JPH06178156A - Adaptive type contour correction device - Google Patents

Abstract

PURPOSE:To obtain an adaptive type contour correction device capable of performing the optimum contour correction corresponding to the size of a contour extraction signal and with few distortion as a contour correction device which corrects the contour part of a video signal in a color television receiver. CONSTITUTION:A noise component and a contour component are discriminated from the output signal of a high-pass contour extraction circuit 10 by a noise/ contour component discrimination circuit 170. When the noise component exists, a signal '0' from a second prescribed value input terminal 22 is selected, and when the contour component exists, the output signal of a first one-picture element delay unit 41 is selected, and distortion due to noise coring can be suppressed by performing the addition processing of the signal '0' and the output signal of a noise coring circuit 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adaptive contour correcting device for correcting a contour portion of a video signal.

[0002]

2. Description of the Related Art As a conventional apparatus, for example, the Television Image Information Engineering Handbook, edited by the Television Society (199)
(Year 0) pp. 183 to 184.

Conventionally, in a color television signal transmission system, the sharpness of an image reproduced by a receiver is lowered because the transmission band is limited. For example, N
In the TSC system, the band of the luminance signal is limited to 4.2 [MHz] or less. Therefore, even when the image is taken with an ideal image pickup tube, the signal when the brightness signal changes in black and white does not become sharper than a certain value at the rising and falling slopes of the signal on the receiver, and the contour part on the screen It looks a little blurry.
In order to improve such image blurring, in the contour correction device, contour correction is performed by emphasizing the high frequency components of the input video signal.

A conventional contour correction device will be described below. FIG. 3 is a block diagram of this conventional contour correction device. In FIG. 3, 1 is a video signal input terminal, 10 is a high-frequency contour extraction circuit for extracting the contour of the high-frequency part of the input video signal, 21 is a predetermined value, in this case, a "threshold value" is input. 1 is a predetermined value input terminal, and 30 is a comparison between the output signal of the high frequency contour extraction circuit 10 and the "threshold" from the first predetermined value input terminal 21 to output the high frequency contour extraction circuit 10. It is a noise coring circuit that removes noise components from a signal.

In the noise coring circuit 30, 31 is an absolute value circuit for taking the absolute value of the output signal of the high frequency band contour extraction circuit 10, 32 is the output signal of the absolute value circuit 31 and the first predetermined value input terminal 21 Each of the "threshold values" is input, and a comparator that compares the magnitude of the output signal of the absolute value circuit 31 and the "threshold value" from the first predetermined value input terminal 21, 33 is a predetermined value, in this case Is a zero input terminal for inputting “0”, and 34 is a selection for selecting either one of the output signals of the high frequency contour extraction circuit 10 and the zero input terminal 33 and the output signal of the comparator 32. Circuit. 140 is a multiplier that multiplies the amplitude value of the output signal of the noise coring circuit 30 by a predetermined coefficient, 150 is a timing adjuster that adjusts the timing of the input video signal, 16
Reference numeral 0 is an adder for adding the output signal of the timing adjuster 150 and the contour correction signal of the multiplier 140, and 2 is an output terminal.

The operation of the contour correcting apparatus having the above-described structure will be described with reference to FIG. FIG. 4 shows waveforms A to D of each part of the circuit of FIG. A video signal like the waveform A in FIG. 4 is input from the input terminal 1 and supplied to the high frequency contour extraction circuit 10 and the timing adjuster 150.
The contour extraction signal from which the high-frequency contour portion has been extracted by the high-frequency contour extraction circuit 10 becomes a contour extraction signal like the waveform B in FIG. 4, and the absolute value circuit 31 and the selection circuit of the noise coring circuit 30 are selected.
Supplied to 34. The output signal of the high frequency band contour extraction circuit 10 supplied to the absolute value circuit 31 is subjected to absolute value processing and supplied to the comparator 32.

In the comparator 32, a first predetermined value input terminal
Input the "threshold value" from 21 and the output signal of absolute value circuit 31, and if the output signal of absolute value circuit 31 is equal to or smaller than "threshold value", logical value signal "1" Is output, and if larger, a logical value signal “0” is output. In the selection circuit 34, if the logical value signal supplied from the comparator 32 is "1", "0" from the zero input terminal 33 is selected, and if the logical value signal is "0", the high frequency band contour extraction circuit 10 The output signal is selected. The output signal from the selection circuit 34 is the multiplier 140.
Is supplied to and is multiplied by a predetermined coefficient to obtain a contour correction signal like the waveform C in FIG.

The contour correction signal from the multiplier 140 is added to the adder 160.
Is added to the input video signal whose timing is adjusted by the timing adjuster 150, and the video signal is output from the output terminal 2. Noise components such as the waveform D in FIG. A contour-corrected video signal having a characteristic of emphasizing a high-frequency part whose rising and falling edges are sharp is obtained. In the conventional contour correction device of FIG. 3, the gain of the multiplier 140 is 1.

In the conventional contour correcting apparatus configured as described above, by obtaining the contour correction signal from which the noise component is removed as shown by the waveform C in FIG. 4, the noise component as shown by the waveform D in FIG. 4 is obtained. It is possible to obtain an image in which a sharp edge portion of the image is suppressed, and an image in which the sharpness of the edge portion of the image is improved is obtained.

[0010]

However, in the above-mentioned conventional configuration, the noise coring circuit 30 of FIG. 3 outputs the noise component (waveform B of FIG. 4) from the contour extraction signal (waveform B of FIG. 4).
When the period h1 of is removed, the amplitude levels of J1, J2, J3, and J4 are removed, so that L1, L2, L3, and L4 of the contour extraction signal (waveform C in FIG. 4) are distorted, and Distortions such as e and f of the waveform D) occur. Therefore, when edge enhancement is performed, thick white edges and black edges are added to the edge part of the image, but if coring processing is used to remove noise components, thin white edges and black edges with distortion are added. It had a problem that it would end up.

In view of the above point, the present invention performs optimum contour correction according to the amplitude level of the contour correction signal of the image and the level of the threshold value, does not distort the contour correction signal, and suppresses enhancement of noise components. An object is to provide an adaptive contour correction device that obtains a contour corrected image.

[0012]

In order to achieve the above object, the present invention comprises a contour extracting means for extracting a contour of a video signal,
Noise coring means for noise coring the output signal of the contour extracting means, noise / contour component discriminating means for discriminating a noise component and a contour component from the output signal of the contour extracting means, and an output signal of the contour extracting means It has a selecting means for inputting a value and selecting either one of the output signals of the noise / contour component judging means, and an adding means for adding the output signal of the selecting means and the output signal of the noise coring means. It is composed.

[0013]

According to the present invention, the noise / contour component discriminating means discriminates the noise component and the contour component from the output signal of the contour extracting means, and if the noise component is a predetermined value,
If it is a contour component, by selecting the output signal of the contour extraction means and performing addition processing with the output signal of the noise coring means,
Distortion due to noise coring can be suppressed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an adaptive contour correction apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 is an input terminal for a video signal,
10 is a high-frequency contour extraction circuit for extracting the contour of the high-frequency part of the input video signal, 21 is a predetermined value, in this case, a first predetermined value input terminal for inputting a "threshold value", 22 is a predetermined value , A second predetermined value input terminal for inputting "0" in this case, and 30 compares the output signal of the high frequency band contour extraction circuit 10 and the threshold value from the first predetermined value input terminal 21. , A noise coring circuit that removes noise components from the output signal of the high-frequency contour extraction circuit 10.

Reference numeral 170 is a noise / contour component discriminating circuit for discriminating a noise component and a contour component from the output signal of the high frequency contour extracting circuit 10. In the noise / contour component discrimination circuit 170, 4
Reference numerals 1 and 42 denote first and second one-pixel delay devices for delaying the output signal of the high frequency contour extraction circuit 10 pixel by pixel, and 51 denotes an output signal of the first one-pixel delay device 41 and a first predetermined value input. The first comparison circuit that compares the magnitude with the "threshold" from the terminal 21
Of the first one-pixel delay device 41 and an output signal of an absolute value circuit (not shown) that performs absolute value processing on the output signal of the first one-pixel delay device 41.
It is composed of a comparator (not shown) for inputting a predetermined value of and comparing the sizes.

Reference numeral 61 denotes the output signal of the high frequency contour extraction circuit 10 and the second signal.
A first selection circuit for inputting a predetermined value of the above and selecting and processing one of them with the output signal of the first comparison circuit 51, and 62 is the output signal of the second one-pixel delay device 42 and the second predetermined value. Entered,
A second selection circuit that selects either one of the output signals of the first comparison circuit 51, and a second selection circuit 52 that compares the output signal of the first selection circuit 61 with the first predetermined value. In the comparison circuit, the second comparison circuit 52 inputs the output signal of an absolute value circuit (not shown) for performing absolute value processing on the output signal of the first selection circuit 61 and the first predetermined value, and sets the magnitude. It is composed of a comparator (not shown) for comparison.

Reference numeral 53 is a third comparison circuit for comparing the output signal of the second selection circuit 62 and the first predetermined value, and the comparison circuit 53 outputs the output signal of the second selection circuit 62 absolutely. It is composed of a comparator (not shown) for inputting an output signal of an absolute value circuit (not shown) for value processing and a first predetermined value and comparing the magnitudes. An exclusive logical sum (EXCLUSIVE) 70 indicates whether the output signals of the second and third comparison circuits 52 and 53 match or do not match.
OR) circuit is a discrepancy detection circuit for making a decision.

Reference numeral 80 is a timing adjuster for adjusting the timing of the output signal of the first one-pixel delay device 41, and 63 is an output signal of the timing adjuster 80 and a second predetermined value, and the output of the mismatch detection circuit 70. A third selection circuit that selectively processes one of the signals, 90 is a timing adjuster that adjusts the timing of the output signal of the noise coring circuit 30, and 110 is the third
An adder for adding the output signal of the selection circuit 63 and the output signal of the timing adjuster 90, 120 is a multiplier for multiplying the amplitude value of the output signal of the adder 110 by a predetermined coefficient, and 100 is an input video signal. Timing adjuster to adjust the timing, 13
Reference numeral 0 is an adder for adding the output signal of the multiplier 120 and the output signal of the timing adjuster 100, and 2 is an output terminal. The noise coring circuit 30 has the same configuration as that shown in the conventional example, and the detailed operation is the same as that described in the conventional example.

The operation of the adaptive contour correction device of FIG. 1 will be described with reference to FIG. 2A to 2F show the waveforms at points A to F in each part of the circuit in FIG. A video signal like the waveform A in FIG. 2 is input from the input terminal 1 and supplied to the high frequency contour extraction circuit 10 and the timing adjuster 100. The contour extraction signal extracted by the high frequency contour extraction circuit 10 becomes a contour extraction signal like the waveform B in FIG. First predetermined value input terminal
From 21, the "threshold" in this case is supplied to the noise coring circuit 30 and the first, second and third comparison circuits 51, 52 and 53, respectively.

The signal "0" in this case is supplied from the second predetermined value input terminal 22 to the first, second and third selection circuits 61, 62 and 63. The output signal of the high frequency contour extraction circuit 10 is supplied to the noise coring circuit 30 and the noise / contour component determination circuit 170, respectively. The output signal supplied to the noise coring circuit 30 is compared in magnitude with the first predetermined value, and if the output signal of the high frequency contour extraction circuit 10 is within the "threshold value", the signal "0" is output. The output signal of the high-frequency contour extraction circuit 10 is output if it is large (shown by the waveform C in FIG. 2),
It is supplied to the timing adjuster 90.

The output signal of the high-frequency contour extraction circuit 10 supplied to the noise / contour component discrimination circuit 170 is delayed by one pixel by the first and second one-pixel delay devices 41 and 42. The delayed signal output from the first one-pixel delay device 41 is the first comparison circuit 51.
And the second one-pixel delay device 42 and the timing adjuster 80, respectively. The delay signal output from the second one-pixel delay device 42 is supplied to the second selection circuit 62. The delay signal from the first one-pixel delay device 41 supplied to the first comparison circuit 51 is subjected to absolute value processing in the first comparison circuit 51, and the magnitude is compared with a first predetermined value to determine whether they are equal or not. If it is smaller, the logical value signal "1" is output. If it is larger, the logical value signal "1" is output.
0 "is output and supplied to the first and second selection circuits 61 and 62.

Next, the output signal of the high frequency band contour extraction circuit 10 and the second predetermined value are input to the first selection circuit 61, and the logical value signal output from the first comparison circuit 51 is "1". If so, the output signal of the high-frequency contour extraction circuit 10 is selected, and if "0", the second predetermined value is selected and supplied to the second comparison circuit 52. Next, the second selection circuit 62 receives the output signal of the second one-pixel delay device 42 and the second predetermined value, and receives the first comparison circuit 51.
If the logical value signal output from is "1", the output signal of the second one-pixel delay device 42 is selected, and if it is "0", the second predetermined value is selected and supplied to the third comparison circuit 53. To be done.

In the second comparison circuit 52, the output signal of the first selection circuit 61 is subjected to absolute value processing, and the magnitude is compared with the first predetermined value.
1 "is output, and if larger, a logical value signal" 0 "is output. In the third comparison circuit 53, the second selection circuit
The output signal of 62 is subjected to absolute value processing, and the absolute value signal and the first
The magnitude is compared with a predetermined value of, and if they are equal or the absolute value signal is small, a logical value signal "1" is output, and if the absolute value signal is large, a logical value signal "0" is output.

The output signals of the second and third comparison circuits 52 and 53 are supplied to the mismatch detection circuit 70, respectively. In the non-coincidence detection circuit 70, a logical value signal "0" is output if the output signals of the second and third comparison circuits 52 and 53 are in agreement, and a logical value signal "1" is output in the case of inconsistency. To be done. The logical value output from the mismatch detection circuit 70 is the third selection circuit 63.
Is supplied to. The output signal of the first one-pixel delay device 41 whose timing is adjusted by the timing adjuster 80 is supplied to the third selection circuit 63. In the third selection circuit 63, if the output signal of the timing adjuster 80 and the signal "0" from the second predetermined value input terminal 22 are input and the logical value signal output from the mismatch detection circuit 70 is "1". If the output signal of the timing adjuster 80 is selected, if it is "0", the second predetermined value input terminal
The signal "0" from 22 is selectively output, and becomes the waveform D in FIG. This waveform D is x1, x2, (waveform B in FIG. 2).
It is a waveform obtained by extracting x3 and x4.

The output signal of the third selection circuit 63 is the adder 110.
Is added to the output signal of the noise coring circuit 30 whose timing has been adjusted by the timing adjuster 90. The output signal of the adder 110 is supplied to the multiplier 120 where it is multiplied by a predetermined coefficient and becomes a contour correction signal like the waveform E in FIG. The output signal of the multiplier 120 is the adder 130
To the input video signal whose timing has been adjusted by the timing adjuster 100, and the video signal is output from the output terminal 2, and the contour portion shown by m and n of the waveform F in FIG. Obtain a contour-free corrected video signal.

As described above, according to this embodiment, the mismatch detection circuit 70 is detected from the output signals of the second and third comparison circuits 52 and 53.
Discrepancy is detected in the case of, and if not, the first 1-pixel delay device
By selecting the contour extraction signal from 41, and when they match, by selecting the signal “0” from the second predetermined value input terminal 22,
Distortion due to noise coring can be suppressed.

Although the second predetermined value is set to "0" in this embodiment, it goes without saying that it may be a value other than this. Further, although the gain of the multiplier 120 is set to 1 in the present embodiment, it is not limited to this, and any value may be selected according to the input video signal. Further, in the present embodiment, the contour correction in the horizontal direction has been described, but it goes without saying that the same processing may be performed in the vertical direction.

[0029]

As described above, according to the present invention, the noise / contour component discriminating means discriminates the noise component and the contour component from the output signal of the contour extracting means. If it is a component, by selecting the output signal of the contour extraction means and performing addition processing with the output signal of the noise coring means, a contour correction signal in which distortion due to noise coring is suppressed can be obtained, and its practical effect is great. .

[Brief description of drawings]

FIG. 1 is a block diagram of an adaptive contour correction device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the adaptive contour correction device in the embodiment.

FIG. 3 is a block diagram of a conventional contour correction device.

FIG. 4 is a waveform diagram for explaining the operation of the conventional example.

[Explanation of symbols]

 10 High-frequency contour extraction circuit 21 First predetermined value input terminal 22 Second predetermined value input terminal 30 Noise coring circuit 31 Absolute value circuit 32 Comparator 33 Zero input terminal 34 Selection circuit 41 First 1-pixel delay device 42 2 1 pixel delay device 51 1st comparison circuit 52 2nd comparison circuit 53 3rd comparison circuit 61 1st selection circuit 62 2nd selection circuit 63 3rd selection circuit 70 Mismatch detection circuit 80 Timing adjuster 90 Timing adjuster 100 Timing adjuster 110 Adder 120 Multiplier 130 Adder 140 Multiplier 150 Timing adjuster 160 Adder 170 Noise / contour component discrimination circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Ueda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Takuji Okamoto, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A contour extracting means for extracting a contour of a video signal, a noise coring means for performing noise coring processing on an output signal of the contour extracting means, and a noise component and a contour component are discriminated from an output signal of the contour extracting means. A noise / contour component discriminating means, a selecting means for inputting an output signal of the contour extracting means and a predetermined value, and selecting one of the output signals of the noise / contour component discriminating means; and an output signal of the selecting means. An adaptive contour correction apparatus comprising: an addition unit that performs an addition process on the output signal of the noise coring unit. 2. A noise / contour component discriminating means, a first delay means for delaying an output signal of the contour extracting means, a second delay means for delaying an output signal of the first delay means, and the first delay means. Of the output signal of the first comparison means for comparing the amplitude value of the output signal with the first predetermined value, and the output signal of the contour extraction means and the second predetermined value are input. First selection means for selecting one, second selection means for inputting the output signal of the second delay means and the second predetermined value, and selecting either one of the output signals of the first comparison means, Second comparing means and third comparing means for comparing the amplitude values of the output signals of the first selecting means and the second selecting means with the first predetermined value, respectively, the second comparing means and the third comparing means.
A non-coincidence detecting means for detecting the non-coincidence of the values with the output signals of the comparing means as inputs, respectively; when the non-coincidence detecting means detects the non-coincidence, the output signal of the first delay means is selected; The adaptive contour correction device according to claim 1, wherein a value is input.