JP5293923B2 - Image processing method and apparatus, image display apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display an easily browsable image of enhanced contrast, by correcting an image of one pixel pitch affecting mostly display of an adjacent pixel, even in the image after resolution-conversion-processed. <P>SOLUTION: Fellow pixel values of the adjacent pixels are compared each other as to an image data, to determine the pixel (peak pixel) with the pixel value getting minimum or maximum, and the pixel value of the pixel adjacent to the peak pixel is brought close to the pixel value of the peak pixel. In concretely saying, fellow pixel values of the respective adjacent pixels are compared using each pixel of the image data as a correction-objective pixel, using the one pixel adjacent to the correction-objective pixel as the first reference pixel, using the other pixel as the third reference pixel, and using the pixel in a position with the first reference pixel with respect to the correction-objective pixel therebetween, as the second reference pixel, the propriety as the peak pixel is determined as to the first reference pixel, and the pixel value of the correction-objective pixel is brought close to the pixel value of the first reference pixel, when determined as the peak pixel. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an image processing technique suitable for an image display apparatus that displays an image through an optical system such as a projector, a projection display, or a head mounted display.

  2. Description of the Related Art Conventionally, in a projection type image display device or the like that uses an image display element that spatially modulates illumination light based on image data and emits the image light as image light, and displays the image light emitted from the image display element on a screen. In the image display element, each pixel is displayed in a range clearly divided for each pixel. In order to enlarge and project it on the screen, it is necessary to project through various optical systems. However, each time an optical component such as a lens or a filter is passed through, aberration is generated, thereby affecting adjacent pixels outside the original pixel display range. In addition, the characteristics of the light from the light source to the image display element and the characteristics of emitting the image light by receiving the light from the light source of the image display element also affect adjacent pixels outside the display range of the original pixel. May occur. In the case where the influence on adjacent pixels is limited to a very narrow range, the influence can be prevented by providing a black matrix between the pixels of the image display element. It will decline. This reduction in the light use efficiency cannot be ignored as the affected range becomes wider. Therefore, it is not practical to use a large black matrix, and it can be used only when the affected range is narrow.

  In such a case, conventionally, edge enhancement processing for enhancing high frequency components such as edges and details has been performed. However, this method cannot cope with the difference in influence due to the pixel profile, and the improvement effect is limited. If the degree of processing increases, the image quality may be deteriorated. Further, in Patent Document 1, an image is sharpened by providing means for determining an achromatic color portion such as a character and performing edge enhancement processing on the achromatic color portion. However, when the image is blurred on the entire screen and affected by the pixel values of the surrounding pixels, the entire image will be blurred. In many cases, the image quality improvement effect is limited.

  Conventionally, as described in Patent Document 2, one frame of image data is divided into a plurality of subframes of image data, pixel shift is performed, and time-division display is performed. A projection-type image display device that realizes the above display is known. In this type of image display device, when the display range of the original pixel is larger than the display range of the pixel of the display resolution, The display has an effect, causing blurring and blurring of the image and a decrease in contrast. FIG. 36 shows an example in which vertical and horizontal ½ pitch pixel shifts are performed, and each display is performed at double resolution. The size of the pixels to be displayed is within the square range of the circle 1, but one of the image display elements. Since the range displayed by the pixels is the range a indicated by shading, the display of the surrounding pixels is greatly affected, and blurring and blurring of the image, a decrease in contrast, and the like occur. For this reason, in Patent Document 1, when the characteristic of the liquid crystal lens array is a convex lens such that the light emitted from the liquid crystal cell of the image display element is parallel to the optical axis of the projection optical system, the optical path is parallel. By providing an optical element that forms a concave lens array that returns light, the display range of the original pixel matches the display range of the pixel with the display resolution. Accurate control to match and installation of optical elements is difficult and expensive.

Japanese Patent No. 2954230 JP 2003-228072 A

  In order to solve the above problems, the present applicant previously identified an image having a width of one pixel having a large influence such as a decrease in contrast due to image blur in Japanese Patent Application No. 2007-128235, and the surrounding pixels. We proposed a method to reduce the influence of contrast reduction by correcting the value close to that of an image with a width of 1 pixel and display an easy-to-view image. However, there is a problem that an image having a width of one pixel to be corrected becomes two or more pixels and cannot be determined, and correction processing cannot be performed. For this reason, the influence such as a decrease in contrast cannot be reduced, and an easy-to-view image cannot be displayed.

  The present invention has a large effect of contrast reduction due to blurring of the image, and particularly corrects the surrounding pixel values such as fine lines even in an image after increasing the resolution by resolution conversion, thereby reducing the influence on the fine lines and the like. An object is to provide an image processing method and apparatus, an image display apparatus, and a program for displaying an image that is closer to the original display and easier to see.

  More specifically, the present invention relates to a projection-type image display device that displays an image through an optical system, in particular, by dividing one frame of image data into a plurality of sub-frame image data, shifting the pixels, and displaying them in a time-division manner. An object of the present invention is to provide an image processing method and apparatus suitable for an image display device in which adjacent pixels affect the display of other pixels, such as a projection-type image display device that realizes display at a resolution higher than that of the display element. To do.

  In the present invention, pixel values of adjacent pixels are compared for resolution-converted image data, etc., a pixel having a minimum or maximum pixel value (hereinafter referred to as a peak pixel) is determined, and a pixel adjacent to the peak pixel Is corrected so as to approach the pixel value of the peak pixel.

  More specifically, each pixel of the input image data is a correction target pixel, one pixel adjacent to the correction target pixel is a first reference pixel, the other pixel is a third reference pixel, and the correction target pixel is a first pixel. The pixel located at a position sandwiching the reference pixel is the second reference pixel, the first reference pixel and the correction target pixel, the correction target pixel and the third reference pixel, and the first reference pixel and the second reference pixel The pixel values of the pixels are compared to determine whether the first reference pixel is a peak pixel, and when it is determined to be a peak pixel, the pixel value of the correction target pixel is brought close to the pixel value of the first reference pixel Correct as follows.

  In one embodiment, the pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one direction, the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and the first When the correction condition that the pixel value of the reference pixel is less than the pixel value of the second reference pixel is satisfied, the correction is performed so that the pixel value of the correction target pixel approaches the pixel value of the first reference pixel.

  When each pixel of the image data is composed of a plurality of primary color components (hereinafter referred to as color components), the third reference pixel is greater than or equal to the pixel value of the correction target pixel in all color components, and the first When the pixel value of the reference pixel is less than the pixel value of the second reference pixel and the correction condition is satisfied that the pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one color component In addition, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel.

  In another embodiment, the pixel value of the correction target pixel is less than the pixel value of the first reference pixel in at least one direction, the third reference pixel is less than or equal to the pixel value of the correction target pixel, and the first When the correction condition that the pixel value of the second reference pixel is less than the pixel value of the first reference pixel is satisfied, the correction is performed so that the pixel value of the correction target pixel approaches the pixel value of the first reference pixel.

  When each pixel of the image data is composed of a plurality of primary color components (hereinafter, color components), the third reference pixel is equal to or less than the pixel value of the correction target pixel in all color components, and the second When the pixel value of the reference pixel is less than the pixel value of the first reference pixel and the correction condition that the pixel value of the correction target pixel is less than the pixel value of the first reference pixel in at least one color component is satisfied. In addition, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel.

  In yet another embodiment, in at least one direction, the pixel value of the first reference pixel is less than the pixel value of the correction target pixel, the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and The pixel value of one reference pixel is less than the pixel value of the second reference pixel, or the pixel value of the correction target pixel is less than the pixel value of the first reference pixel, and the third reference pixel is a pixel of the correction target pixel The pixel value of the correction target pixel is brought close to the pixel value of the first reference pixel when the correction condition is less than the value and the pixel value of the second reference pixel is less than the pixel value of the first reference pixel. Correct as follows.

  If each pixel of the image data is composed of a plurality of primary color components (hereinafter referred to as color components), the third reference pixel is equal to or greater than the pixel value of the correction target pixel in all color components, and the first reference The pixel value of the pixel is less than the pixel value of the second reference pixel, and the pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one color component, or all the color components The third reference pixel is equal to or smaller than the pixel value of the correction target pixel, the pixel value of the second reference pixel is less than the pixel value of the first reference pixel, and the pixel of the correction target pixel is at least one color component. When the correction condition that the value is less than the pixel value of the first reference pixel is satisfied, the correction is performed so that the pixel value of the correction target pixel approaches the pixel value of the first reference pixel.

  Further, when the correction conditions are satisfied in a plurality of directions, the correction target pixel is based on the pixel value of the first reference pixel in the direction in which the difference between the pixel value of the correction target pixel and the pixel value of the first reference pixel is small. The pixel value of is corrected.

  Further, when the correction conditions are satisfied in a plurality of directions, the correction target pixel is based on the pixel value of the first reference pixel in the direction in which the difference between the pixel value of the correction target pixel and the pixel value of the first reference pixel is large. The pixel value of is corrected.

  Further, when the correction conditions are satisfied in a plurality of directions, the pixel value of the correction target pixel is corrected based on the pixel value of the first reference pixel in the predetermined direction by a combination of the satisfied directions.

  Specifically, a value obtained by subtracting the pixel value of the first reference pixel from the pixel value of the correction target pixel and a constant of 1 or less is used as the correction value, and the correction value is subtracted from the pixel value of the correction target pixel. Thus, the pixel value of the correction target pixel is corrected.

  Further, when the correction conditions are satisfied in a plurality of directions, the pixel value of the correction target pixel is corrected based on an intermediate value of the pixel values of the first reference pixels in the plurality of satisfied directions.

  Specifically, a value obtained by subtracting an intermediate value from the pixel value of the correction target pixel is multiplied by a constant equal to or less than 1, and the correction value is subtracted from the pixel value of the correction target pixel by the correction value. The pixel value of the pixel is corrected.

  According to the present invention, it is possible to obtain a clear image such as a fine line even in an image that is greatly affected by a decrease in contrast due to blurring of the image, especially in an image after surrounding pixel values such as a fine line are increased in resolution by resolution conversion. It is possible to display an image that is closer to the original display and easier to view. The effect is particularly great when applied to an image display device in which adjacent pixels affect the display of other pixels.

  In one embodiment, the pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one direction, the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and the first When the correction condition that the pixel value of the reference pixel is less than the pixel value of the second reference pixel is satisfied, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel. An easy-to-view image with improved contrast can be displayed by suppressing the rising due to the influence of the correction target pixel on the dark adjacent pixel display.

  When each pixel of the image data is composed of a plurality of primary color components (hereinafter referred to as color components), the third reference pixel is greater than or equal to the pixel value of the correction target pixel in all color components, and the first A correction condition in which the pixel value of the reference pixel is less than the pixel value of the second reference pixel and the pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one color component When it satisfies, by correcting the pixel value of the correction target pixel so as to be close to the pixel value of the first reference pixel, the floating due to the influence of the bright correction target pixel on the dark adjacent pixel display is suppressed, and the color balance is achieved. An easy-to-view image with improved contrast can be displayed.

  In another embodiment, the pixel value of the correction target pixel is less than the pixel value of the first reference pixel in at least one direction, the third reference pixel is less than or equal to the pixel value of the correction target pixel, and When the correction condition that the pixel value of the second reference pixel is less than the pixel value of the first reference pixel is satisfied, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel. In addition, it is possible to display an easy-to-view image with improved contrast by suppressing sinking due to the influence of the dark correction target pixel on the bright adjacent pixel display.

  When each pixel of the image data is composed of a plurality of primary color components (hereinafter, color components), the third reference pixel is equal to or less than the pixel value of the correction target pixel in all color components, and the second When the pixel value of the reference pixel is less than the pixel value of the first reference pixel and the correction condition that the pixel value of the correction target pixel is less than the pixel value of the first reference pixel in at least one color component is satisfied. In addition, by correcting the pixel value of the correction target pixel so as to be close to the pixel value of the first reference pixel, subsidence due to the influence of the dark adjacent pixel on the bright correction pixel display is suppressed, color balance is achieved, and contrast is increased. An improved easy-to-view image can be displayed.

  The effects of various embodiments other than those described above will be described later in the description of the embodiments.

  FIG. 1 shows a block diagram of an embodiment of an image display apparatus to which the present invention is applied. Input image data (for example, image data subjected to resolution conversion) is temporarily stored in the input image data storage unit 10 in units of pixels, lines, frames, and the like, and sequentially sent to the image processing unit 20. The image processing unit 20 is functionally divided into a correction condition determination unit 22, a correction formula selection unit 24, and a pixel correction processing unit 26. The correction formula selection unit 24 is not used in some embodiments as described later.

  The correction condition determination unit 22 uses the input image data sent from the input image data storage unit 10 for each pixel as a correction target pixel in the horizontal direction or the vertical direction (generally at least in one direction). It is determined whether or not a predetermined correction condition is satisfied using an adjacent predetermined pixel as a reference pixel. When the correction formula selection unit 24 is not used, the pixel correction processing unit 26 sequentially satisfies the correction condition for each pixel (correction target pixel) of the input image data based on the determination result of the correction condition determination unit 22. Performs a correction process using a predetermined correction formula, and if not satisfied, outputs the image data as it is.

  On the other hand, the correction formula selection unit 24 selects a correction formula based on the determination result of the correction condition determination unit 22, and when the correction condition is satisfied in both the horizontal and vertical directions (generally a plurality of directions), A correction formula in one of the determined directions or another third correction formula is selected. When this correction formula selection unit 24 is used, the pixel correction processing unit 26 performs correction processing on the correction target pixel using the correction formula selected by the correction formula selection unit 24.

  The output image data is stored in the output image data storage unit 30, and then sent to and displayed on a display unit 40 such as a projection type image display device. For example, as disclosed in Patent Document 2, the display unit 40 divides one frame of image data into a plurality of subframes of image data, and realizes display in a time division manner that is higher than the resolution of the image display element. Etc. are used.

  The image display apparatus of FIG. 1 is generally configured by a computer device, and the image processing unit 20 is based on a CPU, a program, and the like, functions of the correction condition determination unit 22 and the pixel correction processing unit 26, or the correction condition determination unit 22 The functions of the correction formula selection unit 24 and the pixel correction processing unit 26 are processed together. The image processing method of the present invention relates to the processing algorithm of the image processing unit 20, and various embodiments thereof will be described later.

  FIG. 2 is a diagram showing a positional relationship between a correction target pixel and a reference pixel used in an embodiment described later. In the figure, C3 is a correction target pixel, A3, B3, D3, and E3 are vertical reference pixels, and C1, C2, C4, and C5 are horizontal reference pixels. As will be described later, correction conditions are determined by C1-C4 or C2-C5 for the horizontal direction, and correction conditions are determined by A3-D3 or B3-E3 for the vertical direction.

  In a general projection-type image display device or the like, each pixel is displayed in a clearly delimited range for each pixel on the image display element, but the range in which the pixel is displayed is expanded by passing through an optical system thereafter. This may affect the range of other pixels, causing blurring in the image and degrading the image quality. In particular, in a projection-type image display device that divides image data of one frame to be displayed into image data of a plurality of sub-frames and realizes display that is higher than the resolution of the display element by time division, the display range of the original pixel is the display resolution In most cases, each pixel is affected by the adjacent pixels, resulting in blurring in the image and image quality degradation. At this time, an image having a width of one pixel is most affected.

Here, the principle of the present invention will be described by taking as an example the case of correcting floating in the horizontal direction. FIG. 3 shows an example of the display state before and after the correction processing of the correction target pixel C3 and the horizontal reference pixels C1, C2, C4, and C5. Here, (a), (b), and (c) assume an image that has undergone resolution conversion, and (d) assumes an image that has not undergone resolution conversion.

  In the case of a black line having a width of 1 pixel, a line having a width of 1 pixel in an image that has been subjected to resolution conversion and increased in resolution represents the line over a width of 2 pixels or more as shown in FIG. Therefore, paying attention to the gradient of the pixel value, which is a feature when resolution conversion is performed, for example, between C1 to C4, the pixel to be corrected (interpolated pixel) C3 and the reference pixel C1 are sandwiched as shown in FIG. The case where the reference pixel C2 becomes a valley bottom (minimum) is determined as an image (black line) having a width of one pixel, and the pixel value of the correction target pixel (interpolation pixel) C3 determined to be therearound is referred to. Correction that approaches the pixel value of the pixel C2 is performed (lowering the pixel value). Similarly, a case where the reference pixel C4 sandwiched between the correction target pixel C3 and the reference pixel C5 is a valley bottom as shown in FIG. Correction is performed so that the pixel value of the correction target pixel C3 approaches the pixel value of the reference pixel C4 (lowering the pixel value). This reduces the decrease in contrast due to blur. In the case of FIG. 3C, it is determined that there are two or more pixels, and the pixel value of the correction target pixel C3 is left as it is (not corrected). In addition, the same correction process as in (a) is performed even for an image that has not undergone resolution conversion as shown in FIG. Thereby, the black line can be emphasized. Similarly, the floating can be corrected with respect to the vertical direction.

  The present invention is not limited to the case of correcting the image floating as described above. On the contrary, it is possible to correct the sinking of the image by determining that the maximum value is an image of one pixel width (white line). It is also possible to correct ups and downs simultaneously. Further, it can be applied to both monochromatic and color images. Hereinafter, various embodiments of the present invention will be described in detail.

  The adjacent pixels on the display surface affect each other, thereby causing a deviation from the pixel value to be originally displayed, thereby causing a decrease in contrast. An image of one pixel pitch that is most affected by the display of the adjacent pixels is corrected.

  In the present embodiment, when a predetermined condition is satisfied in an image in which each display pixel is composed of a single color, the pixel value of the correction target pixel is lowered, thereby affecting the display of the dark adjacent pixel of the bright correction target pixel. The image (monochromatic black) is lifted by the above-described image, and an easy-to-see image with improved contrast is displayed.

  4 to 8 show processing flowcharts of the present embodiment. The image processing unit 20 in FIG. 7 and 8 are examples in which the correction formula selection unit 24 is also used. Hereinafter, each processing flowchart will be described.

  FIG. 4 shows an example in which each display pixel is composed of a single color and is adjacent to the correction target pixel in the horizontal or vertical direction in order to correct an image of one pixel pitch that is most affected by the display of adjacent pixels. When the first pixel is the first reference pixel, the other pixel is the third reference pixel, and the pixel located at the position sandwiching the first reference pixel from the correction target pixel is the second reference pixel, at least horizontal or vertical The pixel value of the first reference pixel is less than the pixel value of the correction target pixel with respect to the direction, the pixel value of the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and the pixel of the first reference pixel When the correction condition that the value is less than the pixel value of the second reference pixel is satisfied, the pixel value of the correction target pixel is corrected so as to approach the pixel value of the first reference pixel (the pixel value is lowered). . FIG. 3 shows this case.

  Table 1 summarizes the correspondence between the correction conditions and the correction equations in each direction in the processing flow of FIG.

Here, C1, C2, C3, C4, C5, A3, B3, D3, and E3 are as shown in FIG. 2, and C3 is a correction target pixel. a and b are horizontal correction conditions and correction equations, and c and d are vertical correction conditions and correction equations. When the left correction conditions are satisfied, the corresponding right correction equations are applied. Thus, the pixel value of the correction target pixel c3 is brought closer to the pixel value of the first reference pixel (C2, C4, B3, or D3) (the pixel value is lowered). Note that Z in the correction formula determines the correction ratio and takes a range of 0 <Z <1 (for example, Z = 0.25).
By setting such a correction condition, it is possible to determine a peak (for example, a black line) of an image having a pixel pitch that is darker than the surroundings in an image subjected to resolution conversion.

  In the processing flow of FIG. 4, for each pixel of the input image data, it is determined whether or not the left correction condition is satisfied in the order of “a” to “d” in Table 1 as the correction target pixel C3. The right correction equation is calculated to correct the pixel value of the correction target pixel C3 (lower the pixel value). When all the correction conditions a to d are not satisfied, the correction process is not performed on the correction target pixel C3 (C3 = C3). This is repeated until there is no input image data.

  Note that the processing flowchart of FIG. 4 is merely an example, and the order of processing (horizontal priority in FIG. 4) and the formula for performing correction processing are not limited to those shown in the figure, and when a predetermined condition is satisfied In addition, any process that can reduce the influence of other pixel displays may be used. The same applies to the subsequent processing flowcharts. Hereinafter, the processing flow of FIG. 4 will be described in detail.

  It is determined whether the correction conditions on the left side of Table 1a are satisfied by the horizontal pixels C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 101 to 103). If satisfied, the right correction equation is calculated (step 104), and the pixel value of the correction target pixel C3 is brought close to the pixel value of the reference pixel C2 (the pixel value is lowered). When the correction condition of a in Table 1 is not satisfied, horizontal pixels C2 to C5 (first reference pixel; C4, second reference pixel; C5, third reference pixel; C2) It is determined whether the correction condition is satisfied (steps 105 and 106). If the correction condition is satisfied, the right-side correction formula is calculated (step 107), and the pixel value of the correction target pixel C3 is brought close to the pixel value of the reference pixel C4 (pixel value). Lower).

  When the conditions a and b in Table 1 are not satisfied, that is, when the horizontal correction condition is not satisfied, the vertical pixels A3 to B3 (first reference pixel; B3, second reference pixel; It is determined from the third reference image D3) whether the correction condition on the left side of c in Table 1 is satisfied (steps 108, 109, 110), and if satisfied, the correction expression on the right side is calculated (step 111) to be corrected. The pixel value of the pixel C3 is brought close to the pixel value of the reference pixel B3 (the pixel value is lowered). When the condition of c in Table 1 is not satisfied, correction of the left side of d in Table 1 is performed by vertical pixels B3 to E3 (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3). It is determined whether or not the condition is satisfied (steps 112 and 113). If the condition is satisfied, the correction formula on the right side is calculated (step 114), and the pixel value of the correction target pixel C3 is brought close to the pixel value of the reference pixel D3 (the pixel value is changed). Lower).

  On the other hand, when all the correction conditions a to d in Table 1 are not satisfied, that is, when the correction conditions are not satisfied in both the horizontal and vertical directions, the pixel value of the correction target pixel C3 is left as it is (step 115). ).

  According to the present embodiment, even in the image after the resolution conversion processing, it is possible to correct an image (black line) having a single pixel pitch that is most affected by the display of adjacent pixels, and the bright correction target pixel is dark. An easy-to-see image with improved contrast can be displayed by suppressing the floating due to the influence on the display of adjacent pixels.

  FIG. 34 shows a specific processing example. FIG. 34 is an enlarged view. Actually, a, b, etc. in (A) are black lines with a width of one pixel (one pixel pitch). By performing resolution conversion processing on an image such as (A), as shown in (B), a black line with a width of one pixel is expressed by two or more pixels, resulting in floating (for example, c, d, e, etc.) . (C) is an image after correction processing, and the pixel values of pixels such as c, d, and e are brought close to the pixel values of adjacent black lines (the pixel values are lowered) (c ′, d ′, e ′). Etc.), and the contrast is improved (black line emphasis) and an easy-to-view image can be displayed. The same applies to other examples.

  FIG. 5 determines whether or not the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). If the correction condition is satisfied, the pixel values of the correction target pixel and the horizontal and vertical directions satisfying the correction condition are determined. Using the correction formula with the smaller difference from the pixel value of one reference pixel, the pixel value of the correction target pixel is corrected so as to approach the pixel value of the first reference pixel (lowering the pixel value). is there. The process when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in the processing flow of FIG. 5 is the same as that in Table 1 in FIG. Hereinafter, the processing flow of FIG. 5 will be described in detail.

  It is determined whether the correction condition on the left side of Table 1a is satisfied by the horizontal pixels C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 201 to 203). ). If satisfied, it is determined whether the correction condition on the left side of c in Table 1 is satisfied by the vertical pixels A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) ( Steps 204-206). When this is also satisfied, that is, when the correction conditions of a and c in Table 1 are satisfied, the pixel values of C2 and B3, which are the first reference pixels, are compared (step 207), and the larger one (C3 and Is calculated (Step 208 or 209), and the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered).

  When the correction condition a in Table 1 is satisfied and the correction condition c is not satisfied, the vertical pixels B3 to E3 (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) determines whether the correction condition on the left side of d in Table 1 is satisfied (steps 210 and 211). Then, when satisfied, that is, when the correction conditions of a and d in Table 1 are satisfied, the pixel values of C2 and D3 as the first reference pixels are compared (step 212), and the larger one is supported. The right-side correction formula is calculated (step 209 or 213), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is lowered).

  If the correction condition a in Table 1 is satisfied and neither the correction condition c nor d is satisfied, the correction equation on the right side of a is directly calculated (step 209), and the pixel value of the correction target pixel C3 is calculated. To the pixel value of C2 (lower the pixel value).

  When the correction condition of a in Table 1 is not satisfied, horizontal pixels C2 to C5 (first reference pixel; C4, second reference pixel; C5, third reference pixel; C2) It is determined whether the left correction condition is satisfied (steps 214 and 215). If satisfied, it is determined whether the correction condition on the left side of c in Table 1 is satisfied by the vertical pixels A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) ( Steps 216-218). When satisfied, that is, when the correction conditions b and c in Table 1 are satisfied, the pixel values of C4 and B3, which are the first reference pixels, are compared (step 219), and the larger one (difference from c3) Is calculated (step 220 or 221), and the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C4 (the pixel value is lowered).

  When the correction condition b in Table 1 is satisfied and the correction condition c is not satisfied, the pixels B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) Thus, it is determined whether the correction condition on the left side of d in Table 1 is satisfied. (Steps 222 and 223). When satisfied, that is, when the correction conditions of b and d in Table 1 are satisfied, the pixel values of C4 and D3 as the first reference pixels are compared (step 224), and the right side corresponding to the larger one is compared. The correction formula is calculated (step 221 or 225), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C4 or D3 (the pixel value is lowered).

  If the correction condition of b in Table 1 is satisfied and neither of the correction conditions of c and d is satisfied, the correction formula on the right side of b is calculated as it is (step 221), and the pixel value of the correction target pixel C3 is calculated. To the pixel value of C4 (lower the pixel value).

  When the correction conditions a and b in Table 1 are not satisfied, that is, when the correction conditions are not satisfied in the horizontal direction, the pixels A3 to D3 in the vertical direction (first reference pixel; B3, second reference pixel; A3, Whether or not the correction condition on the left side of c in Table 1 is satisfied is determined by the third reference pixel; D3) (steps 226 to 228). If satisfied, the correction expression on the left side is calculated as it is (step 229), and the correction target The pixel value of the pixel C3 is brought close to the pixel value of B3 (the pixel value is lowered). If not, it is determined whether the correction condition on the left side of d in Table 1 is satisfied by the vertical pixels B3 to E3 (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) ( In Steps 230 and 231), when satisfied, the right correction equation is calculated as it is (Step 232), and the pixel value of the correction target pixel C3 is brought close to the pixel value of D3 (the pixel value is lowered).

  If all the correction conditions a to d in Table 1 are not satisfied, that is, if the correction conditions are not satisfied in both the horizontal and vertical directions, the pixel value of the correction target pixel c3 is left as it is (step 233).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the correction target pixel is calculated using the correction formula with the smaller difference between the correction target pixel C3 and the first reference pixel. By correcting the pixel value of C3 (lowering the pixel value), the contrast of the display image can be improved without the effect becoming too large.

  6, contrary to FIG. 5, when the correction conditions are satisfied in both the horizontal and vertical directions (generally, in a plurality of directions), the pixel values of the correction target pixels and the horizontal and vertical directions that satisfy the correction conditions are satisfied. Using a correction formula having a larger difference from the pixel value of the first reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (lowering the pixel value) It is. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in the processing flow of FIG. 6 is the same as that of Table 1 in FIG.

  In the processing flow of FIG. 6, the difference from FIG. 5 is that the magnitude comparison determination in steps 307, 312, and 324 is only in the opposite relation to steps 207, 212, 219, and 224 of FIG. 5. The other processes are exactly the same as in FIG. Hereinafter, the processing flow of FIG. 6 will be described in detail.

  It is determined whether or not the condition of a in Table 1 is satisfied by the horizontal pixels C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 301 to 303). In this case, it is determined whether the correction condition of c in Table 1 is satisfied by the vertical pixels A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) (steps 304 to 304). 306). Then, when the correction conditions of a and c in Table 1 are satisfied, the pixel values of C2 and B3, which are the first reference pixels, are compared (step 307), and the smaller one (the difference from C3 is large) is handled. The correction formula is calculated (step 308 or 309), and the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered).

  If the correction condition a in Table 1 is satisfied and the condition c is not satisfied, the vertical pixels B3 to E3 (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) ) To determine whether the condition of d in Table 1 is satisfied (steps 310 and 311). When the conditions a and d in Table 1 are satisfied, the pixel values of C2 and D3, which are the first reference pixels, are compared (step 312), and a correction formula corresponding to the smaller one is calculated (step 309). Or 313), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is lowered).

  When the condition of a in Table 1 is not satisfied, correction of b in Table 1 is performed by horizontal pixels C2 to C5 (first reference pixel; C4, second reference pixel; C5, third reference pixel; C2). Whether or not the condition is satisfied is determined (steps 314 and 315). If the condition is satisfied, the vertical pixels A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) are Whether or not the condition of c is satisfied is determined (steps 316 to 318). When the correction conditions b and c in Table 1 are satisfied, the pixel values of C4 and B3, which are the first reference pixels, are compared (step 319), and the correction corresponding to the smaller one (the difference is larger than c3). The equation is calculated (step 320 or 321), and the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C4 (the pixel value is lowered).

  When the correction condition b in Table 1 is satisfied and the correction condition c is not satisfied, the vertical pixels B3 to E3 (first reference pixel; D3, second reference pixel; E3, third reference pixel; Whether or not the correction condition d in Table 1 is satisfied is determined by B3) (steps 322 and 323). When the correction conditions b and d in Table 1 are satisfied, the pixel values of C4 and D3, which are the first reference pixels, are compared (step 324) and correspond to the smaller one (the difference from C3 is large). The correction formula is calculated (step 321 or 325), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C4 or D3 (the pixel value is lowered).

  On the other hand, if any one of the correction conditions a to d in Table 1 is satisfied, the corresponding correction formula is calculated as it is (steps 309, 321, 329, or 332), and the pixel value of the correction target pixel C3 is determined as appropriate. Approach the pixel value of the first reference pixel (lower the pixel value). If none of the conditions a to d in Table 1 is satisfied, the pixel value of the correction target pixel C3 is left as it is (step 333).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the correction target is corrected using the correction formula having the larger difference between the correction target pixel C3 and the first reference pixel. By correcting the pixel value of the pixel c3 (lowering the pixel value), excessive correction may be applied to the reference pixel side having a small difference, but the frequency is generally low and the influence on the entire image is slight. The influence can be reduced by the value of Z (correction ratio). Compared with the influence, the contrast is much improved and an easy-to-view image can be displayed.

  FIG. 7 shows that when the correction condition is satisfied in both the horizontal and vertical directions (generally, in a plurality of directions), the pixel value of the correction target pixel is calculated using a predetermined correction formula depending on the combination of the satisfied directions. Correction is performed so as to approach the pixel value of one reference pixel (lowering the pixel value). That is, correction is performed using a difference between a predetermined correction target pixel, a pixel value of a reference pixel having a value different from that of the adjacent correction target pixel, and a pixel value of the correction target pixel according to a combination of the satisfied directions. . The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in the processing flow of FIG. 7 is the same as in Table 1 in FIG. Hereinafter, the processing flow of FIG. 7 will be described in detail.

  It is determined whether the correction condition on the left side of Table 1a is satisfied by the horizontal pixels C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 401 to 403). ). If satisfied, D3 ≧ C3 is determined (step 404). If the determination result is YES, the correction formula on the right side of a is calculated (step 405), and the pixel value of the correction target pixel C3 is set to C2 (first reference). Pixel) (close the pixel value). That is, when the correction condition a in Table 1 is satisfied and the correction condition c is satisfied (when possible), the pixel value of the correction target pixel c3 is corrected using the correction expression a. If the determination result of D3 ≧ C3 is NO, B3 ≧ C3, E3> D3 is determined (steps 406 and 407). If both are YES, the correction formula on the right side of d in Table 1 is calculated. (Step 408), the pixel value of the correction target pixel C3 is brought close to the pixel value of D3 (first reference pixel) (the pixel value is lowered). That is, when the conditions of a and d in Table 1 are satisfied, the pixel value of the correction target pixel c3 is corrected using the d correction equation. If NO is determined in any of steps 406 and 407, that is, if only the correction condition a in Table 1 is satisfied, the pixel value of the correction target pixel c3 is corrected using the correction formula a. (Step 405).

  On the other hand, when the correction condition a in Table 1 is not satisfied, horizontal pixels C2 to C5 (first reference pixel; C4, second reference pixel; C5, third reference pixel; C2) It is determined whether the correction condition on the left side of b is satisfied (steps 409 and 410). If satisfied, D3 ≧ C3 is determined. If the determination result is YES, A3> B3, C3> B3 is determined (steps 412 and 413). If both are YES, the correction on the right side of c in Table 1 is performed. The equation is calculated (step 414), and the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 (first reference pixel) (the pixel value is lowered). That is, when the correction conditions b and c in Table 1 are satisfied, the pixel value of the correction target pixel C3 is corrected using the correction formula c. If the determination result of D3 ≧ C3 is NO, the correction formula for b is calculated (step 415), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C4 (first reference pixel) ( Reduce the pixel value). That is, when the correction condition b in Table 1 is satisfied and the correction condition d is satisfied (when it may be satisfied), the pixel value of the correction target pixel c3 is corrected using the correction expression b. If NO is determined in any of steps 412 and 413, that is, if only the correction condition for b is satisfied, the pixel value of the correction target pixel C3 is corrected using the correction formula for b (step 415).

  When the correction conditions a and b in Table 1 are not satisfied, that is, when the correction conditions are not satisfied in the horizontal direction, the pixels A3 to D3 in the vertical direction (first reference pixel; B3, second reference pixel; A3, Whether or not the correction condition on the left side of c in Table 1 is satisfied is determined by the third reference pixel; D3) (steps 416 to 418). If satisfied, the correction expression on the left side is calculated as it is (step 419), and the correction target The pixel value of the pixel C3 is brought close to the pixel value of B3 (the pixel value is lowered). If not, it is determined whether the correction condition on the left side of d in Table 1 is satisfied by the vertical pixels B3 to E3 (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) ( If the conditions are satisfied, the right correction formula is calculated (step 422), and the pixel value of the correction target pixel C3 is brought close to the pixel value of D3 (the pixel value is lowered).

  If all the correction conditions a to d in Table 1 are not satisfied, that is, if the correction conditions are not satisfied both in the horizontal and vertical directions, the pixel value of the correction target pixel C3 is left as it is (step 423).

  As is clear when FIG. 7 is compared with FIG. 5 and FIG. 6, when the correction conditions are satisfied in a plurality of directions, the pixel value of the correction target pixel is determined using a predetermined correction formula depending on the combination of the satisfied directions. By correcting the above, the processing is simplified. Therefore, the circuit scale for performing the correction process can be reduced and the cost can be reduced. In addition, since the correction conditions are satisfied in multiple directions and the difference between the pixel value of the reference pixel value and the interpolated pixel is different in the multiple directions, it is small when viewed from the whole image, and the influence on the image quality is often small. Although the difference is small, it is possible to display an easy-to-view image with low cost and improved contrast.

  FIG. 8 shows the values between the pixel values of the first reference pixels that satisfy the correction condition and the pixels of the correction target pixel when the correction condition is satisfied in both the horizontal and vertical directions (generally a plurality of directions). The pixel value of the correction target pixel is corrected (the pixel value is lowered) using the difference from the value. FIG. 8 shows an example in which an average value is used as a value between two first reference pixel values that satisfy the correction condition in the horizontal and vertical directions. The processing when the correction condition is satisfied in one direction is the same as in FIG.

  Table 2 shows a correspondence relationship between a combination of correction conditions in the satisfied direction and a correction formula to be applied when the correction conditions are satisfied in both the horizontal and vertical directions. The correspondence between the correction condition and the correction formula when the correction condition is satisfied in one direction is the same as that in Table 1 in FIG.

  Hereinafter, the processing flow of FIG. 8 will be described in detail. It is determined whether or not the correction condition of a in Table 1 is satisfied by the horizontal pixels C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 501 to 503), If it is satisfied, it is determined whether the correction condition of c in Table 1 is satisfied by the vertical pixels A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) (step 504). ~ 506). When the correction conditions of a and c in Table 1 are satisfied, that is, when the correction condition on the left side of 1 in Table 2 is satisfied, a correction equation on the right side is calculated (step 507), and the correction target pixel C3 is calculated. Is corrected (lowers the pixel value). That is, the correction process is performed using the difference between the average value of the reference pixels C2 and B3 and the pixel value of the correction target pixel C3.

  When the correction condition a in Table 1 is satisfied and the correction condition c is not satisfied, the vertical pixels B3 to E3 (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) determines whether the condition of d in Table 1 is satisfied (steps 508 and 509). When the correction conditions of a and d in Table 1 are satisfied, that is, when the correction conditions on the left side of 2 in Table 2 are satisfied, a correction expression on the right side is calculated (step 510), and the correction target pixel C3 is calculated. Is corrected (lowers the pixel value). That is, the correction process is performed using the difference between the average value of the reference pixels C2 and D3 and the pixel value of the correction target pixel C3.

  When the correction condition of a in Table 1 is not satisfied, horizontal pixels C2 to C5 (first reference pixel; C4, second reference pixel; C5, third reference pixel; C2) Whether or not the condition is satisfied is determined (steps 512 and 513). If the condition is satisfied, the vertical pixels A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) are Whether the correction condition of c is satisfied is determined (steps 514 to 516). When the correction conditions b and c in Table 1 are satisfied, that is, when the correction conditions on the left side of 3 in Table 2 are satisfied, a correction expression on the right side is calculated (step 517), and the correction target pixel C3 is calculated. Is corrected (lowers the pixel value). That is, the correction process is performed using the difference between the average value of the reference pixels C4 and B3 and the pixel value of the correction target pixel C3.

  When the correction condition b in Table 1 is satisfied and the condition c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) Thus, it is determined whether the condition of d in Table 1 is satisfied (steps 518 and 519). When the conditions of b and d in Table 1 are satisfied, that is, when the correction condition on the left side of 4 in Table 2 is satisfied, the right side correction equation is calculated (step 520), and the correction target pixel C3 is calculated. Correct the pixel value (lower the pixel value). That is, the correction process is performed using the difference between the average value of the reference pixels C4 and D3 and the pixel value of the correction target pixel C3.

  On the other hand, when any one of the correction conditions a to d in Table 1 is satisfied, the corresponding correction formula is calculated as it is (steps 511, 521, 525 or 528), and the pixel value of the correction target pixel C3 is calculated. Approach the pixel value of the first reference pixel (lower the pixel value). If none of the conditions a to d in Table 1 is satisfied, the pixel value of the correction target pixel C3 is left as it is (step 529).

  In the case of FIG. 8, for example, the processing is simplified as compared with FIG. 5, so that the circuit scale for performing the correction processing is reduced, and the cost can be reduced. In addition, when correction conditions are satisfied in multiple directions, image processing is performed while balancing the correction amount using the difference between each reference pixel value and the correction target pixel value, thereby improving contrast at low cost. Thus, an easy-to-see image can be displayed.

  In this embodiment, in an image in which each display pixel is configured in a single color, contrary to the first embodiment, when a predetermined correction condition is satisfied, the correction target pixel is raised to increase the dark correction target pixel. The image (monochromatic white) is prevented from sinking due to the influence on the display of bright adjacent pixels, and an easy-to-view image with improved contrast is displayed.

  9 to 13 show processing flowcharts of the present embodiment. The image processing unit 20 in FIG. 12 and 13 are examples in which the correction formula selection unit 24 is also used. Hereinafter, each processing flowchart will be described.

  FIG. 9 shows that in an image in which each display pixel is composed of a single color, one pixel adjacent to the correction target pixel in the horizontal or vertical direction is the first reference pixel, and the other pixel is the third reference pixel. When a pixel located at a position sandwiching the first reference pixel from the target pixel is the second reference pixel, the pixel value of the correction target pixel is less than the pixel value of the first reference pixel at least in the horizontal or vertical direction And the pixel value of the third reference pixel is less than or equal to the pixel value of the correction target pixel and the pixel value of the second reference pixel is less than the pixel value of the first reference pixel. The pixel value is corrected so as to be close to the pixel value of the first reference pixel (the pixel value is increased).

  Table 3 summarizes the correspondence between the correction conditions and the correction formulas in the processing flow of FIG.

Here, C1, C2, C3, C4, A3, B3, D3, and E3 are as shown in FIG. 2, and C3 is a correction target pixel. a and b are correction conditions and correction formulas in the horizontal direction, and c and d are correspondence relations between correction conditions and correction formulas in the vertical direction. When the correction conditions on the left side are satisfied, the corresponding correction formula on the right side is applied. Thus, the pixel value of the correction target pixel C3 is brought close to the pixel value of the first reference pixel (C2, C4, B3, or D3) (the pixel value is increased).
By setting such a correction condition, it is possible to determine a peak (white line or the like) of an image having a pixel pitch that is brighter than the surroundings in the resolution-converted image.

  The processing flow of FIG. 9 is basically the same as the processing flow of FIG. 4 (in FIG. 4 and FIG. 9, only the inequality signs of the correction conditions are reversed), and detailed description thereof is omitted. As in FIG. 4, for each pixel of the input image data, it is determined whether or not the left correction condition is satisfied in the order of “a” to “d” in Table 3 as the correction target pixel C <b> 3. The correction formula on the right side is applied to correct the pixel value of the correction target pixel C3 so as to approach the pixel value of the first reference pixel (C2, C4, B3, or D3) (increase the pixel value). If all the correction conditions a to d in Table 3 are not satisfied, that is, if the correction conditions are not satisfied in both the horizontal direction and the vertical direction, the correction process is not performed on the correction target pixel C3 ( C3 = C3). This is repeated until there is no input image data.

  For example, the correction conditions of a in Table 3 are determined based on C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 601 to 603) and satisfied If this is the case, the corresponding right-side correction formula is calculated (step 604), and the pixel value of the correction target pixel C3 is corrected so as to approach the pixel value of the first reference pixel C2 (the pixel value is increased).

  According to the present embodiment, even in the image after the resolution conversion processing, an image with a single pixel pitch (white line) that is most affected by the display of adjacent pixels can be corrected, and a bright adjacent to a dark correction target pixel. It is possible to display an easy-to-view image with improved contrast by suppressing the sinking of the image due to the influence on the display of the pixels.

  FIG. 35 shows a specific processing example. Similarly to FIG. 34, FIG. 35 is an enlarged view. Actually, a, b, etc. in (A) are white lines of one pixel width (one pixel pitch). By performing resolution conversion processing on an image such as (A), as shown in (B), a white line having a width of one pixel is expressed by two or more pixels, and sinking occurs (for example, c, d, e, f). Such). (C) is an image after correction processing, and the pixel values of pixels such as c, d, e, and f are brought close to the pixel values of adjacent white lines (the pixel values are increased) (c ′, d ′, e). ', F', etc.), subsidence is suppressed, contrast is improved (white lines are emphasized), and an easy-to-view image can be displayed. The same applies to other examples.

  FIG. 10 determines whether the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), and if satisfied, the pixel values of the correction target pixels and the horizontal and vertical directions satisfying the correction condition are determined. Using the correction formula with the smaller difference from the pixel value of one reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (the pixel value is increased). is there. The processing when the correction condition is satisfied in one direction is the same as in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 10 is the same as that in Table 3 in FIG. The processing flow in FIG. 10 is basically the same as the processing flow in FIG. 5 (in FIG. 5 and FIG. 10, only the inequality signs of the correction conditions are reversed), and detailed description thereof is omitted.

  For example, it is determined whether the correction condition of a in Table 3 is satisfied by horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 701 to 703). If satisfied, it is determined whether the correction condition of c in Table 3 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 704). ~ 706). When the correction conditions of a and c in Table 1 are satisfied, the pixel values of C2 and B3 are compared (step 707), and the right-side correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Step 708 or 709), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  When the correction condition of a in Table 3 is satisfied and the correction condition of c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) Then, the correction condition of d in Table 3 is determined (steps 710 and 711). If the correction conditions of a and d in Table 3 are satisfied, the pixel values of C2 and D3 are compared (step 712), and the right-side correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Step 709 or 713), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is increased).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, in a plurality of directions), the correction target pixel C3 is corrected using a correction formula having a smaller difference between the correction target pixel C3 and the first reference pixel. By correcting the pixel value (increasing the pixel value), the contrast of the display image can be improved without the effect becoming too great.

  In contrast to FIG. 10, when the correction conditions are satisfied in both the horizontal and vertical directions (generally a plurality of directions), FIG. 11 shows the horizontal and vertical directions that satisfy the pixel values of the correction target pixels and the correction conditions. Using the correction formula having the larger difference from the pixel value of the first reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (the pixel value is increased). It is. The processing when the correction condition is satisfied in one direction is the same as in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 11 is the same as that in Table 3 in FIG. Further, the processing flow of FIG. 11 is basically the same as the processing flow of FIG. 6 (only the inequality sign of the correction condition is reversed in FIGS. 6 and 11), and thus detailed description thereof is omitted.

  For example, it is determined whether the correction condition of a in Table 3 is satisfied by horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 801 to 803). If satisfied, it is determined whether the correction condition of c in Table 1 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 804806). ). When the correction conditions a and c in Table 1 are satisfied, the pixel values of C2 and B3 are compared (step 807), and the right-side correction equation corresponding to the smaller one (the difference from C3 is large) is calculated. (Step 808 or 809), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  When the correction condition of a in Table 3 is satisfied and the correction condition of c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) Then, the correction condition of d in Table 3 is determined (steps 810 and 811). When the correction conditions of a and d in Table 1 are satisfied, the pixel values of C2 and D3 are compared (step 812), and the right-side correction formula corresponding to the smaller one (the difference from C3 is large) is calculated. (Step 809 or 813), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is increased).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the correction target pixel is calculated using the correction formula having the larger difference between the correction target pixel C3 and the first reference pixel. Correcting the pixel value of C3 (increasing the pixel value) can similarly improve the contrast of the display image.

  FIG. 12 shows that when the correction condition is satisfied in both the horizontal and vertical directions (generally, in a plurality of directions), the pixel value of the correction target pixel is calculated using a predetermined correction formula depending on the combination of the satisfied directions. The correction is performed so as to approach the pixel value of the first reference pixel (the pixel value is increased). The processing when the correction condition is satisfied in one direction is the same as in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 12 is the same as that in Table 3 in FIG. The processing flow in FIG. 12 is basically the same as the processing flow in FIG. 7 (in FIG. 7 and FIG. 12, the inequality signs of the correction conditions are reversed), and detailed description thereof is omitted. .

  For example, it is determined whether the correction condition of a in Table 3 is satisfied by horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 901 to 903). If satisfied, D3 ≦ C3 is determined (step 904), and if the determination result is YRS (the correction condition of c may also be satisfied), the correction equation on the right side of a in Table 3 is calculated ( Step 905), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 (the pixel value is increased). If the determination result of D3 ≦ C3 is NO, B3 ≦ C3, E3 ≦ D3 is determined (steps 906 and 907), and if both are YES (the correction conditions of a and d are satisfied), d in Table 3 The right-side correction formula is calculated (step 908), and the pixel value of the correction target pixel C3 is brought close to the pixel value of D3 (the pixel value is increased).

  As is clear when the processing flow of FIG. 12 is compared with that of FIG. 10 or FIG. 11, when the correction conditions are satisfied in a plurality of directions, the correction target is determined using a predetermined correction formula depending on the combination of the satisfied directions. By correcting the pixel value of the pixel, the process is simplified. Therefore, the circuit scale for performing the correction process can be reduced and the cost can be reduced. In addition, since the correction conditions are satisfied in multiple directions and the difference between the pixel value of the reference pixel value and the interpolated pixel is different in the multiple directions, it is small when viewed from the whole image, and the influence on the image quality is often small. Although the difference is small, it is possible to display an easy-to-view image with low cost and improved contrast.

  FIG. 13 shows values (herein, average values) between pixel values of the first reference pixels that satisfy the correction condition when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). The pixel value of the correction target pixel is corrected (the pixel value is increased) using the difference between the correction value and the pixel value of the correction target pixel. The processing when the correction condition is satisfied in one direction is the same as in FIG.

  Table 4 shows a correspondence relationship between a combination of correction conditions in the satisfied direction and a correction formula to be applied when the correction conditions are satisfied in both the horizontal and vertical directions. Since the correspondence relationship between the correction condition and the correction formula when the correction condition is satisfied in one direction is the same as that in Table 3 in FIG.

  The processing flow of FIG. 13 is basically the same as the processing flow of FIG. 8 (only the inequality signs of the correction conditions are reversed in FIGS. 8 and 13), and detailed description thereof is omitted.

  For example, it is determined whether the correction condition of a in Table 3 is satisfied by C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 1001 to 1003). If satisfied, it is determined whether the correction condition of c in Table 3 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 1004). ~ 1006). When the correction conditions a and c in Table 3 are satisfied, the correction formula 1 in Table 4 is calculated (step 1007), and the pixel value of the correction target pixel C3 is corrected (the pixel value is increased). That is, the correction process is performed using the difference between the average value of the first reference pixels C2 and B3 and the pixel value of the correction target pixel C3.

  When the correction condition of a in Table 3 is satisfied and the correction condition of c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) Then, the correction condition of d in Table 3 is determined (steps 1008 and 1009). When the correction conditions a and d in Table 3 are satisfied, the correction formula 2 in Table 4 is calculated (step 1010), and the pixel value of the correction target pixel C3 is corrected (the pixel value is increased). That is, the correction process is performed using the difference between the average value of the first reference pixels C2 and D3 and the pixel value of the correction target pixel C3.

  In the case of FIG. 13, for example, the processing is simplified compared to FIG. 10, so that the circuit scale for performing the correction processing is reduced, and the cost can be reduced. In addition, when correction conditions are satisfied in multiple directions, image processing is performed while balancing the correction amount using the difference between each reference pixel value and the correction target pixel value, thereby improving contrast at low cost. Thus, an easy-to-see image can be displayed.

  This embodiment is a combination of the first and second embodiments. That is, in an image in which each display pixel is composed of a single color, the contrast of monochrome black and monochrome white is suppressed by suppressing the sinking and lifting of the image due to the influence of the dark or bright neighboring pixel on the bright or dark correction target pixel. An easy-to-view image with improved display is displayed.

  14 to 18 show processing flowcharts of the present embodiment. The image processing unit 20 in FIG. 17 and 18 are examples in which the correction formula selection unit 24 is also used. Hereinafter, each processing flowchart will be described.

  FIG. 14 shows that in an image in which each display pixel is composed of a single color, one pixel adjacent to the correction target pixel in the horizontal or vertical direction is a first reference pixel, and the other pixel is a third reference pixel. When a pixel located at a position sandwiching the first reference pixel from the target pixel is the second reference pixel, the pixel value of the first reference pixel is less than the pixel value of the correction target pixel at least in the horizontal or vertical direction The pixel value of the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and the pixel value of the first reference pixel is less than the pixel value of the second reference pixel, or the correction target pixel Is less than the pixel value of the first reference pixel, the third reference pixel is less than or equal to the pixel value of the correction target pixel, and the pixel value of the second reference pixel is the pixel value of the first reference pixel If the correction condition is less than It corrects the value as close to the pixel value of the first reference pixel (raise or lower the pixel value) is intended.

  FIG. 14 summarizes the correspondence between the correction conditions and the correction formulas in the processing flow as shown in Table 5.

  Table 5 is a combination of Table 1 and Table 3, and a1, b1, c1, and d1 correspond to Table 1, and a2, b2, c2, and d2 correspond to Table 3, respectively. That is, when any one of the correction conditions a1, b1, c1, and d1 is satisfied, the pixel value of the correction target pixel C3 is lowered, and when any one of the correction conditions a2, b2, c2, and d2 is satisfied. Is raised to bring the pixel value of the correction target pixel C3 closer to the pixel value of the first reference pixel (C2, C4, B3 or D3). By using these two types of correction conditions, it is possible to determine the black-and-white peak of an image having a single pixel pitch in an image subjected to resolution conversion.

  The processing flow in FIG. 14 is basically a combination of the processing flows in FIG. 4 and FIG. As in FIG. 4 and FIG. 9, for each pixel of the input image data, it is determined whether the correction condition on the left side is satisfied in the order of a1 to d2 in Table 5 with the pixel as the correction target pixel C3. At that time, the right correction equation is calculated to correct the pixel value of the correction target pixel C3 (lower or increase the pixel value). When all the correction conditions a1 to d2 are not satisfied, the correction process is not performed on the correction target pixel C3 (C3 = C3). This is repeated until there is no input image data.

  As an example, a case will be described in which correction conditions are determined based on C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) in the horizontal direction. Based on C1 to C4, the correction condition of a1 in Table 5 is determined (steps 1101 to 1103), and when satisfied, the corresponding right-side correction formula is calculated (step 1104), and the pixel value of the correction target pixel C3 is lowered. Thus, it approaches the pixel value of the first reference pixel C2. When the correction condition of a1 in Table 5 is not satisfied, the correction condition of a2 in Table 5 is determined by C1 to C4 (Steps 1105 to 1107). Calculation is performed (step 1104), the pixel value of the correction target pixel C3 is increased, and the pixel value of the first reference pixel C2 is approached.

  According to the present embodiment, even in the image after the resolution conversion processing, an image with one pixel pitch that is most affected by the display of the adjacent pixels can be corrected, and the display of the adjacent pixels of the correction target pixel can be corrected. It is possible to suppress the influence and display an easy-to-see image with improved contrast in either monochrome black or monochrome white.

  FIG. 15 determines whether the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), and if satisfied, the pixel values of the correction target pixels and the horizontal and vertical first values that satisfy the correction condition are determined. Using the correction formula having the smaller difference from the pixel value of one reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (lowering or raising the pixel value). Is. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 15 is the same as that in Table 5 in FIG. Further, the processing flow of FIG. 15 is basically a combination of the processing flows of FIG. 5 and FIG.

  As an example, C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) in the horizontal direction and A3 to D3 (first reference pixel; B3, second reference pixel) in the vertical direction. A3, third reference pixel; D3) will be described for determining the correction condition. The correction conditions for a1 in Table 5 are determined from C1 to C4 (steps 1201 to 1203). If satisfied, the correction conditions for c1 in Table 5 are determined from A3 to D3 (steps 1204 to 1206). If the correction conditions of a1 and c1 in Table 5 are satisfied, the pixel values of C2 and B3 are compared (step 1207), and the right correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Step 1208 or 1209), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered). If the correction condition of a1 in Table 5 is not satisfied, the correction condition of a2 in Table 5 is determined by C1 to C4 (steps 1210 to 1212). If satisfied, the correction condition of c2 in Table 5 is determined by A3 to D3. The correction condition is determined (steps 1213 to 1215). When the correction conditions of a2 and c2 in Table 5 are satisfied, the pixel values of C2 and B3 are similarly compared (step 1216), and the right-side correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Step 1217 or 1218), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  16, contrary to FIG. 15, it is determined whether the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). If the correction condition is satisfied, the pixel value of the correction target pixel and the correction condition are determined. Correction is performed so that the pixel value of the correction target pixel approaches the pixel value of the first reference pixel by using a correction formula having a larger difference from the pixel value of the filled first and second reference pixels in the horizontal and vertical directions. (Pixel value is lowered or raised). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence between the correction condition and the correction formula in FIG. 16 is the same as that in Table 5 in FIG. Also, the processing flow of FIG. 16 is basically a combination of the processing flows of FIG. 6 and FIG.

  Here, as an example, C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) and A3 to D3 in the vertical direction (first reference pixel; B3, first) The case where the correction condition is determined by 2 reference pixels; A3, the third reference pixel; D3) will be described. Whether or not the correction condition of a1 in Table 5 is satisfied is determined based on C1 to C4 (Steps 1301 to 1303). If satisfied, the correction condition of c1 in Table 5 is determined based on A3 to D3 (Steps 1304 to 1306). ). If the correction conditions of a1 and c1 in Table 5 are satisfied, the pixel values of C2 and B3 are compared (step 1307), and the right-side correction formula corresponding to the smaller one (the difference from C3 is large) is calculated. (Step 1308 or 1309), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered). When the correction condition of a1 of Table 5 is not satisfied, the correction condition of a2 of Table 5 is determined by C1 to C4 (steps 1310 to 1312). When satisfied, the correction condition of c2 of Table 5 is determined by A3 to D3. The correction condition is determined (steps 1313 to 1315). If the correction conditions of a2 and c2 in Table 5 are satisfied, the pixel values of C2 and B3 are similarly compared (step 1316), and the right-side correction formula corresponding to the smaller one (the difference from C3 is large) is calculated. (Step 1317 or 1318), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  FIG. 17 shows that when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the pixel value of the correction target pixel is calculated by using a predetermined correction formula depending on the combination of the satisfied directions. The correction is performed so as to approach the pixel value of the first reference pixel (the pixel value is decreased or increased). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 17 is the same as that in Table 5 in FIG. Also, the processing flow of FIG. 17 is basically a combination of the processing flows of FIG. 7 and FIG. 12, and detailed description thereof will be omitted.

  Here, as an example, C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) A3 to D3 in the vertical direction (first reference pixel; B2, second The case where the correction condition is determined by the reference pixel; A3, the third reference pixel; D3) will be described. Based on C1 to C4, the correction condition of a1 in Table 5 is determined (Steps 1401 to 1403). If satisfied, D3 ≦ C3 is determined (Step 1404). If the determination result is YES (correction of c1 in Table 5) The condition may also be satisfied), and the correction formula of a1 in Table 5 is calculated (step 1405), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 (the pixel value is lowered). When the correction condition of a1 in Table 5 is not satisfied, the correction condition of a2 in Table 5 is determined based on C1 to C4 (Steps 1406 to 1408). If the correction condition of a2 in Table 5 is satisfied, D3 ≦ C3 is determined (step 1409), and if the determination result is YES (c2 correction condition of Table 5 may also be satisfied), a2 of Table 5 Is calculated (step 1405), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 (the pixel value is increased).

  As is clear when the processing flow of FIG. 17 is compared with that of FIGS. 15 and 16, when correction conditions are satisfied in a plurality of directions, a correction target is determined using a predetermined correction formula depending on the combination of the satisfied directions. By correcting the pixel value of the pixel, the process is simplified. Therefore, the circuit scale for performing the correction process can be reduced and the cost can be reduced. In addition, since the correction conditions are satisfied in multiple directions and the difference between the pixel value of the reference pixel value and the interpolated pixel is different in the multiple directions, it is small when viewed from the whole image, and the influence on the image quality is often small. Although the difference is small, it is possible to display an easy-to-view image with low cost and improved contrast.

  FIG. 18 shows values (herein, average values) between pixel values of the first reference pixels that satisfy the correction condition when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). And the pixel value of the correction target pixel are used to correct the pixel value of the correction target pixel (lower or increase the pixel value). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  Table 6 shows a correspondence relationship between a combination of correction conditions in the satisfied direction and a correction formula to be applied when the correction conditions are satisfied in both the horizontal and vertical directions. The correspondence relationship between the correction condition and the correction formula when the correction condition is satisfied in one direction is the same as that in Table 5 in FIG.

  The processing flow of FIG. 18 is basically a combination of the processing flows of FIG. 8 and FIG.

  Here, as an example, C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) and A3 to D3 in the vertical direction (first reference pixel; B3, first) The case where the correction condition is determined by 2 reference pixels; A3, the third reference pixel; D3) will be described. The correction conditions for a1 in Table 5 are determined from C1 to C4 (Steps 1501 to 1503), and if satisfied, the correction conditions for c1 in Table 5 are determined from A3 to D3 (Steps 1504 to 1506). When the correction conditions a1 and c1 in Table 5 are satisfied, the correction formula 1 in Table 6 is calculated (Step 1507), and the pixel value of the correction target pixel C3 is corrected (the pixel value is lowered). That is, the correction process is performed using the difference between the average value of the first reference pixels C2 and B3 and the pixel value of the correction target pixel C3. If the correction condition of a1 in Table 5 is not satisfied, the correction condition of a2 in Table 5 is determined by C1 to C4 (steps 1508 to 1510). If satisfied, the correction condition of c2 in Table 5 is determined by A3 to D3. Correction conditions are determined (steps 1511 to 1513). If the correction conditions a2 and c2 in Table 5 are satisfied, the correction formula 2 in Table 6 is calculated (step 1514), and the pixel value of the correction target pixel C3 is corrected (the pixel value is increased). That is, the correction process is performed using the difference between the average value of the first reference images C2 and B3 and the pixel value of the correction target pixel C3.

  In the case of FIG. 18, for example, the processing is simplified compared to FIG. In addition, when correction conditions are satisfied in multiple directions, image processing is performed while balancing the correction amount using the difference between each reference pixel value and the correction target pixel value, thereby improving contrast at low cost. Thus, an easy-to-see image can be displayed.

  In this embodiment, the previous embodiment 1 is extended to a color image. In the display using a plurality of color components (primary color components), if the determination of correction processing is performed individually for each color component, different processing may be performed for each color component, and the color balance is lost by performing different processing.

  In the present embodiment, in the image in which each display pixel is configured with a plurality of color components, when the conditions for performing the correction process of the first embodiment are satisfied for all the color components, by lowering the pixel value of the correction target pixel, By suppressing the floating of an image (color black) due to the influence on the display of bright adjacent pixels, an easy-to-view image with improved color balance and display of a plurality of color components is displayed.

  19 to 23 show processing flowcharts of the present embodiment. The processing is managed by the image processing unit 20 in FIG. 22 and 23 are examples in which the correction formula selection unit 24 is also used. Hereinafter, each processing flowchart will be described.

19 expands the processing flow of FIG. 4 to an image in which each display pixel is composed of a plurality of color components (primary color components), and one pixel adjacent to the correction target pixel in the horizontal or vertical direction is displayed as a first pixel. Reference pixel, the other pixel as the third reference pixel, and the pixel located at the position sandwiching the first reference pixel from the correction target pixel as the second reference pixel, all at least in the horizontal or vertical direction In the color component, the pixel value of the first reference pixel is less than the pixel value of the second reference pixel, the pixel value of the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and at least one color When the pixel satisfies the correction condition that the pixel value of the first reference pixel is less than the pixel value of the correction target pixel (the pixel value of the first reference pixel of the other color component is equal to the pixel value of the correction target pixel) in the component, The pixel value of the correction target pixel is brought close to the pixel value of the first reference pixel Corrected to those which (lower pixel values).
Table 7 summarizes the correspondence between the correction conditions and the correction formulas in FIG.

Here, C1, C2, C3, C4, A3, B3, D3, and E3 are as shown in FIG. 2, and C3 is a correction target pixel. a and b are horizontal correction conditions and correction equations, and c and d are vertical correction conditions and correction equations. When the left correction conditions are satisfied, the corresponding right correction equations are applied. Thus, the pixel value of the correction target pixel C3 is brought close to the pixel value of the first reference pixel (C2, C4, B3, or D3) (the pixel value is lowered).
By setting the correction conditions in Table 7, it is possible to determine the peak of an image having a pixel pitch that is darker than the surroundings in the image subjected to resolution conversion.

  The processing flow of FIG. 19 is an extension of the processing flow of FIG. 4 when each display pixel is composed of a plurality of color components, and the processing is basically the same. For each pixel of the input image data, it is determined whether the left correction condition is satisfied in the order of “a” to “d” in Table 7 with this pixel as the correction target pixel C3. The calculation is repeated by the number of components to correct the pixel value of the correction target pixel C3 (lower the pixel value). When all the correction conditions a to d in Table 7 are not satisfied, the correction process is not performed on the correction target pixel C3 (C3 = C3). This is repeated until there is no input image data.

  For example, the correction conditions of a in Table 7 are determined based on C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 1601 to 1604) and satisfied. In such a case, the corresponding correction formula on the right side is repeatedly calculated by the number of color components (steps 1605 to 1607) to correct the pixel value of the correction target pixel C3. As a result, the pixel value of the color component of C3> C2 in C3 decreases and approaches the pixel value of C2.

  By performing the correction process as shown in FIG. 19, even an image after performing the resolution conversion process can correct an image of one pixel pitch that is most affected by the display of adjacent pixels, and the bright correction target pixels can be corrected. Suppresses the rise of the image due to the effect on the display of bright neighboring pixels, and uses all the color components for judgment of the correction condition, thereby displaying an easy-to-view image with no color shift, color balance, and improved contrast can do.

  FIG. 20 determines whether the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). If the correction condition is satisfied, the first value in the horizontal and vertical directions satisfying the pixel value of the correction target pixel and the correction condition is determined. Using the correction formula with the smaller difference from the pixel value of the reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (the pixel value is lowered). . The process when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 20 is the same as in Table 7 in FIG. The processing flow of FIG. 20 is an extension of the processing flow of FIG. 5 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, whether or not the correction condition of a in Table 7 is satisfied is determined based on horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 1701 to 1704). If satisfied, it is determined whether the correction condition of c in Table 7 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 1705). ~ 1708). When the correction conditions a and c in Table 7 are satisfied, the pixel values of C2 and B3 are compared for each color component, and the right correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Steps 1709, 1710 or 1711, 1712, 1713), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered).

  If the correction condition a in Table 7 is satisfied and the correction condition c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3 ) To determine the correction condition of d in Table 7 (steps 1714 to 1716). When the correction conditions a and d in Table 7 are satisfied, the pixel values of C2 and D3 are compared for each color component, and the right correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Steps 1717, 1718 or 1719, 1720, 1721), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is lowered).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, in a plurality of directions), for each color component, the correction formula with the smaller difference between the correction target pixel C3 and the first reference pixel is used. By correcting the pixel value of the correction target pixel C3 (lowering the pixel value), the color balance can be achieved and the contrast of the display image can be improved without increasing the effect.

  In contrast to FIG. 20, when the correction conditions are satisfied in both the horizontal and vertical directions (generally a plurality of directions), FIG. 21 shows the horizontal and vertical directions that satisfy the pixel values of the correction target pixels and the correction conditions. Using a correction formula having a larger difference from the pixel value of the first reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (lowering the pixel value) It is. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 21 is the same as that in Table 7 in FIG. The processing flow of FIG. 21 is an extension of the processing flow of FIG. 6 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, it is determined whether or not the correction condition of a in Table 7 is satisfied based on horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 1801 to 1804). If satisfied, it is determined whether or not the correction condition of c in Table 7 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 1805). ~ 1808). When the correction conditions a and c in Table 7 are satisfied, the pixel values of C2 and B3 are compared for each color component, and the right-side correction formula corresponding to the smaller one (the difference from C3 is large) is calculated. (Steps 1809, 1810 or 1811, 1812, 1813), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered).

  If the correction condition a in Table 7 is satisfied and the correction condition c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3 ) To determine the correction condition of d in Table 7 (steps 1814 to 1816). Then, when the correction conditions of a and d in Table 7 are satisfied, the pixel values of C2 and D3 are compared, and the right correction equation corresponding to the smaller one (the difference from C3 is large) is calculated (step 1817). 1818 or 1819, 1820, 1821), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is lowered).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the correction target pixel is calculated using the correction formula having the larger difference between the correction target pixel C3 and the first reference pixel. By correcting the pixel value of C3 (lowering the pixel value), excessive correction may be applied to the reference pixel side with a small difference, but the frequency is generally low and the influence on the entire image is subtle, and the constant Z The use of sympathy can be reduced by the value of (correction ratio). Compared with the influence, it is possible to display an easy-to-view image with much improved contrast and color balance.

  FIG. 22 shows that when the correction condition is satisfied in both the horizontal and vertical directions (generally, in a plurality of directions), the pixel value of the correction target pixel is calculated using a predetermined correction formula depending on the combination of the satisfied directions. The correction is made so as to approach the pixel value of the first reference pixel (the pixel value is lowered). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence between the correction condition and the correction formula in FIG. 22 is the same as that in Table 7 in FIG. The processing flow of FIG. 22 is an extension of the processing flow of FIG. 7 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, it is determined whether the correction condition of a in Table 7 is satisfied by C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 1901 to 1904). . If satisfied, it is determined whether all the color components are D3 ≧ C3 (step 1905). If the determination result is YES, the correction formula on the right side of Table 7a is calculated for each color component (steps 1906 to 1908), The pixel value of the correction target pixel C3 is brought close to the pixel value of C2 (the pixel value is lowered). That is, when the correction condition a in Table 7 is satisfied and the correction condition c is satisfied (when it may be satisfied), the pixel value of the correction target pixel C3 is corrected using the correction expression a.

  If the determination result of D3 ≧ C3 is NO, the correction condition for d in Table 7 is determined (Steps 1909 to 1911), and if satisfied, that is, the correction conditions for a and d in Table 7 are satisfied. When satisfied, the correction formula on the right side of d in Table 7 is calculated for each color component (steps 1912 to 1914), and the pixel value of the correction target pixel C3 is brought close to the pixel value of D3 (the pixel value is lowered).

  As is clear from comparing FIG. 22 with FIG. 20 and FIG. 21, when the correction conditions are satisfied in a plurality of directions, the pixel value of the correction target pixel is determined using a predetermined correction formula depending on the combination of the satisfied directions. By correcting the above, the processing is simplified. Therefore, the circuit scale for performing the correction process can be reduced and the cost can be reduced. In addition, since the correction conditions are satisfied in multiple directions and the difference between the pixel value of the reference pixel value and the interpolated pixel is different in the multiple directions, it is small when viewed from the whole image, and the influence on the image quality is often small. However, it is possible to display an easy-to-see image with low color, good color balance and improved contrast.

  FIG. 23 shows values (here, average values) between pixel values of the first reference pixels that satisfy the correction condition when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). The pixel value of the correction target pixel is corrected (the pixel value is lowered) using the difference between the pixel value of the correction target pixel and the pixel value of the correction target pixel. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  Table 8 shows a correspondence relationship between a combination of correction conditions in the satisfied direction and a correction formula to be applied when the correction conditions are satisfied in both the horizontal and vertical directions. The correspondence between the correction condition and the correction formula when the correction condition is satisfied in one direction is the same as that in Table 7 in FIG.

  The processing flow of FIG. 23 is an extension of the processing flow of FIG. 8 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, whether or not the correction condition of a in Table 7 is satisfied is determined based on horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 2001 to 2004). When satisfied, it is determined whether the correction condition of c in Table 7 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 2005). ~ 2008). When the correction conditions a and c in Table 7 are satisfied, the correction formula 1 in Table 8 is calculated for each color component (Steps 2009 to 2011), and the pixel value of the correction target pixel C3 is corrected (pixels). Lower the value). That is, the correction process is performed using the difference between the average value of the first reference pixels C2 and B3 and the pixel value of the correction target pixel C3.

  If the correction condition a in Table 7 is satisfied and the correction condition c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3 ) Is determined (steps 2012 to 2014). If the correction conditions a and d in Table 7 are satisfied, the correction formula on the right side of 2 in Table 8 is calculated for each color component (steps 2015 to 2017), and the pixel value of the correction target pixel C3 is corrected. (Decrease the pixel value). That is, the correction process is performed using the difference between the average value of the first reference pixels C2 and D3 and the pixel value of the correction target pixel C3.

  In the case of FIG. 23, for example, the processing is simplified as compared with FIG. 20, so that the circuit scale for performing the correction processing is reduced, and the cost can be reduced. In addition, when correction conditions are satisfied in multiple directions, image processing is performed while balancing the correction amount using the difference between each reference pixel value and the correction target pixel value, thereby improving contrast at low cost. This makes it possible to display an easy-to-view image with a well-balanced color.

  In this embodiment, in an image in which each display pixel is composed of a plurality of color components, contrary to the fourth embodiment, the image (color white) sinks due to the influence on the display of bright adjacent pixels of all the color components. The image is displayed with an easy-to-view image with good color balance and improved contrast.

  24 to 28 show processing flowcharts of the present embodiment. The image processing unit 20 in FIG. 27 and 28 are examples in which the correction formula selection unit 24 is also used. Hereinafter, each processing flowchart will be described.

  FIG. 24 shows that in an image in which each display pixel is composed of a plurality of color components, one pixel adjacent to the correction target pixel in the horizontal or vertical direction is the first reference pixel, and the other pixel is the third reference. When a pixel located at a position sandwiching the first reference pixel from the pixel to be corrected is a second reference pixel, the pixel of the second reference pixel in all color components at least in the horizontal or vertical direction The pixel value of the correction target pixel is less than the pixel value of the first reference pixel, the pixel value of the third reference pixel is less than or equal to the pixel value of the correction target pixel, and the pixel value of the correction target pixel is at least one color component. When the correction condition that is less than the pixel value of the reference pixel (the pixel value of the first reference pixel of the other color component is equal to the pixel value of the correction target pixel) is satisfied, the pixel value of the correction target pixel is set to the first reference pixel. Correct the pixel value closer to (by increasing the pixel value ) It is intended.

  Table 9 summarizes the correspondence between the correction conditions and the correction formulas in FIG.

Here, C1, C2, C3, C4, A3, B3, D3, and E3 are as shown in FIG. 2, and C3 is a correction target pixel. a and b are correction conditions and correction formulas in the horizontal direction, and c and d are correspondence relations between correction conditions and correction formulas in the vertical direction. When the correction conditions on the left side are satisfied, the corresponding correction formula on the right side is applied. Thus, the pixel value of the correction target pixel C3 is brought close to the pixel value of the first reference pixel (C2, C4, B3, or D3) (the pixel value is increased).
By setting such a correction condition, it is possible to determine a peak (white line or the like) of an image having a pixel pitch that is brighter than the surroundings in the resolution-converted image.

  The processing flow of FIG. 24 is an extension of the processing flow of FIG. 9 when each display pixel is composed of a plurality of color components, and the processing is basically the same. For each pixel of the input image data, it is determined whether or not the left correction condition is satisfied in the order of “a” to “d” in Table 9 with this pixel as the correction target pixel C3. The calculation is repeated by the number of components to correct the pixel value of the correction target pixel C3 (increase the pixel value). If all the correction conditions a to d in Table 9 are not satisfied, the correction process is not performed on the correction target pixel C3 (C3 = C3). This is repeated until there is no input image data.

  For example, the correction conditions of a in Table 9 are determined based on C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) in the horizontal direction (steps 2101 to 2104) and satisfied. In this case, the corresponding correction formula on the right side is repeatedly calculated by the number of color components (steps 2105 to 2107), and correction is performed so that the pixel value of the correction target pixel C3 approaches the pixel value of the first reference pixel C2 ( Increase the pixel value).

  By performing the correction process as shown in FIG. 24, it is possible to correct an image of one pixel pitch that is most affected by the display of adjacent pixels even in an image after performing the resolution conversion process. By suppressing the sinking of the image due to the effect on the display of bright neighboring pixels, and using all the color components for the determination of the correction condition, an easy-to-view image with no color shift, color balance, and improved contrast can be obtained. Can be displayed.

  FIG. 25 determines whether or not the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), and if satisfied, the pixel values of the correction target pixels and the horizontal and vertical directions satisfying the correction condition are determined. Using the correction formula with the smaller difference from the pixel value of one reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (the pixel value is increased). is there. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence between the correction condition and the correction formula in FIG. 25 is the same as that in Table 9 in FIG. The processing flow of FIG. 25 is an extension of the processing flow of FIG. 10 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, whether or not the correction condition of a in Table 9 is satisfied is determined based on horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 2201 to 2204). If satisfied, it is determined whether the correction condition of c in Table 9 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 2205). ~ 2208). When the correction conditions a and c in Table 9 are satisfied, the pixel values of C2 and B3 are compared for each color component, and the right correction equation corresponding to the larger one (the difference from C3 is small) is calculated ( Step 2209, 2210 or 2211, 2122, 2213), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  When the correction condition a in Table 9 is satisfied and the correction condition c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3) Then, the correction condition of d in Table 9 is determined (steps 2214 to 2216). When the correction conditions of a and d in Table 9 are satisfied, the pixel values of C2 and D3 are compared for each color component, and the right-side correction equation corresponding to the larger one (the difference from C3 is small) is calculated ( Step 2217, 2218 or 2219, 2220, 2221), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is increased).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, in a plurality of directions), for each color component, the correction formula with the smaller difference between the correction target pixel C3 and the first reference pixel is used. By correcting the pixel value of the correction target pixel C3 (increasing the pixel value), it is possible to achieve color balance and improve the contrast of the display image without increasing the effect.

  In contrast to FIG. 25, when the correction conditions are satisfied in both the horizontal and vertical directions (generally a plurality of directions), FIG. 26 shows the horizontal and vertical directions that satisfy the pixel values of the correction target pixels and the correction conditions. Using the correction formula having the larger difference from the pixel value of the first reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (the pixel value is increased). It is. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 26 is the same as that in Table 9 in FIG. The processing flow of FIG. 26 is an extension of the processing flow of FIG. 11 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, whether or not the correction condition of a in Table 9 is satisfied is determined based on horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 2301 to 2304). If satisfied, it is determined whether the correction condition of c in Table 9 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 2305). ~ 2308). When the correction conditions of a and c in Table 9 are satisfied, the pixel values of C2 and B3 are compared for each color component, and the right correction equation corresponding to the smaller one (the difference from C3 is large) is calculated ( Step 2309, 2310 or 2311, 2312, 2313), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  If the correction condition a in Table 9 is satisfied and the correction condition c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3 ) To determine the correction condition of d in Table 9 (steps 2314 to 2316). When the correction conditions of a and d in Table 9 are satisfied, the pixel values of C2 and D3 are compared for each color component, and the correction formula on the right side corresponding to the smaller one (the difference from C3 is large) is calculated ( Steps 2317, 2318 or 2319, 2320, 2321), the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 or D3 (the pixel value is increased).

  As described above, when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the correction target pixel is calculated using the correction formula having the larger difference between the correction target pixel C3 and the first reference pixel. By correcting the pixel value of C3 (increasing the pixel value), it is possible to display an easy-to-view image with improved contrast and color balance.

  In FIG. 27, when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the pixel value of the correction target pixel is calculated by using a predetermined correction formula depending on the combination of the satisfied directions. The correction is performed so as to approach the pixel value of the first reference pixel (the pixel value is increased). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence between the correction condition and the correction formula in FIG. 27 is the same as that in Table 9 in FIG. The processing flow of FIG. 27 is an extension of the processing flow of FIG. 12 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, it is determined whether the correction condition of a in Table 9 is satisfied based on horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 2401 to 2404). If satisfied, it is determined whether all the color components are D3 ≦ C3 (step 2405). If the determination result is YRS, that is, if the correction condition a in Table 9 is satisfied and the correction condition c is also satisfied (c correction) If there is a possibility that the condition is also satisfied), the correction expression on the right side of a in Table 9 is calculated for each color component (steps 2406 to 2408), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 ( Increase the pixel value).

  If the determination result of D3 ≦ C3 is NO, the correction condition for d in Table 9 is determined (steps 2409 to 2411), and if satisfied, that is, the correction conditions for a and d in Table 9 are satisfied. In this case, the correction formula on the right side of d in Table 9 is calculated for each color component (steps 2412 to 2414), and the pixel value of the correction target pixel C3 is brought close to the pixel value of D3 (the pixel value is increased).

  As is clear when comparing the processing flow of FIG. 27 with that of FIG. 25 or FIG. 26, when the correction conditions are satisfied in a plurality of directions, correction is performed using a predetermined correction formula depending on the combination of the satisfied directions. By correcting the pixel value of the target pixel, the process is simplified. Therefore, the circuit scale for performing the correction process can be reduced and the cost can be reduced. In addition, since the correction conditions are satisfied in multiple directions and the difference between the pixel value of the reference pixel value and the interpolated pixel is different in the multiple directions, it is small when viewed from the whole image, and the influence on the image quality is often small. However, it is possible to display an easy-to-see image with low color, good color balance and improved contrast.

  FIG. 28 shows values (here, average values) between the pixel values of the first reference pixels that satisfy the correction condition when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). The pixel value of the correction target pixel is corrected (the pixel value is increased) using the difference between the correction value and the pixel value of the correction target pixel. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  Table 10 shows a correspondence relationship between a combination of correction conditions in the satisfied direction and a correction formula to be applied when the correction conditions are satisfied in both the horizontal and vertical directions. The correspondence between the correction condition and the correction formula when the correction condition is satisfied in one direction is the same as in Table 9 in FIG.

  The processing flow of FIG. 28 is an extension of the processing flow of FIG. 13 when each display pixel is composed of a plurality of color components, and the processing is basically the same.

  For example, whether or not the correction condition of a in Table 9 is satisfied is determined based on horizontal C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) (steps 2501 to 2504). If satisfied, it is determined whether the correction condition of c in Table 9 is satisfied by A3 to D3 (first reference pixel; B3, second reference pixel; A3, third reference pixel; D3) in the vertical direction (step 2505). ~ 2508). When the correction conditions a and c in Table 9 are satisfied, the correction formula 1 in Table 10 is calculated for each color component (Steps 2509 to 2511), and the pixel value of the correction target pixel C3 is corrected (pixels). Increase the value). That is, the correction process is performed using the difference between the average value of the first reference pixels C2 and B3 and the pixel value of the correction target pixel C3.

  If the correction condition a in Table 9 is satisfied and the correction condition c is not satisfied, B3 to E3 in the vertical direction (first reference pixel; D3, second reference pixel; E3, third reference pixel; B3 ) To determine d correction conditions in Table 3 (steps 2512 to 2514). When the correction conditions of a and d in Table 3 are satisfied, the two correction expressions in Table 10 are calculated for each color component (steps 2517 to 2517), and the pixel value of the correction target pixel C3 is corrected (pixels). Increase the value). That is, the correction process is performed using the difference between the average value of the first reference pixels C2 and D3 and the pixel value of the correction target pixel C3.

  In the case of FIG. 28, for example, the processing is simplified as compared with FIG. 25, so that the circuit scale for performing the correction processing is reduced and the cost can be reduced. In addition, when correction conditions are satisfied in multiple directions, image processing is performed while balancing the correction amount using the difference between each reference pixel value and the correction target pixel value, thereby improving contrast at low cost. This makes it possible to display an easy-to-view image with a well-balanced color.

  This embodiment is a combination of the previous embodiment 4 and embodiment 5. In other words, in an image in which each display pixel is composed of a plurality of color components, a plurality of color components are suppressed by suppressing the sinking and floating of the image due to the influence of the bright or dark correction target pixels on the display of dark or bright adjacent pixels. In this display, an easy-to-see image with a good color balance and improved contrast between color black and color white is displayed.

  29 to 33 show processing flowcharts of the present embodiment. The image processing unit 20 in FIG. 32 and 33 are examples in which the correction formula selection unit 24 is also used. In FIG. 29 to FIG. 33, the description regarding the color components in the determination block is omitted in order to avoid complication of the drawing. Hereinafter, each processing flowchart will be described.

FIG. 29 shows, in an image in which each display pixel is composed of a plurality of color components, one pixel adjacent to the correction target pixel in the horizontal or vertical direction is a first reference pixel, and the other pixel is a third reference. When a pixel located at a position sandwiching the first reference pixel from the pixel to be corrected is the second reference pixel, the pixel values of the first reference pixels of all color components at least in the horizontal or vertical direction Is less than the pixel value of the second reference pixel, the pixel value of the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and the pixel value of the first reference pixel is the correction target pixel with at least one color component (The pixel value of the first reference pixel of the other color component is equal to the correction target pixel value) or the pixel value of the second reference pixel is the first pixel value in all color components. If the third reference pixel is less than the pixel value of the reference pixel, The pixel value of the correction target pixel is less than the prime value and is less than the pixel value of the first reference pixel in at least one color component (the pixel value of the first reference pixel of the other color component is equal to the correction target pixel value) ) Is corrected so as to bring the pixel value of the correction target pixel closer to the pixel value of the first reference pixel (lower or increase the pixel value).
FIG. 29 summarizes the correspondence between the correction conditions and the correction formulas in the processing flow, as shown in Table 11.

Table 11 is a combination of Table 7 and Table 9, and a1, b1, c1, and d1 correspond to Table 7,
a2, b2, c2, and d2 correspond to Table 9, respectively. That is, a1, b1, c1, d1
If any of the correction conditions is satisfied, the pixel value of the correction target pixel C3 is decreased, and if any of the correction conditions a2, b2, c2, d2 is satisfied, the correction target pixel C3 is increased. Is made closer to the pixel value of the first reference pixel (C2, C4, B3 or D3). By using these two types of correction conditions, it is possible to determine the color black-and-white peak of an image having a single pixel pitch in an image subjected to resolution conversion.

  The processing flow of FIG. 29 is an extension of the processing flow of FIG. 14 when each display pixel is composed of a plurality of color components, and is basically a combination of the processing flows of FIG. 19 and FIG. As in FIG. 14, for each pixel of the input image data, it is determined whether the correction condition on the left side is satisfied in the order of a1 to d2 in Table 11 with this pixel as the correction target pixel C3. The correction formula on the right side is repeatedly calculated for the number of color components to correct the pixel value of the correction target pixel C3 (lower or increase the pixel value). When all the correction conditions a1 to d2 are not satisfied, the correction process is not performed on the correction target pixel C3 (C3 = C3). This is repeated until there is no input image data.

  As an example, a case will be described in which correction conditions are determined based on C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) in the horizontal direction. Based on C1 to C4, the correction condition of a1 in Table 11 is determined (steps 2601 to 2604), and if satisfied, the corresponding correction formula on the right side is repeatedly calculated by the number of color components (steps 2605 to 2607) to correct. The pixel value of the target pixel C3 is lowered to approach the pixel value of the first reference pixel C2. When the correction condition of a1 in Table 11 is not satisfied, the correction condition of a2 in Table 11 is determined by C1 to C4 (Steps 2608 to 2612). Is repeatedly calculated for the number of color components (steps 2605 to 2607), and the pixel value of the correction target pixel C3 is increased to approach the pixel value of the first reference pixel C2.

  According to the present embodiment, even in the image after the resolution conversion processing, an image with one pixel pitch that is most affected by the display of the adjacent pixels can be corrected, and the display of the adjacent pixels of the correction target pixel can be corrected. It is possible to display an easy-to-view image with suppressed influence, color balance, and improved contrast.

  FIG. 30 determines whether or not the correction condition is satisfied in both the horizontal and vertical directions (generally a plurality of directions), and if satisfied, the pixel values of the correction target pixels and the horizontal and vertical directions satisfying the correction condition are determined. Using the correction formula having the smaller difference from the pixel value of one reference pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel (lowering or raising the pixel value). Is. The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 30 is the same as in Table 11 in FIG. The processing flow of FIG. 30 is an extension of the processing flow of FIG. 15 when each display pixel is composed of a plurality of color components. Basically, the processing flow of FIGS. 20 and 25 is combined. It is. In FIG. 30, the processing for determining the correction conditions in the vertical directions c1, c2, d1, d2 after the correction conditions in the horizontal directions a1, a2, b1, b2 are not satisfied is the same as in FIG. Omitted. The same applies to FIGS. 31 to 33.

  As an example, C1 to C4 (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) in the horizontal direction and A3 to D3 (first reference pixel; B3, second reference pixel) in the vertical direction. A3, third reference pixel; D3) will be described for determining the correction condition. The correction conditions for a1 in Table 11 are determined from C1 to C4 (steps 2701 to 2704). If satisfied, the correction conditions for c1 in Table 11 are determined from A3 to D3 (steps 2705 to 2708). When the correction conditions of a1 and c1 in Table 11 are satisfied, the pixel values of C2 and B3 are compared for the color component, and the right correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Steps 2709, 2710 or 2711, 2712, 2713), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered). If the correction condition of a1 in Table 11 is not satisfied, the correction condition of a2 in Table 11 is determined by C1 to C4 (steps 2714 to 2718). If satisfied, the correction condition of c2 in Table 11 is determined. (Steps 2719-2722). If the correction conditions of a2 and c2 in Table 11 are satisfied, the pixel values of C2 and B3 are compared for each color component, and the right correction equation corresponding to the larger one (the difference from C3 is small) is calculated. (Steps 2723, 2724 or 2725, 2726, 2727), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  In contrast to FIG. 30, in FIG. 31, it is determined whether the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). If the correction condition is satisfied, the pixel value of the correction target pixel and the correction condition are determined. Correction is performed so that the pixel value of the correction target pixel approaches the pixel value of the first reference pixel by using a correction formula having a larger difference from the pixel value of the filled first and second reference pixels in the horizontal and vertical directions. (Pixel value is lowered or raised). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence between the correction condition and the correction formula in FIG. 31 is the same as that in Table 11 in FIG. Further, the processing flow of FIG. 31 is an extension of the processing flow of FIG. 16 when each display pixel is composed of a plurality of color components, and is basically a combination of the processing flows of FIG. 21 and FIG. is there.

  Here, as an example, C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) and A3 to D3 in the vertical direction (first reference pixel; B3, first) The case where the correction condition is determined by 2 reference pixels; A3, the third reference pixel; D3) will be described. Whether or not the correction condition of a1 in Table 11 is satisfied is determined by C1 to C4 (steps 2801 to 2804). If satisfied, the correction condition of c1 of Table 11 is determined from A3 to D3 (steps 2805 to 2808). ). When the correction conditions of a1 and c1 in Table 11 are satisfied, the pixel values of C2 and B3 are compared for each color component, and the right correction equation corresponding to the smaller one (the difference from C3 is large) is calculated. (Step 2809, 2810 or 2811, 2912, 2813), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is lowered). If the correction condition of a1 in Table 11 is not satisfied, the correction condition of a2 in Table 11 is determined by C1 to C4 (steps 2814 to 2818), and if satisfied, the correction condition of c2 in Table 11 is determined by A3 to D3. Correction conditions are determined (steps 2819 to 2822). When the correction conditions of a2 and c2 in Table 11 are satisfied, the pixel values of C2 and B3 are compared for each color component, and the correction formula on the right side corresponding to the smaller one (the difference from C3 is large) is calculated. (Steps 2823, 2824 or 2825, 2826, 2827), the pixel value of the correction target pixel C3 is brought close to the pixel value of B3 or C2 (the pixel value is increased).

  FIG. 32 shows that when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions), the pixel value of the correction target pixel is determined by using a predetermined correction formula depending on the combination of the satisfied directions. The correction is performed so as to approach the pixel value of the first reference pixel (the pixel value is decreased or increased). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  The correspondence relationship between the correction condition and the correction formula in FIG. 32 is the same as that in Table 11 in FIG. The processing flow of FIG. 32 is an extension of the processing flow of FIG. 17 when each display pixel is composed of a plurality of color components, and is basically a combination of the processing flows of FIG. 22 and FIG. It is.

  Here, as an example, C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) A3 to D3 in the vertical direction (first reference pixel; B2, second The case where the correction condition is determined by the reference pixel; A3, the third reference pixel; D3) will be described. Based on C1 to C4, the correction condition of a1 in Table 11 is determined (Steps 2901 to 2904), and if satisfied, it is determined whether all the color components are B3 ≧ C3 (Step 2905), and if the determination result is NO (Table 11) The correction condition of c1 of Table 11 may also be satisfied), and the correction formula of a1 of Table 11 is repeatedly calculated for the number of color components (Steps 2906 to 2908), and the pixel value of the correction target pixel C3 is set to the pixel value of C2. (Close the pixel value). If the correction condition for a1 in Table 11 is not satisfied, the correction condition for a2 in Table 11 is determined based on C1 to C4 (steps 2909 to 2913). When the correction condition of a2 in Table 11 is satisfied, it is determined whether all the color components are B3 ≧ C3 (step 2914). If the determination result is YES (the correction condition of c2 in Table 11 may also be satisfied), The correction formula a2 in Table 11 is calculated by the number of color components (steps 2915 to 2917), and the pixel value of the correction target pixel C3 is brought close to the pixel value of C2 (the pixel value is increased).

  As is clear from comparing the processing flow of FIG. 32 with that of FIGS. 30 and 31, when the correction conditions are satisfied in a plurality of directions, the correction target is determined using a predetermined correction formula depending on the combination of the satisfied directions. By correcting the pixel value of the pixel, the process is simplified. Therefore, the circuit scale for performing the correction process can be reduced and the cost can be reduced. In addition, since the correction conditions are satisfied in multiple directions and the difference between the pixel value of the reference pixel value and the interpolated pixel is different in the multiple directions, it is small when viewed from the whole image, and the influence on the image quality is often small. However, it is possible to display an easy-to-see image with low color, good color balance and improved contrast.

  FIG. 33 shows values (here, average values) between the pixel values of the first reference pixels that satisfy the correction condition when the correction condition is satisfied in both the horizontal and vertical directions (generally, a plurality of directions). And the pixel value of the correction target pixel are used to correct the pixel value of the correction target pixel (lower or increase the pixel value). The processing when the correction condition is satisfied in one direction is the same as that in FIG.

  Table 12 shows a correspondence relationship between a combination of correction conditions in the satisfied direction and a correction formula to be applied when the correction conditions are satisfied in both the horizontal and vertical directions. Since the correspondence relationship between the correction condition and the correction formula when the correction condition is satisfied in one direction is the same as that in Table 11 in FIG.

The processing flow of FIG. 33 is an extension of the processing flow of FIG. 18 when each display pixel is composed of a plurality of color components, and is basically a combination of the processing flows of FIG. 23 and FIG. .
Here, as an example, C1 to C4 in the horizontal direction (first reference pixel; C2, second reference pixel; C1, third reference pixel; C4) and A3 to D3 in the vertical direction (first reference pixel; B3, first) The case where the correction condition is determined by 2 reference pixels; A3, the third reference pixel; D3) will be described. The correction conditions for a1 in Table 11 are determined from C1 to C4 (Steps 3001 to 3004). If satisfied, the correction conditions for c1 in Table 11 are determined from A3 to D3 (Steps 3305 to 3008). When the correction conditions of a1 and c1 in Table 11 are satisfied, the correction expression of 1 in Table 12 is calculated by the number of color components (Steps 3009 to 3011), and the pixel value of the correction target pixel C3 is corrected ( Reduce the pixel value). That is, for each color component, correction processing is performed using the difference between the average value of the first reference pixels C2 and B3 and the pixel value of the correction target pixel C3. When the correction condition of a1 of Table 11 is not satisfied, the correction condition of a2 of Table 11 is determined by C1 to C4 (Steps 3012 to 3016). When satisfied, the correction condition of c2 of Table 11 is determined by A3 to D3. Correction conditions are determined (steps 3017 to 3020). When the correction conditions of a2 and c2 in Table 11 are satisfied, the two correction expressions in Table 12 are calculated by the number of color components (steps 3021 to 3023), and the pixel value of the correction target pixel C3 is corrected ( Increase the pixel value). That is, for each color component, correction processing is performed using the difference between the average value of the first reference images C2 and B3 and the pixel value of the correction target pixel C3.

  In the case of FIG. 33, for example, the processing is simplified as compared with FIG. 30, so the circuit scale for performing the correction processing is reduced, and the cost can be reduced. In addition, when the correction conditions are satisfied in multiple directions, image processing is performed while balancing the correction amount using the difference between each reference pixel value and the correction target pixel value, so that color balance can be achieved at low cost. It is possible to display an easy-to-view image with improved contrast.

  Although various embodiments have been described above, it is needless to say that the processing procedure shown in each embodiment can be configured by a computer program, and the program can be executed by the computer. Can be recorded on a computer-readable recording medium, such as FD, MO, ROM, memory card, CD, DVD, removable disk, etc. It is possible to distribute the program through the network.

1 is a block diagram illustrating a configuration example of an image display device to which the present invention is applied. The figure which shows the positional relationship of the correction object pixel and reference pixel which are used in the Example of this invention. The figure for demonstrating the principle of this invention. 5 is a process flowchart of case 1 of the first embodiment. 6 is a process flowchart of case 2 of the first embodiment. 6 is a process flowchart of case 3 of the first embodiment. 6 is a process flowchart of case 4 of the first embodiment. 9 is a process flowchart of case 5 of the first embodiment. 9 is a process flowchart of case 1 of the second embodiment. 9 is a process flowchart of case 2 of the second embodiment. 10 is a process flowchart of case 3 of the second embodiment. 10 is a process flowchart of case 4 of the second embodiment. 10 is a process flowchart of case 5 of the second embodiment. 10 is a processing flowchart of case 1 of the third embodiment. 10 is a process flowchart of case 2 of the third embodiment. 10 is a process flowchart of case 3 of the third embodiment. 9 is a process flowchart of case 4 of the third embodiment. 9 is a process flowchart of case 5 of the third embodiment. 10 is a process flowchart of case 1 of the fourth embodiment. 9 is a process flowchart of case 2 of the fourth embodiment. 9 is a process flowchart of case 3 of the fourth embodiment. 10 is a process flowchart of case 4 of the fourth embodiment. 10 is a process flowchart of case 5 of the fourth embodiment. 10 is a process flowchart of case 1 of the fifth embodiment. 10 is a processing flowchart of case 2 of the fifth embodiment. 10 is a process flowchart of case 3 of the fifth embodiment. 10 is a process flowchart of case 4 of the fifth embodiment. 10 is a process flowchart of case 5 of the fifth embodiment. 10 is a process flowchart of case 1 of the sixth embodiment. 10 is a process flowchart of case 2 of the sixth embodiment. 10 is a process flowchart of case 3 of the sixth embodiment. 10 is a process flowchart of case 4 of the sixth embodiment. 10 is a process flowchart of case 5 of the sixth embodiment. The figure which shows the specific process example of this invention. The figure which shows the other specific process example of this invention. The figure which shows the display pixel and display range example of the display by pixel shifting.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Input image data memory | storage part 20 Image processing part 22 Correction condition determination part 24 Correction type selection part 26 Pixel correction process part 30 Output image data storage part 40 Display part

Claims (17)

For the input image data, the pixel values of adjacent pixels are compared to determine the pixel having the minimum or maximum pixel value (hereinafter referred to as peak pixel), and the pixel value of the pixel adjacent to the peak pixel is the peak value. An image processing method for correcting a pixel value to approach a pixel value,
Each pixel of the input image data is set as a correction target pixel, one pixel adjacent to the correction target pixel is a first reference pixel, the other pixel is a third reference pixel, and the correction target pixel to the first correction pixel A pixel located at a position sandwiching the reference pixel as a second reference pixel,
The pixel values of the first reference pixel and the correction target pixel, the correction target pixel and the third reference pixel, and the first reference pixel and the second reference pixel are compared, and the first reference pixel and the correction target pixel are compared. It is determined whether the reference pixel is a peak pixel, and when it is determined that the pixel is a peak pixel, the pixel value of the correction target pixel is corrected so as to be close to the pixel value of the first reference pixel. Processing method.   The pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one direction, the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and the first When the correction condition that the pixel value of the reference pixel is less than the pixel value of the second reference pixel is satisfied, the pixel value of the correction target pixel is corrected to be close to the pixel value of the first reference pixel. The image processing method according to claim 1.   Each pixel of the image data is composed of a plurality of primary color components (hereinafter referred to as color components), and the third reference pixel is greater than or equal to the pixel value of the correction target pixel in all color components, and the first reference pixel The pixel value of the first reference pixel is less than the pixel value of the second reference pixel, and the pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one color component. 3. The image processing method according to claim 2, wherein the correction is performed so that a pixel value of the correction target pixel approaches a pixel value of the first reference pixel.   The pixel value of the correction target pixel is less than the pixel value of the first reference pixel in at least one direction, the third reference pixel is less than or equal to the pixel value of the correction target pixel, and the second When the correction condition that the pixel value of the reference pixel is less than the pixel value of the first reference pixel is satisfied, the pixel value of the correction target pixel is corrected to be close to the pixel value of the first reference pixel. The image processing method according to claim 1.   Each pixel of the image data is composed of a plurality of primary color components (hereinafter referred to as color components), and the third reference pixel is less than or equal to the pixel value of the correction target pixel in all color components, and the second reference pixel The pixel value of the correction target pixel is less than the pixel value of the first reference pixel and the pixel value of the correction target pixel is less than the pixel value of the first reference pixel in at least one color component. 5. The image processing method according to claim 4, wherein the correction is performed so that a pixel value of the correction target pixel approaches a pixel value of the first reference pixel.   In at least one direction, the pixel value of the first reference pixel is less than the pixel value of the correction target pixel, the third reference pixel is greater than or equal to the pixel value of the correction target pixel, and the first The pixel value of the reference pixel is less than the pixel value of the second reference pixel, or the pixel value of the correction target pixel is less than the pixel value of the first reference pixel, and the third reference pixel is the correction target The pixel value of the correction target pixel is set to the first pixel value when the correction condition is less than the pixel value of the pixel and the pixel value of the second reference pixel is less than the pixel value of the first reference pixel. The image processing method according to claim 1, wherein the correction is performed so as to approach the pixel value of the reference pixel.   Each pixel of the image data is composed of a plurality of primary color components (hereinafter referred to as color components), and the third reference pixel is equal to or greater than the pixel value of the correction target pixel in all color components, and the first reference pixel The pixel value is less than the pixel value of the second reference pixel, and the pixel value of the first reference pixel is less than the pixel value of the correction target pixel in at least one color component, or all color components The third reference pixel is less than or equal to the pixel value of the correction target pixel, the pixel value of the second reference pixel is less than the pixel value of the first reference pixel, and at least one color component When the correction condition that the pixel value of the correction target pixel is less than the pixel value of the first reference pixel is satisfied, the pixel value of the correction target pixel is corrected to be close to the pixel value of the first reference pixel. The image processing method according to claim 6.   When the correction conditions are satisfied in a plurality of directions, the pixel of the correction target pixel is based on the pixel value of the first reference pixel in the direction in which the difference between the pixel value of the correction target pixel and the pixel value of the first reference pixel is small. The image processing method according to claim 2, wherein the value is corrected.   When the correction conditions are satisfied in a plurality of directions, the pixel of the correction target pixel is based on the pixel value of the first reference pixel in the direction in which the difference between the pixel value of the correction target pixel and the pixel value of the first reference pixel is large. The image processing method according to claim 2, wherein the value is corrected.   When the correction conditions are satisfied in a plurality of directions, the pixel value of the correction target pixel is corrected based on the pixel value of the first reference pixel in the predetermined direction by a combination of the satisfied directions. Item 8. The image processing method according to any one of Items 2 to 7.   By subtracting only the correction value from the pixel value of the correction target pixel, a value obtained by subtracting the pixel value of the first reference pixel from the pixel value of the correction target pixel and a constant of 1 or less is used as a correction value. The image processing method according to claim 2, wherein a pixel value of the correction target pixel is corrected.   The pixel value of the correction target pixel is corrected based on an intermediate value of the pixel values of the first reference pixels in the plurality of directions that are satisfied when the correction condition is satisfied in a plurality of directions. The image processing method according to any one of 2 to 7.   By subtracting only the correction value from the pixel value of the correction target pixel, a value obtained by subtracting the intermediate value from the pixel value of the correction target pixel and a constant of 1 or less is used as the correction value. The image processing method according to claim 12, wherein the pixel value is corrected.   The image processing method according to claim 1, wherein the image data has been subjected to resolution conversion processing on the original image data.   Input image data storage means for storing input image data, image processing means for processing image data stored in the input image data storage means, and output image for storing image data processed by the image processing means 15. An image processing apparatus comprising data storage means, wherein the image processing means implements the image processing method according to any one of claims 1 to 14.   16. An image display device comprising: the image processing device according to claim 15; and image display means for displaying image data stored in output image data storage means of the image processing device. A program for causing a computer to execute the image processing method according to any one of claims 1 to 13 .

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