JP2018151541A - Image processing apparatus, image display device, image processing method, and image display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus and the like that, when an image is displayed, which has a pattern in which pixels with a large pixel value and pixels with a small pixel value are alternately arranged, improves the displayed image.SOLUTION: An image processing apparatus correcting an image signal comprises: a filter part that performs filtering to a luminance signal of the image signal; a luminance signal correction amount calculation part that calculates the amount of correction of the luminance signal of the image signal on the basis of a result of filtering performed by the filter part; and a luminance signal correction part that corrects the luminance signal of the image signal by using the correction amount calculated by the luminance signal correction amount calculation part. The filter part has at least two filters that performs different characteristics of averaging to the same pixel blocks for the luminance signal of the image signal, and the luminance signal correction amount calculation part adjusts the correction amount on the basis of a result of filtering performed with the at least two filters.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image processing device, an image display device, an image processing method, and an image display method.

  In recent years, the number of gradations or the dynamic range of an image tends to increase. For this reason, when an image is displayed, if the dark or bright portion of the displayed image is not sufficiently expressed due to insufficient contrast of the display device, or the details of the dark or bright portion of the displayed image are completely reproduced May not be. In order to express such dark or bright details of an image, an image adaptive tone correction process called black and white expansion may be performed.

  Further, Patent Document 1 proposes an image processing apparatus that improves image details without affecting other luminance regions (see Patent Document 1). In the technique described in Patent Document 1, an averaging process is performed by a plurality of filter circuits provided in a multistage filter circuit, and a gain for correction is obtained.

JP 2010-63064 A

  In the conventional technique, for example, when an image having a specific pattern (a so-called checkered pattern) in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged one dot at a time is displayed. In some cases, it is easy to see the contradiction of correction. As a contradiction, for example, image blur such as a change in gradation or a change in color has occurred.

  The present invention has been made in view of the above points, and an image to be displayed when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is displayed. An object is to provide an image processing apparatus, an image display apparatus, an image processing method, and an image display method that can be improved.

In order to solve at least one of the above problems, an aspect of the present invention is an image processing device that corrects an image signal, and includes a filter unit that performs filtering on a luminance signal of the image signal, and the filter unit. A luminance signal correction amount calculation unit that calculates a correction amount of the luminance signal of the image signal based on a result of the filtering performed, and the correction amount calculated by the luminance signal correction amount calculation unit, the image signal A luminance signal correction unit that corrects the luminance signal of the image signal, and the filter unit includes at least two filters that average different characteristics of the luminance signal of the image signal for the same pixel block And the luminance signal correction amount calculation unit adjusts the correction amount based on a result of filtering by the at least two filters. It is a processing apparatus.
With this configuration, in the image processing apparatus, the luminance signal of the image signal is averaged with respect to the same pixel block by using at least two filters, and based on the result of filtering by the at least two filters. Adjust the correction amount. Thereby, in the image processing apparatus, for example, when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is displayed, the displayed image can be improved.

According to another aspect of the present invention, in the image processing apparatus, the luminance signal correction amount calculation unit has a correspondence between a result of filtering by the at least two filters and information for adjusting the correction amount. A configuration in which the correction amount is adjusted based on the correspondence and the result of filtering by the at least two filters may be used.
With this configuration, the image processing apparatus adjusts the correction amount based on the correspondence between the result of filtering by at least two filters and the information for adjusting the correction amount, and the result of filtering by the at least two filters. To do. Thus, in the image processing apparatus, for example, when an image having a pattern in which pixels with a large pixel value and pixels with a small pixel value are alternately arranged is displayed based on a preset correspondence. Image can be improved.

In one embodiment of the present invention, in the image processing device, one of the two filters includes an odd-numbered row and an odd-numbered column pixel and an even-numbered row and an even-numbered column pixel included in the same pixel block. The other filter has the characteristic of averaging the values of the odd-numbered and even-numbered pixels and the even-numbered and odd-numbered pixels included in the same pixel block. A configuration may be used.
With this configuration, in the image processing apparatus, the values of the odd-numbered and odd-numbered pixels and the even-numbered and even-numbered pixels included in the same pixel block are averaged by one filter, and the same filter is used by the other filter. The values of the odd-numbered and even-numbered pixels and the even-numbered and odd-numbered pixels included in the pixel block are averaged. Thereby, in the image processing apparatus, for example, when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged for each pixel in each row and column is displayed. The displayed image can be improved.

In one embodiment of the present invention, in the image processing apparatus, the filter unit includes a plurality of filters corresponding to a plurality of pixel blocks having different sizes, and the luminance signal correction amount calculation unit includes the plurality of filters. A configuration may be used in which the correction amount is adjusted based on a result of filtering by a filter corresponding to a pixel block having a size other than the smallest among the filters.
With this configuration, the image processing apparatus adjusts the correction amount based on the result of filtering by a filter corresponding to a pixel block having a size other than the minimum among a plurality of filters corresponding to a plurality of pixel blocks having different sizes. To do. Thereby, in the image processing apparatus, based on the result of filtering by a filter corresponding to a pixel block having a size other than the minimum, for example, a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is arranged. The displayed image can be improved when the image it has is displayed.

In one embodiment of the present invention, in the image processing apparatus, the luminance signal correction amount calculation unit calculates the correction amount based on a result of filtering by a filter corresponding to the largest pixel block among the plurality of filters. A configuration that adjusts may be used.
With this configuration, the image processing apparatus adjusts the correction amount based on the result of filtering by the filter corresponding to the largest pixel block among the plurality of filters. Thereby, the image processing apparatus displays an image having a pattern in which, for example, pixels having a large pixel value and pixels having a small pixel value are alternately arranged based on the result of filtering by the filter corresponding to the largest pixel block. When displayed, the displayed image can be improved.

In one embodiment of the present invention, in the image processing apparatus, the luminance signal correction amount calculation unit is not so when the absolute value of the difference between the results of filtering by the two filters exceeds a predetermined threshold. A configuration may be used in which the degree of influence of the correction amount is adjusted to be smaller than the case.
With this configuration, in the image processing apparatus, when the absolute value of the difference between the results of filtering by the two filters exceeds a predetermined threshold, the degree of influence of the correction amount is reduced compared to the case where it is not. adjust. Thereby, in the image processing apparatus, for example, when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is displayed, the displayed image can be improved.

In order to solve at least one of the above problems, one embodiment of the present invention is an image display device that displays an image based on an image signal, the image processing device correcting the image signal, and the image processing device. And an image display unit that displays an image based on the corrected image signal.
With this configuration, the image display apparatus displays an image based on the image signal corrected by the image processing apparatus. Thereby, in the image display device, for example, when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is displayed, the displayed image can be improved.

In order to solve at least one of the above problems, an aspect of the present invention is an image processing method for correcting an image signal, wherein the filter unit performs filtering on the luminance signal of the image signal to correct the luminance signal. The amount calculation unit calculates a correction amount of the luminance signal of the image signal based on the result of filtering performed by the filter unit, and the luminance signal correction unit calculates the correction calculated by the luminance signal correction amount calculation unit. The luminance signal of the image signal is corrected using the amount, and the filter unit includes at least two filters that perform averaging of different characteristics for the same pixel block with respect to the luminance signal of the image signal. And the luminance signal correction amount calculation unit adjusts the correction amount based on a result of filtering by the at least two filters. It is the law.
With this configuration, in the image processing method, the luminance signal of the image signal is averaged with different characteristics for the same pixel block by using at least two filters, and based on the result of filtering by the at least two filters. Adjust the correction amount. Thereby, in the image processing method, for example, when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is displayed, the displayed image can be improved.

In order to solve at least one of the above problems, one embodiment of the present invention is an image display method for displaying an image based on an image signal, wherein the image display unit is based on the image signal corrected by the image processing method. This is an image display method for displaying images.
With this configuration, in the image display method, an image is displayed based on the image signal corrected by the image processing method. Thereby, in the image display method, for example, when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is displayed, the displayed image can be improved.

  As described above, according to the image processing device, the image display device, the image processing method, and the image display method according to the present invention, the luminance signal of the image signal differs with respect to the same pixel block by at least two filters. The characteristics are averaged, and the correction amount is adjusted based on the result of filtering by the at least two filters. Thus, according to the image processing device, the image display device, the image processing method, and the image display method according to the present invention, for example, an image having a pattern in which pixels having large pixel values and pixels having small pixel values are alternately arranged. When is displayed, the displayed image can be improved.

It is a figure which shows the schematic structural example of the image display system which concerns on embodiment (1st Embodiment) of this invention. It is a figure which shows the schematic structural example of the image process part which concerns on embodiment (1st Embodiment) of this invention. It is a figure which shows the schematic structural example of the luminance signal correction amount calculation circuit which concerns on embodiment (1st Embodiment) of this invention. It is a figure which shows an example of the pixel block which has a some pixel which concerns on embodiment (1st Embodiment) of this invention. It is a figure which shows an example of the pixel block in the image which has the pattern where the pixel with a big pixel value and pixel with a small pixel value which concern on embodiment (1st Embodiment) of this invention are located in a line. It is a figure which shows an example of the relative magnitude | size of the luminance gain which concerns on embodiment (1st Embodiment) of this invention. It is a figure which shows the schematic structural example of the luminance signal correction amount calculation circuit which concerns on embodiment (2nd Embodiment) of this invention.

Embodiments of the present invention will be described in detail with reference to the drawings.
In this embodiment, a configuration obtained by improving the image processing unit described in FIG. 4 of Patent Document 1 will be described as an example. For this reason, in this embodiment, the same technology as that of Patent Literature 1 may be applied to the same components as those of Patent Literature 1.

(First embodiment)
[Overview of image display system configuration and operation]
FIG. 1 is a diagram showing a schematic configuration example of an image display system 1 according to an embodiment (first embodiment) of the present invention.
The image display system 1 includes a projector 11 (an example of an image display device) and a screen 12 (an example of a projection surface).
The projector 11 includes an image processing unit 31 (an example of an image processing device) and a projection unit 32.

The projector 11 receives an image signal from an external device. The external device may be an arbitrary device, for example, a computer or a portable storage medium. As another configuration example different from that in FIG. 1, an image signal may be generated inside the projector 11.
The image processing unit 31 performs a predetermined process on the image signal input to the projector 11 and outputs the image signal subjected to the process to the projection unit 32. The predetermined processing may include arbitrary processing, for example, processing for adjusting the characteristics of the image, or processing for superimposing another image on the image of the input image signal. Also good.
The projection unit 32 generates light corresponding to the image of the image signal input from the image processing unit 31 and projects the light on the screen 12 outside the projector 11.
Note that the screen 12 may be an arbitrary one. For example, not only a screen prepared exclusively for projecting the projection light from the projector 11 but also a wall of a room may be used as the screen 12. .

Here, the projection unit 32 projects an image to be displayed on the screen 12. As a result, the projected image is displayed on the screen 12. The display target image may be an arbitrary image, and may include, for example, a menu image that allows the user to specify an item from among a plurality of items.
Specifically, the projection unit 32 includes a liquid crystal panel, a light source, and a projection lens. The projection unit 32 converts the signal of the display target image into image information representing the gradation of each pixel of the liquid crystal panel for each of RGB (Red, Green, Blue), and a drive voltage corresponding to the image information. Is applied (driven) to each pixel of the liquid crystal panel. By this application, the liquid crystal panel forms light incident on the liquid crystal panel from the light source as light (modulated light) that displays an image corresponding to the image information described above. The projection unit 32 may include a reflector that reflects light emitted from the light source toward the liquid crystal panel, and the reflected light may be formed on the liquid crystal panel as light that displays an image corresponding to the image information described above. The projection unit 32 projects the light that projects the image formed on the liquid crystal panel through the projection lens.
The light source is, for example, a discharge-type light source lamp made of an ultra-high pressure mercury lamp or a metal halide lamp, but is not limited to a light source lamp, and an LED (Light Emitting Diode) light source or a laser light source may be used. The liquid crystal panel is, for example, a transmissive liquid crystal panel corresponding to each of RGB, which is the three primary colors of light, in which liquid crystal is sealed between a pair of transparent substrates. The liquid crystal panel is not limited to a transmissive liquid crystal panel, and a reflective liquid crystal panel may be used. Moreover, as a light valve of the projection part 32, it replaces with the structure provided with a liquid crystal panel, and the structure provided with DMD (Digital Mirror Device) etc. may be used.

FIG. 2 is a diagram illustrating a schematic configuration example of the image processing unit 31 according to the embodiment (first embodiment) of the present invention.
The image processing unit 31 includes a line memory 111, a line memory 112, a multistage filter circuit 131, a luminance signal correction amount calculation circuit 132, a luminance signal correction circuit 133, a color difference gain calculation circuit 134, and a color difference signal correction circuit 135. Is provided.
The multistage filter circuit 131 includes four filter circuits 151-1 to 151-4.

  Here, in the present embodiment, the luminance signal correction and the color difference signal correction performed in the image processing unit 31 will be described as an example. For this reason, in the present embodiment, the configuration in which the circuit that performs these corrections is provided in the image processing unit 31 is shown. However, for example, the image processing unit 31 may further include a circuit that performs other processing. In the present embodiment, since correction of the color difference signal is not essential, the image processing unit 31 may not include a circuit for correcting the color difference signal (for example, the color difference gain calculation circuit 134 and the color difference signal correction circuit 135).

An image signal input to the image processing unit 31 from the outside of the projector 11 includes a Y signal, a U signal, and a V signal. Here, the Y signal is a luminance signal, the U signal is a signal obtained by subtracting the luminance signal from the blue signal, and a predetermined coefficient, and the V signal is a predetermined coefficient obtained by subtracting the luminance signal from the red signal. The multiplied signal.
Note that the image signal is not necessarily a YUV signal, and may be any other signal.

A Y signal is input to the line memory 111.
The line memory 111 has a memory function, stores (stores) the input Y signal, and outputs the Y signal corresponding to each of the four filter circuits 151-1 to 151-4. Output to the filter circuits 151-1 to 151-4.
Further, the line memory 111 outputs the input Y signal to each of the luminance signal correction amount calculation circuit 132, the luminance signal correction circuit 133, and the color difference gain calculation circuit 134.
Note that each of the filter circuits 151-1 to 151-4, the luminance signal correction amount calculating circuit 132, the luminance signal correcting circuit 133, and the color difference gain calculating circuit 134 of the multistage filter circuit 131 is stored in the line memory 111. A configuration for extracting necessary information (Y signal) from the signal may be used.

In the present embodiment, each of the two filter circuits 151-1 to 151-2 is a circuit that performs filtering on a pixel block of a matrix of (vertical 7 pixels × horizontal 7 pixels). A Y signal corresponding to the pixel block is output from the line memory 111 to the filter circuits 151-1 to 151-2. In the present embodiment, the two filter circuits 151-1 to 151-2 are set to have different filtering characteristics, and can have different outputs for the same input.
The filter circuit 151-3 is a circuit that performs filtering on a pixel block of a matrix of (vertical 5 pixels × horizontal 5 pixels). A Y signal corresponding to the pixel block is output from the line memory 111 to the filter circuit 151-3.
The filter circuit 151-4 is a circuit that performs filtering on a pixel block of a matrix of (vertical 3 pixels × horizontal 3 pixels). A Y signal corresponding to the pixel block is output from the line memory 111 to the filter circuit 151-4.

A U signal and a V signal are input to the line memory 112.
The line memory 112 has a memory function, stores (stores) the input U signal and V signal, and outputs the U signal and the V signal to the color difference signal correction circuit 135.
A configuration in which the color difference signal correction circuit 135 extracts necessary information (U signal and V signal) from the U signal and V signal stored in the line memory 112 may be used.

Each of the filter circuits 151-1 to 151-4 performs filtering of each pixel block on the Y signal input from the line memory 111, and outputs a signal of the filtering result to the luminance signal correction amount calculation circuit 132. .
The luminance signal correction amount calculation circuit 132 is based on the Y signal input from the line memory 111 and the filtering result signals input from the respective filter circuits 151-1 to 151-4. Signal correction amount), and a signal (luminance signal correction amount signal) representing the calculated luminance signal correction amount is output to the luminance signal correction circuit 133.
The luminance signal correction circuit 133 corrects the Y signal input from the line memory 111 using the luminance signal correction amount input from the luminance signal correction amount calculation circuit 132, and corrects the corrected Y signal (in this embodiment, in this embodiment). Y1 signal) is output to each of the color difference gain calculation circuit 134 and the projection unit 32. In the present embodiment, the luminance signal correction circuit 133 outputs a signal obtained as a result of adding the luminance signal correction amount input from the luminance signal correction amount calculation circuit 132 to the Y signal input from the line memory 111, and the corrected Y signal. (Y1 signal).

The color difference gain calculation circuit 134 calculates a color difference gain based on the Y signal input from the line memory 111 and the Y1 signal input from the luminance signal correction circuit 133, and a signal representing the calculated color difference gain is used as the color difference signal. The result is output to the correction circuit 135.
The color difference signal correction circuit 135 corrects the color difference of the U signal and V signal input from the line memory 112 using the color difference gain signal input from the color difference gain calculation circuit 134, and the corrected U signal ( In this embodiment, it is also referred to as a U1 signal) and a corrected V signal (also referred to as a V1 signal in this embodiment) is output to the projection unit 32.
The projection unit 32 inputs Y1 signal, U1 signal, and V1 signal as image signals, and projects an image according to these input signals.

FIG. 3 is a diagram showing a schematic configuration example of the luminance signal correction amount calculation circuit 132 according to the embodiment (first embodiment) of the present invention.
The luminance signal correction amount calculation circuit 132 includes a filter circuit 211, a weight calculation circuit 212, three multipliers 213-1 to 213-3, one adder 214, a determination circuit 231, and a luminance gain calculation. A circuit 232 and a multiplier 233 are provided.

Filtering result signals output from the two filter circuits 151-1 to 151-2 are input to the filter circuit 211 and the determination circuit 231, respectively.
The filtering result signal output from the filter circuit 151-3 is input to each of the multiplier 213-2 and the weight calculation circuit 212.
The filtering result signal output from the filter circuit 151-4 is input to each of the multiplier 213-3 and the weight calculation circuit 212.
The Y signal output from the line memory 111 is input to the luminance gain calculation circuit 232.

The filter circuit 211 performs filtering on the filtering result signal input from each of the two filter circuits 151-1 to 151-2, and the filtering result signal is applied to the multiplier 213-1 and the weight calculation circuit 212. Output to each of.
Here, for example, instead of the two filter circuits 151-1 to 151-2, the filter circuit 211 performs filtering on the entire pixel block of a matrix of (vertical 7 pixels × horizontal 7 pixels). The filter circuit is set to have a characteristic for generating a signal of a filtering result similar to the case where the filter circuit is provided.

  The weight calculation circuit 212 corrects the signal output from the filter circuit 211 based on the filtering result signals input from the one filter circuit 211 and the two filter circuits 151-3 to 151-4. A weighting coefficient, a weighting coefficient for correcting the signal output from the filter circuit 151-3, and a weighting coefficient for correcting the signal output from the filter circuit 151-4 are calculated. The weighting calculation circuit 212 outputs a signal (weighting coefficient signal) representing the weighting coefficient calculated for the signal output from the filter circuit 211 to the multiplier 213-1 and calculates the signal output from the filter circuit 151-3. The weighted coefficient signal (weighting coefficient signal) is output to the multiplier 213-2, and the signal indicating the weighting coefficient calculated for the signal output from the filter circuit 151-4 (weighting coefficient signal) is output to the multiplier 213. To -3. Here, in the weighting calculation circuit 212, for example, the correspondence between the three input filtering result signals and the three weighting coefficient signals to be output at that time is set in advance in an LUT (lookup table) or the like. The correspondence is referred to.

The multiplier 213-1 multiplies the filtering result signal input from the filter circuit 211 by the weighting coefficient signal input from the weighting calculation circuit 212, and outputs the multiplication result signal to the adder 214.
The multiplier 213-2 multiplies the filtering result signal input from the filter circuit 151-3 by the weighting coefficient signal input from the weighting calculation circuit 212, and outputs the multiplication result signal to the adder 214. To do.
The multiplier 213-3 multiplies the filtering result signal input from the filter circuit 151-4 and the weighting coefficient signal input from the weighting calculation circuit 212, and outputs the multiplication result signal to the adder 214. To do.
The adder 214 adds the signals input from the three multipliers 213-1 to 213-3, and outputs a signal resulting from the addition to the multiplier 233.

The determination circuit 231 determines whether the image of the image signal being processed has a predetermined pattern based on the filtering result signal input from each of the two filter circuits 151-1 to 151-2. Then, a signal indicating the result of this determination (determination result signal) is output to the luminance gain calculation circuit 232.
The luminance gain calculation circuit 232 receives the Y signal from the line memory 111 and the determination result signal from the determination circuit 231. The luminance gain calculation circuit 232 calculates a luminance gain based on the Y signal input from the line memory 111 and the determination result signal input from the determination circuit 231, and a signal (luminance gain signal) representing the calculated luminance gain. Is output to the multiplier 233.
The multiplier 233 multiplies the addition result signal input from the adder 214 by the luminance gain signal input from the luminance gain calculation circuit 232, and the multiplication result signal is used as a luminance signal correction amount signal (VA signal). ) To the luminance signal correction circuit 133.

[Details of multi-stage filter circuit and luminance signal correction amount calculation circuit]
<Description of multi-stage filter circuit>
FIG. 4 is a diagram showing an example of a pixel block having a plurality of pixels 1011 and 1012 according to the embodiment (first embodiment) of the present invention.
In the example of FIG. 4, a pixel block of (vertical 7 pixels × horizontal 7 pixels) is shown. In the present embodiment, the vertical direction is represented by rows, and the horizontal direction is represented by columns.
In the example of FIG. 4, in order to make the drawing easier to see, only some of the pixels 1011 and 1012 are denoted by reference numerals, not all pixels. Among the 7 rows × 7 columns of pixels, a pixel 1011 is a pixel corresponding to an odd row and odd column pixel and an even row and even column pixel (also referred to as “first pixel” in this embodiment). A pixel corresponding to an odd-numbered row and even-numbered column pixel and an even-numbered row and odd-numbered column pixel (also referred to as a “second pixel” in this embodiment) is represented by a pixel 1012. In addition, among the pixels in 7 rows × 7 columns, the pixel in 4 rows and 4 columns is a central pixel and is represented by a pixel 1021 (one pixel 1011).

In the present embodiment, the line memory 111 stores at least a Y signal of (vertical 7 pixels × horizontal 7 pixels).
Each of the two filter circuits 151-1 to 151-2 has one pixel 1021 as a processing target, and the pixel value (Y signal) having the pixel 1021 as the center (vertical 7 pixels × horizontal 7 pixels). , Perform predetermined filtering. The predetermined filtering is, for example, a convolution operation between a pixel value of (vertical 7 pixels × horizontal 7 pixels, that is, 1st to 7th rows and 1st to 7th columns) and a predetermined filter coefficient matrix. Equivalent to.
The filter circuit 151-3 performs predetermined filtering on a pixel value (Y signal) having a pixel 1021 as a processing target and having the pixel 1021 as the center (vertical 5 pixels × horizontal 5 pixels). The predetermined filtering is, for example, a convolution operation between a pixel value of a pixel (5 pixels in the vertical direction × 5 pixels in the horizontal direction, that is, in the 2nd to 6th rows and the 2nd to 6th columns) and a predetermined filter coefficient matrix. Equivalent to.
The filter circuit 151-4 performs predetermined filtering on a pixel value (Y signal) having one pixel 1021 as a processing target and centering on the pixel 1021 (vertical 3 pixels × horizontal 3 pixels). The predetermined filtering is, for example, a convolution operation between the pixel value of the pixel (3 pixels in the vertical direction × 3 pixels in the horizontal direction, that is, in the third to fifth rows and the third to fifth columns) and a predetermined filter coefficient matrix. Equivalent to.
In the present embodiment, the processing target pixel 1021 (Y signal, U signal, V signal) is processed in synchronization with these filtering result signals.

  Here, in the present embodiment, of the two filter circuits 151-1 to 151-2, one filter circuit 151-1 performs a process of averaging the pixel values of the first pixel (pixel 1011) as filtering. The other filter circuit 151-2 performs a process of averaging the pixel values of the second pixel (pixel 1012) as filtering.

FIG. 5 is a diagram illustrating an example of a pixel block in an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged according to an embodiment (first embodiment) of the present invention.
FIG. 5 shows a pixel block of (vertical 7 pixels × horizontal 7 pixels) as in the example of FIG.
In the example of FIG. 5, the pixel 1111 corresponding to the first pixel is a pixel having a large pixel value, and the pixel 1112 corresponding to the second pixel is a pixel having a small pixel value. In the example of FIG. 5, the central pixel 1121 (pixel 1111) among (vertical 7 pixels × horizontal 7 pixels) is a pixel having a large pixel value. That is, the image signal to be processed is an image signal having a pattern in which pixels with a large pixel value and pixels with a small pixel value are alternately arranged one by one (a so-called checkered pattern). In the example of FIG. 5, every time the time for one pixel advances, the pixel having a large pixel value and the pixel having a small pixel value are switched. For example, when the time for one pixel advances, the first pixel The pixel 1111 corresponding to is a pixel having a small pixel value, and the pixel 1112 corresponding to the second pixel is a pixel having a large pixel value.
In the example of FIG. 5, for convenience of description, pixels with a large pixel value are represented by white pixels and pixels with a small pixel value are represented by black pixels. The image is not limited to a scale image, and may be a color image.

When the image signal according to the example of FIG. 5 is processed, the filtering result signal by each of the two filter circuits 151-1 to 151-2 averages a plurality of large pixel values of one filtering result signal. And the other filtering result signal is a signal obtained by averaging a plurality of small pixel values. Note that the large pixel value and the small pixel value are switched every time the time for one pixel progresses.
Here, in this embodiment, it is assumed that the luminance signal (Y signal) has a value of 0 to 255. In this embodiment, the pixel value is large when the luminance signal has a value of 255 (or a value close to 255), and small when the luminance signal has a value of 0 (or a value close to 0). It is assumed that it is a pixel value. In the example of FIG. 5, the case where the luminance signal is a value of 255 or 0 is shown for easy understanding, but the luminance signal can actually take a value of 1 to 254.

<Luminance signal correction amount calculation circuit>
The determination circuit 231 detects the absolute value of the difference between the signals of the filtering results of the two filter circuits 151-1 to 151-2, and determines whether the detected absolute value of the difference exceeds a predetermined threshold value. judge.
If the determination circuit 231 determines that the detected absolute value of the difference exceeds a predetermined threshold (in this example, a positive value), the image of the image signal being processed has a predetermined pattern. Then, a determination is made and a signal (determination result signal) representing the result of this determination is output to the luminance gain calculation circuit 232.
On the other hand, if the determination circuit 231 determines that the detected absolute value of the difference is equal to or less than a predetermined threshold, the determination circuit 231 determines that the image of the image signal being processed does not have a predetermined pattern, and A signal representing the result (determination result signal) is output to the luminance gain calculation circuit 232.
Thus, in this embodiment, the determination circuit 231 determines whether the image of the image signal being processed is an image having a pattern in which pixels with large pixel values and pixels with small pixel values are alternately arranged. judge. That is, in the present embodiment, the predetermined pattern is a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged.
Normally, when the difference between two values (here, the absolute value) is large, the correlation between the two values is small, and when the difference between the two values (here, the absolute value) is small. The correlation between the two values is large.

Here, in this embodiment, the determination circuit 231 determines whether or not the absolute value of the detected difference exceeds a predetermined threshold value. However, if a similar determination result is obtained, the determination method is arbitrary. May be. For example, the determination circuit 231 is divided into a case where the detected difference is positive and a case where the difference is negative (when the difference is 0, the difference may be included in either one or another). You may determine using a threshold value.
In this embodiment, the determination circuit 231 determines whether or not the detected absolute value of the difference exceeds a predetermined threshold. As another configuration example, the detected absolute value of the difference is a predetermined threshold. You may determine whether it is above. That is, when the absolute value of the detected difference matches a predetermined threshold value, it may be included when it exceeds the threshold value, or may be included when it is less than the threshold value.
Also, any value may be used as the threshold value.

  In this embodiment, the determination circuit 231 outputs determination result signals to the luminance gain calculation circuit 232 for both of the two types of determination results. As another configuration example, the luminance gain calculation circuit 232 outputs the determination results. If it can be grasped, the determination circuit 231 may output a determination result signal to the luminance gain calculation circuit 232 for one of the two types of determination results. For example, the luminance gain calculation circuit 232 determines that the determination result signal is one when the determination result signal is not received from the determination circuit 231, and determines that the determination result signal is the other determination result when the determination result signal is received from the determination circuit 231. May be.

  If the luminance gain calculation circuit 232 determines that the image of the image signal being processed is not an image having a predetermined pattern based on the determination result signal input from the determination circuit 231, the luminance gain calculation circuit 232 inputs from the line memory 111. Based on the luminance signal (Y signal), the luminance gain signal having a value (luminance gain) corresponding to the luminance signal is output to the multiplier 233. Here, in the luminance gain calculation circuit 232, for example, the correspondence between the input luminance signal and the luminance gain signal to be output at that time is set in advance in the LUT or the like, and the correspondence is referred to.

  On the other hand, if the luminance gain calculation circuit 232 determines that the image of the image signal being processed is an image having a predetermined pattern based on the determination result signal input from the determination circuit 231, this is not the case. Is output to the multiplier 233 having a smaller value (in this case, absolute value) of luminance gain. Thus, when the luminance signal (Y signal) output from the line memory 111 is the same, the image of the image signal being processed is an image having a predetermined pattern as compared to the case where it is not. The absolute value of the luminance signal correction amount signal output from the multiplier 233 is reduced, and the influence level of the luminance signal correction amount signal is reduced.

  As an example, when the luminance gain calculation circuit 232 determines that the image of the image signal being processed is an image having a predetermined pattern based on the determination result signal input from the determination circuit 231, the luminance gain calculation circuit 232 is 0. A luminance gain signal having a luminance gain may be output to the multiplier 233. That is, when the image of the image signal being processed is an image having a predetermined pattern, the value of the luminance signal correction amount signal (VA signal) may be set to zero.

FIG. 6 is a diagram showing an example of the relative magnitude of the luminance gain according to the embodiment (first embodiment) of the present invention.
In the graph shown in FIG. 6, the horizontal axis represents the result of averaging pixel values of the first pixel (pixel 1011 in the example of FIG. 4), and the vertical axis represents the second pixel (pixel in the example of FIG. 4). 1012) shows an averaged result of pixel values.
FIG. 6 shows two characteristics 2011 and 2012. A characteristic 2011 is represented by a straight line having a positive slope in contact with the vertical axis at a position where the value of the vertical axis is greater than zero. A characteristic 2012 is represented by a straight line that is in contact with the horizontal axis at a position where the value of the horizontal axis is greater than 0 and has a positive slope. The slopes of the two characteristics 2011 and 2012 may be arbitrary values, for example, 1. In addition, the slopes of the two characteristics 2011 and 2012 may be the same or different. Further, the position (value on each axis) where each of the two characteristics 2011 and 2012 is in contact with the axis (vertical axis or horizontal axis) may be arbitrary, may be the same, or May be different.

  In the example of FIG. 6, the luminance gain is set to a large value (here, absolute value) in the region between the two characteristics 2011 and 2012, and the luminance gain is small (here, in this case). Absolute value). That is, when the value on the horizontal axis is the same as or close to the value on the vertical axis, the difference (absolute value) between them is small, and it is determined that the image of the image signal being processed is not an image having a predetermined pattern. , A luminance gain having a large value (here, an absolute value) is set. On the other hand, when the value on the horizontal axis is not close to the value on the vertical axis, the difference (absolute value) between them is large, and it is determined that the image of the image signal being processed is an image having a predetermined pattern, A luminance gain having a small value (here, an absolute value) is set.

  Here, the information of the graph shown in FIG. 6 may be set in the determination circuit 231 as information such as an LUT. In this case, the determination circuit 231 sets, as the determination result signal for the luminance gain calculation circuit 232, the method of setting the luminance gain (the value of the luminance gain) determined based on the information of the graph and the two input filtering result signals. May be output). Then, the luminance gain calculation circuit 232 sets the luminance gain based on the input determination result signal (how to set the luminance gain).

In the example of FIG. 6, different brightness gains are set for each of two types of regions such as a region sandwiched between the two characteristics 2011 and 2012 and another region. However, as another configuration example, each of three or more types of regions is set. Different brightness gains may be set.
As another configuration example, a continuously changing value may be set as the luminance gain based on the difference between the two filtering result signals.

[Summary of First Embodiment]
As described above, in the image processing unit 31 (image processing apparatus) in the projector 11 according to the present embodiment, a pattern in which pixels with large pixel values and pixels with small pixel values are alternately arranged (so-called checkered pattern) is predetermined. In the case where the image to be processed has the predetermined pattern, the correction gain in the detail enhancer (in the example of FIG. 6, the luminance gain) is suppressed (decreased), thereby reducing the display contradiction ( (Image blur) is suppressed. Thereby, in the image processing unit 31 (image processing apparatus), when an image having a pattern in which pixels having a large pixel value and pixels having a small pixel value are alternately arranged is displayed, the displayed image is improved. be able to.

  In this embodiment, in the example of FIG. 3, the signal of the filtering result by the filter circuit 211 is input to the weighting calculation circuit 212. As another configuration example, instead of the signal of the filtering result by the filter circuit 211, A configuration may be used in which one or both of the signals of the filtering results obtained by the two filter circuits 151-1 and 151-2 are input to the weighting calculation circuit 212 and used. Alternatively, as another configuration example, one or both of the filtering result signals of the two filter circuits 151-1 and 151-2 are input to the weighting calculation circuit 212 together with the filtering result signal of the filter circuit 211. A configuration that is used may be used.

  In the present embodiment, the luminance signal correction amount calculation circuit 132 includes the determination circuit 231 and the luminance gain calculation circuit 232 as separate bodies, but these may be integrally provided as another configuration example.

Further, in the present embodiment, filtering is performed using pixel blocks of three types such as (vertical 7 pixels × horizontal 7 pixels), (vertical 5 pixels × horizontal 5 pixels), and (vertical 3 pixels × horizontal 3 pixels). However, as another configuration example, filtering may be performed using one or more types of pixel blocks having an arbitrary size.
Further, in the present embodiment, whether the image of the image signal is an image having a predetermined pattern using the largest pixel block among a plurality of types of pixel blocks (three types in the present embodiment). However, as another configuration example, it may be determined whether the image of the image signal is an image having a predetermined pattern using the second and subsequent largest pixel blocks.

In the present embodiment, the pixel block having a size of (vertical 7 pixels × horizontal 7 pixels) includes two filter circuits 151-1 to 151-2, and the image of the image signal has a predetermined pattern. It is determined whether or not the image is an image. As another configuration example, the size of the pixel block used for this determination may be other sizes. As an example, the size of the pixel block used for this determination may be (vertical 5 pixels × horizontal 5 pixels). The size of the pixel block used for this determination is preferably larger to some extent. For example, the size of a pixel block having 1% (%) or more of vertical and horizontal pixels with respect to the number of pixels of the entire image. For example, when the number of pixels of the entire image is (vertical 1000 pixels × horizontal 1000 pixels), the number of pixels of the pixel block is (vertical 10 pixels × horizontal 10 pixels) or more. It may be.
In the present embodiment, it is determined whether the image of the image signal is an image having a predetermined pattern using the filtering results of the two filter circuits 151-1 to 151-2. As an example, it may be determined whether or not the image of the image signal is an image having a predetermined pattern by using the filtering results of three or more filter circuits. As an example, a configuration for selecting a filtering result to be used for determination from filtering results by three or more filter circuits, or a configuration using an average of two or more filtering results by three or more filter circuits Etc. may be used.

For the image of the image signal to be processed (entire image), for example, an image having the same number of vertical pixels and the same number of horizontal pixels may be used, or the number of vertical pixels and the horizontal number of pixels may be used. An image having a different number of pixels may be used.
Further, as the pixel block to be filtered, for example, a pixel block having the same number of vertical pixels and the same number of horizontal pixels may be used, or the number of vertical pixels and the number of horizontal pixels are different. Pixel blocks may be used.

(Second Embodiment)
In the present embodiment, a projector having a configuration different from that of the projector 11 according to the first embodiment is shown.
Compared with the projector 11 according to the first embodiment, the projector according to the present embodiment includes a luminance signal correction amount calculation circuit 311 illustrated in FIG. 7 instead of the luminance signal correction amount calculation circuit 132 illustrated in FIG. 3. .
In this embodiment, regarding the projector, for convenience of explanation, components other than the components of the luminance signal correction amount calculation circuit 311 shown in FIG. 7 are denoted by the same reference numerals as those in the first embodiment.

FIG. 7 is a diagram showing a schematic configuration example of the luminance signal correction amount calculation circuit 311 according to the embodiment (second embodiment) of the present invention.
In the luminance signal correction amount calculation circuit 311 according to the present embodiment, the determination result signal output from the determination circuit 351 is weighted (not the luminance gain calculation circuit) as compared with the luminance signal correction amount calculation circuit 132 illustrated in FIG. This is the same except that it is used by the calculation circuit 332. In the present embodiment, the luminance signal correction amount calculation circuit 311 will be described mainly regarding differences from the luminance signal correction amount calculation circuit 132 according to the first embodiment, and the luminance signal correction amount calculation circuit 132 according to the first embodiment will be described. A description of the same points as in FIG.

The luminance signal correction amount calculation circuit 311 includes a filter circuit 331, a weight calculation circuit 332, three multipliers 333-1 to 333-3, one adder 334, a determination circuit 351, and luminance gain calculation. A circuit 371 and a multiplier 372 are provided.
Signals of filtering results output from the two filter circuits 151-1 to 151-2 are input to the filter circuit 331 and the determination circuit 351, respectively.
The filtering result signal output from the filter circuit 151-3 is input to the multiplier 333-2 and the weighting calculation circuit 332, respectively.
The filtering result signal output from the filter circuit 151-4 is input to the multiplier 333-3 and the weight calculation circuit 332.
Further, the Y signal output from the line memory 111 is input to the luminance gain calculation circuit 371.

The filter circuit 331 performs filtering on the filtering result signal input from each of the two filter circuits 151-1 to 151-2, and the filtering result signal is applied to the multiplier 333-1 and the weight calculation circuit 332. Output to each of.
Here, for example, instead of the two filter circuits 151-1 to 151-2, the filter circuit 331 performs one filtering on the entire pixel block of a matrix of (vertical 7 pixels × horizontal 7 pixels). The filter circuit is set to have a characteristic for generating a signal of a filtering result similar to the case where the filter circuit is provided.

  The determination circuit 351 determines whether the image of the image signal being processed has a predetermined pattern based on the filtering result signals input from the two filter circuits 151-1 to 151-2. Then, a signal indicating the result of this determination (determination result signal) is output to the weight calculation circuit 332.

  The weight calculation circuit 332 performs filtering based on the filtering result signal output from one filter circuit 331 and the two filter circuits 151-3 to 151-4 and the determination result signal input from the determination circuit 351. Weighting coefficient for correcting the signal output from the circuit 331, weighting coefficient for correcting the signal output from the filter circuit 151-3, and weighting for correcting the signal output from the filter circuit 151-4 Calculate the coefficient. The weighting calculation circuit 332 outputs a signal (weighting coefficient signal) representing the weighting coefficient calculated for the signal output from the filter circuit 331 to the multiplier 333-1 and calculates the signal output from the filter circuit 151-3. The weighted coefficient signal (weighting coefficient signal) is output to the multiplier 333-2, and the signal indicating the weighting coefficient calculated for the signal output from the filter circuit 151-4 (weighting coefficient signal) is output to the multiplier 333. To -3.

Here, when the weight calculation circuit 332 determines that the image of the image signal being processed is not an image having a predetermined pattern based on the determination result signal input from the determination circuit 351, the weight calculation circuit 332 is input. Based on the three filtering result signals, three weighting coefficient signals corresponding to these signals are output to the multipliers 333-1 to 333-3. Here, in the weighting calculation circuit 332, for example, correspondence between three input filtering result signals and three weighting coefficient signals to be output at that time is set in advance in an LUT or the like. Is referenced.
On the other hand, if the weight calculation circuit 332 determines that the image of the image signal being processed is an image having a predetermined pattern based on the determination result signal input from the determination circuit 351, this is not the case. Compared with the case where the determination is made, the weighting coefficient signal that decreases the value (here, the absolute value) of the signal output from the adder 334 is output to each of the multipliers 333-1 to 333-3. As a result, when the three filtering result signals input to the weight calculation circuit 332 are the same, when the image of the image signal being processed is an image having a predetermined pattern, it is not the case. In comparison, the value of the signal output from the adder 334 (here, the absolute value) is small. As a result, the absolute value of the luminance signal correction amount signal output from the multiplier 372 is reduced, and the degree of influence of the luminance signal correction amount signal is reduced.

  For the three weighting coefficient signals output from the weighting calculation circuit 332, as the weighting coefficient signals that reduce the value (here, absolute value) of the signal output from the adder 334, for example, Three weighting factor signals having smaller values (here, absolute values) may be used, or other aspects may be used.

The multiplier 333-1 multiplies the filtering result signal input from the filter circuit 331 by the weighting coefficient signal input from the weighting calculation circuit 332, and outputs the multiplication result signal to the adder 334.
Multiplier 333-2 multiplies the filtering result signal input from filter circuit 151-3 by the weighting coefficient signal input from weighting calculation circuit 332, and outputs the multiplication result signal to adder 334. To do.
The multiplier 333-3 multiplies the filtering result signal input from the filter circuit 151-4 by the weighting coefficient signal input from the weight calculation circuit 332, and outputs the multiplication result signal to the adder 334. To do.
The adder 334 adds the signals input from the three multipliers 333-1 to 333-3, and outputs a signal resulting from the addition to the multiplier 372.

The luminance gain calculation circuit 371 receives the Y signal from the line memory 111. The luminance gain calculation circuit 371 calculates a luminance gain based on the Y signal input from the line memory 111 and outputs a signal (luminance gain signal) representing the calculated luminance gain to the multiplier 372. Here, in the luminance gain calculation circuit 371, for example, the correspondence between the input luminance signal and the luminance gain signal to be output at that time is set in advance in the LUT or the like, and the correspondence is referred to.
The multiplier 372 multiplies the addition result signal input from the adder 334 by the luminance gain signal input from the luminance gain calculation circuit 371, and the multiplication result signal is used as a luminance signal correction amount signal (VA signal). ) To the luminance signal correction circuit 133.

  Here, in the example of FIG. 6 in the first embodiment, the graphs (characteristics 2011 and 2012) for determining the luminance gain based on the signals of the two filtering results are shown. However, in this embodiment, the luminance gain is shown. A weighting factor is used instead of. In the present embodiment, the three weighting factors may be set (determined) using the same characteristic or may be set (determined) using different characteristics.

[Summary of Second Embodiment]
As described above, the image processor 31 (image processing apparatus) in the projector 11 according to the present embodiment can obtain the same effects as those of the first embodiment.

  Here, in this embodiment, in the example of FIG. 7, the signal of the filtering result by the filter circuit 331 is input to the weighting calculation circuit 332. As another configuration example, instead of the signal of the filtering result by the filter circuit 331, A configuration may be used in which one or both of the signals of the filtering results by the two filter circuits 151-1 and 151-2 are input to the weighting calculation circuit 332 and used. Alternatively, as another configuration example, one or both of the filtering result signals of the two filter circuits 151-1 and 151-2 are input to the weighting calculation circuit 332 together with the filtering result signal of the filter circuit 331. A configuration that is used may be used.

  In the present embodiment, the luminance signal correction amount calculation circuit 311 includes the determination circuit 351 and the weighting calculation circuit 332 as separate bodies, but these may be integrally provided as another configuration example.

[Summary of the above embodiments]
As one configuration example, an image processing apparatus that corrects an image signal (in the example of FIG. 1, an apparatus having the function of the image processing unit 31), and a filter unit that performs filtering on the luminance signal of the image signal (FIG. 2). In the example of FIG. 2, a luminance signal correction amount calculation unit (in the example of FIG. 2, in the example of FIG. 2, the luminance signal) calculates the correction amount of the luminance signal of the image signal based on the result of filtering performed by the multistage filter circuit 131). Correction amount calculation circuit 132), a luminance signal correction unit (in the example of FIG. 2, luminance signal correction circuit 133) that corrects the luminance signal of the image signal using the correction amount calculated by the luminance signal correction amount calculation unit, and . The filter unit has at least two filters for averaging different characteristics of the luminance signal of the image signal for the same pixel block (in the example of FIG. 2, two filter circuits 151-1 to 151-2). The luminance signal correction amount calculation unit adjusts the correction amount based on the result of filtering by the at least two filters.
As one configuration example, in the image processing apparatus, the luminance signal correction amount calculation unit has a correspondence between the result of filtering by the at least two filters and information for adjusting the correction amount. The correction amount is adjusted based on the result of filtering by the at least two filters.
As an example of the configuration, in the image processing apparatus, one of the two filters described above averages the values of pixels in odd rows and odd columns and pixels in even rows and even columns included in the same pixel block. The other filter has a characteristic of averaging the values of the odd-numbered and even-numbered pixels and the even-numbered and odd-numbered pixels included in the same pixel block ( For example, the example of FIG.
As an example of the configuration, in the image processing apparatus, the filter unit includes a plurality of pixel blocks having different sizes (in the example of FIG. 2, (vertical 7 pixels × horizontal 7 pixels), (vertical 5 pixels × horizontal 5 pixels), ( A plurality of filters corresponding to a pixel block of 3 pixels in the vertical direction and 3 pixels in the horizontal direction), and the luminance signal correction amount calculating unit corresponds to a pixel block having a size other than the minimum among the plurality of filters. The correction amount is adjusted based on the result of filtering by.
As an example of the configuration, in the image processing apparatus, the luminance signal correction amount calculation unit corresponds to the largest pixel block among the plurality of filters (in the example of FIG. 2, (vertical 7 pixel × horizontal 7 pixel pixel block)). The correction amount is adjusted based on the result of filtering by the filter.
As an example of the configuration, in the image processing apparatus, the luminance signal correction amount calculation unit performs correction when the absolute value of the difference between the results of filtering by the two filters exceeds a predetermined threshold as compared to the case where it is not. Adjust so that the influence of quantity is small.
As one configuration example, an image display device that displays an image based on an image signal (in the example of FIG. 1, a device having the function of the projector 11), and the above image processing device that corrects the image signal; An image display device including an image display unit (projection unit 32 in the example of FIG. 1) that displays an image based on the image signal corrected by the image processing device.

Note that a method (image processing method) for executing processing similar to the processing performed by the above-described image processing apparatus may be performed.
In addition, a method (image display method) for executing a process similar to the process performed by the image display device may be performed.

  Note that a program for realizing the function of an arbitrary component in the above-described apparatus (for example, an apparatus corresponding to the image processing unit 31) is recorded (stored) in a computer-readable recording medium (storage medium). The program may be loaded into a computer system and executed. The “computer system” here includes an operating system (OS) or hardware such as peripheral devices. The “computer-readable recording medium” means a portable medium such as a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), a CD (Compact Disc) -ROM, or a hard disk built in a computer system. Refers to the device. Further, the “computer-readable recording medium” means a volatile memory (RAM: Random Access) inside a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. Memory that holds a program for a certain period of time, such as Memory).

In addition, the above program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
Further, the above program may be for realizing a part of the functions described above. Further, the program may be a so-called difference file (difference program) that can realize the above-described functions in combination with a program already recorded in the computer system.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.
For example, the image processing unit 31 (image processing apparatus) according to the present embodiment may be applied to an apparatus other than a projector, or may be applied to image processing in a liquid crystal television or a plasma television.

DESCRIPTION OF SYMBOLS 1 ... Image display system, 11 ... Projector, 12 ... Screen, 31 ... Image processing part, 32 ... Projection part, 111-112 ... Line memory, 131 ... Multistage filter circuit, 132, 311 ... Luminance signal correction amount calculation circuit, 133 ... Luminance signal correction circuit 134... Color difference gain calculation circuit 135 135 Color difference signal correction circuit 151-1 to 151-4, 211, 331 Filter circuit 212, 332 Weighting calculation circuit 213-1 to 213-3 233, 333-1 to 333-3, 372... Multiplier, 214, 334... Adder, 231, 351... Judgment circuit, 232, 371 .. luminance gain calculation circuit, 1011 to 1012, 1021, 1111 to 1112, 1121 ... Pixels, 2011-2012 ... Characteristics

Claims (9)

An image processing apparatus for correcting an image signal,
A filter unit for filtering the luminance signal of the image signal;
A luminance signal correction amount calculation unit that calculates a correction amount of the luminance signal of the image signal based on a result of filtering performed by the filter unit;
A luminance signal correction unit that corrects the luminance signal of the image signal using the correction amount calculated by the luminance signal correction amount calculation unit;
The filter unit includes at least two filters that perform averaging of different characteristics for the same pixel block with respect to the luminance signal of the image signal,
The luminance signal correction amount calculation unit adjusts the correction amount based on a result of filtering by the at least two filters.
Image processing device. The luminance signal correction amount calculation unit has a correspondence between a result of filtering by the at least two filters and information for adjusting the correction amount, and the correspondence and filtering by the at least two filters are performed. Adjusting the correction amount based on the result;
The image processing apparatus according to claim 1. One of the two filters has a characteristic of averaging values of pixels in odd rows and odd columns and pixels in even rows and even columns included in the same pixel block, The filter has a characteristic of averaging the values of the odd-numbered and even-numbered pixels and the even-numbered and odd-numbered pixels included in the same pixel block.
The image processing apparatus according to claim 1. The filter unit has a plurality of filters corresponding to a plurality of pixel blocks of different sizes,
The luminance signal correction amount calculation unit adjusts the correction amount based on a result of filtering by a filter corresponding to a pixel block having a size other than the minimum among the plurality of filters.
The image processing apparatus according to any one of claims 1 to 3. The luminance signal correction amount calculation unit adjusts the correction amount based on a filtering result by a filter corresponding to the largest pixel block among the plurality of filters.
The image processing apparatus according to claim 4. When the absolute value of the difference between the results of filtering by the two filters exceeds a predetermined threshold, the luminance signal correction amount calculation unit is less affected by the correction amount than when it is not. To adjust,
The image processing apparatus according to any one of claims 1 to 5. An image display device that displays an image based on an image signal,
The image processing apparatus according to claim 1, wherein the image signal is corrected.
An image display unit for displaying an image based on the image signal corrected by the image processing device;
An image display device. An image processing method for correcting an image signal,
The filter unit performs filtering on the luminance signal of the image signal,
A luminance signal correction amount calculation unit calculates a correction amount of the luminance signal of the image signal based on the result of filtering performed by the filter unit,
The luminance signal correction unit corrects the luminance signal of the image signal using the correction amount calculated by the luminance signal correction amount calculation unit,
The filter unit includes at least two filters that perform averaging of different characteristics for the same pixel block with respect to the luminance signal of the image signal,
The luminance signal correction amount calculation unit adjusts the correction amount based on a result of filtering by the at least two filters.
Image processing method. An image display method for displaying an image based on an image signal,
The image display unit displays an image based on the image signal corrected by the image processing method according to claim 8.
Image display method.

Images