Black component generation
View Patent ↗A system and method for generating achromatic components for output incorporate receiving input color data defined in a first color space. The received input color data is converted to intermediate color data defined in an intermediate color space. Typically the intermediate color space is defined only in terms of chromatic components. A black or achromatic component is then calculated. The black or achromatic color component is a function of both the input color data in the first color space and the intermediate color data in the intermediate color space. This black or achromatic color component is associated with the intermediate color data for further processing and output.
1. In an image output terminal, a method of outputting a digital color image comprising:
converting input components corresponding to a color in a first color space to intermediate components in a second color space, where the second color space includes at least one intermediate component that is different from the input components; and,
deriving an output black component from both the intermediate components and the input components, wherein said deriving includes:
applying a defined process to the input components;
applying a different process to the intermediate components; and,
combining the processed input components and the differently processed intermediate components;
wherein the first color space includes HSV and the applying a defined process comprises applying a function including H, S and V, where the function is different depending on the position of a V value with respect to a threshold.
2. In an image output terminal, a method of outputting a digital color image comprising:
converting input components corresponding to a color in a first color space to intermediate components in a second color space, where the second color space includes at least one intermediate component that is different from the input components; and,
deriving an output black component from both the intermediate components and the input components, wherein said deriving includes:
applying a defined process to the input components;
applying a different process to the intermediate components; and,
combining the processed input components and the differently processed intermediate components;
wherein the first color space includes HSV and the applying a defined process comprises applying a function including H, S and V, where the function is different depending on the position of an S value with respect to a threshold.
3. The method of outputting a digital color image as set forth in claim 2 , where the applying a different process to the intermediate components comprises minimizing CMY values.
4. In an image output terminal, a method of outputting a digital color image comprising:
converting input components corresponding to a color in a first color space to intermediate components in a second color space, where the second color space includes at least one intermediate component that is different from the input components; and
deriving an output black component from both the intermediate components and the input components;
wherein the first color space comprises HSV and the deriving comprises:
applying a function to the intermediate components; and
for input components including V below a V threshold and S below an S threshold, applying a function varying with V and the V threshold.
5. The method of outputting a digital color image as set forth in claim 4 , further comprising outputting data comprising the intermediate components and the output black component.
6. The system as set forth in claim 4 , where the input color space is defined in HSV and the functions include a first function g(H,S,V), and a second function h depending on the intermediate color separation, the system further comprising a calculator which calculates g(H,S,V) by implementing the equation:
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7. The system as set forth in claim 4 , where the intermediate color separations are defined in CMY.
8. The system as set forth in claim 4 , further comprising a post-processor that adjusts the intermediate color separations based on the calculated achromatic color separation.