| 摘要 |
An electronic signal representing the density of a scanned image is electronically halftoned by combining the pictorial signal with a rectangular array of halftone screen values to form an electronic halftone image. The electronic screen function represented by the array of halftone screen values is rotated at variable angles to the original electronic image by defining a repetitive rectangular matrix representative of any predetermined halftone cell approximating a parallelogram and incorporating a shifting parameter for the repetitive rectangular matrix. An efficient, high speed, partial-dot halftoning technique is performed by indexing the screen function rectangular array, under the supervision of the shifting parameter, against the scanned image values for a realtime serial combination of the functional values.
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