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US 5,315,415 AGranted
Color image processing apparatus
AssigneeCanon Kabushiki Kaisha
InventorsTakashi Kawai, Akihiro Usami, Ken-ichi Ohta, Yoshiko Horie, Seita Shono, Eiji Ohta
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Abstract
Interpolation processing is applied to the output of a look-up table in which a correlation between color-separation signals and density signals ideal for these color-separation signals are stored, with a quantization error produced when quantizing the color-separation signals being adopted as an interpolation coefficient. The quantization and the interpolation processing are executed in a uniform color space.
Claims10
A color image processing apparatus which comprises:
- input means for inputting color component signals which include a luminance component and a chrominance component;
- quantization means for quantizing the input color component signals and outputting quantitized color component signals;
- a look-up table for storing a correlation between the quantized color component signals and density signals suitable for respective ones of the quanitized color component signals;
- interpolation means for interpolating the density signals output from said look-up table in accordance with the levels of the density signals,
- wherein said interpolation means computes a quantization error which arises when input color component signals are quantized by said quantization means, and executes the interpolation processing with regard to an output from said look-up table by using the quantization error as an interpolation coefficient.
2 more elements
A color image processing apparatus which comprises:
- image input means for inputting color-image information;
- a look-up table for storing a correlation between color-separation signals, which are obtained by separating the color-image information into individual color components, and density signals suitable for respective ones of the color-separation signals;
- image processing means for converting the color-separation signals into corresponding density signals by referring to said look-up table;
- and
- image output means for displaying a color image on a recording medium in conformity with the density signals from said image processing means,
- wherein said image processing means quantizes the color-separation signals and inputs the quantized signals to said look-up table, and said image processing means executes interpolation processing with regard to an output from said look-up table in accordance with the levels of the density signals output from said look-up table, and
- wherein said image processing means computes a quantization error which arises when the color-separation signals are quantized, and executes the interpolation processing with regard to an output from said look-up table by using the quantization error as an interpolation coefficient.
4 more elements
Dependencies are inferred from the claim text.