1 January 2011 Halftone moiré due to imager distortion
Author Affiliations +
Abstract
Moiré in color printing is an undesirable visible artifact that can arise from overlaying multiple halftone color separations. Halftone geometric configurations designed to avoid moiré in the overlays strictly require that individual halftone color separations must possess a low degree of relative distortion. However, optical and mechanical errors of multiple imaging systems within a printer usually produce differences between the color planes in the trajectory and placement of the exposure spots. We study color halftone moiré due to these optical and mechanical errors for otherwise moiré-free halftone configurations. Distortions due to commonly used imaging systems in xerography (i.e., raster output scanners and image bars) are categorized into two classes that depend on the direction of the displacement errors [i.e., process direction distortions (such as shear, bow, and skew) and cross-process direction distortions (such as scanline magnification, magnification imbalance, and high-order scanline distortions)]. Using frequency vector representation of color halftones, we derive analytical expressions for acceptability bounds on these distortions. We evaluate the analytical expressions for a classical halftone screen configuration and a minimum rosette geometry to enable specification allocations for different imaging components in the design of an imaging system.
©(2011) Society of Photo-Optical Instrumentation Engineers (SPIE)
Orhan Bulan, Robert Paul Loce, and Beilei Xu "Halftone moiré due to imager distortion," Journal of Electronic Imaging 20(1), 013008 (1 January 2011). https://doi.org/10.1117/1.3537830
Published: 1 January 2011
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KEYWORDS
Distortion

Halftones

Imaging systems

Printing

Color printing

Image processing

Light emitting diodes

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