JP2009014840A - Image processing method and image processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing method which improves processing speed and has little possibility of malfunction when displaying an image on a display panel by thinning image information included in an input image signal. <P>SOLUTION: The image processing method includes: a step of cyclically extracting image information of a plurality of pixels in terms of respective color signal components included in the input image signal at a predetermined rate; a step of calculating the variation of a luminance level between the plurality of pixels based on the image information of the specified pixel where the rate of the image information of any one extracted pixel is equal to or above a set value and the image information of at least one pixel adjacent thereto; a step of detecting the edge of the image by comparing the variation of the luminance level with a threshold; and a step of lowering the color signal level of the pixel positioned on the high luminance side of the edge of the image and/or raising the color signal level of the pixel positioned on the low luminance side of the edge of the image. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing method and an image processing apparatus for correcting a color shift of a contour portion that occurs when an image is displayed on a display panel such as an LCD (liquid crystal display) panel or a PDP (plasma display panel).

  Small LCD panels are used in electronic devices such as printers and mobile phones. In a small LCD panel, since the number of dots is not so large, instead of displaying all image information of RGB (red green blue) included in the image signal, by thinning out the image information, for example, R signal information is displayed for the first pixel, G signal information is displayed for the second pixel, and B signal information is displayed for the third pixel.

  According to this display method, when displaying a white region, the red component of the first pixel is displayed on the first dot from the left of the LCD panel, and the green component of the second pixel is displayed on the second dot. Is displayed, and the blue component of the third pixel is displayed on the third dot, and by repeating this, it is visually recognized as a white region as a whole.

  In this way, when a white region is represented by repetition of a red component, a green component, and a blue component of a series of pixels, when an input image signal that displays an image with a clear outline such as a character is used, for example, white Assuming that the area is equivalent to 4 pixels, a problem may occur that starts with red and ends with red. As a result, the proportion of RGB dots is not uniform, and a phenomenon occurs in which red is emphasized at the edge of the white region. In particular, since red is easily noticeable visually, color shift is noticeable when red is displayed on the edge of a white region. Therefore, various techniques have been developed to eliminate such color misregistration.

  As a related technique, Patent Document 1 discloses a contour color that prevents color misregistration at a contour portion when an image having a clear contour such as a personal computer image is displayed on a display having a large size of one pixel such as a PDP. A correction circuit is disclosed. The contour color correction circuit includes a color misregistration detection unit that detects a color misregistration amount between both pixels from a level difference between RGB signals of a target pixel of an input video signal and pixels adjacent thereto, and the color misregistration detection. A correction amount calculation unit that calculates a correction amount by multiplying the color misregistration occurrence amount detected by the unit by a preset coefficient, and an addition unit that corrects and corrects the correction amount obtained by the correction amount calculation unit to the video signal It is made up of.

  Patent Document 2 discloses that a color image correction apparatus is provided with a color misregistration correction circuit in order to eliminate color misregistration of dots (R or B) at both ends of a high luminance area. The color misregistration correction circuit has a luminance difference of a predetermined pixel or more when the adjacent pixels of a plurality of pixels are displayed at a predetermined luminance with a certain color component. A luminance comparison detection circuit for detecting the pixel, and a dot that constitutes a higher luminance pixel among the adjacent pixels when the luminance comparison detection circuit detects the luminance difference, and the lower luminance pixel The dot adjacent to is controlled so as to appear at a predetermined luminance at a predetermined position in the pixel having the higher luminance.

However, according to the contour color correction circuit of Patent Document 1 and the color misregistration correction circuit of Patent Document 2, the processing of the image signal is complicated and the circuit scale is increased, and there is a risk of malfunction due to the complicated processing. To increase.
JP 2004-61930 A (first page, FIG. 1) JP-A-10-105108 (page 1-2, FIG. 1)

  Accordingly, in view of the above points, the present invention improves image processing speed and reduces the risk of malfunction when displaying image on a display panel by thinning out image information included in an input image signal. It is an object to provide a method and an image processing apparatus.

  In order to solve the above problems, an image processing method according to one aspect of the present invention is based on an input image signal, and image information of an R signal, a G signal, and a B signal is applied to a plurality of dots of a display panel. Is an image processing method used in a system for displaying a plurality of pixels periodically with respect to an R signal component, a G signal component, and a B signal component included in an input image signal. The ratio of the image information of any one pixel extracted in step (a) and the image information of the specific pixel whose ratio is equal to or greater than the set value and at least one pixel adjacent thereto Based on the image information, the step (b) of calculating the change amount of the luminance level between the plurality of pixels, and the change amount of the luminance level calculated in step (b) is compared with a threshold value. (C) detecting the edge of the image, and reducing the color signal level of the pixel located on the high luminance side of the edge of the image detected in step (c) and / or step (c). (D) increasing the color signal level of the pixel located on the low luminance side of the edge of the image detected in step (d).

  Here, step (a) alternatively extracts the R signal component, the G signal component, and the B signal component in order from the image information of a plurality of pixels included in the input image signal. In addition, the specific pixel may be a pixel from which the R signal component is alternatively extracted.

  In addition, step (b) includes calculating a reduction amount of the luminance level between the two pixels based on the image information of the specific pixel and the image information of the subsequent pixel, and step (c) Detecting the falling edge of the image by comparing the amount of decrease in the luminance level calculated in step (b) with a threshold value, wherein step (d) includes the falling edge of the image in step (c) When an edge is detected, it may include reducing the color signal level of a specific pixel.

  Alternatively, step (b) includes calculating the amount of change in the luminance level between the three pixels based on the luminance level of the specific pixel and the luminance levels of the two pixels before and after the specific pixel, and step (c) Comprises detecting a falling edge of the image by comparing the amount of change in the brightness level calculated in step (b) with a threshold value, wherein step (d) includes detecting the falling edge of the image in step (c). When a falling edge is detected, the color signal level of a specific pixel may be reduced.

  In that case, when the image processing method sets the threshold based on the luminance levels of the two pixels before and after the specific pixel, and the set threshold is smaller than a predetermined value, And a step of changing the set threshold value to a predetermined value.

  An image processing apparatus according to an embodiment of the present invention is used in a system that displays information of an R signal, a G signal, and a B signal on a plurality of dots of a display panel based on an input image signal. An image extracting means for periodically extracting image information of a plurality of pixels at a predetermined ratio with respect to the R signal component, the G signal component, and the B signal component included in the input image signal; Based on the image information of a specific pixel in which the ratio of the image information of any one pixel extracted by the image extraction means is equal to or greater than a set value, and the image information of at least one pixel adjacent to the pixel, A luminance calculating means for calculating the amount of change in the luminance level, and an edge detecting the edge of the image by comparing the amount of change in the luminance level calculated by the luminance calculating means with a threshold value. A color signal level of a pixel located on the high brightness side of the edge of the image detected by the detection means and the edge detection means and / or a position on the low brightness side of the edge of the image detected by the edge detection means Image correction means for increasing the color signal level of the pixel to be processed.

  Here, the image extraction means alternatively extracts the R signal component, the G signal component, and the B signal component in order from the image information of a plurality of pixels included in the input image signal, The pixel may be a pixel from which the R signal component is alternatively extracted.

  According to the present invention, when image information of a plurality of pixels is periodically extracted at a predetermined ratio, the image information of a specific pixel in which the ratio of the image information of any one pixel is equal to or greater than a set value and the adjacent information By correcting the color misregistration based on the image information of at least one pixel, it is possible to provide an image processing method and an image processing apparatus that improve the processing speed and reduce the risk of malfunction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.
FIG. 1 is a block diagram showing a part of the configuration of an image processing apparatus according to an embodiment of the present invention. This image processing apparatus extracts a part of image information included in an input image signal to generate an R signal, a G signal, and a B signal, and outputs the R signal to red, green, and blue dots of the display panel. , G signal, and B signal are used in a system for displaying image information. The input image signal (image data) is, for example, an 8-bit R signal component (R data), an 8-bit G signal component (G data), and an 8-bit B signal component (B) for each pixel. Data).

  As shown in FIG. 1, this image processing apparatus periodically outputs image information of a plurality of pixels with respect to an R signal component, a G signal component, and a B signal component included in an input image signal. The image extraction unit 10 that extracts at a ratio, the luminance calculation unit 20 that calculates the amount of change in luminance level between a plurality of pixels, and the amount of change in the luminance level calculated by the luminance calculation unit 20 is compared with a threshold value. Accordingly, the edge detection unit 30 for detecting the edge of the image and the color signal level of the pixel located on the high luminance side of the edge of the image detected by the edge detection unit 30 are reduced and / or the edge detection unit 30 And an image correction unit 40 that increases the color signal level of the pixel located on the low luminance side of the detected edge of the image.

  However, since the processing becomes enormous if the amount of change in luminance level is calculated for all pixels, the luminance calculation unit 20 has a ratio of image information of any one pixel extracted by the image extraction unit 10 equal to or greater than a set value. Focusing on a specific pixel, the amount of change in the luminance level between the plurality of pixels is calculated based on the image information of the specific pixel and the image information of at least one pixel adjacent thereto. This improves the processing speed and reduces the risk of malfunction.

Next, an image processing method according to an embodiment of the present invention implemented in the image processing apparatus shown in FIG. 1 will be described.
FIG. 2 is a flowchart showing an image processing method according to an embodiment of the present invention.
First, in step S1, the image extraction unit 10 initializes the count value n to “1”, for example. Next, in step S2, the image extraction unit 10 periodically outputs image information of a plurality of pixels at a predetermined ratio with respect to the R signal component, the G signal component, and the B signal component included in the input image signal. By performing extraction, sub-sampling of the input image signal is performed to generate an image signal for the nth dot (subpixel) of the display panel (n = 1, 2,...). In the present embodiment, R signal image information is displayed on the first dot of the display panel, G signal image information is displayed on the second dot, and B signal image information is displayed on the third dot. Are displayed, and color display is repeated in this order.

  In step S <b> 3, the luminance calculation unit 20 determines whether or not the pixel used for generating the image signal for the nth dot includes a pixel for luminance calculation. In the present embodiment, in order to generate an image signal for one dot, when the image information of one pixel is used at a ratio of a set value (for example, 80%) or more, that pixel is set as a specific pixel. By setting, whether or not the image signal needs to be corrected is determined based on the amount of change in the luminance level. In order to calculate the amount of change in the luminance level, the specific pixel and at least one pixel adjacent to the specific pixel are subject to luminance calculation. When the input image signal corresponding to the nth dot includes a pixel that is subject to luminance calculation, the process proceeds to step S4, and the pixel that is subject to luminance calculation is not included. In step S9, the process proceeds to step S9.

In step S4, the luminance calculation unit 20, the pixels that are the subject of luminance calculated in step S3, the brightness level E _Y of the input image signal calculated by the following equation.
E _Y = 0.30E _R + 0.59E _G + 0.11E _B
Here, E _R is the level of the R signal component of the input image signal, E _G is the level of the G signal component of the input image signal, E _B is the level of the B signal component of the input image signal.

In step S5, the edge detecting unit 30 calculates the amount of change Delta] E _Y of the luminance levels between a plurality of pixels. In step S6, the edge detecting section 30, by comparing the variation Delta] E _Y of the calculated brightness level in step S5 and the threshold value Th, detects an edge of an image (change steep portion of the luminance). That is, the edge detection unit 30, when a Delta] E _Y> Th, it is determined that the image edge is present, the process control proceeds to step S7, and if not Delta] E _Y> Th, the image edge is present If it is determined not to be performed, the process proceeds to step S9.

  In step S7, the image correction unit 40 calculates a correction amount of the color signal level. In step S8, the image correction unit 40 uses the correction amount calculated in step S7 to lower the color signal level of the pixel located on the high luminance side of the edge of the image detected in step S6, and / or The image signal is corrected by increasing the color signal level of the pixel located on the low luminance side of the edge of the image.

  In step S9, the image extraction unit 10 increments the count value n by 1, and returns the process to step S2. Thereby, the process of step S2-step S9 is repeatedly performed about all the pixels contained in the input image signal.

Now, a first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a diagram for explaining extraction of image information in the first embodiment of the present invention.
As described above, since the number of dots is not so large in a small display panel, not all the RGB (red, green, and blue) image information included in the image signal is displayed. Thinning out has been done. In the first embodiment, an image is displayed on a display panel having 720 × 240 dots (240 × 240 dots for each of RGB) based on an input image signal having image information of 720 × 240 pixels for each of RGB. The case where it does is demonstrated.

As shown in FIG. 3, the input image signal, and R signal components _R 1, G signal component _G 1, B signal components _{B 1} of the first pixel, the R signal component _R 2, G signal of the second pixel The component G ₂ , the B signal component B ₂ , the R signal component R ₃ of the third pixel, the G signal component G ₃ , the B signal component B _{3, and the} like are included.

The image extraction unit 10 alternatively extracts the R signal component R1 of the _first pixel as image information to be displayed on the first dot (red) of the display panel, and the second dot (green) of the display panel. the G signal component of the second pixel as the image information G ₂ and displaying alternatively extracted, the third pixel as the image information to be displayed in the third dot of the display panel (blue) B signal component B ₃ Are extracted alternatively, and thereafter the extraction is repeated in this order.

  That is, for the first dot, the R signal component of the first pixel is extracted at a rate of 100%, the R signal component of the second pixel is extracted at a rate of 0%, and the R signal of the third pixel is extracted. Ingredients are extracted at a rate of 0%. For the second dot, the G signal component of the first pixel is extracted at a rate of 0%, the G signal component of the second pixel is extracted at a rate of 100%, and the G signal component of the third pixel is extracted. Extracted at a rate of 0%. For the third dot, the B signal component of the first pixel is extracted at a rate of 0%, the B signal component of the second pixel is extracted at the rate of 0%, and the B signal component of the third pixel is extracted. Extracted at a rate of 100%. In this manner, the image extraction unit 10 subsamples the input image signal and generates an image signal for display.

  As shown in FIG. 3, when the luminance level is high in the first pixel to the fourth pixel and the luminance level is low from the fourth pixel, the image signal is white in the first pixel to the fourth pixel. Although the area represents the area, red, green, blue, and red are displayed in the first to fourth dots on the display panel, so the ratio of the RGB dots is not uniform and the edge of the white area A phenomenon occurs in which red is emphasized. In particular, since red is easily noticeable visually, color shift is noticeable when red is displayed on the edge of a white region. Therefore, in the first embodiment, in order to eliminate such color misregistration, the pixel from which the R signal component is alternatively extracted (100%) is set as the specific pixel, and the specific pixel is the standing of the image. The image signal is corrected when positioned on the high luminance side of the downstream edge.

  The luminance calculation unit 20 determines whether or not the pixel corresponding to the nth dot is a luminance calculation target based on the count value n. In the first embodiment, the (3m + 1) th pixel corresponding to the (3m + 1) th dot (red) and the subsequent (3m + 2) th pixel are subjected to luminance calculation. (M = 0, 1, 2,...) For example, when m = 1 and n = 4, the fourth and fifth pixels are subject to luminance calculation.

In this case, the edge detection unit 30 obtains the luminance level change amount ΔE _Y by the following equation.
ΔE _Y = E _Y4 -E _Y5
This luminance level change amount ΔE _Y represents the amount of decrease in the luminance level E _Y5 of the subsequent pixel with respect to the luminance level E _Y4 of the specific pixel corresponding to the fourth dot (red).

Edge detecting unit 30, the calculated luminance level variation Delta] E _Y by comparing the threshold Th, detecting the falling edge of the image. In the first embodiment, the threshold value Th is preset as a parameter (see FIG. 1). As a result, in the case of Delta] E _Y> Th, it is determined that the edge detection unit 30, the falling edge of the image exists.

When it is determined that a falling edge of the image exists, the image correction unit 40 calculates the correction amount dER of the _R signal by the following equation, for example.
dE _R = | E _Y4 −E _Y5 | / 5
Here, the correction amount dE _R of the R signal is proportional to the difference value of the luminance level between a particular pixel and the pixel following thereafter.

The image correction unit 40 obtains a corrected color signal level E _R4 ′ by reducing the color signal level E _R4 of the fourth dot according to the following equation.
E _R4 '= E _R4 -dE _R
As a result, the red level displayed on the fourth dot is lowered, and the color shift is eliminated.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram for explaining extraction of image information in the second embodiment of the present invention. In the second embodiment, an image is displayed on a display panel having 960 × 240 dots (320 × 240 dots for each of RGB) based on an input image signal having image information of 720 × 240 pixels for each of RGB. The case where it does is demonstrated.

As shown in FIG. 4, the image signal input to the image extraction unit 10 includes an R signal component R ₁ , a G signal component G ₁ , a B signal component B _{1 of} the first pixel, and an R signal of the second pixel. A signal component R ₂ , a G signal component G ₂ , a B signal component B ₂ , an R signal component R ₃ , a G signal component G ₃ , a B signal component B _{3, and the} like of the third pixel are included.

The image extraction unit 10 periodically extracts these color signal components at a predetermined ratio, thereby causing the signal E ₁ having image information to be displayed on the first dot (red) of the display panel, the second of the display panel. A signal E ₂ having image information to be displayed on the first dot (green), a signal E ₃ having image information to be displayed on the third dot (blue) of the display panel, and the like are calculated by the following equations.
E ₁ = E _R1
E ₂ = (E _G1 + 3E _G2 ) / 4
E ₃ = (2E _B2 + 2E _B3 ) / 4
E ₄ = (3E _R3 + E _R4 ) / 4
E ₅ = E _G4

  That is, for the first dot, the R signal component of the first pixel is extracted at a rate of 100%. For the second dot, the G signal component of the first pixel is extracted at a rate of 25%, and the G signal component of the second pixel is extracted at a rate of 75%. For the third dot, the B signal component of the second pixel is extracted at a rate of 50%, and the B signal component of the third pixel is extracted at a rate of 50%. For the fourth dot, the R signal component of the third pixel is extracted at a rate of 75%, and the R signal component of the fourth pixel is extracted at a rate of 25%. For the fifth dot, the G signal component of the fourth pixel is extracted at a rate of 100%.

  In this manner, the image extraction unit 10 subsamples the input image signal and generates an image signal for display. Here, when the signal for one dot is generated, if the ratio of the color signal component of a specific pixel is large, the color shift is easily noticeable at the edge of the image. In the second embodiment, in order to eliminate such color misregistration, the image signal is corrected when a specific pixel is located on the high luminance side of the falling edge of the image.

  The luminance calculation unit 20 determines whether or not the pixel corresponding to the nth dot is a luminance calculation target based on the count value n. In the second embodiment, the (3m + 1) -th pixel in which the ratio of the extracted image information is equal to or greater than a set value (for example, 80%), the (3m) -th pixel and the ( The 3m + 2) -th pixel is selected as a luminance calculation target (m = 1, 2,...). For example, when m = 1 and n = 5, the third to fifth pixels are subjected to luminance calculation.

In that case, the edge detection unit 30 obtains the amount of change Delta] E _Y of the luminance level by the following equation.
ΔE _Y = 2E _Y4 −E _Y3 −E _Y5
Variation Delta] E _Y of the luminance level, a fourth pixel corresponding to the green dot (n = 5), and represents the amount of change in the luminance level of the third pixel and the fifth pixel adjacent thereto.

In addition, the edge detection unit 30 determines, for example, a threshold value according to the following equation based on the luminance levels of the third pixel and the fifth pixel before and after the fourth pixel corresponding to the green dot (n = 5). Set Th.
Th = | E _Y5 −E _Y3 | / 2
Further, the edge detection unit 30 sets the set threshold value Th when the set threshold value Th is smaller than a predetermined value (for example, 50% of the difference between the maximum value and the minimum value of the luminance level). Is changed to a predetermined value. This is to avoid a malfunction when E _Y3 ≈E _{Y4 ≈E Y5} .

Edge detecting unit 30, the calculated luminance level variation Delta] E _Y by comparing the threshold Th, detecting the falling edge of the image. As a result, when ΔE _Y > Th, the edge detection unit 30 determines that a falling edge of the image exists.

When the falling edge of the image is determined to exist, the image correcting unit 40, for example, calculates the correction amount dE _G of the G signal by the following equation.
_{dE G = | E Y4 -E Y5} | / 5

The image correction unit 40 obtains a corrected signal level E ₅ ′ (color signal level E _G4 ′) by reducing the color signal level E _G4 of a specific pixel according to the following equation.
_{E 5 '= E G4' =} E G4 -dE G
As a result, the green level displayed on the fifth dot is reduced, and the color shift is eliminated.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a diagram for explaining extraction of image information in the third embodiment of the present invention. In the second embodiment, an image is displayed on a display panel having 720 × 240 dots (360 × 240 dots for each of RGB) based on an input image signal having image information of 720 × 240 pixels for each of RGB. The case where it does is demonstrated.

In the image signal input to the image extraction unit 10, the R signal component of the first pixel is R ₁ , the G signal component is G ₁ , the B signal component is B _1, and the R signal component of the second pixel is R _2. The G signal component is G ₂ , the B signal component is B ₂ , the R signal component of the third pixel is R ₃ , the G signal component is G ₃ , the B signal component is B _3, etc.

The image extraction unit 10 periodically extracts these color signal components at a predetermined ratio, thereby displaying the signal E ₁ displayed on the first dot (red) of the display panel and the second dot (green) of the display panel. signal E ₂ to be displayed on) _is calculated by the following equation signal E ₃ for displaying the third dot of the display panel (blue).
E ₁ = E _R1
E ₂ = (E _G1 + 2E _G2 ) / 3
E ₃ = (2E _B2 + E _B3 ) / 3
E ₄ = E _R3

  That is, for the first dot, the R signal component of the first pixel is extracted at a rate of 100%. For the second dot, the G signal component of the first pixel is extracted at a rate of 33%, and the G signal component of the second pixel is extracted at a rate of 66%. For the third dot, the B signal component of the second pixel is extracted at a rate of 66%, and the B signal component of the third pixel is extracted at a rate of 33%. For the fourth dot, the R signal component of the third pixel is extracted at a rate of 100%.

  FIG. 6 is a diagram for explaining a method for determining the ratio of the color signal components of two pixels extracted to generate a signal of one dot. In FIG. 6, two pixels A and B are adjacent on one line, and a signal for a dot O representing one of RGB colors is generated based on the image information.

Here, if the distance between the dot O and the pixel A is Km2, and the distance between the dot O and the pixel B is Km1, the signal level E _O for the dot _O is the color for the same color in the pixel A. Based on the signal level E _A and the color signal level E _B for the same color in the pixel B, calculation is performed by the following equation (bilinear interpolation).
E _O = Km1 · E _A + Km2 · E _B
However, Km1 and Km2 are values normalized so that Km1 + Km2 = 1.

  In this case, the condition for correcting the image signal is that Km1 or Km2 is smaller than the threshold value δ. The threshold value δ is set in the range of 0 to 0.2, for example. Other image processing is the same as that described in the second embodiment.

1 is a block diagram showing a part of the configuration of an image processing apparatus according to an embodiment of the present invention. 5 is a flowchart illustrating an image processing method according to an embodiment of the present invention. The figure explaining extraction of the image information in 1st Example of this invention. The figure explaining extraction of the image information in 2nd Example of this invention. The figure explaining extraction of the image information in the 3rd Example of this invention. The figure for demonstrating the method of determining the ratio of the color signal component of two pixels extracted.

Explanation of symbols

  10 image extraction unit, 20 luminance calculation unit, 30 edge detection unit, 40 image correction unit

Claims (7)

An image processing method used in a system for displaying R signal, G signal, and B signal image information on a plurality of dots of a display panel based on an input image signal,
A step (a) of periodically extracting image information of a plurality of pixels at a predetermined ratio with respect to an R signal component, a G signal component, and a B signal component included in an input image signal;
Based on the image information of the specific pixel in which the ratio of the image information of any one pixel extracted in step (a) is greater than or equal to the set value and the image information of at least one pixel adjacent thereto, Calculating the amount of change in luminance level at (b);
Detecting an edge of the image by comparing the amount of change in the brightness level calculated in step (b) with a threshold;
Reduce the color signal level of the pixel located on the high luminance side of the edge of the image detected in step (c) and / or the pixel located on the low luminance side of the edge of the image detected in step (c) Increasing the color signal level of (d),
An image processing method comprising: Step (a) includes alternatively extracting an R signal component, a G signal component, and a B signal component in order from image information of a plurality of pixels included in the input image signal;
The specific pixel is a pixel from which an R signal component is alternatively extracted.
The image processing method according to claim 1. Step (b) includes calculating an amount of decrease in luminance level between two pixels based on the image information of the specific pixel and the image information of subsequent pixels;
Step (c) comprises detecting a falling edge of the image by comparing the amount of decrease in luminance level calculated in step (b) with a threshold value;
Step (d) includes reducing the color signal level of the particular pixel when a falling edge of the image is detected in Step (c).
The image processing method according to claim 1 or 2. Step (b) includes calculating the amount of change in the luminance level between the three pixels based on the luminance level of the specific pixel and the luminance levels of the two pixels before and after the specific pixel;
Step (c) comprises detecting a falling edge of the image by comparing the amount of change in luminance level calculated in step (b) with a threshold;
Step (d) includes reducing the color signal level of the particular pixel when a falling edge of the image is detected in Step (c).
The image processing method according to claim 1 or 2. Setting a threshold based on luminance levels of two pixels before and after the specific pixel;
Changing the set threshold value to a predetermined value when the set threshold value is smaller than the predetermined value;
The image processing method according to claim 4, further comprising: An image processing apparatus used in a system for displaying information of R signal, G signal, and B signal on a plurality of dots of a display panel based on an input image signal,
Image extraction means for periodically extracting image information of a plurality of pixels at a predetermined ratio with respect to the R signal component, the G signal component, and the B signal component included in the input image signal;
Based on the image information of a specific pixel in which the ratio of the image information of any one pixel extracted by the image extraction means is equal to or greater than a set value and the image information of at least one pixel adjacent thereto, a plurality of pixels A luminance calculation means for calculating the amount of change in luminance level at
Edge detection means for detecting an edge of an image by comparing the amount of change in the brightness level calculated by the brightness calculation means with a threshold;
Pixels located on the low brightness side of the edge of the image detected by the edge detection means and / or the color signal level of the pixels located on the high brightness side of the edge of the image detected by the edge detection means are reduced Image correction means for increasing the color signal level of
An image processing apparatus comprising: The image extraction means alternatively extracts an R signal component, a G signal component, and a B signal component in order from image information of a plurality of pixels included in an input image signal,
The specific pixel is a pixel from which an R signal component is alternatively extracted.
The image processing apparatus according to claim 6.

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