JP2011166638A - Video processor and video display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform image quality correction processing in each region of a video more appropriately. <P>SOLUTION: There are provided: an input signal processing section to which an input signal is input; a region classification section that classifies an input video included in an input signal input to the input signal processing section into a plurality of classified regions according to the feature amount of the video and calculates area ratios of the plurality of classified regions in a predetermined range on the periphery of a pixel to be corrected; and a video correction section that calculates a new pixel value of the pixel to be corrected by multiplying the plurality of corrected pixel values calculated by performing a plurality of image corrections at different levels for each classified region classified by the region classification section by the respective area ratios of the corresponding classified regions and adding the results to the target pixel value of the input video. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a video processing apparatus, and more particularly to a technique for classifying video into a plurality of regions and preferably correcting image quality.

In general, for video signals input to video processing devices such as televisions and video cameras,
When image quality correction such as contrast correction, edge enhancement, and noise reduction is performed, the entire screen is often processed with constant parameters and threshold values. In this case, the correction effect is applied to the entire screen.
It is difficult to set a correction effect in some video areas and no side effects in other areas.

In the image quality correction for the entire screen, it is necessary to weaken the correction effect so that the side effect does not occur.

Therefore, in order to suppress the deterioration of the correction effect due to the image quality correction on the entire screen, there is a method of classifying the video into a plurality of areas according to the feature quantities such as frequency, luminance, and color information, and correcting the image quality for each area. See, for example, US Pat.

JP 2000-57335 A

However, in the image quality correction for each classified region, there is a difference in correction effect at the boundary between the regions, so that there is a principle problem that the boundary appears as an intermittent image. Therefore, it is necessary to set so that a large difference does not occur in the correction effect between the regions, and as a result, the correction effect is reduced.

In order to solve the problem, a method of averaging pixel values in the vicinity of the region boundary can be considered. However, when the boundary and the edge of the object in the video overlap, the edge becomes blurred. Also,
In the case of the boundary between the texture areas, there is a problem that the area in the vicinity of the averaged boundary looks like a band.

It is an object of the present invention to suppress image deterioration such as the correction process for the entire screen and to perform image quality correction appropriately.

In order to solve the above problems, according to an embodiment of the present invention, an input signal processing unit to which an input signal is input, and an input video included in the input signal input to the input signal processing unit are characterized by video. A region classification unit that classifies the plurality of classification regions according to the amount and calculates an area ratio of the plurality of classification regions within a predetermined range around the correction target pixel, and the region classification into the target pixel value of the input video The correction target is obtained by multiplying and adding a plurality of correction pixel values calculated by performing a plurality of image corrections at different levels for each classification region classified by the unit, by multiplying the area ratio for the corresponding classification region, respectively. A video correction unit that calculates a new pixel value for each pixel.

According to the image processing apparatus of the present invention configured as described above, it is possible to suppress the deterioration of the correction effect in each region of the video and correct image quality more suitably.

1 is a block diagram illustrating a configuration of an image processing apparatus according to Embodiment 1 of the present invention. It is a figure explaining the effect of the image processing which concerns on the Example of this invention. It is a figure explaining the input / output characteristic of contrast correction. It is a block diagram explaining the structure of the area | region classification part by the luminance which concerns on the Example of this invention. It is a block diagram explaining the structure of the area | region classification | category part by the frequency which concerns on the Example of this invention. It is a figure explaining the area | region determination method by the luminance which concerns on the Example of this invention. It is a figure explaining the area | region determination method by the frequency which concerns on the Example of this invention. It is a figure explaining the area ratio calculation method which concerns on the Example of this invention. It is a figure explaining the area ratio calculation method which concerns on the Example of this invention. It is a block diagram explaining a part of structure of the image processing apparatus which concerns on Example 2 of this invention. It is a block diagram explaining the structure of the image processing apparatus which concerns on Example 3 of this invention. It is a figure explaining the area | region detection method by the frequency corresponding to the some flame | frame (3 frames) which concerns on the Example of this invention. It is a figure explaining the area | region classification method by the frequency which concerns on the Example of this invention. It is a figure explaining the area | region detection method by the frequency which concerns on the Example of this invention. It is a figure explaining the area ratio calculation method corresponding to several frames (3 frames) which concerns on the Example of this invention. It is a block diagram explaining the structure of the image processing apparatus which concerns on Example 4 of this invention. It is a figure explaining the motion vector detection method which concerns on the Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not necessarily limited to these embodiments. In the figure for explaining the embodiment,
In principle, the same members are denoted by the same reference numerals, and repeated description thereof is omitted.

First, an example of a video processing apparatus according to Embodiment 1 of the present invention will be described with reference to the configuration diagram of FIG.

The video processing apparatus of this embodiment includes an input signal processing unit 1, a contrast a correction unit 3, a contrast b correction unit 4, a contrast c correction unit 5, a region classification unit 6, and a contrast / blend unit 13.
, A timing control unit 15, an LCD panel 16, and the like. Here, the contrast a correction unit 3, the contrast b correction unit 4, the contrast c correction unit 5, and the contrast / blend unit 13 may constitute one video correction unit called a contrast correction unit.

In the input signal processing unit 1, for example, a broadcast signal received by a built-in tuner is used as an input signal, a decoding process is performed, and a video signal 2 is output.

The area classification unit 6 uses the video signal 2 as an input signal and divides the video signal 2 into a plurality of classification areas (for example, three classification areas of area a, area b, and area c) based on the video feature amount, and the area ratio of the area a 7,
The area ratio 8 of the region b and the area ratio 9 of the region c are output. Details of the processing of the area classification unit 6 will be described later.

The contrast a correction unit 3 performs contrast correction on the region a using the video signal 2 as an input signal, and outputs the video signal 10 after the contrast a correction. The contrast b correction unit 4 performs the contrast correction on the region b using the video signal 2 as an input signal, and outputs the video signal 11 after the contrast b correction. The contrast c correction unit 5 performs the contrast correction on the region c using the video signal 2 as an input signal, and outputs the video signal 12 after the contrast c correction.

Here, the contrast a correction unit 3, the contrast b correction unit 4, and the contrast c correction unit 5
Performs contrast correction with different levels of contrast correction.

FIG. 3 is a diagram for explaining input / output characteristics of a luminance signal as an example of contrast correction.
In the figure, the horizontal axis represents the input luminance signal (IN) and the vertical axis represents the output luminance signal, and the broken line in the figure represents the input / output characteristics with respect to the luminance. That is, the input / output of the luminance signal is determined by the broken line. For example, when a luminance value _YIN is input as shown in the figure, _YOUT is output.

Returning to FIG. 1, the contrast blending unit 13 includes an area ratio 7 for the region a, an area ratio 8 for the region b, an area ratio 9 for the region c, a video signal 10 after contrast a correction, and an image after contrast b correction. Using the signal 11 and the video signal 12 after the contrast c correction as an input signal, the video signal 14 after the contrast correction is output by weighted averaging using a predetermined arithmetic processing.

Here, the weighted average using a predetermined calculation process is to multiply the area ratio of each region in a predetermined range around the target pixel by multiplying the video signal whose contrast is corrected in each region and add them. Details will be described later.

Note that the contrast / blending unit 13 is an image processing synthesis unit that combines the effects of contrast correction, and the video signal 14 after contrast correction is a new corrected signal generated by the contrast / blending unit 13 for the correction target pixel. Including a large pixel value.

The output video signal 14 after contrast correction is displayed on the LCD panel 16 via the timing control unit.

Next, the region classification unit 6 will be described with reference to FIGS. 4A, 4B, 5A, 5B, 6A, and 6B.

FIG. 4A is a diagram for explaining the configuration of a region classification unit based on luminance as an example of a feature amount. The area classification unit based on luminance includes a luminance determination unit 101, an area ratio a calculation unit 103, an area ratio b calculation unit 104,
The area ratio c calculation unit 105 is configured.

The luminance determination unit 101 receives the video signal 2 as an input signal, and sets a low luminance region, an intermediate luminance region, a threshold Y _TH0 that divides preset low luminance and intermediate luminance, and a threshold Y _TH1 that divides intermediate luminance and high luminance, The area signal 102 is output by classifying the area into a high luminance area. Here, in the following example, the low luminance area is defined as area a, the intermediate luminance area is defined as area b, and the high luminance area is defined as area c.

FIG. 5A is a diagram showing regions classified by luminance, where the horizontal axis represents the luminance value, the vertical axis represents the number of pixels, and is a histogram showing the luminance distribution in one screen. The region signal 102 is a signal for identifying the classified region. For example, when the region signal is α,
(Equation 1)
When region a (0 ≦ Y <Y _TH0 ), α = 0
When region b (Y _TH0 ≦ Y <Y _TH1 ), α = 1
When region c (Y _TH1 ≦ Y ≦ Y _MAX ), α = 2
It is represented by the numerical value.

6A and 6B are diagrams for explaining an area ratio calculation method. The rectangle in FIG. 6a represents a pixel, and the thick framed pixel represents the position of the correction target pixel. A range surrounded by a dotted line is a range including pixels to be counted, and is a pixel count target range (hereinafter, area ratio calculation target region) for area ratio calculation. Here, the total number of pixels in the area ratio calculation target region is N.
FIG. 6 b shows the relationship between the pixels in the area ratio calculation target region and the classified regions. here,
If the number of pixels belonging to the region α is N _α ,

を満たす。この時、領域αと面積比率算出対象領域内の面積比が個数の比に等しいとする
と、Ｎ_α／Ｎが求める面積比率算出対象領域内の面積比となる。例えば、図６ｂの面積比
率算出対象領域は５×５画素で構成されており、全画素数Ｎ＝１５、領域ａに属する画素
数Ｎ_０＝１０である。よって、面積比率算出対象領域内の領域ａの面積比は１０／１５＝
２／３となる。面積比率算出対象領域内の領域ｂの面積比、面積比率算出対象領域内の領
域ｃの面積比も同様の方法で算出できる。

Meet. At this time, if the area ratio in the area α and the area ratio calculation target area is equal to the ratio of the number, N _α / N is the area ratio in the area ratio calculation target area obtained. For example, the area ratio calculation target region in FIG. 6b is composed of 5 × 5 pixels, total pixel number N = 15, a pixel number N _{0 =} 10 belonging to the area a. Therefore, the area ratio of the area a in the area ratio calculation target area is 10/15 =
2/3. The area ratio of the region b in the area ratio calculation target region and the area ratio of the region c in the area ratio calculation target region can be calculated by the same method.

Returning to FIG. 4A, the area ratio a calculation unit 103 receives the area signal 102, counts the number of pixels in which the area signal of the area ratio calculation target area is the area a, that is, α = 0, and the area ratio of the area a. 7 is output. The area ratio b calculation unit 104 receives the area signal 102, counts the number of pixels in which the area signal of the area ratio calculation target area is the area b, that is, α = 1, and outputs the area ratio 8 of the area b. The area ratio c calculation unit 105 receives the area signal 102, counts the number of pixels in which the area signal of the area ratio calculation target area is the area c, that is, α = 2, and outputs the area ratio 8 of the area c.

Next, FIG. 4B is a diagram for explaining the configuration of the region classification unit 6 in the case where a frequency is used as a modification of the feature amount used in the region classification unit 6. In this case, the area classifying unit 6 includes the frequency converting unit 201.
A frequency determination unit 203, an area ratio a calculation unit 205, an area ratio b calculation unit 206, and an area ratio c calculation unit 207.

The frequency conversion unit uses the video signal 2 as an input signal, performs frequency conversion by discrete Fourier transform or discrete cosine transform, for example, and outputs a frequency component 202. Frequency determination unit 203
The frequency component 202 is input, and a frequency distribution belonging to a preset threshold value F _TH0 that divides a low frequency region and an intermediate frequency region and a threshold value F _TH1 that divides an intermediate frequency region and a high frequency region are examined, The signal is classified into a frequency domain and a high frequency domain, and a domain signal 204 is output. Here, in the following example, a low frequency region is a region a, an intermediate frequency region is a region b, and a high frequency region is a region c.

FIG. 5b is a diagram showing regions classified by frequency. In the actual video space, the horizontal axis represents the horizontal pixel position, the vertical axis represents the vertical pixel position, and the rectangle represents the luminance value of the pixel position. The horizontal axis of the frequency space represents the horizontal frequency, the vertical axis represents the vertical frequency, and the rectangle represents the frequency component. 8 × 8 surrounded by dotted line
Is a range to be frequency converted (hereinafter referred to as a conversion target region). For example, the region signal is α, and the number of frequency components in which the frequency component f of the frequency F = (F _u , F _v ) is greater than or equal to the threshold value f _α is counted. At this time, for the region where the frequency of the region α is equal to or higher than the threshold value n _α ,

なる数値にて領域を識別する。

The area is identified by the numerical value.

  However, the absolute value of the frequency F is

である。

It is.

Returning to FIG. 4B, the area ratio a calculation unit 205 receives the area signal 204, counts the number of pixels in which the area signal of the area ratio calculation target area is the area a, that is, α = 0, and the area ratio of the area a. 7 is output. The area ratio b calculation unit 206 receives the area signal 204, counts the number of pixels in which the area signal of the area ratio calculation target area is the area b, that is, α = 1, and outputs the area ratio 8 of the area b. The area ratio c calculation unit 207 receives the area signal 204, counts the number of pixels in which the area signal of the area ratio calculation target area is the area c, that is, α = 2, and outputs the area ratio 8 of the area c.

Then, the contrast-blending unit 13, by using the area ratio and contrast correction value Y _alpha for each area calculated by the area classification unit, is calculated by Equation 5 below corrected luminance value Y of the correction target pixel.

As shown in Equation 5, the correction of the correction target pixel is performed using the contrast correction value calculated by performing the weighted average of the contrast correction value of each region with the area ratio of each region for a predetermined range around the correction target pixel. By setting the luminance value, it is possible to perform more suitable image quality correction with less blur.

Note that in the case of a general contrast correction technique using averaging, the luminance average Y _α (i, j) in the range of the distance d with the correction target pixel as the center is the weight coefficient N _ij (in the case of the average value). Often uses N _ij = 1) to calculate the corrected luminance value as shown in Equation 6 below.

この場合、周囲画素の輝度値を平均化してしまい、ぼやけを生じてしまう。

In this case, the luminance values of surrounding pixels are averaged, resulting in blurring.

According to the calculation method of the corrected luminance value of the present embodiment described using Expression 5, such blurring can be reduced.

The effect of the image processing of the video processing apparatus according to the first embodiment of the present invention described above will be described using FIG.

For example, as shown in FIG. 2, in an image of a bright outdoor and dark room, or an image taken under backlight, the entire house is beautiful, but a dark low-luminance area such as the room cannot be seen. In some cases, the image may be crushed black (hereinafter referred to as black crushed), or a bright area with high brightness such as a blue sky or a cloud may be saturated with white (hereinafter referred to as white crushed).

Here, if contrast correction is performed so as to widen the high luminance and low luminance bands in order to reduce black crushing and white crushing, the intermediate luminance band of landscapes such as trees is narrowed, resulting in gradation degradation. .

In the conventional technology, this problem video is divided into a flat video area (low frequency area) and a texture area (high frequency area), and corrected by changing the contrast input / output characteristics individually. Will appear and the video will be intermittent. Further, if the correction difference is blurred by the average value, blurring does not occur at the edges of branches such as trees and leaves, and as a result, the video is deteriorated.

On the other hand, in the image processing of the video processing device according to the first embodiment of the present invention described above, the area ratio of each region in the predetermined range around the target pixel is subjected to contrast correction of each region at the boundary portion of the region. By interpolating the input / output characteristics of contrast by weighted average processing that multiplies and adds to the video signal, while preventing blurring of edges such as branches and leaves such as trees,
The problem video can be corrected continuously.

According to the above-described image processing of the video processing apparatus according to the first embodiment of the present invention, it is possible to suppress the reduction in the correction effect in each area of the video and correct image quality more suitably.

In the first embodiment described above, an example using the luminance or frequency characteristics as the feature amount has been described. However, other pixel values such as chromaticity may be used instead of the luminance.

In the first embodiment, one type of image quality correction is performed on the divided areas. In the second embodiment, multiple types of image quality correction are performed on the divided areas.

  An example of a video processing apparatus according to the second embodiment of the present invention will be described with reference to the configuration diagram of FIG.

The video processing apparatus according to the second embodiment is obtained by changing the configuration of the video processing apparatus according to the first embodiment other than the input signal processing unit 1, the timing control unit 15, and the LCD panel 16 to the configuration illustrated in FIG. . Since the configuration of the input signal processing unit 1, the timing control unit 15, and the LCD panel 16 is the same as that of the video processing apparatus according to the first embodiment, illustration and description thereof are omitted.

As shown in FIG. 7, the video processing apparatus according to the second embodiment has an NRa processing unit 2 other than the above configuration.
0 (Here, “NR” is an abbreviation for Noise Reduction, “noise reduction”.
Means. Noise reduction processing is also one of image correction processing. ), NRb processing unit 21, NR
It has components such as a c processing unit 22, an NR blend unit, a contrast a correction unit 3, a contrast b correction unit 4, a contrast c correction unit 5, a region classification unit 6, and a contrast / blend unit 13. Here, the NRa processing unit 20, the NRb processing unit 21, the NRc processing unit 22, and the NR blending unit may constitute a first video correction unit called an NR (noise reduction) unit. The b correction unit 4, the contrast c correction unit 5, and the contrast / blend unit 13 may constitute a second video correction unit called a contrast correction unit.

The area classification unit 6 uses the video signal 2 output from the input signal processing unit 1 as an input signal, and divides it into a plurality of areas, for example, area a, area b, and area c, based on the video feature amount, The area ratio 7 of the area a, the area ratio 8 of the area b, and the area ratio 9 of the area c are output.

The details of the region dividing process and the area ratio calculating process based on the video feature amount in the region classifying unit 6 are the same as those in the first embodiment, and thus detailed description thereof is omitted.

The NRa processing unit 20 performs a noise reduction process on the region a using the video signal 2 as an input signal, and outputs a video signal 23 after the noise reduction a process. The NRb processing unit 21 receives the video signal 2
As an input signal, a noise reduction process is performed on the region b, and a video signal 24 after the noise reduction b process is output. The NRc processing unit 22 performs a noise reduction process on the region c using the video signal 2 as an input signal, and outputs a video signal 25 after the noise reduction c process.

Here, the noise reduction processing is expressed by, for example, a luminance average expression of Expression 6, and the weight coefficient N _ij is assumed to follow a Gaussian distribution.

The NRa processing unit 20, the NRb processing unit 21, and the NRc processing unit 22 perform noise reduction processing with different levels of noise reduction.

The NR blend unit 26 includes an area ratio 7 for the area a, an area ratio 8 for the area b, an area ratio 9 for the area c, a video signal 23 after the noise reduction a process, a video signal 24 after the noise reduction b process,
Using the video signal 25 after the noise reduction c processing as an input signal, the video signal 27 after the noise reduction processing is output by weighted averaging using a predetermined arithmetic processing.

Here, the weighted average using a predetermined arithmetic process is to multiply and add the area ratio of each area in a predetermined range around the target pixel to the video signal after the noise reduction process of each area.

The NR blend unit 26 is an image processing synthesis unit that synthesizes the effect of noise reduction.
The video signal 27 after the noise reduction process includes the pixel value after the noise reduction process generated by the NR blend unit 26 for the correction target pixel.

The contrast a correction unit 3 performs the contrast correction on the region a using the video signal 27 after the noise reduction process as an input signal, and outputs the video signal 10 after the contrast a correction.
The contrast b correction unit 4 uses the video signal 27 after the noise reduction processing as an input signal, and outputs the region b
And the video signal 11 after the contrast b correction is output. The contrast c correction unit 5 performs the contrast correction on the region c using the video signal 27 after the noise reduction process as an input signal, and outputs the video signal 12 after the contrast c correction.

The contrast / blending unit 13 includes an area ratio 7 for the region a, an area ratio 8 for the region b, and a region c.
And the video signal 10 after contrast a correction, the video signal 11 after contrast b correction, and the video signal 12 after contrast c correction are input signals, and the contrast correction is performed by weighted average using a predetermined arithmetic processing. The subsequent video signal 14 is output. The video signal 14 after the contrast correction includes a new pixel value after correction generated by the contrast / blending unit 13 for the correction target pixel.

Here, the weighted average using a predetermined calculation process is to multiply the area ratio of each region in a predetermined range around the target pixel by multiplying the video signal whose contrast is corrected in each region and add them.

The output video signal 14 after contrast correction is displayed on the LCD panel 16 via the timing control unit. The output video signal 14 after contrast correction is displayed on the LCD panel 16 via the timing control unit.

In the configuration of FIG. 7, the configuration example of the two types of image quality correction processing for the divided areas has been described.
In this image quality correction processing method, the calculation formula of the correction signal when the number of divided areas and the number of types of image quality correction processing are generalized is shown as Equation 7.

In other words, Expression 7 shows the relationship between the input data signal X _i (for example, luminance signal) and the output data signal X _{i + 1 in} the i-th image quality correction process F _{α, i} divided into n areas. .

In the example of FIG. 7, for example, in the NR blend unit 26, the relationship between the input data and the output data is defined by an arithmetic expression in the case where i = 0 in Expression 7 above.

In the example of FIG. 7, the contrast / blending unit 13 uses i = 1 in Equation 7 above.
The relation between the input data and the output data is defined by the arithmetic expression in the case of

According to the image processing of the video processing apparatus according to the second embodiment of the present invention described above, even when a plurality of image quality corrections are performed on each area of the video, the reduction in the correction effect is suppressed and the image quality correction is performed more suitably. Can do.

  In the first and second embodiments, it has been shown that one frame of video can be classified into a plurality of regions and image quality can be suitably corrected. However, for example, in a natural image, edges, frequency components, luminance, and the like often fluctuate in the time direction, so that an object in the current frame may not be classified as the same region in the next frame.

  In particular, in a still video region, when an individual image quality correction for each region is performed on a video region in which the region classification changes between frames as described above, a luminance difference occurs between the frames, and thus flickers appear.

  In the third embodiment, based on the first embodiment, an area signal of a plurality of frames continuous on the time axis is used to perform image quality correction that suppresses flicker due to fluctuation between frames.

  An example of a video processing apparatus according to Embodiment 3 of the present invention will be described with reference to the configuration diagram of FIG.

  The video processing apparatus according to the third embodiment is obtained by changing the configuration of the video processing apparatus according to the first embodiment other than the input signal processing unit 1, the timing control unit 15, and the LCD panel 16 to the configuration illustrated in FIG. . Since the configuration of the input signal processing unit 1, the timing control unit 15, and the LCD panel 16 is the same as that of the video processing apparatus according to the first embodiment, illustration and description thereof are omitted.

  The configurations of the contrast a correction unit 3, the contrast b correction unit 4, and the contrast c correction unit 5 are the same as those of the video processing apparatus according to the first embodiment, and thus description thereof is omitted.

  As shown in FIG. 8, the video processing apparatus according to the third embodiment has a configuration such as a region classification unit 30 and a contrast / blend unit 40 in addition to the above configuration.

  The area classification unit 30 uses the video signal 2 as an input signal and divides the video signal 2 into a plurality of classification areas (for example, three classification areas of area a, area b, and area c) based on the feature amount of the video, 31, the area ratio 32 of the region b, and the area ratio 33 of the region c are output. Also, the classification ratio of the past two frames, that is, the area ratio 34 of the area a delayed by one vertical synchronization (hereinafter referred to as 1v), the area ratio 35 of the area b, the area ratio 36 of the area c, and two vertical synchronizations The area ratio 37 of the area “a”, the area ratio 38 of the area “b”, and the area ratio 39 of the area “c” which are delayed by the minute (hereinafter referred to as 2v) are output. Here, an example is given in which the number of past frames is two frames, but the present invention is not limited to this. Details of the processing of the area classification unit 30 will be described later.

  The contrast blend unit 40 includes an area ratio 31 of the area a of the current frame, an area ratio 32 of the area b, an area ratio 33 of the area c, an area ratio 34 of the area a of the 1v delay frame, an area ratio 35 of the area b, an area area ratio 36 of c, area ratio 37 of area a of 2v delay frame, area ratio 38 of area b, area ratio 39 of area c, video signal 10 after correction of contrast a of current frame, contrast b of current frame Using the corrected video signal 11 and the video signal 12 after the contrast c correction of the current frame as input signals, the video signal 14 after the contrast correction is output by weighted averaging using a predetermined arithmetic process. In the present embodiment, the current frame is a correction target frame including pixels to be corrected.

  Here, the weighted average using the predetermined arithmetic processing is to multiply the video signal whose contrast is corrected in each region by the area ratio of each region in a predetermined range around the target pixel and a predetermined fixed ratio for each frame. To add. Details will be described later.

  Next, the region classification unit 30 will be described with reference to FIGS. 9, 10, 11, and 12.

  FIG. 9 is a diagram for explaining the configuration of an area classification unit corresponding to a plurality of frames (3 frames). The region classification unit includes a region detection unit 300, a region signal storage frame memory 304, an area ratio calculation unit 305, an area ratio calculation unit 306, and an area ratio calculation unit 307.

  The region detection unit 300 receives the video signal 2 as an input signal, detects a region based on the feature amount, and then outputs a region signal 301 of the current frame.

  FIG. 10 is a diagram for explaining the configuration of a region detection unit based on frequency as an example of a feature amount. The frequency detection unit includes a frequency conversion unit 201 and a frequency determination unit 203. In addition, when the area acquisition detection unit 305 is replaced with the luminance determination unit 101, the determination is performed using the luminance value as the feature amount.

  The area ratio calculation unit 305 receives the area signal 301 of the current frame as an input, calculates the area ratio of each area, then, the area ratio 31 of the area a of the current frame, the area ratio 32 of the area b, and the area ratio 33 of the area c. Is output.

  FIG. 11 is a diagram illustrating the configuration of the area ratio calculation unit. The area ratio calculation unit for the current frame includes an area ratio a calculation unit 205, an area ratio b calculation unit 206, and an area ratio c calculation unit 207. Note that the region classification unit including only the region detection unit 300 and the current frame area ratio calculation unit 305 is the same as the region classification unit configured in FIG. 4B.

  The area signal storage frame memory 304 is a memory for storing area signals for two frames. The area signal 301 for the current frame is a write signal, the area signal 302 for a 1v delay frame, and the area signal 303 for a 2v delay frame is a read signal. To do.

  The area ratio calculation unit 306 receives the region signal 302 of the 1v delay frame, calculates the area ratio of each region, and then calculates the area ratio 34 of the region a of the 1v delay frame, the area ratio 35 of the region b, and the area of the region c. The ratio 36 is output.

  The area ratio calculation unit 307 receives the area signal 303 of the 2v delay frame, calculates the area ratio of each area, and then calculates the area ratio 37 of the area a, the area ratio 38 of the area b, and the area c of the area c. The ratio 39 is output.

  The configuration of the area ratio calculation unit 306 and the area ratio calculation unit 307 is the same as that of the area ratio calculation unit 305.

  FIG. 12 is a diagram illustrating an area ratio calculation method. The time axis advances from the left to the right, and the left is a 2v delay frame, the center is a 1v delay frame, and the right is an example of region classification for 3 frames. In particular, the region classification example on the right is equivalent to FIG.

When the total number of pixels in the area ratio calculation target region for three frames is N, and the number of pixels belonging to the region α of the kv delay frame is N _{k, α} , the total number of pixels is

となる。この時、ｋｖ遅延フレームの領域αの面積比率は、Ｎ_ｋ，α／Ｎとなる。

It becomes. At this time, the area ratio of the region α of the kv delay frame is N _{k, α} / N.

Next, the contrast blend unit 40 uses a weighted average _obtained by adding a fixed ratio β _k determined as a weight for each frame to the area ratio of each region calculated by the region classification unit, and a contrast correction value Y _α, thereby correcting pixels to be corrected The corrected luminance value Y is calculated by the following formula 9.

固定比率β_ｋは、例えば各フレームの等価平均の場合はβ_０：β_１：β_２＝１：１：１、また、現在フレームに重みを置く場合はβ_０：β_１：β_２＝２：１：１の様に設定するとよい。

Fixed ratio beta _k, for example in the case of equivalent average of each frame _{β 0: β 1: β 2} = 1: 1: 1, In the case of placing the weight to the current frame _{β 0: β 1: β 2} = 2 It is good to set like 1: 1.

  As described above, the contrast correction is performed using the contrast correction value generated by weighted average of the area ratios of the areas of the plurality of frames, so that flicker between frames can be suppressed and more suitable contrast correction with less blur can be performed.

  In the third embodiment described above, an example in which contrast correction is used as the image quality correction has been described. However, a plurality of other image quality corrections such as an enhancer and NR may be used in succession instead of contrast correction. In this case, since the image quality correction is performed using the image quality correction value generated by weighted averaging the area ratios of the areas of the plurality of frames, it is possible to suppress flicker between frames and perform more preferable image quality correction with less blur. .

  In the third embodiment, a method of suppressing flickering is shown by performing weighted averaging of the area ratios of regions of a plurality of continuous frames on the time axis. This method is effective for a small-motion natural image such as a tree swinging in an image as shown in FIG. 2, for example, but in a large-motion image, the area signal is averaged with different classification areas to correct image quality for each area. There is a case where the difference disappears, that is, the same image quality correction as the screen does not change.

  Therefore, since the region classification of the current frame and the previous frame is different in a moving video region, image quality correction is performed for each region using the area ratio of the current frame region. Flickering is suppressed by using a weighted average.

  In the fourth embodiment, based on the third embodiment, a motion vector detector used in a motion compensated frame rate converter or the like is used to detect a still image region and a moving image region and perform image quality correction.

  An example of a video processing apparatus according to Embodiment 4 of the present invention will be described with reference to the configuration diagram of FIG.

  The video processing apparatus according to the fourth embodiment is obtained by changing the configuration of the video processing apparatus according to the first embodiment other than the input signal processing unit 1, the timing control unit 15, and the LCD panel 16 to the configuration illustrated in FIG. . Since the configuration of the input signal processing unit 1, the timing control unit 15, and the LCD panel 16 is the same as that of the video processing apparatus according to the first embodiment, illustration and description thereof are omitted.

  The configurations of the contrast a correction unit 3, the contrast b correction unit 4, and the contrast c correction unit 5 are the same as those of the video processing apparatus according to the first embodiment, and thus description thereof is omitted.

  As shown in FIG. 13, the video processing apparatus according to the fourth embodiment has a configuration of an area classification unit 50, a contrast / blend unit 51, a video signal storage frame memory 52, a motion vector detection unit 54, and the like in addition to the above configuration. Have.

  The video signal storage frame memory 52 is a memory for storing a video signal for one frame. The video signal 2 is a write signal, and the video signal 53 of a 1v delay frame is a read signal.

  The motion vector detection unit 54 detects a motion vector from the difference between the two frames using the current frame video signal 2 and the video signal 53 of the 1v delay frame as input signals, and outputs a vector signal 55.

  FIG. 14 is a diagram illustrating a vector detection method based on a 3 × 3 pixel block matching method as an example of a motion vector detection method.

  In this embodiment, the 1v delay frame is a correction target frame including a correction target pixel. The detection of the motion vector is such that the 3 × 3 pixel block centered on the pixel to be corrected in the 1v delay frame is centered on the same position as the pixel to be corrected in the current frame, for example, 21 × 21 pixels. When matching with a block in the search range, the relative position with the matching pixel that is the center of the matching block is detected as a motion vector.

  Note that the block match is determined by whether or not the absolute value of the luminance difference between the blocks is minimized within the search range. In addition, the motion vector signal at the pixel position to be corrected determines whether it is in the moving image region or the still image region.

  The region classification unit 50 includes a region detection unit 300, a region detection unit 308, an area ratio calculation unit 305, and an area ratio calculation unit 306.

  The area ratio calculation unit 305 receives the area signal 301 of the current frame as an input, calculates the area ratio of each area, then, the area ratio 31 of the area a of the current frame, the area ratio 32 of the area b, and the area ratio 33 of the area c. Is output.

  The area ratio calculation unit 306 receives the 1v delay frame region signal 309, calculates the area ratio of each region, and then calculates the area ratio 34 of the region a of the 1v delay frame, the area ratio 35 of the region b, and the area c of the region c. The ratio 36 is output.

  The vector signal 55 described above is a signal synchronized with this area ratio.

  The contrast blend unit 51 includes a vector signal 55, an area ratio 31 of the area a of the current frame, an area ratio 32 of the area b, an area ratio 33 of the area c, an area ratio 34 of the area a of the 1v delay frame, and a contrast. The video signal 10 after a correction, the video signal 11 after contrast b correction, and the video signal 12 after contrast c correction are input.

  Here, when the absolute value of the magnitude of the vector obtained from the vector signal 55 is smaller than a predetermined threshold value or a threshold value set from the outside, the contrast blending unit 51 performs the same as in the third embodiment. Contrast correction is output with a weighted average based on the weight and area ratio of the current and 1v delay frames.

  In addition, when the absolute value of the magnitude of the vector obtained from the vector signal 55 is equal to or greater than the threshold value, the contrast / blending unit 51 performs the contrast correction by the weighted average based on the area ratio of only the 1v delay frame, and then the video. The signal 14 is output.

  The area classification unit 50 receives the video signal 2 of the current frame and the video signal 53 of the 1v delay frame as input signals, and based on the video feature quantity, the area ratio 31 of the area a, the area ratio 32 of the area b, The area ratio 33 of c, the area ratio 34 of the area a of the 1v delay frame, the area ratio 35 of the area b, and the area ratio 36 of the area c are output.

  In the above description, the number of delay frames stored in the frame memory is exemplified as one frame, but the present invention is not limited to this. However, when increasing the number of frames to be stored, it is desirable to provide a vector storage memory and hold a vector signal corresponding to an area signal for storing a moving image area or a still image area in the vector storage memory.

  According to the image processing of the video processing apparatus according to the fourth embodiment of the present invention described above, even in a video with a large movement, flicker and a reduction in correction effect can be suppressed, and contrast correction can be performed more suitably.

  In the fourth embodiment described above, the example using the contrast correction as the image quality correction has been described. However, other image quality correction such as an enhancer or NR may be used instead of the contrast correction. In this case, even in a video with a large motion, it is possible to suppress flickering and a decrease in the correction effect and perform image quality correction more suitably.

  In the fourth embodiment described above, the case where the 1v delay frame is the correction target frame using the block matching method (FIG. 14) as the motion vector detection technique has been described. The relationship between the correction target frame and the preceding and following frames in the motion vector detection technique is not limited to the configuration shown in FIG. In the detection of the motion vector of the fourth embodiment, it is only necessary to obtain the motion of the correction target pixel and the motion vector of the pixel, and video processing other than the motion vector detector described above may be in phase with the correction target pixel output. . For example, in FIG. 14, the current frame in FIG. 14 may be replaced with a 1v delay frame, and the 1v delay frame in FIG. 14 may be replaced with the current frame. It may be a detection technique using a plurality of frames as disclosed in 2006-165602.

DESCRIPTION OF SYMBOLS 1 Input signal processing part 2 Video signal 3 Contrast a correction part 4 Contrast b correction part 5 Contrast c correction part 6 Area classification | category part 7 Area ratio 8 of area a Area ratio 9 of area b Area ratio 10 of area c After contrast a correction Video signal 11 after contrast b correction video signal 12 after contrast c correction 13 contrast / blend unit 14 video signal 15 after contrast correction timing control unit 16 LCD panel 20 NRa processing unit 21 NRb processing unit 22 NRc processing unit 23 Video signal 24 after noise reduction a process 24 Video signal after noise reduction b process Video signal 26 after noise reduction c process NR blend unit 27 Video signal 30 after noise reduction process Area corresponding to multiple frames (3 frames) Classification unit 31 Current frame area a area ratio 32 Current frame Area ratio 33 of the area b Area ratio 34 of the area c of the current frame Area ratio 35 of the area 1a of the 1v delay frame Area ratio 36 of the area b of the 1v delay frame 36 Area ratio of the area c of the 1v delay frame 37 Area of the 2v delay frame Area ratio of a 38 Area ratio of area 2b of 2v delay frame 39 Area ratio of area c of 2v delay frame 40 Contrast / blend unit 50 corresponding to multiple frames (3 frames) Area classification corresponding to multiple frames (2 frames) Unit 51 Contrast / Blend Unit 52 Using Motion Vector Detection 52 Video Signal Storage Frame Memory 53 1v Delay Frame Video Signal 54 Motion Vector Detection Unit 55 Vector Signal 101 Luminance Judgment Unit 102 Area Signal 103 Area Ratio a Calculation Unit 104 Area Ratio b calculation unit 105 area ratio c calculation unit 201 frequency conversion unit 202 Frequency component 203 Frequency determination unit 204 Area signal 205 Area ratio a calculation unit 206 Area ratio b calculation unit 207 Area ratio c calculation unit 300 Region detection unit 301 Region signal 302 of current frame Region signal 303 of 1v delay frame 2v of delay frame Area signal 304 Frame signal storage frame memory 305 Current frame area ratio calculation unit 306 1v delay frame area ratio calculation unit 307 2v delay frame area ratio calculation unit 308 1v delay frame area detection unit 309 1v delay frame area signal

Claims (20)

An input signal processing unit to which an input signal is input;
The input video included in the input signal input to the input signal processing unit is classified into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel. An area classification unit for calculating an area ratio;
A classification region corresponding to a plurality of correction pixel values calculated by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit to the pixel value of the correction target pixel of the input video. And a video correction unit that calculates a new pixel value for the pixel of the correction target pixel by multiplying and adding each of the area ratios.   The video processing apparatus according to claim 1, wherein the feature amount of the video used in the region classification processing by the region classification unit is luminance or frequency characteristics of a video signal.   The video processing apparatus according to claim 2, wherein the plurality of image corrections at different levels in the video correction unit are different levels of contrast correction. An input signal processing unit to which an input signal is input;
The input video included in the input signal input to the input signal processing unit is classified into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel. An area classification unit for calculating an area ratio;
A classification region corresponding to a plurality of correction pixel values calculated by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit to the pixel value of the correction target pixel of the input video. A first image correction unit that calculates a first pixel value by multiplying and adding each of the area ratios;
A plurality of image corrections at different levels for each of the classification regions classified by the region classification unit to the first pixel value calculated by the first video correction unit, the plurality of image corrections performed in the first video correction unit The correction target pixel is obtained by multiplying the plurality of correction pixel values calculated by performing a plurality of image corrections that are different from the image correction of the above by multiplying the corresponding area ratio by the respective area ratios. And a second video correction unit that calculates a second pixel value that is a new pixel value for the pixel.   The video processing apparatus according to claim 4, wherein the feature amount of the video used in the region classification processing by the region classification unit is luminance or frequency characteristics of a video signal. The plurality of different levels of image correction in the first video correction unit are different levels of noise reduction processing,
The video processing apparatus according to claim 5, wherein the plurality of image corrections at different levels in the second video correction unit are different levels of contrast correction. An input signal processing unit to which an input signal is input;
The input video included in the input signal input to the input signal processing unit is classified into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel. An area classification unit for calculating an area ratio;
For a plurality of correction pixel values calculated by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit to the pixel value of the correction target pixel of the input video, A video correction unit that calculates a new pixel value for the pixel of the correction target pixel by multiplying and adding each of the area ratios, and
An image display device comprising: an image display unit that displays an image including a new pixel value calculated by the image correction unit.   The video display device according to claim 7, wherein the feature amount of the video used in the region classification processing by the region classification unit is a luminance or frequency characteristic of a video signal.   9. The video display apparatus according to claim 8, wherein the plurality of image corrections at different levels in the video correction unit are different levels of contrast correction. An input signal processing unit to which an input signal is input;
The input video included in the input signal input to the input signal processing unit is classified into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel. An area classification unit for calculating an area ratio;
A classification region corresponding to a plurality of correction pixel values calculated by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit to the pixel value of the correction target pixel of the input video. A first image correction unit that calculates a first pixel value by multiplying and adding each of the area ratios;
A plurality of image corrections at different levels for each of the classification regions classified by the region classification unit to the first pixel value calculated by the first video correction unit, the plurality of image corrections performed in the first video correction unit The correction target pixel is obtained by multiplying the plurality of correction pixel values calculated by performing a plurality of image corrections that are different from the image correction of the above by multiplying the corresponding area ratio by the respective area ratios. A second video correction unit that calculates a second pixel value to be a new pixel value for the pixel of
An image display device comprising: an image display unit that displays an image including the second pixel value calculated by the second image correction unit.   The video display device according to claim 10, wherein the feature amount of the video used in the region classification processing by the region classification unit is a luminance or frequency characteristic of a video signal. The plurality of different levels of image correction in the first video correction unit are different levels of noise reduction processing,
12. The video display apparatus according to claim 11, wherein the plurality of image corrections at different levels in the second video correction unit are different levels of contrast correction. An input unit for inputting an input video including a plurality of frames;
For each of the plurality of frames of the input video input to the input unit, classification processing into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel A region classification unit that calculates an area ratio for each region for each frame of the plurality of frames by performing an area ratio calculation process for calculating an area ratio;
A plurality of corrected pixel values are generated by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit on the pixel value of the correction target pixel of the correction target frame of the input video, and the correction target pixel By performing a weighted average using the area ratio for each region in the plurality of frames and the weighting coefficient of the plurality of frames, the pixel of the correction target pixel And a video correction unit that calculates a new pixel value.   The video processing apparatus according to claim 13, wherein the plurality of image corrections at different levels in the video correction unit are contrast corrections at different levels. An input unit for inputting an input video including a plurality of frames;
For each of the plurality of frames of the input video input to the input unit, classification processing into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel A region classification unit that calculates an area ratio for each region for each frame of the plurality of frames by performing an area ratio calculation process for calculating an area ratio;
A plurality of corrected pixel values are generated by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit on the pixel value of the correction target pixel of the correction target frame of the input video, and the correction target pixel By performing a weighted average using the area ratio for each region in the plurality of frames and the weighting coefficient of the plurality of frames for the plurality of correction pixel values for the value, A video correction unit for calculating a new pixel value;
An image display device comprising: an image display unit that displays an image including a new pixel value calculated by the image correction unit.   16. The video display device according to claim 15, wherein the video feature amount used by the region classification unit in the region classification process is a luminance or frequency characteristic of a video signal. An input unit for inputting an input video including a plurality of frames;
For each of the plurality of frames of the input video input to the input unit, classification processing into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel A region classification unit that calculates an area ratio for each region for each frame of the plurality of frames by performing an area ratio calculation process for calculating an area ratio;
A motion vector detector for calculating a motion vector between the plurality of frames;
The motion vector detection is performed by generating a plurality of corrected pixel values by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit on the pixel value of the correction target pixel of the correction target frame of the input video. A video correction unit that calculates a new pixel value for a pixel of the correction target pixel by switching processing for the plurality of correction pixel values according to a motion vector detected by the unit,
The video correction unit performs a weighted average using an area ratio of each region in the plurality of frames and a weighting coefficient of the plurality of frames for the plurality of correction pixel values for the correction target pixel. Accordingly, a first pixel value calculation process for calculating a new pixel value for the pixel of the correction target pixel, and one of the plurality of frames for the plurality of correction pixel values for the correction target pixel. The motion vector detection unit performs a second pixel value calculation process for calculating a new pixel value for the pixel of the correction target pixel by performing a weighted average using an area ratio for each region in only one frame. A video processing apparatus characterized by switching according to a detected motion vector.   The video correction unit performs the first pixel value calculation process when the magnitude of the motion vector detected by the motion vector detection is smaller than a predetermined threshold, and the magnitude of the motion vector detected by the motion vector detection The video processing apparatus according to claim 17, wherein the second pixel value calculation process is performed when the threshold value is equal to or greater than a predetermined threshold value. An input unit for inputting an input video including a plurality of frames;
For each of the plurality of frames of the input video input to the input unit, classification processing into a plurality of classification regions according to the feature amount of the video, and the plurality of classification regions within a predetermined range around the correction target pixel A region classification unit that calculates an area ratio for each region for each frame of the plurality of frames by performing an area ratio calculation process for calculating an area ratio;
A motion vector detector for calculating a motion vector between the plurality of frames;
The motion vector detection is performed by generating a plurality of corrected pixel values by performing a plurality of image corrections at different levels for each classification region classified by the region classification unit on the pixel value of the correction target pixel of the correction target frame of the input video. A video correction unit that calculates a new pixel value for the pixel of the correction target pixel by switching processing for the plurality of correction pixel values according to a motion vector detected by the unit;
A video display unit for displaying a video including a new pixel value calculated by the video correction unit,
The video correction unit performs a weighted average using an area ratio of each region in the plurality of frames and a weighting coefficient of the plurality of frames for the plurality of correction pixel values for the correction target pixel. Accordingly, a first pixel value calculation process for calculating a new pixel value for the pixel of the correction target pixel, and one of the plurality of frames for the plurality of correction pixel values for the correction target pixel. The motion vector detection unit performs a second pixel value calculation process for calculating a new pixel value for the pixel of the correction target pixel by performing a weighted average using an area ratio for each region in only one frame. A video display device characterized by switching according to a detected motion vector.     The video correction unit performs the first pixel value calculation process when the magnitude of the motion vector detected by the motion vector detection is smaller than a predetermined threshold, and the magnitude of the motion vector detected by the motion vector detection The video display device according to claim 19, wherein the second pixel value calculation process is performed when the threshold value is equal to or greater than a predetermined threshold value.

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