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Abstract

Method and system for increasing the effective resolution at which a lower resolution input pixel image is printed on a higher resolution dot matrix printer such an ink-jet or laser printer are described. Illustratively, a 300-dpi by 300-dpi input pixel image is prepared at the printer for printing at 600-dpi by 600-dpi, with otherwise jagged edges appropriately smoothed to produce high print quality. Each pixel and its predefined neighboring pixels in the input image are compared to stored image templates and when a match is found, the corresponding quad pixel, or super-pixel, to be output is altered from a mere replication of the input pixel, thereby to eliminate jagged edges. Memory space in the printer is reduced by storing templates that represent only a fraction of the problem patterns, the input pixel image being reoriented between comparisons in order to account for all possible cases. If it is determined that there are gray-scaled pixels within the neighborhood surrounding and including a given pixel of the input pixel image, the corresponding super-pixel produced at the output for printing preserves the gray-scale of the original.