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US 6,191,874 B1Granted
Image processing apparatus and method, and a recording medium
AssigneeCanon Kabushiki Kaisha
InventorsAkitoshi Yamada, Hiromitsu Hirabayashi
Life of this patent
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Abstract
An image processing system for printing, in which a decrease in saturation in the entire image is prevented while maintaining reproducibility for an achromatic color (gray balance). The image processing system extracts an achromatic-color component from an image signal including C, M and Y signals, and performs color correction for the C, M and Y signals by subtracting the achromatic-color component from the C, M and Y signals. The system then generates a K signal based on the achromatic-color component, and adds the achromatic-color component to the C, M and Y signals subjected to the color correction.
Claims13
An image processing apparatus comprising:
- input means for inputting an image signal including a plurality of color-component signals;
- extraction means for extracting an achromatic-color component from the input image signal and for subtracting the achromatic-color component from the plurality of color-component signals;
- color correction means for performing color correction for a plurality of color-component signals output from said extraction means, and for outputting a plurality of color-component signals subjected to color correction indicated by real numbers;
- and
- generation means for generating an achromatic-color-component signal based on the achromatic-color component extracted by said extraction means, and for generating a plurality component by adding the achromatic-color component to the plurality of color-component signals subjected to the color correction by said color correction means, the plurality of color-component signals being indicated by real numbers,
- wherein when the generation means adds the plurality of color-component signals subjected to the color correction by said color correction means, the plurality of color-component signals being indicated by real numbers, to the achromatic-color component, and when the plurality of color component signals indicates zero or less, the generation means considers the signals as being zero.
3 more elements
An image processing apparatus comprising:
- input means for inputting an image signal including a plurality of color-component signals;
- extraction means for extracting an achromatic-color component from the input image signal and for subtracting the achromatic-color component from the plurality of color-component signals;
- color correction means for performing color correction for the plurality of color-component signals output from said extraction means, and for outputting a plurality of color-component signals subjected to color correction indicated by real numbers;
- and
- generation means for generating an achromatic-color-component signal based on the achromatic-color component extracted by said extraction means, and for adding the achromatic-color component to the plurality of color-component signals subjected to the color correction by said color correction means,
- wherein said color correction means calculates the plurality of color-component signals after the color correction based on primary colors and secondary colors set from the relationship among levels of the plurality of color-component signals.
3 more elements
An image processing method comprising:
- an input step of inputting an image signal including a plurality of color-component signals;
- an extraction step of extracting an achromatic-color component from the input image signal, and subtracting the achromatic-color component from the plurality of color-component signals;
- a color correction step of performing color correction a plurality of color-component signals obtained in said extraction step, and outputting a plurality of color-component signals subjected to color correction indicated by real numbers;
- and
- a generation step of generating an achromatic-color-component signal based on the achromatic-color-component signal based on the achromatic-color component extracted in said extraction step and generating a plurality component by adding the achromatic-color component to the plurality of color-component signals subjected to the color correction in said color correction step, the plurality of color-component signals being indicated by real numbers,
- wherein when the generation means adds the plurality of color-component signals subjected to the color correction by said color correction means, the plurality of color-component signals being indicated by real numbers, to the achromatic-color component, and when the plurality of color-component signals indicates zero or less, the generation means considers the signals as being zero.
3 more elements
An image processing method comprising:
- an input step of inputting an image signal including a plurality of color-component signals;
- an extraction step of extracting an achromatic-color component from the input image signal, and subtracting the achromatic-color component from the plurality of color-component signals;
- a color correction step of performing color correction for the plurality of color-component signals obtained in said extraction step, and outputting a plurality of color-component signals subjected to color correction indicated by real numbers;
- a generation step of generating an achromatic-color-component signal based on the achromatic-color component extracted in said extraction step and adding the achromatic-color component to the plurality of color-component signals subjected to the color correction in said color correction step;
- and
- a density correction step of performing desired density correction for the achromatic-color component extracted in said extraction step and for the plurality of color-component signals subjected to the color correction in said color correction step, and inputting resultant signals to said generation step.
3 more elements
A memory which can be read by a computer and which stores program codes for image processing, said memory comprising:
- a code of an input step of inputting an image signal including a,plurality of color-component signals;
- a code of an extraction step of extracting an achromatic-color component from the input image signal, and subtracting the achromatic-color component from the plurality of color-component signals;
- a code of a color correction step of performing color correction for a plurality of color-component signals obtained in the extraction step, and outputting a plurality of color-component signals subjected to color correction indicated by real numbers;
- and
- a code of a generation step of generating an achromatic-color-component signal based on the achromatic-color component extracted in the extraction step, and generating a plurality component by adding the achromatic-color component to the plurality of color-component signals subjected to the color correction in the color correction step, the plurality of color-component signals being indicated by real numbers,
- wherein when said code of said generation step adds the plurality of color-component signals subject to the color correction by said code of said color correction step, the plurality of color-component signals being indicated by real numbers, to the achromatic-color component, and when the plurality of color-component signals indicates zero or less, said code of said generation step considers the signals as being zero.
3 more elements
An image processing apparatus comprising:
- input means for inputting an image signal including a plurality of color-component signals;
- extraction means for extracting an achromatic-color component from the input image signal and for subtracting the achromatic-color component from the plurality of color-component signals;
- color correction means for performing color correction for a plurality of color-component signals output from said extraction means, and for outputting a plurality of color-component signals including an unnecessary component value;
- generating means for generating an achromatic-color-component signal based on the achromatic-color component extracted by said extraction means;
- and
- composing means for composing a plurality of color-component signals including the unnecessary component value and the achromatic-component signals and for generating output black-component signals and a plurality of output color-component signals,
- wherein as a result of the composition, if the plurality of output color-component signals indicate zero or less, said composing means considers the signals as being zero.
4 more elements
An image processing method comprising;
- an input step of inputting an image signal including a plurality of color-component signals;
- an extraction step of extracting an achromatic-color component from the input image signal and for subtracting the achromatic-color component from the plurality of color-component signals;
- a color correction step of performing color correction for a plurality of color-component signals output by said extraction step, and for outputting a plurality of color-component signals including an unnecessary component value;
- a generating step of generating an achromatic-color-component signal based on the achromatic-color component extracted by said extraction step;
- and
- a composing step of composing a plurality of color-component signals including the unnecessary component and the achromatic-component signals and for generating output black-component signals,
- wherein as a result of the composition, if the plurality of output color-component signals indicate zero or less, said composing step considers the signals as being zero.
4 more elements
Dependencies are inferred from the claim text.