| 摘要 |
A computer program for and a method of generating 1-bit image data from multiple-bit image data, by a process which comprises the steps of receiving multiple-bit image data comprising multiple-bit pixel values, deriving from the multiple-bit pixel values 1-bit image data comprising "on" and "off" pixel values, each pixel value of the 1-bit image data corresponding to a pixel of an output medium, which pixel an output device would attempt to mark when printing the 1-bit image data if the pixel value were "on". When printed, the 1-bit image data produces an image constituted by a plurality of densities of dots, the dots being arranged such that, at least for densities of dots greater than first threshold density, at least a majority of dots form a pair with at least one horizontally is or vertically adjacent dot, and for densities of dots less than a second threshold density, the image is substantially free of blocks of 2*2 horizontally and vertically adjacent dots, the second threshold density being greater than the first threshold density. Further embodiments arrange the dots such that, a majority of pairs of horizontally or vertically adjacent dots form a triplet with a horizontally or vertically adjacent dot, instead of ensuring the image is free of blocks of 2*2 horizontally and vertically adjacent dots. The embodiments described seek to achieve improved halftone image appearance having little or no visible graininess or patterning. |
