Image processing device

• US 7,583,403 B2
• Filed: 09/11/2003
• Issued: 09/01/2009
• Est. Priority Date: 09/12/2002
• Status: Expired due to Fees

• Current Assignee: Godo Kaisha IP Bridge 1 (IP Bridge, Inc.)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ito, Takeshi, Yamashita, Haruo
• Primary Examiner(s): Lee; Thomas D
• Assistant Examiner(s): Brinich; Stephen M
• Application Number:
  US10/527,661
• Publication Number:
  US 20060013478A1
• Time in Patent Office: 2,182 Days
• Field of Search: 358/1.9, 358/2.1, 358/500, 358/504, 358515-523
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only
• CPC Class Codes: H04N 1/628 Memory colours, e.g. skin or sky
• CPC Class Codes: H04N 9/643 Hue control means, e.g. flesh tone control
• CPC Class Codes: H04N 9/68 for controlling the amplitude of colour signals, e.g. automatic chroma control circuits H04N9/71, H04N9/73 take precedence; camera processing pipelines for controlling the colour saturation of colour signals H04N23/86

Abstract

An image processing apparatus of correcting the color of a specific range of a pixel signal for each pixel included in an input image signal, comprises an intensity determination means of generating a correction intensity that is small on the periphery of the color region of the specific range on the basis of two chromaticity signals excluding a luminance component and large in the vicinity of the nearly central portion of the range in the pixel signal, a target color setting means of setting a target color depending on which the pixel signal is corrected, a correction degree setting means of setting correction degree by also using information, other than pixel information, included in the pixel signal, and a correction means of making the image signal close to the target color depending on the correction intensity output from the intensity determination means and the correction degree output from the correction degree setting means.

Claims

1. An image processing apparatus of correcting the color of a predetermined range of a pixel signal for each pixel included in an input image signal, comprising:

a target color setting unit which sets a target color depending on which the color of said pixel signal is corrected, and

a color converter which carries out correction to make the color of said pixel signal coincident with or close to said target color by using a) said pixel signal, b) information of identifying a photographic scene by also using photographic information, and c) said target color, wherein

said color converter comprises;

an intensity determination unit which generates a correction intensity that is smaller on a periphery of a color region and larger in a vicinity of a central portion of said color region, said color region having a specific range set on the basis of two chromaticity components excluding a luminance component in the color of said pixel signal,

a correction degree setting unit which sets a correction degree by using a) said pixel signal, b) said information of identifying said photographic scene, and c) said target color, and

a correction unit which makes the color of said pixel signal coincident with or close to said target color depending on said correction intensity having been generated and said correction degree having been set, wherein

said correction degree setting unit sets said correction degree by identifying at least an image photographing scene according to said input image signal.

2. The image processing apparatus in accordance with claim 1, wherein said correction degree setting unit determines said correction degree according to said input image signal and photographic information at the time when an input image is taken.

3. The image processing apparatus in accordance with claim 2, wherein said correction degree setting unit comprises:

an image identifier which identifies the photographic scene of an image according to said input image signal,

a photographic information identifier which identifies a photographic scene according to the photographic information at the time when said input image signal is photographed, and

a correction degree determination unit which determines said correction degree according to the outputs of said image identifier and said photographic information identifier.

4. The image processing apparatus in accordance with claim 3, wherein said image identifier and said photographic information identifier identify whether a person is included in an image or not.

5. The image processing apparatus in accordance with claim 3, wherein said image identifier and said photographic information identifier identify whether the sky is included in an image or not.

6. The image processing apparatus in accordance with claim 3, wherein said image identifier and said photographic information identifier identify whether green plants are included in an image or not.

11. The image processing apparatus in accordance with claim 1 or 7, wherein said correction unit corrects each of said two chromaticity components to a value obtained when each of said two chromaticity components and two target chromaticity values output from said target color setting unit are internally divided depending on said correction intensity.

12. The image processing apparatus in accordance with claims 1 or 7, wherein

said correction unit has a second polar coordinate converter which converts said two chromaticity components into a hue signal and a saturation signal and said saturation signal output from said second polar coordinate converter being converted to a value obtained when said hue signal and said saturation signal and the target hue signal and the target saturation signal output from said target color setting unit are internally divided depending on said correction intensity.

13. The image processing apparatus in accordance with claim 1 or 7, wherein

said intensity determination unit outputs a hue correction intensity for hue correction and a saturation correction intensity for saturation correction,

said correction unit has a second polar coordinate converter which converts said two chromaticity components into a hue signal and a saturation signal,

a hue correction unit which corrects said hue signal having been converted to a value obtained when said hue signal and the target hue value output from said target color setting unit are internally divided depending on said hue correction intensity, and

a saturation correction unit which corrects said saturation signal having been converted to a value obtained when said saturation signal and the target saturation value output from said target color setting unit are internally divided depending on said saturation correction intensity.

7. An image processing apparatus of correcting the color of a predetermined range of a pixel signal for each pixel included in an input image signal, comprising:

a target color setting unit which sets a target color depending on which the color of said pixel signal is corrected, and

a color converter which carries out correction to make the color of said pixel signal coincident with or close to said target color by using a) the luminance component in the color of said pixel signal, b) two chromaticity components excluding said luminance component in the color of said pixel signal, and c) said target value, wherein

said color converter determines said correction degree by using not only said two chromaticity components of said pixel signal to be corrected but also said luminance component of said pixel signal to be corrected and, wherein

said color converter comprises;

an intensity determination unit which generates a correction intensity that is smaller on a periphery of a color region and larger in a vicinity of a central portion of said color region, said color region having a specific range set on the basis of the luminance component and the two chromaticity components excluding said luminance component in the color of said pixel signal, and

a correction unit which makes the color of said pixel signal coincident with or close to said target color depending on said correction intensity having been generated.

8. An image processing apparatus in accordance with claim 7, wherein said intensity determination unit comprises:

a first function generator which outputs a candidate of a first correction intensity for said luminance signal,

second and third function generators which output candidates of second and third correction intensities for said two chromaticity components, respectively, and

a synthesizer which synthesizes the candidates of said first, second and third correction intensities and outputs the result as said correction intensity.

9. The image processing apparatus in accordance with claim 7, wherein said intensity determination unit comprises:

a first function generator which outputs a candidate of a first correction intensity for said luminance signal,

a two-dimensional function generator which outputs a second correction intensity on the basis of a two-dimensional function typified by an ellipse using said two chromaticity components, and

a synthesizer which synthesizes the candidates of said first and second correction intensities and outputs the result as said correction intensity.

10. The image processing apparatus in accordance with claim 7, wherein said intensity determination unit comprises:

a first function generator which outputs a candidate of a first correction intensity for said luminance signal,

a first polar coordinate converter which converts said two chromaticity components into a hue signal and a saturation signal,

a second function generator which generates a candidate of a second correction intensity for said hue signal,

a third function generator which generates a candidate of a third correction intensity for said saturation signal, and

a synthesizer which synthesizes the candidates of said first, second and third correction intensities and outputs the result as said correction intensity.

14. An image processing apparatus of correcting the color of a predetermined range of a pixel signal for each pixel included in an input image signal, comprising:

a target color setting unit which sets a target color depending on which the color of said pixel signal is corrected,

a color converter which carries out correction to make the color of said pixel signal coincident with or close to said target color by using a) said pixel signal, b) photographic information, and c) said target color, and

an interpolator which interpolates a three-dimensional look-up table of using three input signals as addresses and outputs three output signals or interpolates two of said three-dimensional look-up tables, wherein

the correspondence relationship of making the color of said pixel signal to correspond to the color corrected using said color converter is stored in said three-dimensional look-up table in advance, and

the color of said each pixel signal is corrected using said three-dimensional look-up table.

15. An image processing apparatus of correcting the color of a predetermined range of a pixel signal for each pixel included in an input image signal, comprising:

a target color setting unit which sets a target color depending on which the color of said pixel signal is corrected,

a color converter which carries out correction to make the color of said pixel signal coincident with or close to said target color by using a) the luminance component in the color of said pixel signal, b) two chromaticity components excluding said luminance component in the color of said pixel signal, and c) said target value, and

an interpolator which interpolates a three-dimensional look-up table of using three input signals as addresses and outputs three output signals or interpolates two of said three-dimensional look-up tables, wherein

said color converter determines said correction degree by using not only said two chromaticity components of said pixel signal to be corrected but also said luminance component of said pixel signal to be corrected,

the correspondence relationship of making the color of said pixel signal to correspond to the color corrected using said color converter is stored in said three-dimensional look-up table in advance, and

the color of said each pixel signal is corrected using said three-dimensional look-up table.

16. An image processing apparatus of correcting the color of a predetermined range of a pixel signal for each pixel included in an input image signal, comprising:

a target color setting unit which sets a target color depending on which the color of said pixel signal is corrected,

an intensity determination unit which generates a correction intensity on the basis of at least one chromaticity component,

among the luminance component and the two chromaticity components in the color of said pixel signal, a photographic image information identifier which identifies whether an object as a target of a correction of color is included or not for each input image, the photographic image information identifier identifying according to photographic information at the time when the input image is taken,

a correction degree determination unit which determines a correction degree for each input image, according to the output of said photographic image information identifier and

a correction unit which corrects the color of said pixel signal according to said correction intensity generated for each pixel and said correction degree determined for each input image, wherein

said correction unit performs a correction of said color of said pixel signal so that a difference between said target color and said color becomes smaller after the correction than before the correction.

17. The image processing apparatus according to claim 16, wherein

said photographic image information identifier identifies, according to a distance to object(s) of said photographic information, as to whether a person who is able to be considered as a primary object based on its size is included or not in said input image.

18. The image processing apparatus according to claim 17, wherein

said photographic image information identifier identifies the person who is able to be considered as the primary object based on its size is not included in said input image in the case that the distance to said object(s) is a distance of macro view or a distance of distant view.

19. The image processing apparatus according to claim 16, wherein

said photographic image information identifier identifies, according to an information of said photographic information regarding flash light, a person who is able to be considered as a primary object based on its size is not included in said input image in the case that the flash light is emitted and its returned light is not detected.

20. The image processing apparatus according to claim 19, wherein

the detection of said returned light is performed so as to be judged that said returned light was not detected when the luminance at a central portion in said image was not relatively high.

21. The image processing apparatus according to claim 19, wherein

the detection/non-detection of said returned light is judged according to the information recorded in said photographic information.

22. The image processing apparatus according to claim 19, where

said photographic image information identifier identifies, according to an information of said photographic information regarding a light source, as to whether a sky is to be included or not in said input image.

23. The image processing apparatus according to claim 22, wherein

said photographic image information identifier identifies the sky is not included in said input image in the case that said information regarding the light source indicates said light source is an indoor light.

24. The image processing apparatus according to claim 16, wherein

said photographic image information identifier identifies, according to a photographing time of said photographic information, as to whether a sky is to be included or not in said input image.

25. The image processing apparatus according to claim 16, wherein

said photographic image information identifier identifies, according to an estimated brightness of the object, that a sky is not included in said input image in the case that the estimated brightness is lower than a predetermined value, and

the estimated brightness is estimated according to a shutter speed and a aperture value both of which are included in said photographic information.

26. The image processing apparatus according to claim 16, wherein

said photographic image information identifier identifies, according to a photographic scene information of said photographic information, as to whether a person is included or not in said input image.