WO2017086121A1

WO2017086121A1 - Image processing device and program

Info

Publication number: WO2017086121A1
Application number: PCT/JP2016/081976
Authority: WO
Inventors: 正史東
Original assignee: Eizo株式会社
Priority date: 2015-11-17
Filing date: 2016-10-28
Publication date: 2017-05-26
Also published as: JP6549971B2; JP2017091475A

Abstract

[Problem] A technology for enabling jaggies to be inconspicuous more appropriately than conventional technologies is in demand. [Solution] Provided is an image processing device that performs an anti-aliasing process on pixels included in an inputted image, and that is provided with a process control unit that controls the anti-aliasing process on a pixel of interest on the basis of at least either size information about the size of an object including the pixel of interest or corner information indicating whether or not the pixel of interest is included in a corner of the object.

Description

Image processing apparatus and program

The present invention relates to an image processing apparatus and a program.

As conventional methods of anti-aliasing that make jaggy in an image inconspicuous, MSAA (Multi-Sampling Anti-Aliasing), MLAA (Morphological Anti-Aliasing) and the like have been known (for example, see Patent Document 1).

[Patent Document 1] Japanese Patent Application Laid-Open No. 2014-174867

A technology that can make jaggies less conspicuous appropriately than before has been desired.

According to the first aspect of the present invention, an image processing apparatus is provided. The image processing apparatus performs anti-aliasing processing on pixels included in the input image. The image processing apparatus controls an anti-aliasing process for a target pixel based on at least one of size information regarding a size of an object formed by the target pixel and corner information indicating whether the target pixel forms a corner of the object. A control unit may be provided.

The processing control unit obtains first pixel data acquired by performing anti-aliasing processing on the target pixel, and second pixel data acquired without performing the anti-aliasing processing on the target pixel. A selector unit that selectively outputs may be provided, and the selector unit may output the first pixel data or the second pixel data based on at least one of the size information and the corner information. When the size information indicates that the size of the object is larger than a predetermined size, and the corner information indicates that the pixel of interest does not constitute a corner of the object, the selector unit includes the first portion. Pixel data may be output. The selector unit may output the second pixel data when the size information indicates that the size of the object is not larger than a predetermined size. The selector unit may output the second pixel data when the corner information indicates that the pixel of interest constitutes a corner of the object.

The processing control unit may include an image adjustment unit that controls the processing intensity of the anti-aliasing processing for the pixel of interest based on at least one of the size information and the corner information. When the size information indicates that the size of the object is not larger than a predetermined size, and when the corner information indicates that the target pixel constitutes a corner of the object, the image adjustment unit Compared to the case where the size information indicates that the size of the pixel is larger than a predetermined size and the corner information indicates that the pixel of interest does not constitute a corner of the object, the processing strength of the anti-aliasing process May be lowered. When the size information indicates that the size of the object is larger than a predetermined size, and the corner information indicates that the pixel of interest does not constitute a corner of the object, the image adjustment unit For pixel, pixel data whose pixel value is closer to the pixel data acquired by performing the anti-aliasing process on the target pixel than the pixel data acquired without performing the anti-aliasing process on the target pixel. You may output. When the size information indicates that the size of the object is not larger than a predetermined size, the image adjustment unit is configured such that the pixel value of the target pixel is subjected to the anti-aliasing process for the target pixel. Pixel data closer to the acquired pixel data than the acquired pixel data may be output without performing the anti-aliasing process on the target pixel. When the corner information indicates that the target pixel constitutes a corner of the object, the image adjustment unit acquires a pixel value of the target pixel by performing the anti-aliasing process on the target pixel. Pixel data closer to the pixel data obtained without the anti-aliasing processing being applied to the target pixel than the pixel data may be output.

The image processing apparatus includes, from the input image, an edge pixel detection unit that detects edge pixels that constitute an edge of an object, a pixel value of the pixel of interest that is an edge pixel, and an edge pixel that is adjacent to the pixel of interest. By comparing the pixel value, the same object constituent pixel extraction unit that extracts the edge pixel that forms the edge of the same object as the target pixel, and the length of the edge that the target pixel configures are determined in advance. A size information generation unit that generates the size information indicating that the size of the object is larger than a predetermined size when the length is longer than the length may be further provided.

The image processing device includes, from the input image, an edge pixel detection unit that detects an edge pixel that forms an edge of an object, a pixel value of the pixel of interest that is an edge pixel, and a pixel of an edge pixel adjacent to the pixel of interest The same object constituent pixel extraction unit that extracts edge pixels that form the edge of the same object as the target pixel by comparing the values, and the target pixel that is arranged in the vertical direction or the horizontal direction of the input image With respect to the edge pixel located at the end of the edge pixel group, the edge pixel exists in an oblique direction opposite to the direction in which the edge pixel group exists and in a direction perpendicular to the direction in which the edge pixel group exists. To the pixel of interest when there are more than a predetermined number of edge pixels in a direction perpendicular to the direction in which the edge pixel groups are arranged. It may further comprise a corner information generation unit for generating the corner information indicating that constitutes the corner of the object.

The image processing device includes, from the input image, an edge pixel detection unit that detects an edge pixel that forms an edge of an object, a pixel value of the pixel of interest that is an edge pixel, and a pixel of an edge pixel adjacent to the pixel of interest By comparing the values, the same object component pixel extracting unit that extracts the edge pixel that forms the edge of the same object as the target pixel, and the anti-aliasing processing unit that executes the anti-aliasing process on the target pixel The anti-aliasing processing unit may include the pixel of interest, and does not belong to the same object as the pixel of interest adjacent to the edge pixel group arranged in the vertical direction or the horizontal direction of the input image. One pixel is selected from the pixels, the distance between the one pixel and the target pixel, and the pixel group Accordance percentage based on the, by blending the pixel values of the pixel values and the one pixel of the target pixel may output the pixel data of the pixel of interest.

According to the second aspect of the present invention, there is provided a program for causing a computer to function as the image processing apparatus.

Note that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

An example of functional composition of display 100 is shown roughly. An example of processing by the edge detection unit 112 is schematically shown. An example of the flow of processing by the same object constituent pixel extraction unit 114 is schematically shown. An example of processing by the object information extraction unit 116 is schematically shown. An example of MLAA processing is shown roughly. An example of MLAA processing is shown roughly. An example of the flow of processing by the corner pixel determination unit 118 is schematically shown. An example of MLAA processing is shown roughly. An example of the process by the anti-aliasing process part 120 is shown roughly. An example of the process by the anti-aliasing process part 120 is shown roughly. An example of the process by the anti-aliasing process part 120 is shown roughly. An example of the process by the anti-aliasing process part 120 is shown roughly. 2 shows an exemplary hardware configuration of a computer 900 that functions as an image processing unit 102.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

FIG. 1 schematically shows an example of a functional configuration of the display device 100. The display device 100 may be a liquid crystal display, a plasma display, an organic EL display, or the like. The display device 100 according to the present embodiment performs an anti-aliasing process on the pixels included in the input image, and displays the input image subjected to the anti-aliasing process. The display device 100 may be an example of an image processing device.

The display device 100 includes an image processing unit 102, a display control unit 104, and a display unit 106. The image processing unit 102 performs anti-aliasing processing on the pixels included in the input image. The image processing unit 102 may be an example of an image processing apparatus.

The image processing unit 102 includes an image input unit 110, an edge detection unit 112, an identical object constituent pixel extraction unit 114, an object information extraction unit 116, a corner pixel determination unit 118, an anti-aliasing processing unit 120, and a processing control unit 130.

The image input unit 110 inputs an image. The input image may be a moving image or a still image, or may be a frame included in the moving image. The image input unit 110 may input RGB data, YUV data, or HSV data. The image input unit 110 may sequentially transmit pixel data of pixels included in the input image to the edge detection unit 112, the anti-aliasing processing unit 120, and the processing control unit 130.

The edge detection unit 112 detects edge pixels constituting the edge of the object. In the present embodiment, the object may be an edge, and in this case, the edge detection unit 112 may detect the edge pixels constituting the object. For example, the edge detection unit 112 calculates an absolute difference value between the pixel value of the target pixel and the pixel values of the four neighboring pixels of the target pixel, and the absolute difference value is determined in advance among the four neighboring pixels. If even one pixel is larger than the threshold, the target pixel is determined as an edge pixel. Note that the edge detection unit 112 may detect an edge pixel by using a known method.

In this embodiment, the absolute difference value of the pixel value may be calculated by any method. For example, the absolute difference value of the pixel value is the sum of the absolute difference values of RGB. Further, the absolute difference value of the pixel value may be the maximum value of the absolute difference values of RGB. Further, the absolute difference value of the pixel value may be an absolute difference value of the luminance signal Y.

The same object component pixel extraction unit 114 extracts edge pixels that constitute the same object as the target pixel determined as the edge pixel by the edge detection unit 112. For example, the same object component pixel extraction unit 114 compares the pixel value of the target pixel determined as the edge pixel by the edge detection unit 112 with the pixel value of the edge pixel adjacent to the target pixel, thereby matching the target pixel. Edge pixels constituting the object are extracted. The same object constituent pixel extraction unit 114 may extract an edge pixel that forms an edge of the same object as the target pixel.

The object information extraction unit 116 extracts information on an object that is formed by the target pixel. The object information extraction unit 116 may extract information on an object composed of the pixel of interest and the edge pixels extracted by the same object component pixel extraction unit 114. The object information extraction unit 116 may generate size information related to the size of the object. The size information may indicate whether the size of the object is larger than a predetermined size. The predetermined size may be changeable by a user of the display device 100, for example. The object information extraction unit 116 may be an example of a size information generation unit.

The corner pixel determination unit 118 determines whether or not the target pixel constitutes a corner of the object. The corner pixel determination unit 118 may generate corner information indicating whether or not the target pixel constitutes a corner of the object. For example, the corner pixel determination unit 118 performs an oblique direction opposite to the direction in which the edge pixel group exists with respect to the edge pixel located at the end of the edge pixel group including the target pixel, which is aligned in the vertical direction or the horizontal direction of the input image. And edge pixels exist in a direction perpendicular to the direction in which the edge pixel group exists, and there are more than a predetermined number of edge pixels from the edge pixel in a direction perpendicular to the direction in which the edge pixel group is arranged. Then, corner information indicating that the pixel of interest constitutes a corner of the object is generated. Note that the corner pixel determination unit 118 may determine whether or not the pixel of interest constitutes a corner of the object by using a known method, and may generate corner information according to the determination result. The corner pixel determination unit 118 may be an example of a corner information generation unit.

The anti-aliasing processing unit 120 performs anti-aliasing processing on the pixels included in the input image. The anti-aliasing processing unit 120 executes conventional anti-aliasing processing such as MLAA, for example. Further, as will be described later, the anti-aliasing processing unit 120 is one pixel from a pixel that does not belong to the same object as the target pixel, which is adjacent to the edge pixel group arranged in the horizontal direction of the input image, including the target pixel, in the horizontal direction. And combining the pixel value of the target pixel and the pixel value of the one pixel in accordance with the ratio based on the distance between the target pixel and the one pixel and the length of the edge pixel group including the target pixel. An aliasing process may be executed. In addition, the anti-aliasing processing unit 120 selects one pixel from pixels that are adjacent to the edge pixel group arranged in the vertical direction of the input image including the target pixel and that do not belong to the same object as the target pixel. Perform anti-aliasing processing by blending the pixel value of the target pixel and the pixel value of the one pixel according to the ratio based on the distance between the pixel and the one pixel and the length of the edge pixel group including the target pixel May be.

The processing control unit 130 controls the anti-aliasing processing for the pixel of interest based on at least one of size information regarding the size of the object formed by the pixel of interest and corner information indicating whether the pixel of interest forms a corner of the object. To do. The processing control unit 130 may include a selector unit 132 and an image adjustment unit 134. The processing control unit 130 may include only one of the selector unit 132 and the image adjustment unit 134 or both.

The selector unit 132 selectively outputs pixel data acquired by performing anti-aliasing processing on the target pixel and pixel data acquired without performing anti-aliasing processing on the target pixel. The pixel data acquired by performing the anti-aliasing process on the target pixel may be an example of the first pixel data. The pixel data acquired without performing anti-aliasing processing on the target pixel may be an example of second pixel data.

The selector unit 132 outputs the first pixel data or the second pixel data based on at least one of the size information generated by the object information extraction unit 116 and the corner information generated by the corner pixel determination unit 118. For example, when the size information indicates that the size of the object formed by the pixel of interest is larger than a predetermined size and the corner information indicates that the pixel of interest does not form the corner of the object, the selector unit 132 The first pixel data is output.

Further, for example, when the size information indicates that the size of the object formed by the target pixel is not larger than a predetermined size, the selector unit 132 outputs the second pixel data. For example, the selector unit 132 outputs the second pixel data when the corner information indicates that the target pixel forms a corner of the object.

The image adjustment unit 134 controls the processing strength of the anti-aliasing process for the target pixel based on at least one of the size information generated by the object information extraction unit 116 and the corner information generated by the corner pixel determination unit 118. For example, when the size information indicates that the size of the object is not larger than a predetermined size and when the corner information indicates that the pixel of interest constitutes the corner of the object, the image adjustment unit 134 determines that the size of the object is Compared to the case where the size information indicates that the size is larger than the predetermined size and the corner information indicates that the target pixel does not constitute the corner of the object, the processing strength of the anti-aliasing processing is reduced.

For example, when the size information indicates that the size of the object is larger than a predetermined size and the corner information indicates that the target pixel does not constitute a corner of the object, the image adjustment unit 134 Pixel data whose value is closer to the first pixel data than the second pixel data is output.

Further, for example, when the size information indicates that the size of the object is not larger than a predetermined size, the image adjustment unit 134 is a pixel whose pixel value is closer to the second pixel data than the first pixel data for the target pixel. Output data. Further, for example, when the corner information indicates that the target pixel forms the corner of the object, the image adjustment unit 134 outputs pixel data whose pixel value is closer to the second pixel data than the first pixel data for the target pixel. To do.

The display control unit 104 causes the display unit 106 to display an image using the pixel data output by the processing control unit 130. The display unit 106 displays an image according to control by the display control unit 104.

FIG. 2 schematically shows an example of processing by the edge detection unit 112. Here, a process for detecting edge pixels included in a part 210 of the input image will be described as an example.

The edge detection unit 112 first calculates an absolute difference between the pixel value of the target pixel 211 and the pixel values of the

pixels

212, 213, 214, and 215 in the vicinity of the target pixel 211. Next, the edge detection unit 112 compares the calculated absolute difference value with a threshold value. Then, if any one of the four difference absolute values is larger than the threshold value, the edge detection unit 112 determines the target pixel 211 as an edge pixel. The threshold value may be set in advance. The threshold value may be changeable by a user of the display device 100 or the like.

The edge detection unit 112 detects all the edge pixels included in the example 210 by performing the above-described processing for each pixel included in the example 210. The hatched pixels in Example 220 indicate detected edge pixels.

FIG. 3 schematically shows an example of the flow of processing by the same object constituent pixel extraction unit 114. Here, in the example 230, the process of extracting the edge pixel constituting the edge of the same object as the target pixel 231 will be described as an example.

The same object component pixel extracting unit 114 first detects edge pixels located in the vicinity of 8 of the target pixel 231. When the number of detected edge pixels is two, the same object constituent pixel extraction unit 114 selects the two edge pixels, and in the case of three or more, the same object component pixel extraction unit 114 selects two of the pixel values closer to the pixel value of the target pixel 231. When an edge pixel is selected and the number is less than two, it is determined that the process is finished.

Next, the same object component pixel extraction unit 114 calculates the absolute difference between the pixel value of the target pixel 231 and the pixel value of the target pixel 231 out of the pixel values of the two selected edge pixels. To do. Then, when the calculated difference absolute value is smaller than the threshold value, the same object constituent pixel extraction unit 114 determines the two selected pixels as the contour constituent pixels. The threshold value may be set in advance. The threshold value may be changeable by a user of the display device 100 or the like. In the example 230, the

pixels

232 and 233 are determined to be contour constituent pixels.

Subsequently, the same object constituent pixel extraction unit 114 detects edge pixels located in the vicinity of 8 of the pixel 232 determined as the contour constituent pixel. If the number of detected edge pixels is two including the target pixel 231, the same object component pixel extraction unit 114 selects an edge pixel other than the target pixel 231 out of the two, and if the number is three or more, the target pixel Among the edge pixels other than 231, one edge pixel having a pixel value closer to the pixel value of the pixel 232 is selected.

Next, the same object constituent pixel extraction unit 114 calculates the absolute difference between the pixel value of the selected one edge pixel and the pixel value of the pixel 232. Then, if the calculated difference absolute value is smaller than the threshold value, the same object component pixel extraction unit 114 determines the selected one pixel as the contour component pixel. The same object constituent pixel extraction unit 114 performs the same process on the pixel 233.

The same object constituent pixel extraction unit 114 repeats the above-described processing for the pixels determined to be the contour constituent pixels until it is determined that the processing is finished. Thereby, the edge pixel which comprises the edge of the same object as the attention pixel 231 can be extracted. In the example 230, the

pixels

234, 235, 236, and 237 are determined to be contour constituent pixels. The hatched pixels in the example 240 indicate edge pixels extracted by the same object component pixel extraction unit 114.

FIG. 4 schematically shows an example of processing by the object information extraction unit 116. The object information extraction unit 116 extracts a region 250 having a predetermined size centered on the pixel of interest 251, and an edge pixel included in an edge formed by the pixel of interest 251 exists at the end of the region 250. In addition, size information indicating that the size of the object formed by the target pixel 251 is larger than a predetermined size may be generated. Further, when there is no edge pixel included in the edge formed by the target pixel 251 at the end of the region 250, the object information extraction unit 116 makes the size of the object formed by the target pixel 251 larger than a predetermined size. Size information indicating that there is no data may be generated.

In the region 250 illustrated in FIG. 4, since the edge pixel 252 and the edge pixel 253 included in the edge formed by the target pixel 251 exist at the end of the region 250, the object information extraction unit 116 configures the target pixel 251. Size information indicating that the size of the object is larger than a predetermined size is generated.

Here, on the condition that the edge pixel included in the edge formed by the target pixel 251 exists at the end of the region 250, the size of the object formed by the target pixel 251 is larger than a predetermined size. Although the example which produces | generates the size information shown was given and demonstrated, it is not restricted to this. The condition may be that there are two edge pixels included in the edge formed by the target pixel 251 at the end of the region 250.

In addition, here, the case where the size of the region 250 is 7 × 7 pixels has been described as an example, but the present invention is not limited thereto. The size of the region 250 may be other than 7 × 7 pixels. Further, the size of the region 250 may be changeable by a user of the display device 100 or the like.

5 and 6 schematically show an example of MLAA processing. As shown in the example 260, according to the MLAA process, the target pixel 261 is determined to be a part of the Z-shaped contour 262. Then, the pixel value TargetValue of the pixel of interest 261 and the pixel value OppositeValue of the pixel 264 adjacent to the pixel of interest 261 are blended according to the following formula 1, and the output value OutValue of the pixel value of the pixel of interest 261 is calculated.

[Formula 1]

Here, a represents the area of the region 263.

According to the MLAA processing, as shown in Example 270, even in the case where small objects are densely populated, the pixel of interest 271 is determined to be a part of the Z-shaped contour 272 as in Example 260. Using the area a of the region 273, the pixel value TargetValue of the target pixel 271 and the pixel value OppositeValue of the pixel 274 adjacent to the target pixel 271 are combined to calculate the output value OutValue of the pixel value of the target pixel 271. May end up. In this case, there is a possibility that excessive blending of pixels may occur, which may cause problems such as loss of texture fineness and a decrease in local contrast.

On the other hand, according to the display device 100 according to the present embodiment, the same object component pixel extraction unit 114 extracts edge pixels that constitute the edge of the same object as the target pixel, and the size of the object is determined in advance. When the size is not larger than the obtained size, the selector unit 132 outputs pixel data acquired without performing anti-aliasing processing on the target pixel. Thereby, generation | occurrence | production of the problem mentioned above can be prevented.

Further, according to the display device 100 according to the present embodiment, the image adjustment unit 134 has the pixel value of the pixel of interest anti-aliased more than the pixel data acquired by performing anti-aliasing processing on the pixel of interest. Pixel data close to the pixel data acquired without performing the aliasing process is output. Thereby, the influence of the problem mentioned above can be reduced.

FIG. 7 schematically shows an example of the flow of processing by the corner pixel determination unit 118. The corner pixel determination unit 118 performs an oblique direction opposite to the direction in which the edge pixel group exists with respect to the edge pixel located at the end of the edge pixel group including the target pixel and arranged in the vertical direction or the horizontal direction of the input image. An edge pixel exists in a direction perpendicular to the direction in which the edge pixel group exists, and there are more than a predetermined number of edge pixels in the direction perpendicular to the direction in which the edge pixel group is arranged from the edge pixel. The corner information indicating that the pixel of interest constitutes the corner of the object may be generated. In addition, the corner pixel determination unit 118 obliquely reverses the direction in which the edge pixel group exists with respect to edge pixels located at the end of the edge pixel group including the target pixel, which are arranged in the vertical direction or the horizontal direction of the input image. Edge pixels exist in a direction perpendicular to the direction and the direction in which the edge pixel group exists, and more than a predetermined number of edge pixels exist from the edge pixel in a direction perpendicular to the direction in which the edge pixel group is arranged. Otherwise, corner information indicating that the pixel of interest does not constitute a corner of the object may be generated.

The corner pixel determination unit 118 may use a partial area having a predetermined size as a processing unit. Here, the partial area 280 having a size of 7 × 7 pixels will be described as an example, but the size of the partial area is not limited to this and may be other sizes.

First, the corner pixel determination unit 118 specifies the direction of the edge pixel group arranged in the vertical direction or the horizontal direction of the input image from the target pixel 281. When there are edge pixels adjacent to both the horizontal direction and the vertical direction of the pixel of interest 281, the corner pixel determination unit 118 specifies a direction in which the number of continuous edge pixels is larger. That is, the corner pixel determination unit 118 specifies the direction of a longer straight line from the straight line extending in the horizontal direction and the straight line extending in the vertical direction from the target pixel 281. The corner pixel determination unit 118 specifies the horizontal direction when the adjacent edge pixel exists only in the horizontal direction and the vertical direction when the adjacent edge pixel exists only in the vertical direction among the vertical direction and the horizontal direction of the target pixel 281. . In this example, the horizontal direction is specified.

Next, the corner pixel determining unit 118 specifies an edge pixel that is located at the end in the specified direction and is not located at the end of the partial region in the edge pixel group. In the partial area 280, since the edge pixel 282 is positioned at the end of the partial area 280 among the target pixel 281 and the edge pixel 282 positioned at the end in the specified direction, only the target pixel 281 is specified. Next, the corner pixel determination unit 118 determines whether the edge pixels adjacent to each other at the specified edge pixel are in an oblique direction opposite to the direction in which the edge pixel group exists and in a direction perpendicular to the direction in which the edge pixel group exists. Determine if it exists. In the example 280, it is determined that the adjacent edge pixel 283 exists in the diagonally upper right direction of the target pixel 281.

Next, the corner pixel determination unit 118 determines whether or not there are a predetermined number or more of edge pixels in the direction in which the edge pixels exist and in a direction perpendicular to the specified direction. In the example 280, it is determined whether or not there are more than a predetermined number of edge pixels in the direction indicated by the arrow 284.

When the corner pixel determination unit 118 determines that there are more than a predetermined number of edge pixels, the corner pixel determination unit 118 determines that the target pixel constitutes a corner of the object. If the corner pixel determination unit 118 determines that there are not more than a predetermined number of edge pixels, the corner pixel determination unit 118 determines that the pixel of interest does not form a corner of the object. When the predetermined number is 1, in Example 280, since there is no edge pixel, it is determined that the pixel of interest does not form a corner of the object. The predetermined number may be changeable by a user of the display device 100 or the like.

FIG. 8 schematically shows an example of MLAA processing. According to the MLAA process, as illustrated in the example 300, the L-shaped

contours

301, 302, 303, and 304 are determined, and the pixel value of each pixel is calculated as illustrated in the example 310. As described above, according to the MLAA process, there is a case where a color blur occurs near a corner and the composition of an intentionally created object is destroyed.

On the other hand, according to the selector unit 132 according to the present embodiment, when the corner information indicates that the target pixel constitutes the corner of the object, the pixel data acquired without the anti-aliasing process being performed on the target pixel. Is output. Thereby, generation | occurrence | production of the problem mentioned above can be prevented.

Further, according to the image adjustment unit 134 according to the present embodiment, when the corner information indicates that the target pixel forms the corner of the object, the pixel value of the target pixel is subjected to the anti-aliasing process for the target pixel. The pixel data closer to the pixel data acquired without performing anti-aliasing processing on the pixel of interest than the pixel data acquired by the above is output. Thereby, the influence of the problem mentioned above can be reduced.

9 to 12 schematically show an example of processing by the anti-aliasing processing unit 120. FIG. The anti-aliasing processing unit 120 selects one pixel from the pixels that do not belong to the same object as the target pixel and that are adjacent in the horizontal direction to the edge pixel group that includes the target pixel and is aligned in the horizontal direction of the input image. The pixel data of the target pixel may be output by combining the pixel value of the target pixel and the pixel value of one pixel according to the ratio based on the distance between the pixel and the target pixel and the length of the pixel group. Further, the anti-aliasing processing unit 120 selects one pixel from pixels that do not belong to the same object as the target pixel, adjacent to the edge pixel group that includes the target pixel and is aligned in the vertical direction of the input image. The pixel data of the target pixel may be output by combining the pixel value of the target pixel and the pixel value of the one pixel according to the ratio based on the distance between the one pixel and the target pixel and the length of the pixel group.

When the target pixel is included in the edge pixel group arranged in the horizontal direction, the anti-aliasing processing unit 120 specifies a pixel that is adjacent to the edge pixel group in the horizontal direction and does not belong to the same object as the target pixel. Further, when the target pixel is included in the edge pixel group arranged in the vertical direction, the anti-aliasing processing unit 120 specifies a pixel that does not belong to the same object as the target pixel that is adjacent to the edge pixel group in the vertical direction. When the number of specified pixels is one, the anti-aliasing processing unit 120 selects the pixel.

When the number of specified pixels is two, the anti-aliasing processing unit 120 selects one of the two pixels. The anti-aliasing processing unit 120 first identifies a pixel whose pixel value is close to the pixel value of the target pixel from the two pixels. Next, the anti-aliasing processing unit 120 calculates the absolute value of the difference between the pixel value of the identified pixel and the pixel value of the target pixel and compares it with a threshold value. The threshold value may be set in advance. The threshold value may be changeable by a user of the display device 100 or the like. Then, when the difference absolute value is smaller than the threshold value, the anti-aliasing processing unit 120 selects a pixel whose pixel value is not close to the pixel value of the target pixel from the two pixels. Further, when the difference absolute value is larger than the threshold value, the anti-aliasing processing unit 120 selects a pixel having a distance close to the target pixel from the two pixels.

When the target pixel 321 of the example 320 is to be processed, the anti-aliasing processing unit 120 first includes the target pixel 321 including the target pixel 321 and adjacent to the edge pixel group arranged in the horizontal direction of the input image in the horizontal direction.

Pixels

322 and 323 that are pixels that do not belong to the same object are specified. Next, the anti-aliasing processing unit 120 identifies a pixel 322 whose pixel value is close to the pixel value of the target pixel 321 among the

pixels

322 and 323. Next, the anti-aliasing processing unit 120 calculates an absolute difference value between the pixel value of the target pixel 321 and the pixel value of the pixel 322 and compares it with a threshold value. Here, the description will be continued assuming that the absolute difference value is smaller than the threshold value. The anti-aliasing processing unit 120 selects a pixel 323 whose pixel value is not close to the pixel value of the target pixel 321 among the

pixels

322 and 323.

When the target pixel 331 of the example 330 is set as the processing target, the anti-aliasing processing unit 120 first includes the target pixel 331 and the target pixel 331 that is adjacent to the edge pixel group arranged in the horizontal direction of the input image in the horizontal direction.

Pixels

332 and 333 that are pixels that do not belong to the same object are specified. Next, the anti-aliasing processing unit 120 identifies a pixel whose pixel value is close to the pixel value of the target pixel 331 among the

pixels

332 and 333. Here, the description is continued assuming that the pixel value of the pixel 333 is closer to the pixel value of the target pixel 331. The anti-aliasing processing unit 120 identifies the pixel 333. Next, the anti-aliasing processing unit 120 calculates a difference absolute value between the pixel value of the target pixel 331 and the pixel value of the pixel 333, and compares it with a threshold value. Here, the description will be continued assuming that the absolute difference value is larger than the threshold value. The anti-aliasing processing unit 120 selects a pixel 332 that is close to the target pixel 331 among the

pixels

332 and 333.

Then, the anti-aliasing processing unit 120 calculates the output pixel value OutValue of the target pixel using the following formula 2. The anti-aliasing processing unit 120 outputs the calculated OutValue as pixel data of the target pixel.

[Formula 2]

However, A is the pixel value of the target pixel, B is the pixel value of the selected pixel, Distance is the distance between the target pixel and the selected pixel, and Length is a value based on the length of the pixel group including the target pixel. The weight may be a preset weight value, and may be arbitrarily set by a user of the display device 100 or the like.

The anti-aliasing processing unit 120 may change the method of deriving the Length depending on the reason for selecting the pixel. When the above-described absolute difference value is smaller than the threshold value and the pixel value is not close to the pixel value of the target pixel, the anti-aliasing processing unit 120 sets the length of the edge pixel group as Length. Good. When the difference absolute value described above is larger than the threshold value and the pixel is selected based on the distance from the target pixel, the anti-aliasing processing unit 120 may set half of the length of the edge pixel group as Length.

When the target pixel 321 of the example 320 is a processing target, as illustrated in FIG. 11, the distance between the target pixel 321 and the selected pixel 323 is set to Distance, and the length of the pixel group including the target pixel 321 is Length. It is said. When the target pixel 331 of the example 330 is a processing target, as shown in FIG. 12, the distance between the target pixel 331 and the selected pixel 332 is set to Distance, and is half the length of the pixel group including the target pixel 331. Is referred to as Length.

As described above, the anti-aliasing processing unit 120 may calculate the output pixel value such that the greater the distance value, the higher the blend ratio of the pixel values of the selected pixel. Further, as described above, the anti-aliasing processing unit 120 may calculate the output pixel value such that the smaller the Length value, the higher the blending ratio of the pixel values of the selected pixels.

The anti-aliasing processing unit 120 determines that the pixel value of the target pixel and the pixel of the selected pixel when the OutValue calculated by Equation 2 does not fit between the pixel value of the target pixel and the pixel value of the selected pixel. You may adjust so that it may fall between values. For example, the anti-aliasing processing unit 120 sets the upper value and the lower value of OutValue to the pixel value of the target pixel and the pixel value of the selected pixel, and if the value exceeds the upper value, sets the lower value to the upper value. If it is lower, OutValue may be set as the lower limit value.

In the above embodiment, the case where the image processing unit 102 is disposed inside the display device 100 has been described as an example, but the present invention is not limited thereto. The image processing unit 102 may be a computer outside the display device 100.

FIG. 13 shows an example of a hardware configuration of a computer 900 that functions as the image processing unit 102. The computer 900 according to the present embodiment includes a CPU peripheral unit including a CPU 1000, a RAM 1020, and a graphic controller 1075 connected to each other by a host controller 1082, and a communication I / F 1030 connected to the host controller 1082 by an input / output controller 1084. An input / output unit having a hard disk drive 1040 and a DVD drive 1060, and a legacy input / output unit having a ROM 1010, an FD drive 1050 and an input / output chip 1070 connected to the input / output controller 1084 are provided.

The CPU 1000 operates based on programs stored in the ROM 1010 and the RAM 1020 and controls each unit. The graphic controller 1075 acquires image data generated by the CPU 1000 or the like on a frame buffer provided in the RAM 1020 and displays it on the display 1080. Instead of this, the graphic controller 1075 may include a frame buffer for storing image data generated by the CPU 1000 or the like.

The communication I / F 1030 communicates with other apparatuses via a wired or wireless network. The communication I / F 1030 functions as hardware that performs communication. The hard disk drive 1040 stores programs and data used by the CPU 1000. The DVD drive 1060 reads a program or data from the DVD-ROM 1095 and provides it to the hard disk drive 1040 via the RAM 1020.

The ROM 1010 stores a boot program that the computer 900 executes at startup, a program that depends on the hardware of the computer 900, and the like. The FD drive 1050 reads a program or data from the flexible disk 1090 and provides it to the hard disk drive 1040 via the RAM 1020. The input / output chip 1070 connects the FD drive 1050 to the input / output controller 1084, and connects various input / output devices to the input / output controller 1084 via, for example, a parallel port, a serial port, a keyboard port, and a mouse port. Connect to.

The program provided to the hard disk drive 1040 via the RAM 1020 is stored in a recording medium such as the flexible disk 1090, the DVD-ROM 1095, or an IC card and provided by the user. The program is read from the recording medium, installed in the hard disk drive 1040 via the RAM 1020, and executed by the CPU 1000.

A program that is installed in the computer 900 and causes the computer 900 to function as the image processing unit 102 may work on the CPU 1000 or the like to cause the computer 900 to function as each unit of the image processing unit 102. The information processing described in these programs is read by the computer 900, whereby the image input unit 110 and the edge detection unit 112, which are specific means in which the software and the various hardware resources described above cooperate, are the same. It functions as an object constituent pixel extraction unit 114, an object information extraction unit 116, a corner pixel determination unit 118, an anti-aliasing processing unit 120, and a processing control unit 130. The specific image processing unit 102 corresponding to the purpose of use is constructed by realizing calculation or processing of information according to the purpose of use of the computer 900 in this embodiment by these specific means.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that it can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first,” “next,” etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

100 display device, 102 image processing unit, 104 display control unit, 106 display unit, 110 image input unit, 112 edge detection unit, 114 identical object component pixel extraction unit, 116 object information extraction unit (size information generation unit), 118 corner Pixel determination unit (corner information generation unit), 120 anti-aliasing processing unit, 130 processing control unit, 132 selector unit, 134 image adjustment unit, 210 example, 211 pixel of interest, 212 pixel, 213 pixel, 214 pixel, 215 pixel, 220 Example, 230 example, 231 pixel of interest, 232 pixel, 233 pixel, 234 pixel, 235 pixel, 236 pixel, 237 pixel, 240 example, 250 region, 251 pixel of interest, 252 pixel, 253 pixel, 260 example, 261 pixel of interest 262 Z-shaped contour, 263 area, 264 pixels, 270 examples, 271 attention pixel, 272 Z-shaped contour, 273 area, 274 pixels, 280 partial area, 281 attention pixel, 282 pixels, 283 pixels, 284 arrows, 300 examples, 301 L-shaped contour, 302 L-shaped contour, 303 L-shaped contour, 304 L-shaped contour, 310 examples, 320 examples, 321 pixels of interest, 322 pixels, 323 pixels, 330 examples, 331 pixels of interest, 332 pixels, 333 pixels, 900 computers 1000 CPU, 1010 ROM, 1020 RAM, 1030 communication I / F, 1040 hard disk drive, 1050 FD drive, 1060 DVD drive, 1070 input / output chip, 1075 graphic controller, 1080 Isupurei, 1082 host controller, 1084 input-output controller, 1090 a flexible disk, 1095 DVD-ROM

Claims

An image processing apparatus that performs anti-aliasing processing on pixels included in an input image,
A processing control unit that controls anti-aliasing processing for the pixel of interest based on at least one of size information relating to a size of an object formed by the pixel of interest and corner information indicating whether the pixel of interest forms a corner of the object; An image processing apparatus.
The processing control unit includes first pixel data acquired by performing anti-aliasing processing on the target pixel, and second pixel data acquired without performing the anti-aliasing processing on the target pixel. It has a selector part that selectively outputs,
The image processing apparatus according to claim 1, wherein the selector unit outputs the first pixel data or the second pixel data based on at least one of the size information and the corner information.
In the case where the size information indicates that the size of the object is larger than a predetermined size and the corner information indicates that the target pixel does not constitute a corner of the object, the selector unit The image processing apparatus according to claim 2, wherein the image processing apparatus outputs pixel data.
4. The image processing apparatus according to claim 2, wherein the selector unit outputs the second pixel data when the size information indicates that the size of the object is not larger than a predetermined size.
5. The image processing device according to claim 2, wherein the selector unit outputs the second pixel data when the corner information indicates that the pixel of interest constitutes a corner of the object. 6. .
The image processing apparatus according to claim 1, wherein the processing control unit includes an image adjustment unit that controls a processing intensity of an anti-aliasing process on the target pixel based on at least one of the size information and the corner information.
When the size information indicates that the size of the object is not larger than a predetermined size, and when the corner information indicates that the target pixel constitutes a corner of the object, the image adjustment unit Compared with the case where the size information indicates that the size of the pixel is larger than a predetermined size and the corner information indicates that the target pixel does not constitute a corner of the object, the processing strength of the anti-aliasing process The image processing device according to claim 6, wherein the image processing device is lowered.
When the size information indicates that the size of the object is larger than a predetermined size and the corner information indicates that the pixel of interest does not constitute a corner of the object, the image adjustment unit For pixel, pixel data whose pixel value is closer to the pixel data obtained by performing the anti-aliasing process on the pixel of interest than the pixel data obtained without performing the anti-aliasing process on the pixel of interest The image processing apparatus according to claim 6, which outputs the image processing apparatus.
When the size information indicates that the size of the object is not larger than a predetermined size, the image adjustment unit is configured such that, for the target pixel, a pixel value is applied to the target pixel. 9. The image processing apparatus according to claim 6, wherein the image processing apparatus outputs pixel data closer to the acquired pixel data than the acquired pixel data without performing the anti-aliasing process on the target pixel. 10.
When the corner information indicates that the target pixel constitutes a corner of the object, the image adjustment unit acquires a pixel value of the target pixel by performing the anti-aliasing process on the target pixel. 10. The image processing apparatus according to claim 6, wherein the image processing apparatus outputs pixel data closer to pixel data obtained without performing the anti-aliasing processing on the target pixel than the pixel data obtained.
An edge pixel detection unit for detecting edge pixels constituting the edge of the object from the input image;
The same edge pixels that form the edge of the same object as the target pixel are extracted by comparing the pixel value of the target pixel that is an edge pixel with the pixel value of the edge pixel adjacent to the target pixel. An object component pixel extraction unit;
A size information generating unit configured to generate the size information indicating that the size of the object is larger than a predetermined size when an edge length of the target pixel is longer than a predetermined length; The image processing apparatus according to any one of claims 1 to 10.
An edge pixel detection unit for detecting edge pixels constituting the edge of the object from the input image;
The same object configuration that extracts the edge pixel that forms the edge of the same object as the target pixel by comparing the pixel value of the target pixel that is an edge pixel and the pixel value of the edge pixel adjacent to the target pixel A pixel extractor;
With respect to the edge pixels located at the end of the edge pixel group including the target pixel arranged in the vertical direction or the horizontal direction of the input image, the diagonal direction opposite to the direction in which the edge pixel group exists and the edge pixel group are When the edge pixel exists in a direction perpendicular to the existing direction, and there are more than a predetermined number of edge pixels in the direction perpendicular to the direction in which the edge pixel group is arranged from the edge pixel, the target pixel The image processing apparatus according to claim 1, further comprising: a corner information generation unit configured to generate the corner information indicating that a corner of the object is configured.
An edge pixel detection unit for detecting edge pixels constituting the edge of the object from the input image;
The same object configuration that extracts the edge pixel that forms the edge of the same object as the target pixel by comparing the pixel value of the target pixel that is an edge pixel and the pixel value of the edge pixel adjacent to the target pixel A pixel extractor;
An anti-aliasing processing unit that performs the anti-aliasing processing on the target pixel;
The anti-aliasing processing unit
An edge pixel group that includes the target pixel and is arranged in the vertical direction or the horizontal direction of the input image, selects one pixel from pixels that do not belong to the same object as the target pixel and are adjacent to the direction, The pixel value of the pixel of interest is output by combining the pixel value of the pixel of interest and the pixel value of the one pixel according to the distance between the pixel and the pixel of interest and the ratio based on the length of the pixel group. The image processing apparatus according to any one of claims 1 to 10.
A program for causing a computer to function as the image processing apparatus according to any one of claims 1 to 13.