Image processing device and image processing method
AssigneeMurata Kikai Kabushiki Kaisha
InventorKatsushi Minamino
Life of this patent
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Abstract
When a color image is converted to binary format using a dither pattern, a plurality of dither patterns are first prepared. Then, saturation and hue of the original image are used as parameters in selecting the most appropriate dithering pattern among a plurality of candidates. Therefore, even if the lightness of two original images is the same, these images are converted to different black-and-white images as long as their saturation and hue are different. Such black-and-white images look naturally when compared with the original color images.
Claims15
An image processing device which converts a color image into a binary image using a dither pattern, the color image consisting of a plurality of areas, the image processing device comprising:
- dither pattern supply means for providing a plurality of dither patterns if lightness of a first area in the color image is equal to that of a second area adjacent to the first area;
- first selection means for selecting a first dither pattern from the plurality of dither patterns based on saturation and/or hue of the first area;
- second selection means for selecting a second dither pattern from the plurality of dither patterns based on saturation and/or hue of the second area;
- first conversion means for performing binary conversion to the first area using the first dither pattern;
- and
- second conversion means for performing binary conversion to the second area using the second dither pattern.
An image processing device which converts a color image into a binary image using a dither pattern, the color image consisting of a plurality of areas, the image processing device comprising:
- a scanner for scanning the color image to determine lightness and chromaticity of a first area in the color image, and lightness and chromaticity of a second area in the color image adjacent to the first area;
- means for determining whether the lightness of the first area is equal to that of the second area;
- dither pattern supply means for providing a plurality of dither patterns if the lightness of the first area is equal to that of the second area;
- a first dithering unit for applying a dither process to the first area using the plurality of dither patterns respectively, thereby providing a plurality of first binary images;
- a second dithering unit for applying a dither process to the second area using the plurality of dither patterns respectively, thereby providing a plurality of second binary images;
- first selection means for selecting one first binary image from the plurality of first binary images based on the chromaticity of the first area;
- and
- second selection means for selecting one second binary image from the plurality of second binary images based on the chromaticity of the second area.
An image processing method for converting a color image into a binary image using a dither pattern, the color image consisting of a plurality of areas, the image processing method comprising the steps of:
- A) providing a plurality of dither patterns if lightness of a first area in the color image is equal to that of a second area adjacent to the first area;
- B) selecting a first dither pattern from the plurality of dither patterns based on saturation and/or hue of the first area;
- C) selecting a second dither pattern from the plurality of dither patterns based on saturation and/or hue of the second area;
- D) performing binary conversion to the first area using the first dither pattern;
- and
- E) performing binary conversion to the second area using the second dither pattern.
An image processing method for converting a color image into a binary image using a dither pattern, the color image consisting of a plurality of areas, the image processing method comprising the steps of:
- scanning the color image to determine lightness and chromaticity of a first area in the color image, and lightness and chromaticity of a second area in the color image adjacent to the first area;
- determining whether the lightness of the first area is equal to that of the second area;
- providing a plurality of dither patterns if the lightness of the first area is equal to that of the second area;
- applying a dither process to the first area using the plurality of dither patterns, thereby providing a plurality of first binary images;
- applying a dither process to the second area using the plurality of dither patterns, thereby providing a plurality of second binary images;
- selecting one first binary image from the plurality of first binary images based on the chromaticity of the first area;
- and
- selecting one second binary image from the plurality of second binary images based on the chromaticity of the second area.
Dependencies are inferred from the claim text.