Method and device for edge smoothing in pixel images

摘要

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 disclosed. 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 (E5) 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 (S), 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 (T1...T82) 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 (E5) of the input pixel image, the corresponding super-pixel (S) produced at the output for printing preserves the gray-scale of the original.