36 outputs the absolute value B of this subtraction result (f−g) to the comparison circuit 37.

The comparison circuit 37 compares the absolute value A with the absolute value B, and as a result of the comparison, during the period of A <B, the changeover switch 38 is switched to the input terminal a side by the output of the comparison circuit 37. , And outputs the output signal e of the adder circuit 27. If the comparison result is A = B, the comparison circuit 37
Output, the changeover switch 38 is switched to the input terminal b side, and the output signal f of the delay circuit 31 is output. Further, when the comparison result is A> B, the changeover switch 38 is switched to the input terminal c side by the output of the comparison circuit 37, and the output signal g of the delay circuit 32 is output. as a result,
The output signal h as shown in FIG.
4 and the color modulator 14 modulates the output signal h into a color signal.

Example 4. Next, another embodiment corresponding to the invention of claim 2, that is, a fourth embodiment of the present invention will be described. FIG. 7 is a block diagram showing the configuration of the fourth embodiment. Since the circuit used in the fourth embodiment is basically the same as that in the second embodiment shown in FIG. 3, detailed description thereof will be omitted, and the difference from claim 1, that is, the difference from FIG. Only the points will be explained.

As is clear from comparison of FIG. 7 with FIG. 3, in FIG. 7, in the emphasis signal extraction circuits 15 and 18,
The amplitude limiting circuit 29 is newly inserted between the amplifying circuit 26 and the subtracting circuit 39 in the configuration of FIG. Other configurations are the same as those in FIG.

Next, regarding the operation of the fourth embodiment,
This will be described with reference to the waveform chart of FIG. FIG. 8 shows the signal waveform of each part of FIG. First, the video signal input from the input terminal 1 is separated into a color signal and a luminance signal by the separation circuit 12, and the color signal is
By the color demodulation circuit 13, (RY), (BY)
Of the color difference signal a. When the color difference signal a is, for example, a signal as shown in FIG. 8A, it is differentiated by the secondary differentiating circuit 28 and has a waveform of the secondary differential signal b as shown in FIG. 8B. The waveform of the second-order differential signal b depends on the DC level given from the gain control circuit 17.
The amplification circuit 32 amplifies the signals at the same level, and the amplitude limiting circuit 29 limits the amplitude.

The output signal of the amplitude limiting circuit 29 is output to the subtracting circuit 39. The subtraction circuit 39 subtracts the output signal of the amplitude limiting circuit 29 from the output signal of the delay circuit 21,
The result of the subtraction is output to the contour emphasis circuit 16 as an output signal c (FIG. 8C).

In the contour emphasizing circuits 16 and 19,
FIG. 8 shows the current signal c and the output signal of the delay circuit 31.
The output signal of d, the delay circuit 32 shown in (d) is shown in FIG.
In the subtraction circuit 33, the output signal c of the subtraction circuit 39 is subtracted from the output signal d of the delay circuit 31, and the subtraction result (cd) is output to the absolute value circuit 35. Similarly, in the subtraction circuit 34, the output signal e of the delay circuit 32 is subtracted from the output signal d of the delay circuit 31, and the subtraction result (ce) is obtained.
Output to.

The absolute value circuit 35 outputs the absolute value A of the subtraction result (cd) of the subtraction circuit 33 to the comparison circuit 37, and
The absolute value circuit 36 outputs the absolute value B of the subtraction result (d−e) of the subtraction circuit 34 to the comparison circuit 37. The comparison circuit 37 compares these absolute values A and B, and switches the changeover switch 38 to the input terminal a side by the output signal of the comparison circuit 37 and outputs the output signal c of the subtraction circuit 39 in the period of A <B. To do.

When A = B as a result of the comparison, the changeover switch 38 is changed over to the input terminal b side by the output signal of the comparison circuit 37, and the output signal d of the delay circuit 31 is outputted. Further, in the period of A> B, the comparison circuit 3
The output signal of 7 switches the changeover switch 38 to the input terminal c side, and outputs the output signal e of the delay circuit 32.
As a result, as shown in FIG. 8F, the color modulation circuit 1
The output signal f of the changeover switch 38 is input to 4.
The output signal f is modulated into a color signal by the color modulation circuit 14.

FIG. 9 is a block diagram showing a typical overall configuration of the contour correcting apparatus of the present invention, which is a summary of the first to fourth embodiments described above.
The same parts as those in FIGS. 3, 5 and 7 are designated by the same reference numerals.

[0052]

As described above, according to the present invention, the edge of the abrupt change portion of the color difference signal is extracted by the emphasis signal extraction circuit, and the inclination of the abrupt change portion of the extracted signal is extracted by the contour emphasis circuit. Since it is made steep, contour correction can be performed on all the amplitude signals regardless of the small amplitude, and an erroneous operation when the input signal has a small amplitude can be eliminated.

Further, since the amplitude limiting circuit for limiting the amplitude of the emphasized signal is provided in the emphasized signal extraction circuit, the inclination of the abrupt change portion of the color difference signal can be freely changed, and at the time of large amplitude. This has the effect of reducing unnaturalness.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a contour correction device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the first embodiment.
3 is a signal waveform diagram of each part of FIG.

FIG. 3 is a block diagram showing a configuration of a contour correcting device according to a second embodiment of the present invention.

FIG. 4 is a diagram for explaining the operation of the second embodiment.
3 is a signal waveform diagram of each part of FIG.

FIG. 5 is a block diagram showing a configuration of a contour correction device according to a third embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the third embodiment.
3 is a signal waveform diagram of each part of FIG.

FIG. 7 is a block diagram showing a configuration of a contour correction device according to a fourth embodiment of the present invention.

FIG. 8 is a diagram for explaining the operation of the fourth embodiment of the above.
3 is a signal waveform diagram of each part of FIG.

FIG. 9 is a block diagram showing a typical configuration of the contour correction device of the present invention.

FIG. 10 is a block diagram showing a configuration of a conventional contour correction device.

11 is a signal waveform diagram of each part of FIG. 10 for explaining the operation of the conventional contour correction device.

[Explanation of symbols]

 11 contour correction device 12 separation circuit 13 color demodulation circuit 14 color modulation circuit 15 enhancement signal extraction circuit 16 contour enhancement circuit 17 gain control circuit 18 enhancement signal extraction circuit 19 contour enhancement circuit 21 delay circuit 22 delay circuit 23 subtraction circuit 24 subtraction circuit 25 Adder circuit 26 Amplifier circuit 27 Adder circuit 28 Second derivative circuit 29 Amplitude limiting circuit 31 Delay circuit 32 Delay circuit 33 Subtractor circuit 34 Subtractor circuit 35 Absolute value circuit 36 Absolute value circuit 37 Comparison circuit 38 Changeover switch 39 Subtractor circuit

Claims (2)

[Claims] 1. A separation circuit for separating a video signal into a color signal and a luminance signal, a color demodulation circuit for demodulating the color signal separated by the separation circuit into a color difference signal, and each demodulated by the color demodulation circuit. An emphasis signal extraction circuit that extracts a portion where the color difference signal changes abruptly, a contour emphasis circuit that makes the slope of the portion where the output signal of the emphasis signal extraction circuit changes abruptly more sharp, and an output of the emphasis signal extraction circuit A contour correction device comprising a gain control circuit for controlling the gain of a signal, and a color modulation circuit for modulating the output signal of the contour emphasis circuit into a color signal. 2. A separation circuit for separating a video signal into a color signal and a luminance signal, a color demodulation circuit for demodulating the color signal separated by the separation circuit into a color difference signal, and each color difference demodulated by the color demodulation circuit. An emphasis signal extraction circuit that extracts a portion where the signal changes abruptly, a contour emphasis circuit that makes the slope of the portion where the output signal of the emphasis signal extraction circuit changes abruptly, and an output signal of the emphasis signal extraction circuit A gain control circuit for controlling the gain of the signal, an amplitude limiting circuit for limiting the amplitude of the output signal of the enhancement signal extraction circuit, and a color modulation circuit for modulating the output signal of the contour enhancement circuit into a color signal. Contour correction device equipped.