Image processing using colored colorant amounts and colorless colorant amounts
AssigneeCanon Kabushiki Kaisha
InventorChiaki Kaneko
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Abstract
Image processing in which input image signals are converted into output image signals represented as a combination of colored and colorless colorant amounts. For each pixel of an input image represented by the input image signal, it is determined whether the pixel belongs to a high or low density range. For each pixel belonging to the high density range, it is specified whether the pixel belongs to a high or low frequency region of the input image. Color conversion with a 1st conversion parameter is applied to an input image signal corresponding to a pixel belonging to the high frequency region, and color conversion with a 2nd conversion parameter is applied to an input image signal corresponding to a pixel belonging to the low frequency region.
Claims12
An image processing apparatus which converts input image signals into output image signals represented as a combination of colored colorant amounts and colorless colorant amounts, the apparatus comprising:
- a determination unit configured to determine for each pixel of an input image represented by an input image signal, whether the pixel is belonging to a high density range or a low density range;
- a specification unit configured to specify for each pixel belonging to the high density range, whether the pixel is belonging to a high frequency region of the input image or a low frequency region of the input image;
- and
- a generation unit configured to generate an output image signal by applying color conversion with a 1st conversion parameter to an input image signal corresponding to a pixel belonging to the high frequency region, and applying color conversion with a 2nd conversion parameter to an input image signal corresponding to a pixel belonging to the low frequency region,
- wherein a colorless colorant amount for an output image signal generated by the color conversion with the 1st conversion parameter is larger than a colorless colorant amount for an output image signal generated by the color conversion with the 2nd conversion parameter.
An image processing apparatus which converts input image signals into output image signals represented as a combination of colored colorant amounts and colorless colorant amounts, the apparatus comprising:
- a determination unit configured to determine for each pixel of an input image represented by an input image signal, whether the pixel is belonging to a high density range or a low density range;
- a specification unit configured to specify for each pixel belonging to the high density range, whether the pixel is belonging to a high frequency region of the input image or a low frequency region of the input image;
- and
- a generation unit configured to apply color conversion with a 1st conversion parameter to an input image signal corresponding to a pixel belonging to the high frequency region, to apply color conversion with a 2nd conversion parameter to an input image signal corresponding to a pixel belonging to the low frequency region, and to generate an output image signal by means of weighted addition of results of the color conversion with the 1st conversion parameter and that with the 2nd conversion parameter,
- wherein said generation unit weights the result of the color conversion with the 1st conversion parameter for pixels belonging to the high frequency range, and weights the result of the color conversion with the 2nd conversion parameter for pixels belonging to the low frequency range, and
- wherein a colorless colorant amount for an output image signal generated by the color conversion with the 1st conversion parameter is larger than a colorless colorant amount for an output image signal generated by the color conversion with the 2nd conversion parameter.
A method of controlling an image processing apparatus which converts input image signals into output image signals represented as a combination of colored colorant amounts and colorless colorant amounts, the method comprising:
- determining for each pixel of an input image represented by an input image signal, whether the pixel is belonging to a high density range or a low density range;
- specifying for each pixel belonging to the high density range, whether the pixel is belonging to a high frequency region of the input image or a low frequency region of the input image;
- and
- generating an output image signal by applying color conversion with a 1st conversion parameter to an input image signal corresponding to a pixel belonging to the high frequency region, and applying color conversion with a 2nd conversion parameter to an input image signal corresponding to a pixel belonging to the low frequency region,
- wherein a colorless colorant amount for an output image signal generated by the color conversion with the 1st conversion parameter is larger than a colorless colorant amount for an output image signal generated by the color conversion with the 2nd conversion parameter.
Dependencies are inferred from the claim text.