28 December 2001 High-speed multilevel halftoning hardware
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A high speed multilevel color printer required custom halftoning hardware. For this multitone environment we revised traditional halftone thresholding (i.e. turning the output from no intensity to full intensity). Unfortunately, intermediate values did not print large areas reliably. Legacy image data files existed that were already halftoned. To correct these problems, binary halftone methods were modified to produce multi-bit outputs. This was accomplished by using threshold matrices to determine when to allow printing. The input minus the threshhold value was used to index into a lookup table to select the output intensity. Design of the down-loadable threshold matrices solved the print consistency problem. The custom hardware ensured that a zero input value did not print and a maximum value printed as a saturated output. These solutions were implemented using custom high-speed logic capable of outputting 66 MegaPels/sec.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael Thomas Brady, Michael Thomas Brady, Charles H. Morris, Charles H. Morris, Joan L. Mitchell, Joan L. Mitchell, } "High-speed multilevel halftoning hardware", Proc. SPIE 4663, Color Imaging: Device-Independent Color, Color Hardcopy, and Applications VII, (28 December 2001); doi: 10.1117/12.452996; https://doi.org/10.1117/12.452996

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