JP2003189124A - Image quality enhancing apparatus for video - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image quality enhancing apparatus for video that can provide bright video display with gradation without insufficient gradation of the video and the need for applying excessive gradation correction to a video signal. <P>SOLUTION: The image quality enhancing apparatus is provided with an A/D conversion input signal band calculation means 2 or an A/D conversion input signal band bandwidth calculation means 7 that detects an average luminance or a luminance for each luminance level, a highest signal level and a minimum signal level of a video signal, a sharpness level of a video signal or the like for a prescribed time of the video signal so as to be able to calculate an average value of an input signal band of A/D conversion and the bandwidth depending on the characteristic, and can obtain display of easy to see video with gradation by totally adjusting the average value and the bandwidth of the input signal band for the A/D conversion. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input signal band of A / D conversion for converting an analog signal into a digital signal in a display device for displaying an analog video signal by converting it into a digital video signal and performing image processing. The present invention relates to an image quality improving device that improves image quality deterioration such as image quality blurring due to circuit restrictions, lack of brightness, and lack of resolution.

[0002]

2. Description of the Related Art Conventionally, as an image quality improving device in a display device for displaying an image by converting an analog image signal into a digital image signal and performing image processing, as in a conventional analog television receiver, an image quality improving device is available depending on the characteristics of the image signal. This is done only by correcting the analog or digital video signal itself.

[0003]

DISCLOSURE OF THE INVENTION In a display device for displaying an analog video signal by converting it into a digital video signal and performing image processing, a display device, which is similar to a conventional television receiver, depending on the characteristics of the analog or digital video signal. Since it was performed only by correcting the video signal itself, due to circuit restrictions such as the dynamic range or the number of bits of the video signal processing circuit typified by A / D conversion for converting an analog signal into a digital signal,
There is a risk that the prescribed correction degree cannot be obtained because the limit of the correction degree that can be given to the video signal is low. Therefore,
In particular, there are problems such as easy occurrence of blurring at low and high brightness, no gradation, and dark screen.

[0004]

In order to solve the above-mentioned problems, the image quality improving apparatus of the present invention is a display device for displaying an image by converting an analog image signal into a digital image signal and performing image processing. Video signal average brightness detecting means for detecting the average brightness value of the video signal or the average brightness distribution at each brightness level, or the video signal for detecting the maximum signal level value and the minimum signal level value of the video signal Amplitude level detection means, or video signal sharpness level detection means for detecting the sharpness level of the video signal from the level value and distribution value of the differential signal of the video signal, detects the characteristics of the analog video signal, and according to the characteristics Image quality is improved by comprehensively adjusting the average value and bandwidth of the input signal band for A / D conversion. In which was characterized by Rukoto.

According to the present invention, it is possible to provide a bright image display with gradation without any image blurring, without excessive gradation correction being applied to the image signal.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a display device for displaying an analog video signal by converting it into a digital video signal and performing image processing. /
The characteristics of the video signal are detected for the blurring of the video, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or the number of bits of the video signal processing circuit represented by D conversion. Accordingly, by comprehensively adjusting the input signal band for A / D conversion, a bright image display with no gradation and gradation can be provided, and the image can be easily viewed.

According to a second aspect of the present invention, in a display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, the A / D conversion is performed to convert the analog signal into a digital signal. The average brightness of a video signal, which is a characteristic of the video signal, for a certain period of time against the video blurring, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or bit number of a typical video signal processing circuit. By detecting the value or the average luminance distribution at each luminance level and adjusting the center value of the input signal band of A / D conversion according to the detected value, a bright image display with no gradation and gradation is provided, It has the effect of making the image easier to see.

According to a third aspect of the present invention, in a display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, A / D conversion for converting an analog signal into a digital signal is performed. The maximum signal level value and the minimum value of the video signal, which is the characteristic of the video signal, against the blurring of the video, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or bit number of the typical video signal processing circuit. By detecting the signal level value and adjusting the center value of the input signal band of the A / D conversion according to the detected value, it is possible to provide a bright image display with gradation without gradation and to make the image easy to see. Have.

According to a fourth aspect of the present invention, in a display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, the A / D conversion is performed to convert the analog signal into a digital signal. The average brightness of a video signal, which is a characteristic of the video signal, for a certain period of time against the video blurring, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or bit number of a typical video signal processing circuit. Value or the average brightness distribution at each brightness level, the maximum signal level value and the minimum signal level value of the video signal are detected, and the center value of the input signal band of the A / D conversion is adjusted in accordance with the detected value to adjust the blur. It has the effect of providing a bright image display with no gradation and making the image easy to see.

According to a fifth aspect of the present invention, in a display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, the A / D conversion is performed to convert the analog signal into a digital signal. The maximum signal level value and the minimum value of the video signal, which is the characteristic of the video signal, against the blurring of the video, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or bit number of the typical video signal processing circuit. By detecting the signal level value and adjusting the bandwidth of the input signal band of A / D conversion according to the detected value, it is possible to provide a bright image display with gradation without gradation and to make the image easy to see. Have.

According to a sixth aspect of the present invention, in a display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, the A / D conversion is performed to convert the analog signal into a digital signal. The level value of the differential signal of the video signal, which is the characteristic of the video signal, and the blurring of the video, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or bit number of the typical video signal processing circuit The sharpness level value of the video signal is detected from the distribution value and A / A is detected according to the detected value.
By adjusting the bandwidth of the input signal band of the D conversion, it is possible to provide a bright image display with gradation without gradation and to make it easier to see the image.

According to a seventh aspect of the present invention, in a display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, the A / D conversion is performed to convert the analog signal into a digital signal. The average brightness of a video signal, which is a characteristic of the video signal, for a certain period of time against the video blurring, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or bit number of a typical video signal processing circuit. Value or the average brightness distribution at each brightness level, the maximum signal level value and the minimum signal level value of the video signal are detected, and the center value and bandwidth of the input signal band of the A / D conversion are adjusted according to the detected value. As a result, there is an effect that a bright image display with no gradation is provided and the image can be easily viewed.

In a display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, the present invention provides A / D conversion for converting an analog signal into a digital signal. The average brightness of a video signal, which is a characteristic of the video signal, for a certain period of time against the video blurring, lack of gradation, and lack of brightness due to circuit restrictions such as the dynamic range or bit number of a typical video signal processing circuit. Value or average brightness distribution at each brightness level, and the sharpness level value of the video signal is detected from the level value and distribution value of the differential signal of the video signal, and the input signal band of A / D conversion is detected according to the detected value. By adjusting the center value and bandwidth of the image, it is possible to provide a bright image display with no gradation and to make the image easier to see. It is having an effect.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and FIG. This will be described with reference to FIGS.

(Embodiment 1) FIG. 1 is a block diagram for converting an analog signal into a digital signal, which has a picture quality improving device of the present image.
The block block diagram of the image processing circuit of / D conversion is shown.

In FIG. 1, reference numeral 1 is a video signal average brightness detecting means for detecting an average brightness value or an average brightness distribution at each brightness level of the video signal at a certain time, and reference numeral 2 is a detection from the video signal average brightness detecting means 1. A / D that converts analog signals to digital signals based on data
A / D for calculating the median value of the optimum input signal band of the conversion unit
A conversion input signal band calculation means, reference numeral 3 is an A / D conversion input signal band upper limit value generation means for generating an input signal upper limit value of the A / D conversion unit from the calculation data of the A / D conversion input signal band calculation means 2, and a reference numeral Reference numeral 4 is A / D conversion input signal band lower limit value creating means for creating the input signal lower limit value of the A / D conversion unit from the calculation data of the A / D conversion input signal band calculating means 2, and reference numeral 5 is a digital signal from an analog signal. It is an A / D conversion circuit unit for conversion. 8, 9, and 10 are analog video signals input to the A / D conversion circuit unit 5, upper limit values of input signals of the A / D conversion unit, median value of input signals of the A / D conversion unit, and A / D conversion. FIG. 3 is an explanatory diagram showing the level relationship of the input signal lower limit value of the A / D conversion unit, and the area between the input signal upper limit value of the A / D conversion unit and the input signal lower limit value of the A / D conversion unit is A / D conversion of the analog input signal. The possible video signal band is shown. FIG. 8 shows a conventional type A / D conversion circuit, and FIGS. 9 and 10 show a central value of the input signal of the A / D conversion section adjusted by the image quality improving circuit according to the input video signal. Is for a high luminance signal, and FIG. 10 is for a low luminance signal. FIG. 14 is a display image showing a video image on a display by a shade of a pixel, a display image of FIG. 14 is not based on the image quality improving apparatus of the main image, and FIG. 14b is image quality improving apparatus of the main image. The display image by is shown. By comparing a and b in FIG. 14, it can be seen that the gradation and brightness of the image are improved.

Next, FIGS. 1, 8, 9, 10, and 14.
The basic operation will be described with reference to.

Normally, in a display device which displays an analog video signal by converting it into a digital video signal and performing image processing, A / D for determining the input signal band of the A / D conversion circuit section 5 for converting an analog signal into a digital signal.
The input signal band of the D converter is set to a fixed value. In the image quality improving apparatus, the average value of the input signal band of the A / D conversion unit is adjusted according to the video signal, so that the video signal region of the luminance level with a lot of video information has gradation in the digital signal processing unit. The setting is made so as to match the γ correction curve area that can be displayed, the gradation is enhanced, and the image quality is improved.

Next, referring to the block diagram of the A / D conversion circuit section of FIG. 1 and FIGS. 8, 9, 10, and 14, A / D
A method of adjusting the input signal upper limit value of the D converter and the input signal lower limit value of the A / D converter with respect to the video signal will be described.

First, the average luminance value of the image signal or the average luminance distribution at each luminance level is detected by the image signal average luminance detecting means 1 of FIG.
From the detected average luminance data P, the A / D conversion input signal band median value calculating means 2 is capable of displaying a video signal area of a luminance level having a lot of video information with gradation in the digital signal processing unit. A that fits the area
The average value AV of the input signal band of the / D converter is calculated.
From this average value data AV, the input signal upper limit value setting value of the A / D conversion unit is A / D converted by the A / D conversion input signal band upper limit value creating unit 3 and is A / D converted by the A / D conversion input signal band lower limit value creating unit 4. Input signal lower limit setting value of the part is set and A / D
It is input to the conversion circuit 5. As shown in the explanatory diagrams showing the level relationships between the input video signal of FIG. 9 and FIG. 10, the input signal median of the A / D converter, and the upper and lower limit values of the input signal of the A / D converter, as shown in FIG. By adjusting the conversion input signal band, it becomes possible to express a video signal area having a large amount of information with a γ correction curve area capable of displaying with gradation in the digital signal processing unit, and thus the conventional A / D It is possible to display an image with gradation as compared with the conversion circuit. 14a and 14b show the effect by a screen image, and even the same video signal is displayed as an image with higher gradation.

(Embodiment 2) FIG. 2 is a diagram for converting an analog signal into a digital signal having an image quality improving device for the present image.
The block block diagram of the image processing circuit of / D conversion is shown.

In FIG. 2, reference numeral 6 is a video signal amplitude level detecting means for detecting the maximum signal level value and the minimum signal level value of the video signal of the video signal, and reference numeral 2 is the detection data from the video signal amplitude level detecting means 6. In addition, A / D conversion input signal band calculation means for calculating the optimum central value of the input signal band of the A / D conversion section for converting an analog signal into a digital signal, and reference numeral 3 is A / D conversion input signal band calculation means 2 A / D conversion input signal band upper limit value creating means for creating the input signal upper limit value of the A / D conversion unit from the calculated data of
From the calculation data of the D conversion input signal band calculation means 2 to A / D
A / D conversion input signal band lower limit value creating means for creating an input signal lower limit value of the converter, and reference numeral 5 is an A / D conversion circuit unit for converting an analog signal into a digital signal. 8, 9, and 10 are analog video signals input to the A / D conversion circuit unit 5, upper limit values of input signals of the A / D conversion unit, median value of input signals of the A / D conversion unit, and A / D conversion. FIG. 3 is an explanatory diagram showing the level relationship of the input signal lower limit value of the A / D conversion unit, and the area between the input signal upper limit value of the A / D conversion unit and the input signal lower limit value of the A / D conversion unit is A / D conversion of the analog input signal. The possible video signal band is shown. FIG. 8 shows a conventional type A / D conversion circuit, and FIGS. 9 and 10 show a central value of the input signal of the A / D conversion section adjusted by the image quality improving circuit according to the input video signal. Is for a high luminance signal, and FIG. 10 is for a low luminance signal. FIG. 14 is a display image showing a video image on a display by a shade of a pixel, a display image of FIG. 14 is not based on the image quality improving apparatus of the main image, and FIG. 14b is image quality improving apparatus of the main image. The display image by is shown. By comparing a and b in FIG. 14, it can be seen that the gradation and brightness of the image are improved.

Next, FIG. 2, FIG. 8, FIG. 9, FIG.
The basic operation will be described with reference to.

Normally, in a display device that displays an analog video signal by converting it into a digital video signal and performing image processing, A / D for determining the input signal band of the A / D conversion circuit section 5 for converting an analog signal into a digital signal.
The input signal band of the D converter is set to a fixed value. In the image quality improving apparatus, the average value of the input signal band of the A / D conversion unit is adjusted according to the video signal, so that the video signal region of the luminance level with a lot of video information has gradation in the digital signal processing unit. The setting is made so as to match the γ correction curve area that can be displayed, the gradation is enhanced, and the image quality is improved.

Next, referring to the block diagram of the A / D conversion circuit section in FIG. 1 and FIGS. 8, 9, 10, and 14, A / D
A method of adjusting the input signal upper limit value of the D converter and the input signal lower limit value of the A / D converter with respect to the video signal will be described.

First, the video signal amplitude level detecting means 6 shown in FIG.
At, the highest signal level value and the lowest signal level value of the video signal are detected. A / D conversion input signal band median value calculating means 2 from the detected video signal amplitude level data V
Therefore, the A / A ratio is set so that the video signal area of the amplitude level in which the average level of the video signal is large matches the γ correction curve area capable of displaying with gradation in the digital signal processing unit.
The average value AV of the input signal band of the D converter is calculated. From this average value data AV, the input signal upper limit value setting value of the A / D conversion unit is set to A by the A / D conversion input signal band upper limit value creating unit 3 and is set to A by the A / D conversion input signal band lower limit value creating unit 4.
The input signal lower limit value setting value of the / D conversion unit is set and input to the A / D conversion circuit 5. As shown in the explanatory diagrams showing the level relationships between the input video signal of FIG. 9 and FIG. 10, the input signal median of the A / D converter, and the upper and lower limit values of the input signal of the A / D converter, as shown in FIG. By adjusting the conversion input signal band, it is possible to express the video signal area of the amplitude level where there are many average levels of the video signal with the γ-correction curve area capable of displaying with gradation in the digital signal processing unit. This makes it possible to display an image with gradation as compared with the conventional A / D conversion circuit. 14a and 14b show the effect by a screen image, and even the same video signal is displayed as an image with higher gradation.

(Third Embodiment) FIG. 3 is a diagram for converting an analog signal into a digital signal having an image quality improving device of the present image.
The block block diagram of the image processing circuit of / D conversion is shown.

In FIG. 3, reference numeral 1 is a video signal average brightness detecting means for detecting an average brightness value of the video signal at a certain time or an average brightness distribution at each brightness level, and reference numeral 6 is a maximum signal level value and a minimum signal of the video signal. Video signal amplitude level detecting means for detecting a level value, reference numeral 2 is an A / D conversion for converting an analog signal into a digital signal based on the detection data from the video signal average luminance detecting means 1 and the video signal amplitude level detecting means 6. A / D conversion input signal band median value calculating means for calculating the optimum median value of the input signal band of the section, reference numeral 3 represents the calculated data of the A / D conversion input signal band median value calculating means 2 of the A / D conversion section. A / D conversion input signal band upper limit value creating means for creating an input signal upper limit value, reference numeral 4
Is an A / D conversion input signal band lower limit value creating unit for creating the input signal lower limit value of the A / D conversion unit from the calculation data of the A / D conversion input signal band calculating unit 2, and reference numeral 5 is a conversion from an analog signal to a digital signal. A / D conversion circuit unit. 8, FIG. 9, and FIG. 10 are analog video signals input to the A / D conversion circuit unit 5 and the input signal upper limit value of the A / D conversion unit, A
FIG. 4 is an explanatory diagram showing a level relationship between a median input signal of the A / D conversion unit and a lower limit value of the input signal of the A / D conversion unit, the upper limit value of the input signal of the A / D conversion unit and the input signal of the A / D conversion unit. The area between the lower limit values indicates the video signal band in which the analog input signal can be A / D converted. FIG. 8 shows a conventional type A / D conversion circuit, and FIGS.
The median value of the input signal of the D converter is adjusted according to the input video signal. FIG. 9 is for a high luminance signal and FIG. 10 is for a low luminance signal. FIG. 14 is a display image in which a video image on the display is shown in shades of pixels. A in FIG. 14 is a display image that does not depend on the image quality improving apparatus for the main image, and FIG. The display image by is shown. By comparing a and b in FIG. 14, it can be seen that the gradation and brightness of the image are improved.

Next, FIG. 3, FIG. 8, FIG. 9, FIG.
The basic operation will be described with reference to.

Usually, in a display device that displays an analog video signal by converting it into a digital video signal and performing image processing, A / D that determines the input signal band of the A / D conversion circuit section 5 that converts the analog signal into a digital signal
The input signal band of the D converter is set to a fixed value. In the image quality improving apparatus, the average value of the input signal band of the A / D conversion unit is adjusted according to the video signal, so that the video signal region of the luminance level with a lot of video information has gradation in the digital signal processing unit. The setting is made so as to match the γ correction curve area that can be displayed, the gradation is enhanced, and the image quality is improved.

Next, referring to the block diagram of the A / D conversion circuit section in FIG. 1 and FIGS. 8, 9, 10, and 14, A / D
A method of adjusting the input signal upper limit value of the D converter and the input signal lower limit value of the A / D converter with respect to the video signal will be described.

First, the average luminance value of the image signal in the image signal average luminance detecting means 1 in FIG. 1 or the average luminance distribution at each luminance level, and the maximum signal level value of the image signal in the image signal amplitude level detecting means 6 and The lowest signal level value is detected. From the detected average luminance data P and the video signal amplitude level data V, A /
By the D conversion input signal band median value calculating means 2, the video signal area of the luminance level having a lot of video information and the video signal area of the amplitude level having a large average level of the video signal are displayed with gradation in the digital signal processing section. An average value AV of the input signal band of the A / D converter that fits the possible γ correction curve area is calculated. From this average value data AV, A /
The input signal upper limit value setting value of the A / D conversion unit by the D conversion input signal band upper limit value creating unit 3 and the input signal lower limit value setting value of the A / D conversion unit by the A / D conversion input signal band lower limit value creating unit 4 Is set and input to the A / D conversion circuit 5. As shown in the explanatory diagrams showing the level relationships between the input video signal of FIG. 9 and FIG. 10, the input signal median of the A / D converter, and the upper and lower limit values of the input signal of the A / D converter, as shown in FIG. By adjusting the conversion input signal band, it becomes possible to express a video signal area having a large amount of information with a γ correction curve area capable of displaying with gradation in the digital signal processing unit, and thus the conventional A / D It is possible to display an image with gradation as compared with the conversion circuit. 14a and 14b show the effect by a screen image, and even the same video signal is displayed as an image with higher gradation.

(Embodiment 4) FIG. 4 is a diagram for converting an analog signal into a digital signal, which has a picture quality improving device of the present image.
The block block diagram of the image processing circuit of / D conversion is shown.

In FIG. 4, reference numeral 6 is a video signal amplitude level detecting means for detecting the maximum signal level value and the minimum signal level value of the video signal of the video signal, and reference numeral 7 is the detection data from the video signal amplitude level detecting means 6. In addition, A / D conversion input signal band bandwidth calculation means for calculating the optimum input signal band bandwidth of the A / D conversion unit for converting an analog signal into a digital signal, and reference numeral 3 is an A / D conversion input signal band band. A / D conversion input signal band upper limit value creating means for creating an input signal upper limit value of the A / D converter from the calculation data of the width calculating means 7,
Reference numeral 4 is an A / D that creates an input signal lower limit value of the A / D conversion unit from the calculation data of the A / D conversion input signal band calculation means 2.
A conversion input signal band lower limit value creating means, reference numeral 5 is an A / D conversion circuit section for converting an analog signal into a digital signal. 8, 11, and 12 are analog video signals input to the A / D conversion circuit unit 5, the upper limit value of the input signal of the A / D conversion unit, the central value of the input signal of the A / D conversion unit, and the A / D conversion. FIG. 3 is an explanatory diagram showing a level relationship of input signal lower limit values of the parts,
A region between the input signal upper limit value of the / D conversion unit and the input signal lower limit value of the A / D conversion unit indicates a video signal band capable of A / D conversion of the analog input signal. Figure 8 shows a conventional type A / D
FIG. 11 and FIG. 12 show the case where the input signal bandwidth of the A / D converter is adjusted according to the input video signal by the image quality improving circuit. FIG. 11 and FIG. 12 is for a small amplitude signal. FIG. 14 is a display image in which a video image on the display is shown in shades of pixels. A in FIG. 14 is a display image that does not depend on the image quality improving apparatus for the main image, and FIG. The display image by is shown. 14a and 14b
It can be seen that the gradation and brightness of the image are improved by comparing

Next, FIG. 4, FIG. 8, FIG. 9, FIG.
The basic operation will be described with reference to.

Usually, in a display device that displays an analog video signal by converting it into a digital video signal and performing image processing, A / D that determines the input signal band of the A / D conversion circuit section 5 that converts the analog signal into a digital signal
The input signal band of the D converter is set to a fixed value. In this image quality improving apparatus, the bandwidth of the input signal band of the A / D conversion unit is adjusted according to the video signal, so that the input signal band of the A / D conversion circuit unit 5 is effectively used for the video signal as much as possible. However, the image quality is improved.

Next, referring to the block diagram of the A / D conversion circuit section of FIG. 4 and FIGS. 8, 11, 12, and 14, A
A method of adjusting the input signal upper limit value of the / D conversion unit and the input signal lower limit value of the A / D conversion unit with respect to the video signal will be described.

First, the video signal amplitude level detecting means 6 shown in FIG.
At, the highest signal level value and the lowest signal level value of the video signal are detected. From the detected video signal amplitude level data V, the video signal amplitude level detection means 6 calculates the bandwidth AH of the input signal band of the A / D conversion unit that matches the signal amplitude of the video signal. From this bandwidth data AH, the A / D conversion input signal band upper limit value creating means 3 performs A / D
The input signal upper limit value setting value of the conversion unit is set by the A / D conversion input signal band lower limit value creating means 4 and the input signal lower limit value setting value of the A / D conversion unit is input to the A / D conversion circuit 5.
As shown in the explanatory diagrams showing the level relationship between the input video signal of FIG. 11 and FIG. 12, the input signal upper limit value of the A / D conversion unit, and the input signal lower limit value of the A / D conversion unit, A / D conversion for the video signal is performed. By adjusting the input signal band, A /
The input signal band of the D conversion circuit unit 5 is effectively used for the video signal and the video amplitude processed by 1 bit is subdivided to display a video image with gradation as compared with the conventional A / D conversion circuit. Is possible. 14a and 14b show the effect by a screen image, and even the same video signal is displayed as an image with higher gradation.

(Fifth Embodiment) FIG. 5 is a diagram showing an example of converting an analog signal into a digital signal having an image quality improving device for the present image.
The block block diagram of the image processing circuit of / D conversion is shown.

In FIG. 5, reference numeral 8 is a differentiating circuit for detecting the brightness change point of the video signal, and reference numeral 9 is a video signal for detecting the sharpness level of the video signal from the level value and distribution value of the differential signal of the video signal. Sharpness level detecting means, reference numeral 7
Is an A / D for converting an analog signal into a digital signal based on the detection data from the video signal sharpness level detecting means 9.
A / D for calculating the optimum input signal bandwidth of the converter
Conversion input signal band bandwidth calculation means, reference numeral 3 is A / D from the calculation data of the A / D conversion input signal band bandwidth calculation means 7.
A / D conversion input signal band upper limit value creating means for creating the input signal upper limit value of the conversion unit, and reference numeral 4 indicates the input signal lower limit value of the A / D conversion unit from the calculation data of the A / D conversion input signal band calculation unit 2. A / D conversion input signal band lower limit value creating means to be created, reference numeral 5 is an A / D conversion circuit section for converting an analog signal into a digital signal. 8, 11, and 12 are A /
The analog video signal and A / that are input to the D conversion circuit unit 5
It is explanatory drawing which showed the level relationship of the input signal upper limit of a D conversion part, the input signal median of an A / D conversion part, and the input signal lower limit of an A / D conversion part, and the input signal upper limit of an A / D conversion part. Value and A
The area between the input signal lower limit values of the / D converter indicates the video signal band in which the analog input signal can be A / D converted. Figure 8
11 and 12 show a conventional type A / D conversion circuit, and FIGS. 11 and 12 show a case where the input signal bandwidth of the A / D conversion unit is adjusted by the image quality improving circuit according to the input video signal.
1 is for a large amplitude signal, and FIG. 12 is for a small amplitude signal. FIG. 14 is a display image showing a video image on a display by a shade of a pixel, a display image of FIG. 14 is not based on the image quality improving apparatus of the main image, and FIG. 14b is image quality improving apparatus of the main image. The display image by is shown. By comparing a and b in FIG. 14, it can be seen that the gradation and brightness of the image are improved.

Next, the basic operation will be described with reference to FIGS. 5, 8, 13, and 14.

Normally, in a display device that displays an analog video signal by converting it into a digital video signal and performing image processing, A / D that determines the input signal band of the A / D conversion circuit unit 5 that converts an analog signal into a digital signal
The input signal band of the D converter is set to a fixed value. In this image quality improving apparatus, the bandwidth of the input signal band of the A / D conversion unit is adjusted according to the video signal, so that the input signal band of the A / D conversion circuit unit 5 is effectively used for the video signal as much as possible. However, the image quality is improved.

Next, referring to the block diagram of the A / D conversion circuit section of FIG. 5 and FIGS. 8, 11, 12, and 14, A
A method of adjusting the input signal upper limit value of the / D conversion unit and the input signal lower limit value of the A / D conversion unit with respect to the video signal will be described.

First, the video signal sharpness level detecting means 9 is calculated from the differential signal of the video signal detected by the differentiating circuit 8 in FIG.
Thus, the sharpness level of the video signal is detected from the level value and distribution value of the differential signal of the video signal. Based on the detected video signal sharpness level data S, the band of the input signal band of the A / D conversion unit that was in the signal amplitude region where the luminance change point of the video signal is large by the A / D conversion input signal band bandwidth calculation means 7. The width AH is calculated. From this bandwidth data AH, A / D conversion input signal band upper limit value creating means 3 creates A / D
The input signal upper limit value setting value of the D conversion unit is set by the A / D conversion input signal band lower limit value creating means 4 and the input signal lower limit value setting value of the A / D conversion unit is input to the A / D conversion circuit 5. . As shown in FIG. 11 and FIG. 12, which illustrates the level relationship between the input video signal, the input signal upper limit value of the A / D conversion unit, and the input signal lower limit value of the A / D conversion unit, as shown in FIG.
By adjusting the D conversion input signal band, the input signal band of the A / D conversion circuit unit 5 is used as effectively as possible for the video signal, and the video amplitude to be processed by 1 bit is subdivided. It is possible to display an image having gradation as compared with the A / D conversion circuit. 14a and 14b show the effect by a screen image, and even the same video signal is displayed as an image with higher gradation.

(Embodiment 6) FIG. 6 is a diagram for converting an analog signal into a digital signal, which has an image quality improving device for this image.
The block block diagram of the image processing circuit of / D conversion is shown.

In FIG. 6, reference numeral 1 is a video signal average brightness detecting means for detecting the average brightness value or the average brightness distribution at each brightness level of the video signal at a certain time, and the reference numeral 6 is the maximum signal level value and the minimum signal of the video signal. Video signal amplitude level detecting means for detecting the level value, reference numeral 10 is an A / D conversion for converting an analog signal into a digital signal based on the detection data from the video signal average luminance detecting means 1 and the video signal amplitude level detecting means 6. A / D conversion input signal band median value and bandwidth calculation means for calculating the optimum input signal band median value and bandwidth of the section, and reference numeral 3 indicates A / D conversion input signal band median value and bandwidth calculation means 10. A / D conversion input signal band upper limit value creating means for creating the input signal upper limit value of the A / D conversion unit from the calculated data, and reference numeral 4 is A / D conversion input signal band calculating means A / D conversion input signal bandwidth lower limit generating means for generating an input signal lower-limit value of the A / D converter from the calculated data, reference numeral 5 denotes an A / D converter circuit unit for converting the analog signal to a digital signal. 8 and 13 are A / D
Analog video signal and A / D input to the conversion circuit unit 5
It is an explanatory view showing the level relation between the input signal upper limit value of the conversion unit, the input signal median value of the A / D conversion unit and the input signal lower limit value of the A / D conversion unit, and the input signal upper limit value of the A / D conversion unit. And A /
The area between the lower limit values of the input signal of the D conversion section indicates the video signal band capable of A / D conversion of the analog input signal. FIG. 8 shows a conventional type A / D conversion circuit, and FIG. 13 shows the image quality improvement circuit in which the median value of the input signal of the A / D conversion unit is adjusted according to the input video signal. FIG. 14 is a display image showing a video image on a display by a shade of a pixel, a display image of FIG. 14 is not based on the image quality improving apparatus of the main image, and FIG. 14b is image quality improving apparatus of the main image. The display image by is shown. By comparing a and b in FIG. 14, it can be seen that the gradation and brightness of the image are improved.

Next, the basic operation will be described with reference to FIGS. 3, 8, 13, and 14.

Normally, in a display device that displays an analog video signal by converting it into a digital video signal and performing image processing, A / D that determines the input signal band of the A / D conversion circuit section 5 that converts an analog signal into a digital signal
The input signal band of the D converter is set to a fixed value. In the image quality improving apparatus, the median value and bandwidth of the input signal band of the A / D conversion unit are adjusted according to the video signal, so that the video signal area of the luminance level with a lot of video information is displayed in the gradation of the digital signal processing unit. Along with the γ correction curve area that enables display with good characteristics, A /
The input signal band of the D conversion circuit unit 5 is effectively used for a video signal and the video amplitude to be processed by 1 bit is subdivided to enhance the gradation and improve the image quality.

Next, referring to the block diagram of the A / D conversion circuit section of FIG. 6 and FIGS. 8, 13, and 14, the upper limit value of the input signal of the A / D conversion section and the input signal of the A / D conversion section are shown. A method of adjusting the lower limit value for the video signal will be described.

First, in the video signal average brightness detecting means 1 of FIG. 6, the average brightness value of the video signal at a certain time or the average brightness distribution at each brightness level and the video signal amplitude level detecting means 6 of the maximum signal level value of the video signal and The lowest signal level value is detected. From the detected average luminance data P and the video signal amplitude level data V, A /
The D-converted input signal band median value and the bandwidth calculation means 10 determines a video signal region of a luminance level having a large amount of video information and a video signal region of an amplitude level having a large average level of the video signals as a gradation property in the digital signal processing unit. The input signal band of the A / D conversion circuit unit 5 is effectively used for the video signal as much as possible while matching the γ correction curve region where a certain display is possible, and the video amplitude to be processed by 1 bit is subdivided. The average value and bandwidth VH of the input signal band of the A / D converter that can perform the calculation are calculated. From this data VH, A / D conversion input signal band upper limit value creating means 3 performs A / D
The input signal upper limit value setting value of the conversion unit is set by the A / D conversion input signal band lower limit value creating means 4 and the input signal lower limit value setting value of the A / D conversion unit is input to the A / D conversion circuit 5.
As shown in the explanatory diagram showing the level relationship between the input video signal and the median value of the input signal of the A / D converter and the upper and lower limit values of the input signal of the A / D converter shown in FIG. By adjusting the band, the video signal area with a large amount of information can be expressed by the γ correction curve area that can display with gradation in the digital signal processing unit, and the video amplitude to be processed with 1 bit is subdivided. Therefore, it is possible to display an image having gradation as compared with the conventional A / D conversion circuit. 14a and 14b show the effect by a screen image, and even the same video signal is displayed as an image with higher gradation.

(Embodiment 7) FIG. 7 is a diagram for converting an analog signal into a digital signal, which has a picture quality improving device of the present image.
The block block diagram of the image processing circuit of / D conversion is shown.

In FIG. 7, reference numeral 1 is a video signal average luminance detecting means for detecting an average luminance value or an average luminance distribution at each luminance level of the video signal at a certain time, and reference numeral 8 is for detecting a luminance change point of the video signal. , A reference numeral 9 is a video signal sharpness level detecting means for detecting the sharpness level of the video signal from the level value and distribution value of the differential signal of the video signal, and reference numeral 10 is the video signal average luminance detecting means 1 and the video signal. Based on the detection data from the sharpness level detecting means 9, the A / D conversion input signal band center for calculating the optimum median value and bandwidth of the A / D conversion unit for converting an analog signal into a digital signal A value and bandwidth calculation means, reference numeral 3 creates an input signal upper limit value of the A / D conversion section from the calculation data of the A / D conversion input signal band median value and bandwidth calculation means 10. That A / D conversion input signal bandwidth upper limit value generating means, reference numeral 4 is A / D converted input signal bandwidth calculation means 2
A / D conversion input signal band lower limit value creating means for creating an input signal lower limit value of the A / D conversion unit from the calculated data of, and reference numeral 5 is an A / D conversion circuit unit for converting an analog signal into a digital signal. 8 and 13 show the analog video signal input to the A / D conversion circuit unit 5, the upper limit value of the input signal of the A / D conversion unit, the central value of the input signal of the A / D conversion unit, and the input of the A / D conversion unit. It is explanatory drawing which showed the level relationship of a signal lower limit value.
A region between the input signal upper limit value of the / D conversion unit and the input signal lower limit value of the A / D conversion unit indicates a video signal band capable of A / D conversion of the analog input signal. Figure 8 shows a conventional type A / D
By the conversion circuit, FIG. 13 shows A by this image quality improvement circuit.
The median value of the input signal of the / D converter is adjusted according to the input video signal. FIG. 14 is a display image showing a video image on a display by a shade of a pixel, a display image of FIG. 14 is not based on the image quality improving apparatus of the main image, and FIG. 14b is image quality improving apparatus of the main image. The display image by is shown. By comparing a and b in FIG. 14, it can be seen that the gradation and brightness of the image are improved.

Next, the basic operation will be described with reference to FIGS. 3, 8, 13, and 14.

Normally, in a display device for displaying an analog video signal by converting it into a digital video signal and performing image processing, A / D for determining the input signal band of the A / D conversion circuit section 5 for converting an analog signal into a digital signal.
The input signal band of the D converter is set to a fixed value. In the image quality improving apparatus, the median value and bandwidth of the input signal band of the A / D conversion unit are adjusted according to the video signal, so that the video signal area of the luminance level with a lot of video information is displayed in the gradation of the digital signal processing unit. Along with the γ correction curve area that enables display with good characteristics, A /
The input signal band of the D conversion circuit unit 5 is effectively used for a video signal and the video amplitude to be processed by 1 bit is subdivided to enhance the gradation and improve the image quality.

Next, referring to the block diagram of the A / D conversion circuit section in FIG. 6 and FIGS. 8, 13, and 14, the upper limit value of the input signal of the A / D conversion section and the input signal of the A / D conversion section are shown. A method of adjusting the lower limit value for the video signal will be described.

First, in the video signal average brightness detection means 1 of FIG. 6, the average brightness value of the video signal at a certain time or the average brightness distribution at each brightness level and the video signal sharpness level detection means 9 are differentiated signal level of the video signal. The sharpness level of the video signal is detected from the value and the distribution value. From the detected average luminance data P and the video signal sharpness level data S, the A / D conversion input signal band center value and the bandwidth calculation means 10 causes the video signal area and the video of the amplitude level in which the average level of the video signal is large. The signal region is made to match the γ correction curve region capable of displaying with gradation in the digital signal processing unit, and the input signal band of the A / D conversion circuit unit 5 has as many luminance change points of the video signal as possible. The average value of the input signal band of the A / D conversion unit and the bandwidth data VH capable of subdividing the video amplitude to be processed with 1 bit by matching with the signal amplitude region are calculated. From this data VH, the input signal upper limit value setting value of the A / D conversion unit by the A / D conversion input signal band upper limit value creating unit 3 and the A / D conversion input signal band lower limit value setting unit of the A / D conversion unit by the A / D conversion input signal band lower limit value creating unit 4 The input signal lower limit setting value is set and input to the A / D conversion circuit 5. As shown in the explanatory diagram showing the level relationship between the input video signal and the median value of the input signal of the A / D converter and the upper and lower limit values of the input signal of the A / D converter shown in FIG. By adjusting the band, the video signal area with a large amount of information can be expressed by the γ correction curve area that can display with gradation in the digital signal processing unit, and the video amplitude to be processed with 1 bit is subdivided. Therefore, it is possible to display an image having gradation as compared with the conventional A / D conversion circuit. Figure 1
4a and FIG. 14b show the effect by a screen image, and even the same video signal is displayed as an image with higher gradation.

[0057]

As described above, according to the image quality improving apparatus of the present invention, an analog signal is converted into a digital signal in a display device which displays an analog video signal by converting it into a digital video signal and performing image processing. The characteristics of the video signal are detected and the characteristics of the video signal are detected against deterioration of gradation and brightness due to circuit restrictions such as insufficient dynamic range or insufficient number of bits of the video signal processing circuit represented by A / D conversion. By adjusting the input signal band of the A / D conversion circuit unit according to it, it becomes possible to obtain an image having gradation and brightness.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an A / D conversion video processing circuit for converting an analog signal into a digital signal, which has a main video image quality improving device according to a first embodiment.

FIG. 2 is a block configuration diagram of an A / D conversion video processing circuit for converting an analog signal into a digital signal, which has a main video image quality improving device according to a second embodiment.

FIG. 3 is a block configuration diagram of an A / D conversion video processing circuit for converting an analog signal into a digital signal, which has a main video image quality improving device according to a third embodiment.

FIG. 4 is a block configuration diagram of an A / D conversion video processing circuit for converting an analog signal into a digital signal, which has a main video image quality improving device according to a fourth embodiment.

FIG. 5 is a block configuration diagram of an A / D conversion video processing circuit for converting an analog signal into a digital signal, which has a main video image quality improving device according to a fifth embodiment.

FIG. 6 is a block configuration diagram of an A / D conversion video processing circuit for converting an analog signal into a digital signal, which has a main video image quality improving device according to a sixth embodiment.

FIG. 7 is a block configuration diagram of an A / D conversion video processing circuit for converting an analog signal into a digital signal, which has a main video image quality improving device according to a seventh embodiment.

FIG. 8 is an analog video signal input to a conventional type A / D conversion circuit unit and an input signal upper limit value of the A / D conversion unit, A
Explanatory drawing showing the level relationship between the input signal median of the A / D converter and the lower limit of the input signal of the A / D converter

FIG. 9: A / D by this image quality improvement circuit at high brightness
Description showing the level relationship between the analog video signal input to the conversion circuit unit, the input signal upper limit value of the A / D conversion unit, the input signal median value of the A / D conversion unit and the input signal lower limit value of the A / D conversion unit Figure

FIG. 10: A / by the image quality improving circuit at low brightness
Analog video signal and A / D input to the D conversion circuit unit
Explanatory drawing showing the level relationship between the input signal upper limit value of the conversion unit, the input signal median value of the A / D conversion unit, and the input signal lower limit value of the A / D conversion unit.

FIG. 11: A / by the image quality improving circuit at the time of large amplitude
Analog video signal and A / D input to the D conversion circuit unit
Explanatory drawing showing the level relationship between the input signal upper limit value of the conversion unit, the input signal median value of the A / D conversion unit, and the input signal lower limit value of the A / D conversion unit.

FIG. 12 shows A / by the image quality improving circuit when the amplitude is small.
Analog video signal and A / D input to the D conversion circuit unit
Explanatory drawing showing the level relationship between the input signal upper limit value of the conversion unit, the input signal median value of the A / D conversion unit, and the input signal lower limit value of the A / D conversion unit.

FIG. 13 is a diagram illustrating an analog video signal input to an A / D conversion circuit unit and an input signal upper limit value of the A / D conversion unit, an input signal median value of the A / D conversion unit, and an A / D conversion unit according to the image quality improvement circuit; Explanatory diagram showing the level relationship of the input signal lower limit value of

FIG. 14 is a display image diagram showing a video image on a display by a shade of pixels.

[Explanation of symbols]

1 Video signal average brightness detection means for detecting the average brightness value of a video signal at a certain time or the average brightness distribution at each brightness level 2 A / D conversion for calculating the median value of the optimum input signal band of the A / D conversion unit Input signal band calculation unit 3 A / D conversion input signal band upper limit value creating unit 4 for creating an input signal upper limit value of the A / D conversion unit 4 A / D conversion input signal creating an input signal lower limit value of the A / D conversion unit Band lower limit value creating means 5 A / D conversion circuit section for converting an analog signal into a digital signal 6 Video signal amplitude level detecting means 7 for detecting an amplitude level of a video signal 7 Bandwidth of an optimum input signal band of the A / D converting section A / D conversion input signal bandwidth bandwidth calculating means 8 for calculating the differential circuit 9 for detecting the luminance change point of the video signal Video signal sharpness level detecting means 1 for detecting the luminance change point of the video signal A / D converter of the optimum median and bandwidth of the input signal band to calculate the A / D conversion input signal band median and bandwidth calculating means

Claims (8)

[Claims] 1. A display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing to detect the characteristics of the video signal and convert the analog signal into a digital signal according to the detected characteristics. An apparatus for improving and improving image quality of video, characterized by comprehensively adjusting an input signal band of D / D conversion. 2. A display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing to detect an average brightness value or an average brightness distribution at each brightness level of the video signal for a certain period of time. An apparatus for improving and improving image quality of video, characterized by adjusting a central value of an input signal band process of A / D conversion for converting an analog signal into a digital signal according to a detected value. 3. A display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing to detect the maximum signal level value and the minimum signal level value of the video signal, and to detect the maximum signal level value and the minimum signal level value. An apparatus for improving and improving image quality of video, which adjusts a center value of an input signal band of A / D conversion for converting an analog signal into a digital signal according to an average value of signal level values. 4. A display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, and an average brightness value of a video signal at a certain time or an average brightness distribution at each brightness level, and an average brightness distribution of the video signal. The average value of the highest signal level value and the lowest signal level value is detected from the highest signal level value and the lowest signal level value, and the analog signal is converted into a digital signal in accordance with each detected value. An apparatus for improving and improving the image quality of video, which is characterized by adjusting the center value. 5. A display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, detects the maximum signal level value and the minimum signal level value of the video signal, and detects the maximum signal level value and the minimum signal level value. An image quality improvement device for video, characterized by adjusting an input signal bandwidth of A / D conversion for converting an analog signal into a digital signal according to a signal level value. 6. A display device, which displays an analog video signal by converting it into a digital video signal and performing image processing, detects the sharpness level of the video signal from the level value and distribution value of the differential signal of the video signal, An image quality improvement device for video, characterized by adjusting an input signal bandwidth of A / D conversion for converting an analog signal into a digital signal in accordance with the detected value. 7. A display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, and an average brightness value of the video signal at a certain fixed time or an average brightness distribution at each brightness level, and an average brightness distribution of the video signal. It is characterized by detecting the maximum signal level value and the minimum signal level value, and adjusting the center value and bandwidth of the input signal band of A / D conversion for converting an analog signal into a digital signal according to the detected values. Image quality improvement device. 8. A display device for displaying an analog video signal by converting the analog video signal into a digital video signal and performing image processing, wherein the video signal has an average brightness value at a certain time or an average brightness distribution at each brightness level, and The sharpness level of the video signal is detected from the level value and the distribution value of the differential signal, and the center value and the bandwidth of the input signal band of the A / D conversion for converting the analog signal into the digital signal are detected according to the detected value. An image quality improvement and improvement device for images, which is characterized by adjustment.