JP2003348379A - Image display device and image processing apparatus, and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device and an image processing apparatus, and an image processing method in which a proper image correction is possible. <P>SOLUTION: A sharpness part 200 is provided on a post-stage of a texture intensifying part 100. A luminance signal Y<SB>1</SB>becomes a luminance signal Y<SB>2</SB>by amplifying only its texture component (small amplitude component) comprising fine portions of an image by means of an enhance gain in the texture intensifying part 100. The luminance signal Y<SB>2</SB>becomes a luminance signal Y<SB>3</SB>by applying sharpness processing based on a sharpness gain corresponding to the enhance gain thereto in the sharpness part 200. The luminance signal Y<SB>3</SB>represents a texture intensified image with the proper contour correction applied thereto. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, an image processing device, and an image processing method having a function of performing image quality correction processing on an image signal.

[0002]

2. Description of the Related Art Television receivers, VTRs (Video Taps)
Devices such as e-recorders, digital cameras, television cameras, and printers have image processing functions of performing image quality correction on an input image and then outputting the image, for example, adjusting brightness and contrast, and performing contour correction. . These features are primarily dark, low contrast images,
The details are effectively applied to blurred images. However, in each of these processes, when the degree of correction is high, an image different from the intended one may be generated, and the image quality is not always improved.

[0003] Among them, the contour correction is generally called "sharpness" and is a process of enhancing the edges and contours of a person or an object in an image. In sharpness,
As shown in FIG. 19, in a pulse-like image signal, processing is performed such that the rising and falling edges of the signal are distorted as indicated by arrows. A portion where the amplitude value greatly changes, such as a rising edge or a falling edge, is called an edge and corresponds to an outline of an image. In addition, components corresponding to the difference from the specified signal value caused by distortion are referred to as a preshoot (PS) and an overshoot (OS) before and after the edge, respectively. At this time, the frequency characteristic is as shown in FIG. 20, and it can be seen that the frequency characteristic is emphasized around the specific frequency.

[0004] Such sharpness has such a property that when the correction is applied strongly, the image becomes blackened while the outline is sufficiently sharpened, giving an unnatural impression to a viewer. is there.

On the other hand, in recent years, there has been proposed an image quality correction technique which emphasizes only the details of an image (Japanese Patent No. 32732).
No. 33114, JP-A-2001-298621). In this technique, a component having a relatively high spatial frequency, which represents details of an image, is extracted from image data, and its amplitude level is selectively amplified. In the present specification, in image data, a component corresponding to a main contour in an image is called a structure component.
On the other hand, a component having a higher spatial frequency and corresponding to details of an image is called a texture component. The texture component is, for example, a pattern or a shadow of clothes in a person image, or a portion where tree leaves are dense. That is, this technique emphasizes a texture component in image data.

FIG. 21 shows pulse characteristics in the texture emphasizing process, and FIG. 22 shows frequency characteristics. The feature of the texture emphasizing process is that only the amplitude of the texture component is amplified without preshoot and overshoot unlike sharpness. Therefore, the frequency characteristic changes so as to constantly raise the level from a low band of about 100 KHz. According to this processing, details that tend to be blurred are sharp, but the entire outline is not emphasized, so that an image having a natural impression different from sharpness can be obtained while improving contrast and sharpness.

[0007]

However, in the texture emphasizing process, there is a possibility that an unnecessary component that is mixed into the texture component may be amplified as the texture component is amplified. One of the unnecessary components is noise, but in this processing, the preshoot / overshoot of the input signal has been a problem.

[0008] The tuner demodulated output of the television signal is
RF (Radio Frequency) band limited for transmission and reception
) Because it is a signal, inevitably distorted waveform, the actual frequency characteristics, so swelled band left cut-off frequency f _c as shown in FIG. 23. Cutoff frequency f
_c is, f _c = 5.5 in f _c = 4.2 MHz, PAL scheme in different though (NTSC scheme depending on the type of signal
〜6 MHz), the television signal after the tuner demodulation generally has such frequency characteristics. Of these, 2
The band in which the amplitude is raised around 3 MHz corresponds to preshoot and overshoot in time series.
In other words, the television signal is already in a state where sharpness has been applied at the time of input.

In recent years, signals such as sharpness have been corrected on a recording medium such as a DVD on the sending side, and therefore, preshoots and overshoots have already been intentionally applied to an input signal from a DVD or the like. Has been added.

When texture enhancement is performed on such an input signal, the preshoot / overshoot is recognized as a texture component and is amplified. The characteristics obtained at this time are as shown in FIG. 24, and as a result, only the preshoot / overshoot is emphasized.
In this case, the feature of the texture enhancement processing of contrast enhancement with characteristics different from the sharpness described above is impaired, and there is a possibility that the intended improvement in image quality cannot be expected.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an image display device, an image processing device, and an image processing method capable of performing appropriate image correction.

[0012]

According to the present invention, there is provided an image processing apparatus comprising:
And, the image display device of the present invention is a data separating means for separating the image data into a structural component constituting the contour of the image and a texture component constituting the details of the image, a texture amplifying means for amplifying the texture component, It is provided with a synthesizing means for synthesizing the structure component and the texture component to generate processed data, and an amplification component correcting means for correcting a component amplified by the texture amplifying means.

According to the image processing method of the present invention, image data is
After separating the structure components that make up the outline of the image and the texture components that make up the details of the image, amplify the texture components, and then combine the structure components with the texture components to generate the processed data, as well as texture enhancement processing. The correction of the component amplified as a result of the processing is performed.

According to the image display device, the image processing device, and the image processing method of the present invention, the amount of the component in the output image is controlled by correcting the component amplified in the texture enhancement process.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 shows the overall configuration of an image display apparatus according to a first embodiment of the present invention. The image display device includes a texture emphasizing unit 100 that processes image data including a structure component constituting an outline of an image and a texture component constituting details of the image so as to enhance the texture component in accordance with the enhancement gain TE. There is provided a sharpness section 200 for applying sharpness to the signal subjected to the texture enhancement processing in accordance with the enhancement gain TE. In addition,
On the signal, the structure component corresponds to a component having an average amplitude (a tendency to change amplitude) including an edge, and the texture component corresponds to a component having a small amplitude at a relatively high frequency.

Originally, texture emphasis is a process of emphasizing details, and the effect of clarifying an image is increased because the contrast in the details is increased. However, in order to provide sharpness, it is necessary to emphasize the outline a little. Become.
However, if sharpness is applied first, as described above, texture enhancement is not performed effectively (FIG. 24).
reference). Therefore, in the present embodiment, the sharpness section 200 is provided after the texture enhancement section 100. Further, the sharpness section 200 functions to adjust a correction amount by sharpness after texture emphasis for an input signal having a waveform as if sharpness had been applied from the beginning, such as a television signal.

The input image signal is a television signal, a VCR (VideoCassette Recorder), a DVD (Digi
tal Versatile Disc). These image signals are demodulated to YUV signals by normal processing. The television signal is demodulated by the tuner 101 and a composite signal (CVBS; Comp.
osite Video Burst Signal), but VCR and DVD
Directly inputs a composite signal. These composite signals are separated into a luminance signal Y and a chrominance signal C in a Y / C separation circuit 102, and are decoded into a YUV signal Y ₁ U ₁ V ₁ in a chroma decoder 103. The YUV signal is image data of a two-dimensional digital image, and is a set of pixel values corresponding to positions on the image.
The luminance signal Y represents a luminance level, and 100% white
And a black level that is 100% black. In addition, the color difference signals U and V are signals B−Y, which are obtained by subtracting the luminance signal Y from blue (B; Blue), respectively.
A signal RY obtained by subtracting the luminance signal Y from red (R; Red).
The color (hue, saturation, luminance) is expressed by combining the U signal and the V signal with the luminance signal Y.

The YUV signal Y ₁ U ₁ V ₁ is input to the texture emphasizing unit 100, subjected to a process related to texture emphasis described later, and then output as a YUV signal Y ₂ U ₂ V ₂ . The YUV signal Y ₂ U ₂ V ₂ is input to the sharpness section 200, subjected to sharpness processing, and then output as a YUV signal Y ₃ U ₃ V ₃ .

The matrix circuit 104, to which the YUV signal Y ₃ U ₃ V ₃ is input, reproduces and outputs an RGB signal from the YUV signal. The driver 105 generates and outputs a drive signal for the display 106 based on the input RGB signals. The display 106 is driven by the drive signal and displays an image corresponding to the input drive signal. The display 106 may be any type of display device, such as a CRT (Cathode-Ray Tube).
And PDP (Plasma Display Panel), LCD (Liquid
Crystal Display) is used.

<Structure of Texture Enhancing Unit 100> FIG.
FIG. 3 is a block diagram illustrating a configuration of a texture emphasizing unit. The texture emphasizing unit 100 includes an S / T separation circuit 1
0, a texture amplification circuit 20, a structure correction circuit 30, an adder 40, a delay circuit 50, and a chroma amplifier 60.

The texture emphasizing section 100 performs image data processing as shown in FIG. That is, the input luminance signal Y ₁ is converted by the S / T separation circuit 10 into a structure component S 1 constituting an outline of an image,
The image is separated into a texture component T1 constituting details of the image. Next, the texture component T1 is amplified by the texture amplification circuit 20 to obtain a texture component T2. On the other hand, the structure component S1 is non-linearly corrected by the structure correction circuit 30 in terms of the range and the gradation, and is used as the structure component S2. Further, by adding the texture component T2 and structure component S2 by the adder 40 combining to obtain a luminance signal Y _2.

As shown in FIG. 4, the S / T separation circuit 10 includes a level determination unit 11, a frequency determination unit 12, a filter characteristic determination unit 13, a nonlinear filter 14, and a subtractor 15. The level judging means 11 and the frequency judging means 12 each judge the amplitude level and frequency fluctuation range of the luminance signal Y ₁ and output the judgment result to the filter characteristic deciding means 13. The filter characteristic determining means 13 determines the threshold of the amplitude level and the frequency of the nonlinear filter 14 according to the determination result. The non-linear filter 14 smoothes the luminance signal Y ₁ with the filter characteristics determined by the filter characteristic determining means 13 and extracts the structure component S 1. Subtractor 15 extracts a texture component T1 by subtracting a structure component S1 to the original luminance signal Y _1.

The non-linear filter 14 is different from a commonly used linear low-pass filter, and is a non-linear filter that takes into account both the amplitude level and the frequency of the luminance signal Y ₁ .
They are distinguished from the other components. More specifically, an edge component amplitude variations steep of the luminance signal Y ₁ is preserved, and performs a smoothing with respect to small-amplitude components other than the edge component (JP-2001
-298621). Nonlinear filter 14
Is configured as a two-dimensional non-linear filter or a one-dimensional non-linear filter applied to each of the horizontal direction and the vertical direction of the image. The absolute value of the difference between the pixel value (amplitude) and the center pixel of the filtering is a predetermined threshold value. The pixel values of the peripheral pixels falling below ε are applied as they are, but if the difference between the absolute values of the pixel values is larger than the threshold ε, it is determined to be an edge, and the pixel value of the central pixel is replaced with the pixel value of the peripheral pixel. The smoothing is performed after eliminating the influence of the surrounding pixels by using the pixel values. However, in an actual image, a portion where the amplitude fluctuation is large is not always a contour line on the image, and conversely,
Even if the amplitude fluctuation is small, it may be a contour line. Therefore, here, the smoothing is performed by combining not only the amplitude level but also the information from the frequency, so that the structure component S
The accuracy of extraction of 1 is increased.

The texture amplification circuit 20 is configured as an amplifier that amplifies the texture component T1 output from the S / T separation circuit 10 in accordance with an externally input enhancement gain TE (hereinafter abbreviated as gain TE). Output the component T2. The actual value of the gain TE is
A value between 1 and 2 is appropriate. In normal use, the value is, for example, about 1.3 to 1.4, but above that, the effect of texture emphasis appears strongly. When the value of the gain TE is 2 or more, the texture component is overemphasized and gives an uncomfortable feeling.

The structure correction circuit 30 performs non-linear correction on the structure component S1 input from the S / T separation circuit 10. Here, FIG.
This correction is referred to as gamma correction for the sake of convenience because a correction curve having an offset value ΔY like the gamma curve 31A shown in FIG. The gamma value and the offset value ΔY of the gamma curve 31A are adjusted according to, for example, the degree of amplification of the texture T1, that is, the gain TE.

The adder 40 is a part of the texture amplifying circuit 20.
And the structure component S2 input from the structure correction circuit 30.
And are added. Thus, the luminance signal Y ₂ which structure component is corrected with the texture component is emphasized is generated.

The delay circuit 50 delays the color difference signals U ₁ and V ₁ input from the chroma decoder 103,
And outputs synchronously with the luminance signal Y _2. Further, the chroma amplifier 60 receives the input color difference signal U.
₁ and V ₁ are multiplied by (Y ₂ / Y ₁ ) to obtain color difference signals U ₂ and V 1.
₂ is generated and output. This allows Y
The / C ratio is maintained before and after the texture enhancement processing.

<Structure of Sharpness Unit 200> Here, the sharpness unit 200 is provided after the texture emphasizing unit 100. The sharpness section 200
Sharpness processing is performed on the luminance signal Y ₂ , and the luminance signal Y ₃
And a color difference signal U
_2, after synchronized with the luminance signal Y ₃ over a delay V _2, is constituted by a delay circuit for outputting a U _3, V _3.

FIG. 6 is a block diagram showing the configuration of the sharpness circuit.
It is a lock figure. This sharpness circuit 210 will be described later.
Except for the SG control means 214
I have. Specifically, the delay circuits 211 and 212
, But here, as an example,
That delays twice the clock period D of the input clock signal
And In this circuit, the luminance signal Y_TwoAnd the luminance signal
Y_TwoThe output of the delay circuit 211 delayed by 2D from
Of the delay circuit 212 delayed by 2D from the output of the delay circuit 211
An operation with the output is performed. As a result, as shown in FIG.
As shown in FIG._TwoAgainst pre-shoe
G, component S corresponding to overshoot _P, S_OWith
A sharpness signal SS is generated. Note that K is
This is the coefficient of reshoot / overshoot and is shown in the figure.
As described above, the signal component S_P, S_OThe ratio of the amplitude values of
K: 1−K.

The level adjusting means 213 adjusts the amplitude level of the sharpness signal SS. The level adjusting means 213 is a multiplier, and outputs the sharpness signal SS
Is multiplied by a sharpness gain SG.

The SG control means 214 sets the sharpness gain SG to the gain T in the texture amplification circuit 20.
This is set according to E. That is, the SG control means 214 performs an adjustment to decrease the sharpness gain SG as the gain TE increases.

The reason why the sharpness intensity is adjusted in association with the texture enhancement intensity is as follows.
The sharpness performed here is to be complementarily performed on the texture emphasized image. Therefore, the sharpness here is not as strong as usual, and needs to be weakly added according to the state of the image.

The second reason is that the texture enhancement unit 10
If the pre-shoot / overshoot is already attached to the input signal to 0, the texture amplifying circuit 20
Amplifies the preshoot and overshoot. When sharpening is applied to such an output signal,
Since the same processing is partially repeated, the preshoot / overshoot is excessively amplified. Therefore, in this case, it is necessary to adjust the sharpness to an appropriate level, depending on the state of the image, or to attenuate the preshoot and overshoot derived from the original signal amplified in the texture emphasis processing. Becomes The latter means that the sharpness gain SG is selected to be a negative value.

It is to be noted that if the gain TE is selected in advance to some numerical value, the SG control means 214
It is possible to have a lookup table of a corresponding sharpness gain SG, and output the value of the sharpness gain SG therefrom. Table 1 shows an example of such a correspondence table. Table 1 shows the sharpness gain SG
Is adjusted so as to decrease from the specified value a according to the gain TE. In the figures of the sharpness gain SG in this table, 1 is, for example, 0.5 dB.

[0036]

[Table 1]

The adder 215 to the output of the delay circuit 211, by adding the sharpness signal SS, and generates and output a luminance signal Y _3. The luminance signal Y ₃ includes a component S
Preshoot and overshoot adjusted by _P and S _O are added.

Next, the operation of the image display device according to the present embodiment will be described with reference to FIG. 8 and FIGS.

FIGS. 8A and 8B are diagrams showing changes in the luminance signal waveform for each processing in the image display device. FIG. 8A shows the luminance signal Y ₁ , and FIG. 8B shows the luminance signal Y ₂ after the texture enhancement processing. (C) shows the luminance signal Y after the sharpness processing.
₃ represents the pulse waveform on the top and the frequency characteristics on the bottom.

First, an input image signal is demodulated into a YUV signal. When a television signal is input, the signal is demodulated into a composite signal by a tuner 101, separated into a luminance signal Y and a chrominance signal C by a Y / C separation circuit 102, and a YUV signal Y ₁ U ₁ V by a chroma decoder 103. Decoded to ₁ . When a composite signal is input from a VCR or a DVD, similar processing is performed in the Y / C separation circuit 102 and the chroma decoder 103. In any case, the luminance signal Y ₁ and the color difference signals U ₁ and V ₁ are output from the chroma decoder 103 to the texture emphasizing unit 100. Note that the pre-shoot / overshoot included in the original signal is stored in the luminance signal Y ₁ (FIG. 8A).

[0041] In <texture enhancement process> texture enhancement unit 100, the luminance signal Y ₁ is first input to the S / T separating circuit 10 (FIG. 2, FIG. 4). S / T separation circuit 10
Then, the luminance signal Y ₁ is input to the level judging means 11 and the frequency judging means 12, each of which judges the amplitude level and frequency fluctuation range of the luminance signal Y ₁ , and outputs the judgment result to the filter characteristic determining means 13. The filter characteristic determining means 13 determines the amplitude level and the frequency threshold of the nonlinear filter 14 according to the determination result, and outputs the threshold to the nonlinear filter 14. Nonlinear filter 14 performs smoothing the luminance signal Y ₁ based on the filter characteristics given to the filter characteristics determining unit 13 extracts the structure component S1. The structure component S1 obtained here is
The edge portion is stored as it is, and the other portion is smoothed image data. That is, it is data representing a rough configuration such as a contour line in an image.

Further, subtracter 15 extracts a texture component T1 by subtracting a structure component S1 to the luminance signal Y _1. The obtained texture component T1 is
This is a small-amplitude component obtained by removing the structure component S1 from the original signal, and is data corresponding to fine undulations of details in the image, for example, patterns. Here, Preshoot overshoot included in the luminance signal Y ₁ is incorporated into the texture component T1. Thus, the structure component S1 and the texture component T1 are generated and output from the S / T separation circuit 10 (FIG. 3).

The texture component T1 is input to the texture amplification circuit 20. The gain TE is externally input to the texture amplification circuit 20, and the texture component T1 is amplified according to the gain TE to become a texture component T2 (FIGS. 2 and 3). At this time, the preshoot and overshoot included in the texture component T1 are also simultaneously amplified according to the gain TE. This texture component T2 is output to the adder 40.

On the other hand, the structure component S1 is input to the structure correction circuit 30 and subjected to gamma correction by the gamma curve 31A to become a structure component S2. Thereby, the structure component S2
Is amplified so that the amplitude level on the low luminance side (black side) is raised in conjunction with the amplitude value of the texture T2, and the amplitude level on the high luminance side (white side) is reduced. This structure component S2 is output to the adder 40.

The adder 40 has a structure component S2
And the texture component T2 are input, and the two are added to shine.
Degree signal Y_TwoGenerate At this time, the structure component
The amplitude level on the black side of S2 is determined by the gun with reference to the gain TE.
The amplified text is lifted by the
Even when the texture component T2 is added, the amplitude level on the black side is
It falls within the dynamic range. Also, its white side amplitude
Since the level has been reduced with reference to the gain TE,
Even if the amplified texture component T2 is added, the white side
The amplitude level falls within the dynamic range. Accordingly
And the luminance signal Y _TwoHas been texture enhanced
At the same time as it is within the dynamic range.
It has become. Note that this luminance signal Y_TwoIs
Preshoot overshoot amplified according to in TE
(FIG. 8B).

[0046] Also, for the color difference signals U _1, V _1, the delay circuit 50 by delaying by the time taken for processing the luminance signal Y _2, the luminance signal Y ₂ is multiplied by Y ₂ / Y ₁ by chroma amplifier 60 amplifies only the amplification amount, the color difference signal U ₂ as Y / C ratio is maintained before and after the texture enhancement process,
To generate a V _2. Luminance signal Y ₂ and color difference signals U ₂ , V
₂ is input to the sharpness section 200.

<Sharpness processing> Sharpness section 20
In 0, the luminance signal Y ₂ is inputted to the sharpness circuit 210 (FIG. 6). In the sharpness circuit 210, the luminance signal Y ₂ and the luminance signals Y ₂
Performs calculation of the signal multiplied by the delay component S _P corresponding to Preshoot overshoot, generates a sharpness signal SS having the S _O.

On the other hand, the gain TE is input to the SG control means 214, and the sharpness gain SG is set according to the value of the gain TE. The larger the gain TE,
Since the image has been subjected to strong texture enhancement processing,
In order to balance the effects, the magnitude and sign of the components S _P and S _O must be determined so that the sharpness processing is performed weakly. Further, as the gain TE is large, the pre-shoot overshoot from the original signal is amplified, here, so the pre-shoot overshoot in the luminance signal Y ₃ finally obtained may have an appropriate size _First , the magnitudes and signs of the components S _P and S _O must be determined. It is the sharpness gain SG that adjusts the magnitudes and signs of the components S _P and S _O , where the value and sign of the sharpness gain are determined.

[0049] That is, component S _P, in the case of adding only a little preshoot overshoot the luminance signal Y ₃ using S _O, select the sharpness gain SG to a small value in the range of SG> 0, additionally, original signals from the preshoot overshoot component S _P, when the attenuating by S _O chooses the sharpness gain SG from a negative value (SG <0).

Next, the sharpness signal SS and the sharpness gain SG are input to the level adjusting means 213. Here, the two are multiplied, and the components S _P and S _{O of} the sharpness signal SS are adjusted according to the sharpness gain SG. The magnitude and magnitude of the amplitude of the sharpness signal SS changes according to the sign of the sharpness gain SG and the magnitude of the absolute value.

Further, the sharpness signal SS is added by the adder 215 to the luminance signal Y ₂ output from the delay circuit 211. Thus, the sharpness signal SS is superimposed on the luminance signal Y _2, is output as the luminance signal Y _3. The edge portions of the luminance signal Y _3, pre chute
The overshoot is adjusted to an appropriate size by the components S _P and S _O (FIG. 8C).

By adjusting the amount of the preshoot / overshoot, the sharpness circuit 210 is adjusted.
, Compared luminance signal Y _2, the frequency characteristic is processing that varies as in Figure 9. The amplitude of the middle frequency band, that is, the band corresponding to the preshoot / overshoot, changes according to the sharpness gain SG. SG
At = 0, there is no change in the amplitude and the state is flat.
When SG> 0, the amplitude is amplified according to SG, and the corresponding band is raised. When SG <0, the amplitude is attenuated according to SG, and the corresponding band drops.

The color difference signals U ₂ and V ₂ are delayed by a delay circuit by the time required for processing the luminance signal Y ₂ and output as color difference signals U ₃ and V ₃ .

The luminance signal Y ₃ and the color difference signals U ₃ ,
V ₃ is input to the matrix circuit 104. The matrix circuit 104 reproduces the RGB signals from these YUV signals and outputs the signals to the driver 105. Driver 105
Amplifies the input RGB signals, generates a drive signal having a voltage value corresponding to the luminance gradation, and outputs the drive signal to the display 106. The display 106 displays an image according to the input drive signal.

At this time, since the preshoot and overshoot included in the luminance signal Y ₃ as the original signal are adjusted to an appropriate amount, the image displayed on the display 106 is subjected to the texture emphasis processing by the appropriate contour emphasis. The sharpness is further increased without deteriorating the effect of.

As described above, according to the present embodiment, in the image display device that performs the texture enhancement processing, the sharpness section 200 is provided after the texture enhancement section 100, and the sharpness circuit 210 adjusts the correction amount according to the enhancement gain TE. Since the adjustment is performed, the sharpness is prevented from being excessively increased, and the effects of texture enhancement and sharpness can be balanced to keep the sharpness of the entire image without any unnatural feeling.

In addition, for a television signal or the like which is already in a state where sharpness has been already applied at the time of input, an amplification process for performing preshoot / overshoot before the sharpness section 200 is performed. The offset is canceled in the sharpness section 200. Therefore, Preshoot overshoot included in the luminance signal Y ₃ to be finally output is adjusted to a proper amount. Therefore, an appropriate contour enhancement correction can be applied to the texture-enhanced image.

[Second Embodiment] FIG. 10 shows the overall configuration of an image display device according to a second embodiment.
This image display device has the same configuration as that of the image display device according to the first embodiment, except that a desharpness unit 300 is provided before the texture enhancement unit 100. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

In the present embodiment, preshoot / overshoot is carelessly applied to an image signal such as a television signal after tuner demodulation to which preshoot / overshoot has already been added at the time of input. As a measure for preventing the signal from being amplified, the desharpness unit 300 flattens the frequency characteristic of the signal before the texture emphasizing process and removes the preshoot and the overshoot.

De-sharpness section 300
Performs a de-sharpness process on the luminance signal Y _0, and outputs a luminance signal Y ₁ as a de-sharpness circuit 310. After delaying the color difference signals U ₀ and V ₀ and synchronizing with the luminance signal, U ₁ , It is constituted by a delay circuit for output as V _1.

Desharpness is a process for removing preshoots and overshoots, as opposed to sharpness, and corresponds to the operation when the sharpness gain SG <0 in the sharpness circuit 210 of the first embodiment. Therefore, the configuration of the desharpness circuit 310 is as follows.
The configuration is the same as that of the sharpness circuit 210 as shown in FIG. 11 except that the sharpness signal SS is subtracted from the luminance signal Y ₀ . That is, in the desharpness circuit 310, the level adjusting means 313 adjusts the level of the sharpness signal SS in accordance with the desharpness gain DSG having a negative value (DS
G <0). Further, the adder 315 adds the sharpness signal SS having the inverted sign to the luminance signal Y ₀ output from the delay circuit 311.
An amount corresponding to the magnitude of the (components S _P and S _O ) is subtracted from the luminance signal Y ₀ to output a luminance signal Y ₁ with reduced preshoot and overshoot.

Here, the desharpness circuit 31
The value of the coefficient K of 0 is set so that (1−K) is larger than K. This means that the overshoot is attenuated more than the preshoot (see FIG. 7). The inventor of the present invention pays attention to the fact that overshoot tends to be larger than preshoot in an original signal, particularly a television signal transmitted as radio waves, and to remove overshoot more reliably. Is
I came up with the idea of changing the removal ratio between preshoot and overshoot. Thus, here, in the sharpness signal SS, it is adapted to set the coefficient K to increase the component S _O than component S _P.

Next, the operation of the image display device will be described.
This will be described with reference to FIGS. 10, 11 and 12. FIG.
2 is a diagram showing a change of a luminance signal waveforms of each process in the image display device, the (A) is the luminance signal Y _0,
(B) shows the luminance signal Y ₁ after the desharpness processing,
(C) shows the luminance signal Y ₂ after the texture enhancement processing,
(D) represents a luminance signal Y ₃ after the sharpness processing, respectively on the pulse waveform, the lower is its frequency characteristic.

The input image signal is demodulated into YUV signals Y ₀ , U ₀ , and V ₀ by the same processing as in the first embodiment. Note that the luminance signal Y _0, there remains a pre-shoot overshoot that was included in the original signal (Fig. 12 (A)). The YUV signals Y ₀ , U ₀ , and V ₀ are output to the desharpness unit 300.

In the desharpness section 300, the luminance signal Y
₀ is input to the desharpness circuit 310. In the desharpness circuit 310, the luminance signal Y _{0 is} output by the delay circuit.
Performs an operation of a signal obtained by multiplying the delay, component S _P corresponding to Preshoot overshoot, generates a sharpness signal SS having the S _O. At this time, by adjusting the advance coefficient K, component S _P, the ratio of the amplitude value of the S _O: setting the (K 1-K). Therefore, the component S _O is larger than the component S _P here.

The sharpness signal SS is input to the level adjusting means 313. Further, the desharpness gain DSG is input to the level adjusting means 313, and is multiplied by the sharpness signal SS. As a result, the signs of the sharpness signals SS (components S _P and S _O ) are inverted, and their magnitudes are adjusted to desired values.

Further, the sharpness signal SS is
The luminance signal output from the delay circuit 311 by the arithmetic unit 315
Y₀Is added. Thereby, the luminance signal Y₀Edge of
To the component S of the sharpness signal SS_P, S_OA considerable amount
Removed and the luminance signal Y₁(FIG. 12B). this
When the sharpness signal SS has the component S_PMore component S _O
Is larger, the preshoot overshoot originating from the original signal
Because it follows the shape of the mute
Degree signal Y₀From pre-shoot and overshoot
Removed without excess or deficiency. The resulting luminance signal
Y₁Frequency characteristics are preshoot and overshoot
The mid-range component corresponding to
You.

As described above, before the texture emphasizing process, the preshoot and the extra signal included in the luminance signal Y ₀ are added.
By reducing overshoot and flattening its frequency characteristics, its influence on texture enhancement processing is reduced. Furthermore, it is not necessary to consider the influence of the preshoot and overshoot on the sharpness to be applied thereafter, as in the first embodiment.

This luminance signal Y ₁ is output to the texture enhancement section 100. The color difference signals U ₀ and V ₀ are delayed by the delay circuit by the time required for processing the luminance signal Y _{0, and} are converted into the color difference signals U ₁ and V _{1 by the} texture enhancement unit 1.
Output to 00.

The texture emphasizing section 100 operates in the same manner as in the first embodiment. The input luminance signal Y ₁ is
The extracted and amplified texture component, the luminance signal Y ₂ (FIG. 12 (C)). At this time, since the amplitude of the preshoot overshoot included in the luminance signal Y ₁ is smaller, in the amplification of the texture component,
Almost only the texture component is emphasized. That is, the frequency characteristic changes so as to be lifted from the low frequency side while being flat. Therefore, in this texture enhancement processing, the contrast enhancement of the details, which is the feature thereof, is effectively performed.

The luminance signal Y ₂ is output to the sharpness section 200. The color difference signals U ₁ and V ₁ are delayed in the same manner as in the first embodiment, the amplitude values are corrected, and the color difference signals U ₁ and V ₁ are adjusted.
₂ and V ₂ are output to the sharpness unit 200.

The sharpness section 200 operates in the same manner as in the first embodiment. Here, since it is smaller in amplitude of the pre-shoot overshoot included in the luminance signal Y _2, contour correction performed only in the pre-shoot overshoot to be added in this sharpness unit 200, the luminance signal Y ₃ (FIG. 12D). As described above, in the present embodiment, unlike the first embodiment, it is simpler and more appropriate because the frequency components in the middle band that are amplified and input by the texture emphasis processing need not be considered. Correction is made.

Further, the sharpness applied after the desharpening and the texture emphasizing processing has an effect of amplifying the frequency components from the middle band to the high band once lowered by the desharpening. Therefore, it can be said that this is an effective means for correcting the frequency characteristics.

The color difference signals U ₂ , V ₂ are delayed in the same manner as in the first embodiment, and become color difference signals U ₃ , V ₃ . The luminance signal Y ₃ and the color difference signals U ₂ , V ₂ are output to the matrix circuit 104. Subsequent operations of the apparatus are performed in the same manner as in the first embodiment.

As described above, according to the present embodiment, in the image display apparatus that performs the texture enhancement processing, the desharpness section 300 is provided before the texture enhancement section 100. preshoot overshoot from original signals that have been included in the extra in the luminance signal Y ₀ is reduced, the frequency characteristics are flattened. Therefore, the influence of the preshoot / overshoot derived from the original signal on the texture enhancement process performed thereafter can be reduced, and an image on which texture enhancement has been effectively performed can be obtained.

As can be seen from the changes in the frequency characteristics shown in FIGS. 12A and 12B, according to the desharpness, the frequency characteristics decrease from the middle band to the high band, but the television signal has because it is originally band-limited RF signal, it becomes the characteristic deterioration in the high frequency side of the luminance signal Y ₁ which is suppressed here. Rather, by the frequency characteristic up the midrange is flattened, greater in effect of reducing the amount of pre-shoot overshoot contained in the luminance signal Y _0. To the luminance signal Y ₁ of which the frequency property has been improved up to midrange Thus, by applying a texture enhancement process to lift the frequency characteristic remains flat, pre chute overshoot inconspicuous, the effect of the texture enhancement front Is obtained.

Further, since the coefficient K is set so as to remove the overshoot more largely than the preshoot, the preshoot / overshoot derived from the original signal can be removed more or less.

As a method of correcting the output characteristics of the tuner 101 to be flat, the desharpness is the simplest method and can be easily realized.

[Third Embodiment] FIG. 13 shows the entire configuration of an image display device according to a third embodiment of the present invention. The image display device according to the first embodiment is the same as that of the first embodiment except that the image display device does not include the sharpness unit 200, and instead includes the S / N ratio detection unit 107 and the noise removal circuit 70 of the texture enhancement unit 100. It has the same configuration as the image display device. That is, the image display device detects the S / N ratio of the input image signal, and adjusts the amount of texture enhancement and the amount of the component removed from the texture component T1 in conjunction with the S / N ratio. Operation.

The S / N ratio detector 107 calculates the ratio of the true signal value (S) to the other noise (N) with respect to the composite (CVBS) signal before being input to the Y / C separation circuit 102, That is, the S / N ratio is determined. For the signal value, for example, a voltage value from a black level to a white level is determined in advance as a standard value, and thus the S / N ratio is obtained by detecting the amount of noise.

The detection of the noise amount is performed with reference to a time domain in which no signal component is included in the CVBS signal. For example, it is performed between the pulses shown by the bold line in the vertical synchronization period d1 or the equivalent period d2 in the vertical blanking period shown in FIG. The S / N ratio obtained from the noise amount in this manner is output to the texture enhancement unit 100.

FIG. 15 is a block diagram showing the configuration of the texture emphasizing unit 100 according to the present embodiment. In the present embodiment, the S / T separation circuit 10 and the texture amplification circuit 2
Between 0 and 0, a noise removing circuit 70 is provided.

The noise removing circuit 70 receives the texture component T1 before amplification, removes the noise component from the texture component T1, and outputs it as the texture component T11. The noise removal circuit 70 includes
The S / N ratio is input from the S / N ratio detection unit 107, and here, the magnitude of the signal to be removed is determined based on the S / N ratio.

Specifically, the noise elimination circuit 70 is configured as shown in FIG.
6 is configured as a coring circuit having the input / output characteristics shown in FIG. That is, the minute amplitude region X2 is set as a dead zone, and signal components in this region are regarded as noise and removed from all input values. Here, the width of the dead zone ±
a is set according to the S / N ratio. In the figure, the region where the input signal is larger than the region X2 is defined as the region X1, the region X
A region where the input signal is smaller than 2 is defined as a region X3.
FIG. 17 shows a noise removal circuit 70 as a coring circuit.
1 shows an example of the configuration. As described above, the noise removal circuit 70 includes the comparator 71 for comparing the texture component T1 with the dead zone width a, the comparator 72 for comparing the texture component T1 with the dead zone width -a, and the regions X1 to X3 for the texture component T1. And a switch 76 for switching the connection to the arithmetic circuits 73 to 75 to be output based on the output result from the comparator 72.

In this case, the texture amplification circuit 2
0 is also configured to operate in conjunction with the S / N ratio similarly to the noise removal circuit 70. In the texture amplification circuit 20, the degree of amplification (gain TE) of the texture component T11 is set in accordance with the S / N ratio so that the noise component is not excessively amplified.

The above-mentioned dead zone width a and gain TE
May be set using a look-up table as shown in Table 2. In that case, the S / N ratio detection unit 107
Is input here, and the dead zone width a and the enhancement gain TE selected corresponding to the S / N ratio are input to the noise removing circuit 70 and the texture amplifying circuit 20, respectively. .

[0087]

[Table 2]

As shown in Table 2, the smaller the value of the S / N ratio (the larger the noise), the more the dead zone width a
Are set so as to increase the width of and to decrease the enhancement gain TE.

Next, the operation of the image display device of the present embodiment will be described with reference to the drawings.

First, the input image signal is converted into YUV signals Y ₁ , U ₁ , V ₁ by the same processing as in the first embodiment.
_The signal is demodulated to 1 and input to the texture emphasizing unit 100.

At the same time, the output signal of tuner 101 is
The signal is input to the N ratio detection unit 107, and the S / N ratio is obtained from the noise amount. The noise amount is detected, for example, as a difference from a specified value of the vertical synchronization pulse (the thick line in FIG. 16) in the vertical synchronization period d1 in the image signal. Alternatively, it may be detected as a difference from a prescribed value of the equivalent pulse in the equivalent pulse period d2. Since the detected noise amount is an AC component, its effective value is obtained here. In addition,
The signal value is, for example, 1 V _PP from the black level to the white level.
(V _PP ; a unit representing the peak-to-peak voltage of the signal) and the like, and the value of the effective component is calculated from this. In this example, the effective component of the signal is 0.7 V _PP . The S / N ratio is determined from these values. The obtained S / N ratio is output to the noise removing circuit 70 and the texture amplifying circuit 20 in the texture emphasizing unit 100.

[0092] In the texture enhancement unit 100, the luminance signal Y ₁ is the structure component S1 in S / T separating circuit 10 is separated into the texture component T1, is output.
The texture component T1 is included in the noise removal circuit 7
It is input to 0 and output as a texture component T11, then input to the texture amplification circuit 20 and output as a texture component T2.

The noise removing circuit 70 and the texture amplifying circuit 20 operate according to the S / N ratio, respectively. As illustrated above in the look-up table (Table 2), here, both parameters (dead band width a , Gain TE)
Are varied in relation to each other. When the S / N ratio is low, that is, when the amount of noise is large, it is prioritized that the noise is not greatly amplified rather than texture emphasis. Therefore, the width a of the dead band of coring is increased, and the gain TE is reduced to suppress amplification of noise remaining in the texture component T11. On the other hand, when the S / N ratio is high and the amount of noise is not so large, adjustment is made so as to increase the gain TE in the direction to increase the texture emphasizing effect as much as possible and to reduce the width a of the dead zone of coring at the same time. Do.

The noise removal circuit 70 supplies the S / S
The N ratio and the texture component T1 are input. As described above, the noise elimination circuit 70 determines the upper and lower limits (the dead band width ±) of the signal amplitude to be eliminated according to the S / N ratio.
a), and based on this, the texture component T1
Is removed. As a result, the signal components in the dead zone are regarded as noise and completely removed, and from the signal components outside the dead zone, the component of the amplitude value (a) corresponding to the component in the dead zone is removed as noise. The processed signal is output to the texture amplification circuit 20 as a texture component T11.

The specific circuit operation of the noise elimination circuit 70 will be described below with reference to FIGS. 16 and 17. The texture component T1 is represented by X
The value is input to the comparator 71 to determine where the value is in the region of 1 to X3, and is also input to the calculators 73 and 74 to give a value for calculation.

In the comparator 71, the magnitude of the texture component T1 is compared with the positive value a of the dead zone. If the texture component T1 is larger than a (A> B), the texture component T1 is determined to be the value of the area X1, and a signal corresponding to X1 is input to the switch 76. Conversely, if the texture component T1 is less than or equal to a (A ≦ B), it is determined that the texture component T1 is the value of the region X2 or the region X3,
Further, the comparator 72 makes a determination.

In the comparator 72, the magnitude of the texture component T1 is compared with the negative value -a of the dead zone. If the texture component T1 is equal to or more than -a (A≥B), the texture component T1 has a value of -a≤T1≤a and is determined to be a value of the area X2. Therefore, at this time, a signal corresponding to X2 is input to the switch 76. When the texture component T1 is smaller than -a (A <B), it is determined that the texture component T1 is the value of the region X3,
A corresponding signal is input to the switch 76.

The computing unit 73 outputs a value obtained by subtracting the value a from the texture component T1, and the computing unit 73 outputs a value obtained by adding the value a to the texture component T1. The arithmetic unit 74 returns a value of 0 regardless of the input value. The above output values convert the input value of the texture component T1 into output values in the regions X1, X3 and X2, respectively.

The switch 76 is supplied with a signal indicating which region of X1 to X3 the input value is in from one of the comparators 71 and 72. Therefore, the switch 76 selects the calculators 73 to 75 according to this signal and outputs the calculation result. As a result, the areas X1 to X3 to which the input values correspond
Is obtained, and the texture component T1 shown in FIG.
Coring having characteristics such as 6 is performed. This output is the texture component T11.

Next, the texture amplification circuit 20 includes:
The S / N ratio of the image signal and the texture component T11 are input. The texture amplification circuit 20 sets the gain TE according to the S / N ratio of the image signal as described above, and amplifies the texture component T11 based on the gain TE. At this time, since the noise component of the minute amplitude has been removed first, it does not receive any amplifying action. However, since the minute amplitude component of the texture component T11 is removed together with the noise, it is not amplified at all as a result. Further, by adjusting the gain TE, excessive amplification of the noise included in the texture component T11 is avoided. Instead, the amplification degree of the texture component T11 itself is suppressed. The amplified signal is output to the adder 40 as a texture component T2.

On the other hand, the structure component S1, which is another output of the S / T separation circuit 10, is input to the structure correction circuit 30 and subjected to gamma correction to become a structure component S2. The structure component S2 is also output to the adder 40. Adder 40
It is structure component S2 and the texture component T2 is input, by adding both to generate a luminance signal Y _2. This luminance signal Y ₂ is input to the matrix circuit 104. The following operation is the same as in the first embodiment.

At this time, since the image displayed on the display 106 has been subjected to the texture emphasis processing while reducing and removing the noise according to the S / N ratio, the noise component is emphasized along with the texture emphasis. That has been avoided. In general, an image with a lot of noise may look crisp near the outline, and this may be further enhanced by the texture enhancement process. The phenomenon is also suppressed. In particular, when the image signal is a weak electric field signal having a large amount of noise, it is often the case that the noise is not conspicuous and the image quality is rather good when the texture enhancement is not performed strongly.

As described above, according to the present embodiment, an S / N ratio detection unit 107 and a noise removal circuit 70 are provided in an image display device that performs texture enhancement processing. The enhancement gain TE of the texture amplification circuit 20 is calculated based on the detected S / N
Since the setting is made according to the ratio, the balance between the effect of noise removal / reduction and the effect of texture enhancement is S / N.
Adjusted by the ratio. That is, the texture component T
1 is removed, the amount of noise amplified in the texture-emphasizing process is reduced, and the degree of amplification of the noise component remaining in the texture component T11 is weakened. Emphasis is effectively avoided. Therefore, noise removal
It is possible to obtain an output image in which both the reduction and the texture enhancement are performed to an appropriate degree.

[Fourth Embodiment] FIG. 18 is a block diagram showing a main part of an image display device according to a third embodiment of the present invention. In this image display device, the noise removing circuit 70 is removed from the texture emphasizing unit 100, and the texture amplifying circuit 20 further includes the amplification limiting circuit 23 and the amplifier 2
5, except that it is composed of an adder 27.
The configuration is the same as that of the image display device according to the embodiment. That is, the image display device detects the S / N ratio of the input image signal, adjusts the texture enhancement amount in conjunction with the detected S / N ratio, and restricts the amplification range of the texture component T1. And to do.

The texture amplification circuit 20 of the present embodiment
Then, the input texture component T1 is branched, one of which is added to the adder 27, and the other is added to the amplification limiting circuit 23 and the
5 is processed into a texture component T22 which is an amplification component, and then input to the adder 27.

The amplification limiting circuit 23 limits an area to which the input texture component T1 is to be amplified and outputs it as a texture component T21. More specifically, the output is limited by limiting the range to a small amplitude region so that the amplifier 25 does not amplify the small amplitude component containing much noise in the texture component T1. Here, the amplification limit range is set based on the S / N ratio input from the S / N ratio detection unit 107. The amplification limiting circuit 27 can be configured as a coring circuit, similarly to the noise removing circuit 70 in the third embodiment, in which case, the output value of the minute amplitude region falling within the dead zone is set to zero ( 16 and 17).

The amplifier 25 amplifies the texture component T21, and generates a component corresponding to the amplified component of the texture component T1 as a texture component T22. Here, the amplifier 25 is also configured to operate in conjunction with the S / N ratio similarly to the amplification limiting circuit 23.
The degree of amplification of the texture component T21 (gain A _t)
Is set according to the S / N ratio.

[0108] Incidentally, the amplification limiting circuit 23, operates in accordance with the respective amplifier 25 S / N ratio, the configuration where, as both parameters (dead zone width, the gain A _t) varies related to each other Is done. When the S / N ratio is low, that is, when the amount of noise is large, it is prioritized that the noise is not greatly amplified rather than texture emphasis. Therefore, the gain A _t with widening the width of the dead zone of the coring
To prevent noise included in the texture component T21 from being amplified. On the other hand, a high S / N ratio, when the amount of noise is not so many, to raise as much as possible the texture enhancement effects, adjusted to narrow the width of the dead band of the gain A simultaneously coring is varied in the direction of increasing the _t To do.

The adder 27 combines the texture component 1 and the texture component T22, and outputs an amplified texture component T2. Therefore, the enhancement gain TE in the present embodiment is expressed as 1 + A _t the gain A _t of the adder 25.

Next, of the operation of the image display device, a description will be given of a texture emphasis process which is a characteristic portion of the present embodiment. The other processing is the same as in the third embodiment.

[0111] In the texture enhancement unit 100, first, the luminance signal Y ₁ is the structure component S1 in S / T separating circuit 10 is separated into the texture component T1. The texture component T1 is input to the texture amplifying circuit 20, and is subjected to the following processing. In addition, S / N
The ratio detection unit 107 outputs the obtained S / N ratio to the amplification limiting circuit 23 and the amplifier 25 of the texture amplification circuit 20.

The S / N of the image signal is supplied to the amplification limiting circuit 23.
The ratio and the texture component T1 are input. The amplification limiting circuit 23 sets the upper limit value and the lower limit value of the amplitude region not to be amplified among the texture components T1 to the dead band width, and performs coring. At that time, the dead zone width is S / N
The ratio is set in accordance with the noise level. As a result, the output value of the minute amplitude region (within the dead zone) within the defined range of the texture component T1 becomes zero. From the signal components in the other range (outside the dead zone), the amplitude values corresponding to the components in the dead zone are subtracted. The processed signal is output to the amplifier 25 as a texture component T21.

Next, the texture component T21 is amplified by the amplifier 25. At this time, the texture component T21
Of these, the signal components in the dead zone in the amplification limiting circuit 23 are not amplified at all, and only the signal components outside the dead zone are gain A
Selectively amplified at _t . In this way, the amplification of the noise is suppressed by not amplifying the region of the texture component T21 that is determined to contain most of the noise. Further, here, the amplifier 25 is set according to the gain A _t the S / N ratio of the image signal. Therefore, the degree of amplification is suppressed in accordance with the amount of noise, and the noise remaining in the signal component outside the dead zone is prevented from being excessively emphasized. The amplified signal has a texture component T
22 is output to the adder 27.

The adder 27 adds the input texture component T1 and texture component T22. As a result, a texture component T2 obtained by multiplying the texture component T1 by (1 + A _t ) is output. Texture component T2
Is that a texture enhancement process that does not amplify the noise component is performed according to the S / N ratio, so that while the texture component is enhanced, the noise enhancement accompanying this is avoided.

The following operation is the same as in the third embodiment. In the image displayed on the display 106, the texture component is enhanced, but the noise enhancement accompanying the texture component is avoided, and the image quality is appropriately corrected.

As described above, according to the present embodiment, the S / N ratio detecting section 107 is provided in the image display apparatus for performing the texture emphasizing process, and the texture amplifying circuit 20 includes the amplification limiting circuit 23, the amplifier 25, and the adder 27. The small amplitude region including the noise component in the texture component T1 is not amplified, so that the amplification of the noise is avoided. Moreover, the gain A _t of the dead zone width and an amplifier 25 for amplifying limiting circuit 23, since to set in accordance with the S / N ratio of the image signal, it is possible to properly set the amplification limit range, in anticipation of noise amplification The amplification intensity of the texture component can be adjusted. In the present embodiment, the enhancement of noise is effectively avoided by the synergistic effect of these effects, and an output image in which both noise enhancement suppression and texture enhancement are appropriately performed can be obtained.

Note that the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the configuration of the image display device of the present invention is not limited to the image display devices of the first to third embodiments, and may be realized by combining the configurations of these embodiments. In addition, the circuit configuration of each of the constituent elements described in the above embodiment is merely an example, and any configuration may be used as long as it performs the function described. In that sense, it may be realized not only in the case of being configured as a circuit but also in software.

Although the image display device has been described in the above embodiment, the image processing device of the present invention is not limited to a device having an image display function, but can be applied to all other devices that perform image processing. is there. Such devices include television cameras, VTRs, printers, and the like.

As described above, claims 1 to 10
The image processing apparatus according to claim 1, or claim 1.
According to the image display device of the first aspect or the image processing method of the twelfth aspect, the amplification component correction unit corrects the component amplified as a result of the texture enhancement processing, so that the component amount is appropriate. , And a decrease in image quality can be avoided.

In particular, according to the image processing apparatus of the second or third aspect, in the image processing apparatus of the first aspect, the amplification component correcting means is provided at a stage subsequent to the synthesizing means. Contour correction means for adjusting the amount of the contour emphasizing component for emphasizing the amount of the texture component according to the degree of amplification of the texture component. Since sharpness is applied so as to be adjusted and the outline emphasis effect is corrected, it is possible to finally obtain an output image in which the outline is appropriately emphasized. As a result, the image quality is prevented from being deteriorated due to excessive sharpness. Furthermore, the texture emphasis processing and the sharpness processing can be performed while balancing the effects of each other, and the sharpness of the entire output image can be maintained without any unnatural feeling.

According to the image processing apparatus of any one of the fourth to sixth aspects, in the image processing apparatus of the second aspect, a further amplification component correcting means is provided in a stage preceding the data separating means. In addition to the above, a contour component removing unit for removing a contour enhancing component from a contour portion of an image is provided. Effective components are reduced, and their frequency characteristics are flattened. Therefore, it is possible to reduce the influence of the component having the contour emphasis effect derived from the original signal on the texture emphasis processing performed thereafter, and to obtain a contrast emphasis image in which the texture emphasis effect is brought to the front.

According to the image processing apparatus of claim 7 or claim 8, in the image processing apparatus of claim 1, the S / N for detecting the S / N ratio of the image data is used as the amplification component correcting means. A noise detection unit is provided before the texture detection unit and a noise removal unit that removes, from the texture component, a minute amplitude region in a range corresponding to the S / N ratio of the detected image data. The balance between the noise reduction effect and the texture enhancement effect is adjusted by the S / N ratio. Therefore, it is possible to obtain an output image in which both are applied to an appropriate degree, the noise is not conspicuous, and the contrast is enhanced.

According to the image processing apparatus of the ninth or tenth aspect, in the image processing apparatus of the first aspect, the S / N for detecting the S / N ratio of the image data is used as the amplification component correction means. S is provided before the ratio detecting means and the texture amplifying means.
Since the apparatus has amplification limiting means for limiting the amplification target of the texture component in accordance with the / N ratio, the effect of suppressing noise amplification by limiting the amplification of the minute amplitude region corresponding to the noise component, the texture emphasis effect, and the like. Is adjusted by the S / N ratio. Therefore, it is possible to obtain an output image in which both are applied to an appropriate degree, the noise is not conspicuous, and the contrast is enhanced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an image display device according to a first embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a configuration of a texture emphasizing unit in the image display device shown in FIG.

FIG. 3 is a diagram for explaining an operation of a texture emphasizing unit shown in FIG. 2;

FIG. 4 shows the S / S in the texture emphasizing section shown in FIG.
FIG. 3 is a circuit block diagram illustrating a specific configuration of a T separation circuit.

FIG. 5 is a diagram for explaining an operation of a structure correction circuit in the texture emphasizing unit shown in FIG. 2;

FIG. 6 is a circuit block diagram showing a configuration of a main part of a sharpness unit in the image display device shown in FIG.

FIG. 7 is a signal waveform diagram for describing a sharpness signal generated in the sharpness circuit shown in FIG. 6;

8 is an explanatory diagram of a signal processing flow in the image display device shown in FIG. 1 based on signal waveforms and frequency characteristics.

FIG. 9 is a frequency characteristic diagram illustrating signal processing performed by the sharpness circuit shown in FIG. 6;

FIG. 10 is a block diagram illustrating an overall configuration of an image display device according to a second embodiment of the present invention.

11 is a circuit block diagram showing a configuration of a desharpness circuit in the image display device shown in FIG.

12 is an explanatory diagram of a signal processing flow in the image display device shown in FIG. 10 based on signal waveforms and frequency characteristics.

FIG. 13 is a block diagram illustrating an overall configuration of an image display device according to a third embodiment of the present invention.

FIG. 14 is an S / N diagram of the image display device shown in FIG.
FIG. 7 is a diagram for describing a method of noise detection performed by a ratio detection unit 107.

FIG. 15 is a block diagram showing a configuration of a texture emphasizing unit 100 in the image display device shown in FIG.

16 is a diagram for explaining coring processing of a noise removal circuit 70 in the image display device shown in FIG.

17 is a circuit block diagram showing a specific configuration of a noise removing circuit 70 in the image display device shown in FIG.

FIG. 18 is a block diagram illustrating a main part of an image display device according to a fourth embodiment of the present invention.

FIG. 19 is a signal waveform diagram illustrating general sharpness processing.

FIG. 20 is a frequency characteristic diagram illustrating general sharpness processing.

FIG. 21 is a signal waveform diagram illustrating a general texture enhancement process.

FIG. 22 is a frequency characteristic diagram illustrating a general texture enhancement process.

FIG. 23 is a frequency characteristic diagram of a tuner demodulated output of a general television signal.

FIG. 24 is a diagram showing frequency characteristics after performing a texture emphasis process on the signal shown in FIG. 22;

[Explanation of symbols]

10 S / T separation circuit, 11 level determining means, 12
Frequency determination means, 13 ... Filter characteristic determination means, 14 ...
Nonlinear filter, 15 subtractor, 20 texture amplifying circuit, 23 amplification limiting circuit, 25 amplifier, 27 adder, 30 structure correction circuit, 40 adder,
Reference numeral 50: delay circuit, 60: chroma amplifier, 70: noise removal circuit, 100: texture emphasis section, 200: sharpness section, 210: sharpness circuit, 300: desharpness section, 310: desharpness circuit, 101: tuner, 102 ... Y / C separation circuit, 103: chroma decoder, 104: matrix circuit, 105: driver, 1
06 ... display, 107 ... S / N ratio detector, S1,
S2 ... structure component, T1, T11, T2 ... texture components, TE ... enhancement gain, SG ... sharpness gain, A _t ... amplifier gain, Y ₀ ~Y ₃ ... luminance _{signal, U 0 ~U 3, V 0} ~V 3 ... Color difference signal.

Claims (12)

[Claims] 1. A data separating unit for separating image data into a structure component forming an outline of the image and a texture component forming details of the image; a texture amplifying unit amplifying the texture component; An image processing apparatus comprising: a combining unit that combines texture components to generate processed data; and an amplification component correction unit that corrects a component amplified by the texture amplification unit. 2. A contour adjusting means which is provided after the synthesizing means as the amplification component correcting means and adjusts an amount of a contour emphasizing component for emphasizing a contour of an image in accordance with a degree of amplification of the texture component. The image processing apparatus according to claim 1, further comprising: 3. The contour adjusting means sets, in a signal waveform on the time axis of the processing data, each edge before and after an edge corresponding to the contour of an image in accordance with the degree of amplification of the texture component. 3. The image processing apparatus according to claim 2, wherein an outline correction component having a positive or negative correction amount is added. 4. The image processing apparatus according to claim 1, further comprising a contour component removing unit provided before said data separating unit and removing a contour emphasizing component from a contour portion of the image. 3. The image processing device according to 2. 5. The image processing apparatus according to claim 4, wherein the contour component removing unit smoothes each of the edges before and after the edge corresponding to the contour of the image in the signal waveform on the time axis of the image data. Image processing device. 6. An image processing apparatus according to claim 5, wherein said contour component removing means removes a greater difference from an edge after said edge than from an edge before said edge. 7. An S / N ratio detecting means for detecting an S / N ratio of the image data, wherein the S / N ratio detecting means is provided in front of the texture amplifying means.
From the texture component, S of the detected image data
2. The image processing apparatus according to claim 1, further comprising a noise removing unit that removes a minute amplitude area in a range corresponding to the / N ratio. 8. The texture amplifying means,
8. The image processing apparatus according to claim 7, wherein the texture component is amplified according to an S / N ratio of the detected image data. 9. An S / N ratio detecting unit for detecting an S / N ratio of the image data as the amplification component correcting unit;
2. The image processing apparatus according to claim 1, further comprising amplification limiting means for limiting an amplification target of the texture component according to an S / N ratio of the detected image data. 10. The image processing apparatus according to claim 9, wherein said texture amplification means is configured to amplify said texture component in accordance with an S / N ratio of detected image data. apparatus. 11. A data separating unit for separating image data into a structure component constituting an outline of the image and a texture component constituting details of the image; a texture amplifying unit amplifying the texture component; An image display device comprising: a combining unit that combines texture components to generate processed data; and an amplification component correction unit that corrects a component amplified by the texture amplification unit. 12. The image data is separated into a structure component forming an outline of the image and a texture component forming details of the image, and after amplifying the texture component, processing by combining the structure component and the texture component. An image processing method, comprising: correcting a component amplified as a result of the texture enhancement processing together with a texture enhancement processing for generating data.