| 摘要 |
An input density for a subject pixel position (x, y) is retrieved in S230. A modified density value I'(x, y) is calculated in S240 based on the input density value I(x, y) and the error e(x, y) stored in the corresponding error buffer. Then, in S250, a discrimination value for the subject pixel position (x, y) is retrieved from the bilevel threshold value matrix Mat2( ) which is produced through the blue noise characteristic method. One of two threshold values is assigned to the retrieved discrimination value. Thus, a threshold value T is determined for the subject pixel (x, y). Then, an output density value O(x, y) is determined based on the modified density value I'(x, y) and the threshold value T in S260, S270, and S280. Then, an error value E(x,y) is calculated based on the output density value O(x, y) and the modified density value I'(x, y). The error value E(x,y) is distributed to the error buffer 16 in S300 dependently on the error distribution matrix Bat( ). The above-described process is performed onto all the pixels of the input image.
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