| 摘要 |
This disclosure relates to an image processing method and apparatus for applying binarizing processing to multivalue image data so as to produce binary image data, reproducing an image having shades of light and dark based upon the binary image data, and outputting the image. On the basis of the value of the inputted multivalue image data, a search is performed to determine whether there is a pixel whose value is "1" at the periphery of each pixel of the binarized image data with regard to the image where the value of the image data is small, i.e., a highlighted portion of the image. A pixel defining an isolated point is detected through this search. Next, with regard to a pixel defining an isolated point of the binarized image, if a pixel whose value is "1" exists comparatively near this pixel, the value of this pixel of interest is diffused near the pixel. If a pixel whose value is "1" exists comparatively far from this pixel, the value of this pixel of interest is diffused far from the pixel. Such diffusion relating to the value of an isolated point is executed upon referring to the relationship of a conversion that has been stored in a look-up table (LUT) memory that takes the resolution of the finally outputted image having shades of light and dark into consideration. By virtue of this processing, graininess is reduced with regard to low-density areas (highlighted portions), to which the human eye is most sensitive, in a reproduced image based upon a pseudo-half-tone processing method. A reproduced image having a high resolution is obtained without increasing the size of a page memory for storing image data.
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