WO2014091720A1 - Dispositif de correction de contour et dispositif de traitement d'image - Google Patents

Dispositif de correction de contour et dispositif de traitement d'image Download PDF

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Publication number
WO2014091720A1
WO2014091720A1 PCT/JP2013/007126 JP2013007126W WO2014091720A1 WO 2014091720 A1 WO2014091720 A1 WO 2014091720A1 JP 2013007126 W JP2013007126 W JP 2013007126W WO 2014091720 A1 WO2014091720 A1 WO 2014091720A1
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WO
WIPO (PCT)
Prior art keywords
correction
correction amount
degree
oblique
unit
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Application number
PCT/JP2013/007126
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English (en)
Japanese (ja)
Inventor
板倉　章太郎
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パナソニック株式会社
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Publication date
Application filed by パナソニック株式会社 filed Critical パナソニック株式会社
Priority to JP2014551880A priority Critical patent/JPWO2014091720A1/ja
Publication of WO2014091720A1 publication Critical patent/WO2014091720A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/142—Edging; Contouring
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/70—Denoising; Smoothing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/90—Dynamic range modification of images or parts thereof
    • G06T5/94—Dynamic range modification of images or parts thereof based on local image properties, e.g. for local contrast enhancement
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/20—Special algorithmic details
    • G06T2207/20172—Image enhancement details
    • G06T2207/20192—Edge enhancement; Edge preservation

Definitions

  • the present disclosure relates to image processing, and particularly relates to contour correction processing for correcting the contour of an image.
  • contour correction is performed in the horizontal direction and the vertical direction. Therefore, when there is a diagonal line in the image, the contour correction is performed in both the horizontal direction and the vertical direction with respect to the diagonal line. It will take. As a result, the contour correction for the oblique line is overcorrected, and jaggies and shoots are excessively emphasized. As a result, there is a problem that the quality of the image quality is deteriorated.
  • This disclosure is intended to appropriately perform contour correction even when there is a diagonal line in an image.
  • a contour correction device that corrects a contour of an image represented by a luminance signal calculates a first correction amount for performing contour correction in a horizontal direction and a vertical direction from the luminance signal.
  • a second correction unit that calculates a second correction amount for performing contour correction in a direction orthogonal to the diagonal line at a predetermined angle from the luminance signal, and an image from the luminance signal to the diagonal line at the predetermined angle.
  • An inclination degree detecting unit that detects an inclination degree that represents the degree of approximation, the first correction amount and the second correction amount are adjusted according to the inclination degree, and the luminance signal is used using the adjusted correction amount.
  • a signal correction unit for correcting is used using the adjusted correction amount.
  • the oblique degree detecting unit detects the oblique degree representing the degree to which the image approximates the oblique line of the predetermined angle. Then, in the signal correction unit, a first correction amount for performing contour correction in the horizontal direction and the vertical direction and a second correction amount for performing contour correction in a direction orthogonal to the oblique line of a predetermined angle are detected. Adjustment is made according to the degree of inclination, and the luminance signal is corrected using the corrected amount after adjustment. As a result, it is possible to apply the contour correction in the oblique direction while avoiding the overcorrection applied to the oblique line while applying the contour correction in the horizontal direction and the vertical direction to the vertical line and the horizontal line in the image. . Therefore, even when there is a diagonal line in the image, the contour correction can be appropriately executed.
  • FIG. 1 is a specific configuration example of a contour correction apparatus according to an embodiment.
  • (A), (b) is a figure for demonstrating the inclination degree detection.
  • (A), (b) is a figure for demonstrating the inclination degree detection.
  • (A), (b), (c) is the example of an image which shows the effect of an embodiment.
  • FIG. 1 is a block diagram showing a configuration example of a contour correction apparatus according to this embodiment.
  • the contour correction apparatus according to the present embodiment corrects the contour of an image represented by an input luminance signal so as to be sharper, for example.
  • the contour correction apparatus shown in FIG. 1 includes a horizontal / vertical contour correction unit 11 as a first correction unit, an oblique contour correction unit 12 as a second correction unit, an oblique degree detection unit 13, and a signal correction unit 20. ing.
  • the horizontal / vertical contour correction unit 11 calculates a correction amount for performing contour correction in the horizontal direction and the vertical direction from the input luminance signal. Horizontal lines in the image are emphasized by contour correction in the vertical direction, and vertical lines are emphasized by contour correction in the horizontal direction.
  • the oblique degree detection unit 13 detects the degree of obliqueness indicating how close an image is to an oblique line of a predetermined angle, that is, a so-called oblique line.
  • the degree of obliqueness is an evaluation value that represents the degree to which an image approximates an oblique line with a predetermined angle.
  • the oblique contour correction unit 12 calculates a correction amount for performing contour correction in a direction orthogonal to the oblique line of a predetermined angle from the input luminance signal.
  • the predetermined angle at this time is preferably the same as the predetermined angle of the oblique line when the oblique degree is detected by the oblique degree detection unit 13.
  • the signal correction unit 20 adjusts the correction amount output from the horizontal / vertical contour correction unit 11 and the correction amount output from the oblique contour correction unit 12 in accordance with the oblique degree detected by the oblique degree detection unit 13. . Then, the input luminance signal is corrected using the adjusted correction amount and output as an output luminance signal. In other words, horizontal and vertical contour correction and oblique contour correction are blended according to the degree of obliqueness and applied to the luminance signal.
  • the horizontal line in the image is emphasized by the contour correction in the vertical direction, and the vertical line is emphasized by the contour correction in the horizontal direction.
  • the diagonal line in the image is emphasized by both the contour correction in the vertical direction and the contour correction in the horizontal direction, so that only the horizontal and vertical contour correction is overcorrected. Therefore, the signal correction unit 20 decreases the effect of the correction amount output from the horizontal / vertical contour correction unit 11 and increases the effect of the correction amount output from the diagonal contour correction unit 12 as the degree of inclination increases. Further, the lower the degree of inclination, the greater the effect of the correction amount output from the horizontal / vertical contour correction unit 11 and the smaller the effect of the correction amount output from the oblique contour correction unit 12. Thereby, the oblique line in the image is appropriately corrected by the oblique contour correction without being overcorrected by the horizontal / vertical contour correction.
  • the 1 includes a first adjustment unit 14, a second adjustment unit 15, and a correction amount addition unit 16.
  • the first adjustment unit 14 adjusts the correction amount output from the horizontal / vertical contour correction unit 11 according to the degree of inclination.
  • the second adjustment unit 15 adjusts the correction amount output from the oblique contour correction unit 12 according to the degree of inclination.
  • the correction amount addition unit 16 adds the correction amount after adjustment by the first adjustment unit 14 and the correction amount after adjustment by the second adjustment unit 15 to the input luminance signal.
  • the 1st adjustment part 14 adjusts the correction amount output from the horizontal / vertical outline correction
  • the second adjustment unit 15 adjusts the correction amount output from the oblique contour correction unit 12 so that the correction amount increases as the degree of obliqueness increases and decreases as the degree of obliqueness decreases. Thereby, the horizontal / vertical contour correction and the diagonal contour correction are blended in accordance with the diagonal degree and applied to the luminance signal.
  • FIG. 2 is a diagram showing a specific configuration example of the contour correction apparatus according to the present embodiment.
  • the horizontal / vertical contour correction unit 11 of FIG. 1 is configured by a horizontal contour correction unit 11a and a vertical contour correction unit 11b
  • the first adjustment unit 14 of FIG. 1 is configured by multiplication units 14a and 14b.
  • the second adjustment unit 15 in FIG. 1 is configured by a multiplication unit 15a.
  • the oblique degree detection unit 13 detects an oblique degree relating to an oblique line in the 45 degree direction (upward to the right) or 135 degree direction (upward to the left), and is normally in the range of 0 to 1 as an index indicating the oblique degree.
  • the normalized value DD is calculated.
  • the value DD is “1” when the diagonal degree is the highest and “0” when the diagonal degree is the lowest.
  • the multipliers 14a and 14b multiply the correction amount by the value (1-DD), and the multiplier 15a multiplies the correction amount by the value DD. As a result, the correction amount is adjusted.
  • FIG. 3A shows a part of the image represented by the luminance signal, and includes an oblique line in the 45 degree direction.
  • a cumulative value of luminance differences of pixels that are continuous in the diagonal direction is used for the calculation of the diagonal degree. This is based on the premise that the pixels constituting the diagonal line have a small luminance difference.
  • the oblique degree related to the oblique line in the 45 degree direction or the 135 degree direction is calculated using five consecutive pixels.
  • the pixel marked with (3) be the pixel of interest.
  • ABS represents an absolute value calculation, and the numbers in parentheses and alphabets indicate the luminance value of the pixel.
  • a value DD is calculated from the smaller value of MIN (DIFF45, DIFF135), that is, DIFF45 and DIFF135.
  • the function f (x) is a function in which the DD value approaches “1” as the MIN (DIFF45, DIFF135) decreases, and the DD value approaches “0” as the MIN (DIFF45, DIFF135) increases.
  • the diagonal line is 135 degrees. The determination result is sent from the oblique degree detection unit 13 to the oblique contour correction unit 12.
  • DIFF45 becomes very small because a diagonal line rising to the right is included. Therefore, the value of DD is “1”. Further, since DIFF45 ⁇ DIFF135, it is determined as a 45-degree oblique line.
  • FIG. 4A shows another example of the image indicated by the luminance signal, which includes a diagonal line in the direction of 22.5 degrees, although it goes up to the right.
  • DIFF45 since DIFF45 ⁇ DIFF135, it is determined that the line is an oblique line of 45 degrees.
  • the value of DIFF 45 is larger than that in the case of FIG. That is, if DIFF 45 when a 45-degree diagonal line is included is DIFF 45 (45), and DIFF 45 when a 22.5-degree diagonal line is included is DIFF 45 (22.5), DIFF45 (45) ⁇ DIFF45 (22.5) It becomes.
  • DIFF45 (45) ⁇ DIFF45 (22.5) It becomes.
  • DD by adjusting the function f (x), DD can be set to “0.5” when the diagonal line is 22.5 degrees, for example.
  • the shape of the function f (x) is not limited to that shown in FIGS. 3 and 4, and may have a curve, for example. Further, a known method may be used so that the shape of the function f (x) can be adjusted from the outside of the apparatus.
  • the oblique degree detection unit 13 determines that the image shown in FIG.
  • the correction amount is calculated in a direction orthogonal to the 45 degree direction, that is, in the 135 degree direction. For example, assuming that the pixel marked with (3) is the pixel of interest, the correction amount is calculated using the luminance value of the pixel surrounded by the broken line in the figure.
  • the oblique BPF is a method in which a BPF (Band Pass Filter) is applied in an oblique direction, here a 135 degree direction, and a chute is added to the edge.
  • BPF Band Pass Filter
  • a 5-tap filter with filter coefficients (a, b, c, d, e) is used, the filter output of the pixel of interest (3) is a ⁇ A + b ⁇ B + c ⁇ (3) + d ⁇ C + e ⁇ D It becomes.
  • the oblique transient correction is a method in which the edge is sharpened by subtracting the correction signal from the input luminance signal in the oblique direction, here, in the direction of 135 degrees. Note that the contour correction in the oblique direction is not limited to these methods.
  • FIG. 6 is a diagram illustrating an example of a blending method of horizontal / vertical contour correction and oblique contour correction in the present embodiment.
  • the value DD indicating the degree of obliqueness is “0”.
  • the value “1” is given to the multipliers 14a and 14b, while the value “0” is given to the multiplier 15a.
  • the value DD indicating the degree of inclination is “1”.
  • the value “0” is given to the multipliers 14a and 14b, while the value “1” is given to the multiplier 15a.
  • the value DD indicating the diagonal degree is “0”. .5 ".
  • the value “0.5” is given to the multipliers 14a and 14b, while the value “0.5” is given to the multiplier 15a.
  • the correction amount added to the input luminance signal is (Horizontal correction amount + vertical correction amount) ⁇ 0.5 + oblique correction amount ⁇ 0.5 It becomes. That is, the horizontal and vertical contour correction and the diagonal correction are performed with reduced intensity.
  • FIG. 7 shows the effect of this embodiment.
  • the conventional method applies both horizontal contour correction and vertical contour correction to the input image including the 45-degree oblique line shown in FIG.
  • the line is overcorrected, and jaggies and shoots are overemphasized and image quality is degraded.
  • the horizontal and vertical contour correction is not performed on the diagonal line, and only the diagonal contour correction is performed. Contour correction is realized.
  • the normalized value DD is calculated as an index value indicating the degree of inclination, and the correction amount is multiplied by the value DD and the value (1-DD).
  • the correction according to the degree of inclination is performed.
  • the method of adjusting the amount is not limited to this.
  • the inclination degree detection unit 13 may set a value to be multiplied by each correction amount according to the detected inclination degree. In this case, the relationship between the skew degree and the correction amount adjustment may be controlled from the outside of the apparatus.
  • the oblique degree detection unit 13 gives the detected oblique degree to the first adjustment unit 14 and the second adjustment unit 15, and the first adjustment unit 14 and the second adjustment unit 15 respectively correct the correction amount according to the oblique degree. You may adjust it.
  • the angle of the oblique line when detecting the oblique degree is set to 45 degrees or 135 degrees.
  • the present invention is not limited to this.
  • a plurality of oblique contour correcting units 12 and oblique degree detecting units 13 may be provided, and a plurality of types of oblique contour correction may be executed in combination.
  • the internal configuration of the signal correction unit 20 is not limited to that shown in FIGS. 1 and 2, and the horizontal / vertical contour correction and the diagonal contour correction are blended in accordance with the diagonal degree to obtain a luminance signal. Any configuration is applicable as long as it is applicable.
  • each unit shown in the present embodiment may be configured by a circuit or hardware, or may be realized by executing software by a processor.
  • the contour correction device is used in, for example, an image processing device that displays an image or outputs an image to a monitor.
  • the image processing device include a tablet, a smartphone, a TV device, and various video players.
  • the contour correction can be appropriately executed even when there is a diagonal line in the image, which is effective for displaying the image more clearly on the screen, for example, on a tablet or a smartphone.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
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  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)
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Abstract

La présente invention permet à une correction de contour d'être exécutée de manière appropriée même lorsqu'une image contient une ligne oblique. Une première unité de correction (11) calcule une première quantité de correction pour corriger des contours dans des directions horizontale et verticale, et une seconde unité de correction (12) calcule une seconde quantité de correction pour corriger un contour dans une direction orthogonale à une ligne oblique à un angle prescrit. Une unité de détection de degré d'obliquité (13) détecte un degré d'obliquité représentant l'étendue dans laquelle l'image se rapproche de la ligne oblique à l'angle prescrit. Une unité de correction de signal (20) règle la première quantité de correction et la seconde quantité de correction selon le degré d'obliquité, et corrige un signal de luminance par utilisation des quantités de correction réglées.
PCT/JP2013/007126 2012-12-10 2013-12-04 Dispositif de correction de contour et dispositif de traitement d'image WO2014091720A1 (fr)

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Application Number Priority Date Filing Date Title
JP2014551880A JPWO2014091720A1 (ja) 2012-12-10 2013-12-04 輪郭補正装置および画像処理装置

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JP2012-269754 2012-12-10
JP2012269754 2012-12-10

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001128031A (ja) * 1999-10-30 2001-05-11 Fujitsu General Ltd 輪郭強調方法及び回路
JP2001144995A (ja) * 1999-11-12 2001-05-25 Fujitsu General Ltd 輪郭補正方法及び回路
JP2004213415A (ja) * 2003-01-06 2004-07-29 Ricoh Co Ltd 画像処理装置、画像処理プログラムおよび記憶媒体
JP2007336384A (ja) * 2006-06-16 2007-12-27 Canon Inc 画像処理装置及び方法
JP2008167027A (ja) * 2006-12-27 2008-07-17 Olympus Corp 画像処理装置、画像処理方法、画像処理プログラム

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001128031A (ja) * 1999-10-30 2001-05-11 Fujitsu General Ltd 輪郭強調方法及び回路
JP2001144995A (ja) * 1999-11-12 2001-05-25 Fujitsu General Ltd 輪郭補正方法及び回路
JP2004213415A (ja) * 2003-01-06 2004-07-29 Ricoh Co Ltd 画像処理装置、画像処理プログラムおよび記憶媒体
JP2007336384A (ja) * 2006-06-16 2007-12-27 Canon Inc 画像処理装置及び方法
JP2008167027A (ja) * 2006-12-27 2008-07-17 Olympus Corp 画像処理装置、画像処理方法、画像処理プログラム

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