US 5,636,290 A · Color image processing

Abstract

A first nonlinear conversion section converts input color signals of a kind that is one of plural, different kinds to L*a*b* signals. A second nonlinear conversion section converts the L*a*b* signals to image recording signals of four colors including black. The first nonlinear conversion section includes an input judgment device for judging the kind of input color signals, a weight memory for storing weights for the respective kinds of color signals, and a nonlinear conversion circuit. The weights corresponding to the kind of input color signals identified by the input judgment device are read from the weight memory and set in the nonlinear conversion circuit. The first nonlinear conversion section further has a learning device to accommodate color signals whose conversion relationship with the L*a*b* signals has not been defined.

Claims15

Dependent claims

A color image processing method comprising the steps of:

receiving input color signals;
determining the type of the received input color signals, which type can be one among a plurality of input color signal types, each of the plurality of input color signal types comprising a set of color signals used to identify color information in a corresponding color space;
storing in a storing means conversion coefficients for converting each of a plurality of input color signal types into a uniform color signal type in a uniform color space;
retrieving the conversion coefficients for the determined type of the received input color signals from the storing means
converting the received input color signals to three intermediate color signals of the uniform color signal type in the uniform color space using the retrieved conversion coefficients;
and
converting the three intermediate color signals of the uniform color signal type in the uniform color space to image recording signals of four colors including black.

4 more elements

A color image processing apparatus comprising:

storage means for storing respective sets of information related to conversion coefficients for each of a plurality of color signal types, each of the color signal types comprising a set of color signals used to identify color information in a corresponding color space;
means for receiving input color signals;
means for determining the type of the received input color signals;
means for retrieving from the storage means the respective set of information stored in the storage means for the determined type of the received input color signals;
first converting means for converting the received input color signals to three intermediate color signals of a uniform color signal type in a uniform color space using the retrieved set of information;
and
second converting means for converting the three intermediate color signals of the uniform color signal type in the uniform color space to image recording signals of four colors including black.

4 more elements

Dependencies are inferred from the claim text.

Color image processing

Life of this patent

Color image processing

Life of this patent

Abstract

Claims15