Image processing method, image processing apparatus, and image processing program

Patent metadata

Field	Value
Publication number	US-9367934-B2
Application number	US-201414556417-A
Country	US
Kind code	B2
Filing date	Dec 1, 2014
Priority date	May 30, 2012
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

In the image processing apparatus, Input transform into an input color space is performed on input image data; After the input transform, transform processing of transforming chroma or chromaticity of the input image data or chroma or chromaticity in the input color space is performed so as to reduce a difference between a space of chroma or chromaticity of the input image data and a space of chroma or chromaticity in the input color space to acquire transformed image data; and Output transform into an output color space is performed on the transformed image data using a three-dimensional lookup table including inverse transform processing of returning the chroma or chromaticity of the transformed image data to the chroma or chromaticity of the input image data to acquire output image data.

First claim

What is claimed is:

1. An image processing method comprising:
performing an input transform into an input color space, the input transform being performed on input image data of an input device, wherein the input color space is independent from the input device;
after the input transform, performing transform processing of transforming i) chroma or chromaticity of the input image data or ii) chroma or chromaticity in the input color space, so as to reduce a difference i) between a space of chroma or chromaticity of the input image data and ii) a space of chroma or chromaticity in the input color space, so that the space of chroma or chromaticity of the input image data effectively uses the space of chroma or chromaticity in the input color space to acquire transformed image data; and
performing image processing of transforming the transformed image data into an output image data of an output device, by performing an output transform into an output color space of the output device, the output transform being performed on the transformed image data using a three-dimensional lookup table including inverse transform processing of returning the chroma or chromaticity of the transformed image data to the chroma or chromaticity of the input image data.

2. The image processing method according to claim 1 ,
wherein after the input transform, transform processing of increasing the chroma of the input image data is performed to acquire transformed image data, and
in the output transform, image processing of transforming the transformed image data into the output image data is performed using a three-dimensional lookup table including inverse transform processing of decreasing an amount of chroma increased in the transformed image data to return the chroma to the chroma of the input image data.

3. The image processing method according to claim 1 ,
wherein after the input transform, transform processing of transforming the input image data in the input color space into image data in a high-chroma color space in which chroma has increased with respect to the input color space is performed to acquire transformed image data, and
in the output transform, image processing of transforming the transformed image data into the output image data is performed using a three-dimensional lookup table including inverse transform processing of inversely transforming the transformed image data in the high-chroma color space into the input image data in the input color space.

4. The image processing method according to claim 1 ,
wherein after the input transform, transform processing of transforming the input image data in the input color space into image data in a first color space composed of brightness and chromaticity and transforming the first color space into a low-chromaticity color space in which the chromaticity of the first color space has decreased is performed to acquire transformed image data, and
in the output transform, image processing of transforming the transformed image data into the output image data is performed using a three-dimensional lookup table including inverse transform processing of inversely transforming the low-chromaticity color space into the first color space and inversely transforming the image data in the inversely-transformed first color space into the input image data in the input color space.

5. The image processing method according to claim 1 ,
wherein after the input transform, transform processing of transforming the input image data in the input color space into image data in a second color space composed of brightness, chroma, and hue and transforming the second color space to a low-chroma color space in which the chroma of the second color space has decreased is performed to acquire transformed image data, and
in the output transform, image processing of transforming the transformed image data into the output image data is performed using a three-dimensional lookup table including inverse transform processing of inversely transforming the low-chroma color space into the second color space and inversely transforming the image data in the inversely-transformed second color space into the input image data in the input color space.

6. An image processing method comprising:
performing an input transform into an input color space, the input transform being performed on input image data of an input device, wherein the input color space is independent from the input device;
after the input transform, performing transform processing of transforming chroma of the input image data or chroma in the input color space so as to reduce a difference between i) a space of chroma of the input image data and ii) a space of chroma in the input color space, so that the space of chroma of the input image data effectively uses the space of chroma in the input color space to acquire transformed image data; and
performing an inverse transform processing of returning the chroma of the transformed image data to the chroma of the input image data and image processing of transforming the transformed image data into an output image data of an output device by performing an output transform into an output color space of the output device, the output transform being performed on the transformed image data.

7. The image processing method according to claim 6 ,
wherein after the input transform, transform processing of increasing the chroma of the input image data is performed to acquire transformed image data, and
in the output transform, inverse transform processing of decreasing an amount of chroma increased in the transformed image data to return the chroma to the chroma of the input image data and image processing of transforming the transformed image data into the output image data are performed.

8. The image processing method according to claim 6 ,
wherein after the input transform, transform processing of transforming the input image data in the input color space into image data in a high-chroma color space in which chroma has increased with respect to the input color space is performed to acquire transformed image data and
in the output transform, inverse transform processing of inversely transforming the transformed image data in the high-chroma color space into the input image data in the input color space and image processing of transforming the inversely-transformed input image data into the output image data are performed.

9. The image processing method according to claim 6 ,
wherein after the input transform, transform processing of transforming the input image data in the input color space into image data in a first color space composed of brightness and chromaticity and transforming the first color space into a low-chromaticity color space in which the chromaticity of the first color space has decreased is performed to acquire transformed image data and
in the output transform, inverse transform processing of inversely transforming the low-chromaticity color space into the first color space and inversely transforming the image data in the inversely-transformed first color space into the input image data in the input color space and image processing of transforming the inversely-transformed input image data into the output image data are performed.

10. The image processing method according to claim 6 ,
wherein after the input transform, transform processing of transforming the input image data in the input color space into image data in a second color space composed of brightness, chroma, and hue and transforming the second color space into a low-chroma color space in which the chroma of the second color space has decreased is performed to acquire transformed image data, and
in the output transform, inv

Assignees

• Fujifilm Corp

Inventors

• Iwaki Yasuharu
• Uchida Mitsuhiro

Classifications

• G06T11/10

  Texturing; Colouring; Generation of textures or colours (retouching, inpainting or scratch removal G06T5/77) · CPC title

• G09G5/06

  using colour palettes, e.g. look-up tables · CPC title

• G09G2340/06

  Colour space transformation · CPC title

• G06T11/001 Primary

  Physics · mapped topic

• H04N1/6058 Primary

  Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut · CPC title