Image processing method and apparatus
AssigneeCanon Kabushiki Kaisha
InventorTakeshi Namikata
Life of this patent
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Abstract
It is difficult to adjust a black plate while maintaining accurate color reproduction in a color printer that forms an image using C, M, Y, and K color agents. Upon generating a conversion condition used to convert a signal on a uniform color space into a CMYK signal which depends on a printer, the signal on the uniform color space according to a colorimetric value is temporarily converted into an RGB signal, and the RGB signal is then converted into a CMYK signal. After that, a black amount adjustment unit adjusts a K value using a black amount adjustment function based on a user's instruction.
Claims8
An image processing method of generating a printer model used to convert device-dependent data into device-independent data, on the basis of colorimetric results of color patches output from an output device, and generating a conversion table used to convert the device-independent data into the device-dependent data, on the basis of the printer model, comprising the steps of:
- obtaining tone characteristics of the output device based on the density of a single color patch which is estimated using a device-independent colorimetric value corresponding to the single color patch in a CMYK-device-independent colorimetric value table obtained from the colorimetric results, and calculating a conversion condition used to convert the tone characteristics into linear characteristics;
- and
- generating the printer model used for generating the conversion table, on the basis of a CMYK value obtained by converting the tone characteristics into the linear characteristics and on the basis of the CMYK-device-independent colorimetric value table obtained from the colorimetric results used for obtaining the tone characteristics.
An image processing apparatus for generating a printer model used to convert device-dependent data into device-independent data, on the basis of colorimetric results of color patches output from an output device, and generating a conversion table used to convert the device-independent data into the device-dependent data, on the basis of the printer model, comprising:
- calculation means for obtaining tone characteristics of the output device based on the density of a single color patch which is estimated using device-independent colorimetric value corresponding to the single color patch in a CMYK-device-independent colorimetric value table obtained from the colorimetric results, and calculating a conversion condition used to convert the tone characteristics into linear characteristics;
- and
- generation means for generating the printer model used for generating the conversion table, on the basis of a CMYK value obtained by converting the tone characteristics into the linear characteristics and on the basis of the CMYK-device-independent colorimetric value table obtained from the colorimetric results used for obtaining the tone characteristics.
A computer-readable storage medium storing a computer-executable program for causing a computer to perform an image processing method of generating a printer model used to convert device-dependent data into device-independent data, on the basis of colorimetric results of color patches output from an output device, and generating a conversion table used to convert the device-independent data into the device-dependent data, on the basis of the printer model, the method comprising the steps of:
- obtaining tone characteristics of the output device based on the density of a single color patch which is estimated using a device-independent colorimetric value corresponding to the single color patch in a CMYK-device-independent colorimetric value table obtained from the colorimetric results, and calculating a conversion condition used to convert the tone characteristics into linear characteristics;
- and
- generating the printer model used for generating the conversion table, on the basis of a CMYK value obtained by converting the tone characteristics into the linear characteristics and on the basis of the CMYK-device-independent colorimetric value table obtained from the colorimetric results used for obtaining the tone characteristics.
Dependencies are inferred from the claim text.