Image processing device and image processing method
First Claim
1. An image processing device that executes a pseudo halftone process on multivalued image data comprising a plurality of planes, the device comprising:
- a component allowing image data with a plurality of planes to be input to the device;
a component weighting a quantization error near a target pixel for each of the plurality of planes;
a adding component adding the weighted quantization error to the input image data;
a component setting a threshold for each of the plurality of planes;
a plurality of quantizing components quantizing the input image data based on the set threshold for each of the plurality of planes;
a first quantization error calculating component calculating a plurality of quantization errors resulting from the quantizing process of the quantizing component;
a component generating a correction value on the basis of signs of the calculated plurality of quantization errors, a sum of the plurality of quantization errors and the predetermined threshold;
a component correcting the output from the quantizing component using the correction value; and
a second quantization error calculating component calculating a quantization error from the corrected output from the quantizing component and inputting the calculation to the component weighting the quantization error.
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Abstract
The present invention provides an image processing method and device which can both quickly and easily execute a pseudo halftone process with a large number of output gray levels and which can always execute the pseudo halftone process in the same manner regardless of the number of output gray scales. The present invention provides an image processing device that executes a pseudo halftone process on multivalued image data comprising a plurality of planes, the device including a component executing quantization and outputting for each of the plurality of density components, a component determining a correction value on the basis of a sign of a quantization error in each plane and a comparison of a sum of the quantization errors with a predetermined threshold, and a component correcting a value of the quantization output using the correction value and diffusing the quantization value.
21 Citations
10 Claims
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1. An image processing device that executes a pseudo halftone process on multivalued image data comprising a plurality of planes, the device comprising:
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a component allowing image data with a plurality of planes to be input to the device; a component weighting a quantization error near a target pixel for each of the plurality of planes; a adding component adding the weighted quantization error to the input image data; a component setting a threshold for each of the plurality of planes; a plurality of quantizing components quantizing the input image data based on the set threshold for each of the plurality of planes; a first quantization error calculating component calculating a plurality of quantization errors resulting from the quantizing process of the quantizing component; a component generating a correction value on the basis of signs of the calculated plurality of quantization errors, a sum of the plurality of quantization errors and the predetermined threshold; a component correcting the output from the quantizing component using the correction value; and a second quantization error calculating component calculating a quantization error from the corrected output from the quantizing component and inputting the calculation to the component weighting the quantization error. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An image processing method of executing a pseudo halftone process on multivalued image data comprising a plurality of planes, comprising the steps of:
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allowing image data with a plurality of planes to be input; weighting a quantization error near a target pixel for each of the plurality of planes; adding the weighted quantization error to the input image data; setting a threshold for each of the plurality of planes; quantizing the input image data based on the set threshold for each of the plurality of planes; calculating a plurality of quantization errors resulting from the quantizing process in the quantizing step; generating a correction value on the basis of signs of the calculated plurality of quantization errors, a sum of the plurality of quantization errors and the predetermined threshold; correcting the quantization output using the correction value; and calculating a quantization error from the corrected quantization output.
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10. A non-transitory computer-readable storage medium containing a program to direct a computer to execute the steps of:
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allowing image data with a plurality of planes to be input to the computer; weighting a quantization error near a target pixel for each of the plurality of planes; adding the weighted quantization error to the input image data; setting a threshold for each of the plurality of planes; quantizing the input image data based on the set threshold for each of the plurality of planes; calculating a plurality of quantization errors resulting from the quantizing process in the quantizing step; generating a correction value on the basis of signs of the calculated plurality of quantization errors, a sum of the plurality of quantization errors and the predetermined threshold; correcting the quantization output using the correction value; and calculating a quantization error from the corrected quantization output.
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Specification