| 摘要 |
An error diffusing method and apparatus are used for an image processing in which a tone of each of the pixels of the image is approximated by either a maximum or minimum tone determined from the tone value of that pixel. The pixels are processed sequentially in a predetermined order and either a first code indicative of the maximum tone or a second code indicative of the minimum tone, depending on a magnitude of the tone of the pixel, is allotted to each of the pixels. An error obtained as a difference between the tone value of that pixel and the code allotted thereto is a negative error when the first code is allotted thereto and a positive error when the second code is allotted. When the error is positive it is diffused to the selected adjacent pixels to correct their tone values by predetermined proportions of the error, and when the error is negative, the tone value of each of the selected adjacent pixels is maintained without correction or replaced by a predetermined proportion of the error based on the relationship between the absolute value of the predetermined proportion of the error and the absolute value of the tone value of the pixel, wherein allotting of one of the codes to each pixel is based on the tone value of the pixel corrected by the error diffused from the selected adjacent pixels.
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