JP2830609B2 - Contour correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention corrects the outline of an image,
The present invention relates to a contour correction device for improving sharpness.

[0002]

2. Description of the Related Art As a means for improving sharpness without adding preshoot and overshoot to an outline portion of an image, there is an outline correction device described in Japanese Patent Application No. 4-42557.

FIG. 13 shows an example of a conventional contour correction device. In FIG. 13, 1 is an input terminal of a video signal, 2 is an output terminal, 10 is an average circuit, 20 is a subtractor, 30a, 3
0b, 30c, 30d are one pixel delay devices, 40 is a maximum value detection circuit, 50 is a minimum value detection circuit, 70 is a gain adjuster,
80 is an adder, 90 is a non-linear processing circuit, and 300 is an arithmetic circuit.

The input video signal is supplied to one-pixel delay units 30a, 30
b, 30c, 30d. Input video signal,
The output signals of the one-pixel delay circuits 30a, 30b, 30c, 30d are supplied to a maximum value detection circuit 40 and a minimum value detection circuit 50, respectively. The output signal of the one-pixel delay unit 30b is supplied to one input terminal of the subtractor 20 and one input terminal of the adder 80, respectively. The output signal of the maximum value detection circuit 40 is supplied to the average value circuit 10 and the nonlinear processing circuit 90, respectively.

The output signal of the minimum value detection circuit 50 is supplied to the average value circuit 10 and the nonlinear processing circuit 90, respectively. The output signal of the averaging circuit 10 is supplied to the other input terminal of the subtractor 20. The subtraction result of the subtractor 20 is supplied to a gain adjuster 70, and the output signal of the gain adjuster 70 is supplied to the other input terminal of the adder 80. The addition result of the adder 80 is output to the nonlinear processing circuit 90 by the output signal from the maximum value detection circuit 40 and the minimum value detection circuit 5.
Non-linear processing is performed according to the output signal from 0 and output from the output terminal 2.

[0006] The operation of the conventional contour correction device configured as described above will be described with reference to the waveform diagram shown in FIG. In FIG. 14, the signal waveforms shown in (a) to (l) correspond to the signal waveforms obtained at points a to l in FIG.

First, in FIG.
It is assumed that a video signal having an outline as shown in FIG. This video signal is sent to one-pixel delay units 30a and 30
The signal waveforms shown in FIGS. 14 (b) to (e) are obtained at the respective points b, c, d and e after being delayed by b, 30c and 30d.
The maximum value detection circuit 40 compares the magnitudes of the input signals a to e and outputs the maximum value. Therefore, FIG.
The signal waveform shown in (f) is obtained.

The minimum value detection circuit 50 compares the magnitudes of the input signals a to e and outputs the minimum value. Therefore, the signal waveform shown in FIG. 14 (g) is obtained at point g. The signals shown in FIGS.
To obtain the signal waveform shown in FIG.

In the subtractor 20, a one-pixel delay unit 30
The signal at the point h is subtracted from the output signal c of FIG.
The signal waveform of (i) is obtained. When the gain of the gain adjuster 70 is set to, for example, 1, the output signal of FIG.
The signal waveform shown in (j) is obtained. If the adder 80 adds the signal to the output signal from the one-pixel delay unit 30b shown in FIG. 14C, the signal waveform shown in FIG. Get. This signal is subjected to nonlinear processing in the nonlinear processing circuit 90 in accordance with the output signals of the maximum value detection circuit 40 and the minimum value detection circuit 50.

For example, signal waveforms (f), (k), (l)
Are compared, and if the signal (k) is larger than the signal (f), the signal (f) is output. When the signal (k) is smaller than the signal (g), the signal (g) is output. Otherwise, a signal (k) is output. That is, the amplitude is limited using the detected maximum value or minimum value. According to this, as an output signal of the non-linear processing circuit 90, FIG.
As shown in (l), a video signal having a sharp contour is obtained.

As described above, according to the conventional contour correction device,
The sharpness can be improved without adding undershoot and overshoot (for convenience of the following description, the above-described contour correction method is referred to as a contour gradient correction type).

[0012]

[0013]

[0014]

[0015]

However, the above-described configuration has a disadvantage that a contour having a large amplitude is distorted.

For example, when the conventional contour correction processing is performed on the contour signals ((A) and (B)) having different contour amplitudes as shown in FIG. Become like Particularly for a contour having a large amplitude, the amplitude suppressed in the non-linear processing is large, so that the effect of improving the sharpness is great, but the distortion also increases accordingly. Such a phenomenon particularly occurs in an image displayed by a raster difference, such as a television signal, for example, as shown in FIG.
This is noticeable when an image having a contour in an oblique direction as in (a) is corrected. The waveform corresponding to each scanning line in FIG. 17A is as shown in FIG.

When the image shown in FIG. 17A is subjected to the contour correction processing, an image as shown in FIG. 17C is obtained, and a stepwise distortion is generated at an oblique contour portion. The waveform corresponding to each scanning line in FIG. 17C is as shown in FIG. FIG.
As is clear from FIG. 7 (d), the distortion is caused by the fact that the minimum amount of phase shift for each scanning line for displaying an oblique line is one pixel unit, and the shift amount within one pixel cannot be expressed. It becomes more conspicuous as the contour amplitude increases and the contour correction effect increases. When the contour amplitude is small, the distortion is hardly noticeable because the contrast is originally small.

Accordingly, the present invention has been made in view of the above problems, and provides an outline correction apparatus capable of performing outline correction without causing distortion even in an oblique outline.

[0019]

In order to achieve the above object,
The contour correction device of the present invention detects a maximum value from a plurality of pixel signals near a target pixel of an input video signal and a minimum value from a plurality of pixel signals near a target pixel of the input video signal. Minimum value detection means, the maximum value and
Average value calculating means for calculating an average value with the minimum value;
Coefficient multiplying means for multiplying the average by a coefficient;
Adding means for adding the output signal of the calculating means and the pixel signal of interest
And the addition result is shaken according to the maximum value and the minimum value.
Amplitude limiting means for limiting the width, and the amplitude of the contour of the input video signal
And a contour amplitude detecting means for detecting the

[0020]

[0021]

[0022]

[0023]

According to the present invention, compensation is performed at a portion where the contour amplitude is large.
Distortion caused by oblique contours due to setting a small positive amount
Can be suppressed .

[0024]

[0025]

[0026]

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an outline correction apparatus according to an embodiment of the present invention. FIG. 1 is a diagram showing a configuration of a contour correction device according to a first embodiment of the present invention.

In FIG. 1, 1 is an input terminal of a video signal,
2 is an output terminal, 10 is an average circuit, 20 is a subtractor, 30
Reference numerals a, 30b, 30c, and 30d denote one-pixel delay devices, 40 denotes a maximum value detection circuit, 50 denotes a minimum value detection circuit, 70 denotes a gain adjuster, 80 denotes an adder, 90 denotes a non-linear processing circuit, and 100 denotes a position detection circuit. is there. The difference from the conventional example shown in FIG. 13 is that a position detection circuit 100 is provided.

An input video signal and output signals of the one-pixel delay units 30a, 30b, 30c, 30d, the maximum value detection circuit 40, and the minimum value detection circuit 50 are input to the position detection circuit 100. The output signal of the position detection circuit 100 is supplied to a gain adjuster 70.

The operation of the contour correction device shown in FIG. 1 will be described below with reference to FIG. 1 correspond to the waveforms shown in FIGS. 2A to 2M.

For example, when the same trapezoidal signal as shown in FIG. 15A is input, at each of the points a to e, the signals shown in FIGS.
2 (f) and (g) are output signals of the maximum value detection circuit 40 and the minimum value detection circuit 50. Therefore, as an output signal of the average value circuit 10, FIG.
The waveform of (h) is obtained, and the waveform of FIG. The operations so far are the same as those described in the conventional example.

Here, the input signal and the one-pixel delay unit 30
a, 30b, 30c, 30d output signals (a) to (e)
The output signals (f) and (g) of the maximum value detection circuit 40 and the minimum value detection circuit 50 are supplied to the position detection circuit 100, respectively.

The position detecting circuit 100 is constituted by, for example, the circuit shown in FIG. In FIG. 3, 101a, 101b, 1
01c, 101d, 101e, 101f, 101g, 1
01h, 101i and 101j are comparators, and 120 is a logic circuit. First, the comparators 101a to 101e compare FIGS. 2A to 2E with FIG. 2G. If they are equal, for example, the logical value is “1”, and if they are not equal, the logical value is “0”.
Are output to the logic circuit 120 as comparison results A1 to A5.

The comparators 101f to 101j compare FIGS. 2A to 2E with 2F, and supply the results to the logic circuit 120 as comparison results B1 to B5, respectively. For example, the logic circuit 120 outputs “0” as a logical value only when one of the eight combinations shown in (Table 1) is satisfied, and outputs “1” otherwise.

[0035]

[Table 1]

In the logic shown in Table 1, if the signal at point c in FIG. 1 is taken as the point of interest, the contour correction is performed as an error if the maximum value and the minimum value are detected in the same direction with respect to the point of interest. Control not to be. This logic signal (m) is supplied to the gain adjustment circuit 70, and when the logic signal is "0", the gain is controlled so that the gain becomes zero. Therefore, the waveform of FIG. 2 (j) is obtained as an output signal of the gain adjuster 70, and the waveform of FIG. 2 (k) is obtained by adding the waveform of FIG. 2 (c). The waveform shown in FIG. 2 (k) is subjected to nonlinear processing in the nonlinear processing circuit 90 in accordance with the waveforms shown in FIGS. 2 (f) and 2 (g) in the same manner as in the conventional example to obtain the waveform shown in FIG. 2 (l). FIG.
As is clear from (l), no distortion occurs in the upper and lower parts of the trapezoidal waveform.

As described above, according to the contour correcting apparatus in the first embodiment of the present invention, a contour can be corrected for a specific contour image without losing the geometric structure of the original image. .

Note that the combination of the logic circuits is not limited to this, and the use of various combinations enables more accurate control.

FIG. 4 is a diagram showing the configuration of a contour correction device according to a second embodiment of the present invention. The difference from the conventional example shown in FIG. 13 is that a contour amplitude detection circuit 110 is added. The contour amplitude detection circuit 110 includes a maximum value detection circuit 40.
And the output signal of the minimum value detection circuit 50 are supplied, and the output signal of the contour amplitude detection circuit 110 is supplied to the gain adjuster 70.

The operation of the contour correction device in the second embodiment shown in FIG. 4 will be described with reference to FIG. For example, FIG.
6, the contour signals having different amplitudes (FIG. 5)
(A) and (B)), the waveform at the point of interest is shown in FIG. 5C, and the corresponding maximum value detection circuit 40
And the output signal of the minimum value detection circuit 50 are as shown in FIGS. Therefore, the signal waveform of FIG. 5 (i) is obtained as the output signal of the subtractor 20. The operation up to this point is the same as that of the conventional contour correction device.

Here, the signals of FIGS. 5F and 5G are also supplied to the contour amplitude detection circuit 110. The contour amplitude detection circuit 110 is constituted by, for example, the circuit shown in FIG.

In FIG. 6, 111 is a subtractor, and 112 is a coefficient generator. FIG. 5F input in FIG.
5 (g) is subtracted by the subtractor 111 to become the signal waveform shown in FIG.
12 is supplied. That is, the subtraction result of the subtractor 111 indicates the magnitude of the contour amplitude. The coefficient generator 112 controls the gain adjuster 70 according to the magnitude of the input contour amplitude.
And outputs a coefficient kn for setting the gain.

The coefficient generator 112 is composed of, for example, a comparator. When the coefficient generator 112 is larger than the threshold value, the coefficient kn is set to, for example, kn = 0.5. If it is smaller than the threshold value, the coefficient kn is, for example, kn
= 1.0.

Accordingly, the output waveform (i) of the subtractor 20 is shown in FIG.
The amplitude is adjusted as shown in (j), added to the target pixel signal (c) by the adder 80, and then supplied to the nonlinear processing circuit 150. The nonlinear processing circuit includes the output signal (f) of the maximum value detection circuit 40 and the minimum value detection circuit 5 as in the conventional example.
Non-linear processing is performed according to the output signal (g) of 0, and the contour correction waveform shown in FIG.

As is clear from this waveform, for a contour having a large contour amplitude and a contrast, the gain is reduced to weaken the correction effect, and in particular, distortion generated in a contour in an oblique direction is suppressed. Further, contour correction can be performed on a contour having a small contour amplitude as in the conventional example.

As described above, according to the contour correcting apparatus of the second embodiment of the present invention, contour correction can be performed on any contour in any diagonal direction without any distortion.

The coefficients of the coefficient generator are 0.5 and 1.0.
It is not limited to the two types, and other values may be set. Further, control may be performed in multiple stages according to the magnitude of the contour amplitude.

FIG. 7 is a diagram showing the configuration of the contour correction device according to the third embodiment of the present invention. The difference from the second embodiment shown in FIG. 4 is that a contour extraction circuit 120, a gain adjuster 130, an adder 140, and a mixing circuit 150 are added. The signals at points a, b, c, d, and e in FIG. 7 are supplied to the contour extraction circuit 120, and the output signal of the contour extraction circuit 120 is supplied to the gain adjuster. The output signal of the gain adjuster 130 is supplied to one input terminal of the adder 140. The signal at the point c is supplied to the other input terminal of the adder 140, and the addition result is output to the mixing circuit 15.
0 is supplied to one input terminal. The output signal of the nonlinear processing circuit 90 is supplied to the other input terminal of the mixing circuit 150, and the mixing circuit 150 is controlled by the output signal of the contour amplitude detection circuit 110. The output signal of the mixing circuit 150 is supplied to the output terminal 2.

The operation of the contour correction device in the third embodiment shown in FIG. 7 will be described with reference to FIG. For example, FIG.
8, contour signals having different amplitudes (FIG. 8)
(A) and (B)), the waveform at the point of interest is shown in FIG. 8C, and the output signal of the non-linear processing circuit 90 is a contour gradient correction type processing as shown in FIG. The received contour correction signal is obtained. The operations so far are the same as those described in the conventional example.

The signals at points a, b, c, d and e in FIG. Contour extraction circuit 1
Reference numeral 20 includes, for example, a circuit shown in FIG. In FIG. 9, 121a, 121b and 121c are coefficient multipliers,
Reference numeral 122 denotes a multi-input adder. Coefficient multiplier 121a, 1
If the coefficients of 21b and 121c are set to, for example, k1 = − ／, k2 = １ ／, and k3 = − ／, and the multiplication result is added by the multi-input adder 122, the multiplication result becomes as shown in FIG. Obtain the waveform of (q). That is, the contour extraction circuit 120 is a well-known high-pass filter and extracts a contour component.

The output signal of the contour extraction circuit 120 is amplitude-adjusted by the gain adjuster 140, added to the original signal (c) by the adder 140, and output as an added output as shown in FIG.
A high-frequency emphasis type contour correction waveform having undershoot and overshoot as shown in FIG.

The contour amplitude detection circuit 110 basically has the configuration shown in FIG.
The signal shown in FIG. 8 (o) is obtained as the output signal of the subtractor 111 of FIG. Coefficient generator 112
Outputs a coefficient kn for controlling the mixing circuit 150 according to the input signal amplitude. For example, kn = 1.0 when the amplitude is smaller than the preset threshold 1, kn = 0.5 when the amplitude is larger than the threshold 1 and smaller than the threshold 2, and kn = 0 when the amplitude is larger than the threshold 2. The mixing circuit 150 has a coefficient k
For example, the operation of (Equation 1) is performed according to n.

[0053]

(Equation 1)

According to (Equation 1), the smaller the kn, that is, the larger the contour amplitude, the larger the mixing ratio of the high-frequency emphasis type contour correction signal shown in FIG.
Therefore, as an output signal of the mixing circuit 150, FIG.
Is obtained.

As is clear from this waveform, for a contour having a large contour amplitude and a contrast, the ratio of the high-frequency-frequency-enhanced contour correction signal is increased, thereby suppressing the occurrence of distortion particularly in a contour in an oblique direction. In addition, a contour correction effect can be obtained. Since all high-frequency-frequency emphasizing contour corrections are linear processing, no distortion occurs even when processing contours in oblique directions. For a contour having a small contour amplitude, contour gradient correction type contour correction is performed.

As described above, according to the contour correcting apparatus of the third embodiment of the present invention, contour correction can be performed on any contour in any diagonal direction without any distortion.

The mixing ratio of the mixing circuit is not limited to three steps, but may be set in multiple steps according to the magnitude of the contour amplitude. The configuration of the contour extraction circuit is not limited to this, and any configuration may be used as long as it realizes a high-pass frequency characteristic.

FIG. 10 is a diagram showing a configuration of a contour correcting device according to a fourth embodiment of the present invention. In FIG.
0 is a sampling rate converter, and 400 is an outline correction unit. The contour correction unit has basically the same configuration as the conventional contour correction device shown in FIG. 13, for example. The difference from the conventional example is that the one-pixel delay unit of the conventional example is a four-pixel delay unit 300a,
This is the point that 300b, 300c, and 300d are replaced.

Hereinafter, the contour correction device shown in FIG. 10 will be described with reference to FIG.
The operation will be described with reference to FIG. First, as shown in FIG. 11A, the input video signal is a sampling value sequence sampled at a sampling period Ts (sec) per pixel, and this sample value sequence is supplied to the sampling rate converter 200. . Sampling rate converter 200 is formed of, for example, a circuit shown in FIG. In FIG. 12, reference numeral 201 denotes a zero insertion circuit, and 202 denotes an interpolation circuit.

First, the sequence of sampling values shown in FIG. 11A is supplied to the zero insertion circuit 201. For example, when converting the original sampling period Ts (sec) to 1/4, the zero insertion circuit 201 inserts three zeros at intervals of Ts / 4 between each sampling value sampled at the sampling period Ts. By inserting the zeros, the sampling period between each pixel is converted to Ts / 4, including the inserted zeros as shown in FIG. FIG. 11B
As shown in the figure, the sampling period is Ts /
The sample value sequence converted to 4 is supplied to the interpolation circuit 202. The interpolation circuit 120 is, for example, a load adder, and the inserted zero is interpolated by weight addition using the original sampling values in the vicinity thereof, and a sampling value sequence of a sampling period Ts / 4 as shown in FIG. Is obtained. The sampling value sequence of the sampling period Ts / 4 is supplied to the contour correction unit 400. The contour correction section 400 is processed in the same manner as the contour correction circuit described in the conventional example, and the contour correction waveform (sampling value sequence) shown in FIG.

As can be seen from this figure, the interval (minimum shift width) of one pixel is 1/4 of that of the conventional contour correction device.
Therefore, it is possible to suppress distortion generated when the contour is corrected for the oblique contour.

As described above, according to the contour correcting apparatus in the fourth embodiment of the present invention, the contour can be corrected without causing distortion even in the oblique contour.

Note that the sampling rate converter is not limited to this configuration, and any configuration may be used as long as the sampling period after conversion is smaller than the sampling period before conversion. The 4-pixel delay unit is not limited to this value, and may be set arbitrarily according to the sampling period after conversion.

[0064]

As described above, the present invention provides a maximum value detecting means for detecting a maximum value from a plurality of pixel signals near a target pixel of an input video signal, Minimum value detecting means for detecting a minimum value; calculating means for performing arithmetic processing with the maximum value detecting circuit, the minimum value detecting circuit and the input video signal as inputs; and amplitude adjusting means for receiving an output signal of the arithmetic means as an input Adding means for adding the output signal of the amplitude adjusting means and the input video signal; non-linear processing means receiving the output signal of the adding means as input; detecting a plurality of pixel signals near the target pixel and detecting the maximum value The output signal from the means and the output signal from the minimum value detection means are input and the position detection means for detecting the position where the maximum value and the minimum value are generated is provided, so that the original geometric structure of the original image can be lost. High-quality contour correction image without can be obtained.

A maximum value detecting means for detecting a maximum value from a plurality of pixel signals in the vicinity of a target pixel of the input video signal, and a minimum value detecting means for detecting a minimum value from a plurality of pixel signals in the vicinity of the target pixel of the input video signal Means, calculating means for inputting and processing the maximum value detecting means, the minimum value detecting means and the input video signal, amplitude adjusting means for inputting an output signal of the calculating means, and output of the amplitude adjusting means Adding means for adding a signal to the input video signal; non-linear processing means receiving the output signal of the adding means as input; output signals from the maximum value detecting means and output signals from the minimum value detecting means; By providing the contour amplitude detecting means for detecting the amplitude of the image, it is possible to obtain a high-quality contour corrected image in which distortion generated in the contour in the oblique direction is suppressed.

Further, maximum value detecting means for detecting a maximum value from a plurality of pixel signals near a target pixel of the input video signal,
A minimum value detection unit that detects a minimum value from a plurality of pixel signals near a target pixel of an input video signal, and a calculation unit that performs an arithmetic process by using the input video signal as an input and the maximum value detection unit, the minimum value detection unit, and An amplitude adjusting unit that receives an output signal of the arithmetic unit, an first adding unit that adds the output signal of the amplitude adjusting unit and the input video signal, and an input signal that is an output signal of the first adding unit. Non-linear processing means;
A contour amplitude detecting means for receiving an output signal from the maximum value detecting means and an output signal from the minimum value detecting means to detect a contour amplitude; and a plurality of pixel signals near a target pixel of the input video signal as input for contour correction. Contour extracting means for extracting components, second adding means for adding an output signal from the contour extracting means and the input video signal, an output signal from the second adding means, and an output signal from the non-linear processing means And a mixing unit that mixes the images, it is possible to obtain a high-quality contour-corrected image to which distortion generated in an oblique contour is suppressed and undershoot and overshoot are added.

Further, sampling period conversion means for converting the discretized video signal of the sampling period t1 to the sampling period t2, and contour correction means for inputting the discretized video signal converted to the sampling period t2 are provided. With such a configuration, it is possible to suppress distortion generated in a contour in an oblique direction.

[Brief description of the drawings]

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

FIG. 2 is a waveform chart for explaining the operation of the contour correction device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a position detection circuit.

FIG. 4 is a configuration diagram of a contour correction device according to a second embodiment of the present invention.

FIG. 5A is a waveform diagram for explaining the operation of the contour correction device according to the second embodiment; FIG. 5B is a waveform diagram for explaining the operation of the contour correction device;

FIG. 6 is a configuration diagram of a contour amplitude detection circuit.

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

FIG. 8A is a waveform diagram for explaining the operation of the contour correction device according to the third embodiment; FIG. 8B is a waveform diagram for explaining the operation of the contour correction device;

FIG. 9 is a configuration diagram of a contour extraction circuit.

FIG. 10 is a configuration diagram of a contour correction device according to a fourth embodiment of the present invention.

FIG. 11 is a waveform chart for explaining the operation of the contour correction device according to the fourth embodiment of the present invention.

FIG. 12 is a configuration diagram of a sampling rate converter.

FIG. 13 is a configuration diagram of a contour correction device in a conventional example.

FIG. 14 is a waveform chart for explaining the operation of the conventional contour correction device.

FIG. 15 is a waveform chart for explaining a problem of the contour correction device in the conventional example.

16A is a waveform diagram for explaining a problem of the conventional contour correction device, and FIG. 16B is a waveform diagram for explaining a problem of the conventional contour correction device.

FIG. 17 is a waveform chart for explaining a problem of the contour correction device in the conventional example.

[Explanation of symbols]

 Reference Signs List 1 input terminal 2 output terminal 10 average value circuit 20 subtractor 30 1 pixel delay device 40 maximum value detection circuit 50 minimum value detection circuit 70 gain adjuster 80 adder 90 non-linear processing circuit 100 position detection circuit 110 contour amplitude detection circuit 120 contour Extraction circuit 130 Gain adjuster 140 Adder 150 Mixing circuit 200 Sampling rate converter 300 Operation circuit 400 Contour correction unit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masanori Hamada 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-222777 (JP, A) JP-A-57- 174985 (JP, A) JP-A-61-71773 (JP, A) JP-A-63-164765 (JP, A) JP-A-2-76479 (JP, A) JP-A-2-94965 (JP, A) JP-A-4-10773 (JP, A) JP-A-63-108285 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 5/14-5/217

Claims (2)

(57) [Claims] 1. A contour correction device for enhancing a contour of an image, comprising: a maximum value detecting means for detecting a maximum value from a plurality of pixel signals near a target pixel of an input video signal; A minimum value detecting means for detecting a minimum value from a plurality of pixel signals; and an average value calculating means for calculating an average value of the maximum value and the minimum value.
Calculating means, coefficient multiplying means for multiplying the average value by a coefficient , and adding the output signal of the coefficient multiplying means and the pixel signal of interest.
Adding means for controlling the addition result according to the maximum value and the minimum value.
Amplitude limiting means for limiting the amplitude of the contour of the input video signal.
And a contour amplitude detection means for detecting, the according to the detection result from the contour amplitude detection means
Controlling the coefficient of a coefficient multiplier, wherein the amplitude limiting means
Limit the calculation result so that it does not exceed the maximum value and the minimum value
Contour correcting device, characterized in that that. 2. The contour amplitude detecting means includes: subtracting means for calculating a difference between an output signal from a maximum value detecting means and an output signal from a minimum value detecting means; and a coefficient based on a subtraction result from the subtracting means. The contour correction device according to claim 1 , further comprising a coefficient generation unit that generates the coefficient.