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- Gooran, Sasan, et al.
(författare)
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Hybrid Halftoning : A novel Algorithm for Using Multiple Halftoning Technologies
- 1996
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Konferensbidrag (refereegranskat)abstract
- The rendering quality in halftoning is a critical issue. The quality aspects are more important in some images than in others. The quality of skin tone rendering of halftoned images generated by frequency modulated (FM) halftoning techniques differs from those generated by conventional halftoning techniques. Some judge the conventional halftoning techniques as superior in smoothly varying tones whereas frequency modulated halftoning techniques excel in heavily textured images. This paper describes an algorithm that can incorporate both technologies simultaneously. The technique is an iterative optimization of the binary halftone image with respect to the differences between the original and the halftoned images. The performance of the algorithm can be controlled by the nature of the original state of the iteration. The algorithm can in effect accommodate any type of halftone that can be described by a threshold matrix.
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- Gooran, Sasan, et al.
(författare)
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Near-optimal model-based halftoning technique with dot gain
- 1998
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Ingår i: SPIE Volume 3308 - Very High Resolution and Quality Imaging III. - : SPIE - International Society for Optical Engineering.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present a novel halftoning technique for transformation of continuous tone images into binary halftoned separations. The algorithm is based on a successive assessment of the near optimum sequence of positions to render. The impact of each rendered point is fed back to the process as a distribution function thereby influencing the following evaluations. The distribution function is not constant over the density range. In order to be able to separate the dots adequately in the highlights the 'width or radius' of the distribution has to be made larger than in the mid-tones. The human visual system and the effect of dot gain are also taken into account in this algorithm. The notion of incremental dot gain is introduced. Since the series of positions to render are not known in advance the final necessary dot gain compensation is impossible to assess. However the incremental dot gain can be computed in advance for each configuration of dots and taken into account in the process of generating the output. Some aspects of the process have certain resemblance with error distribution based algorithms. However the raster scanning sequence of rendering the output points in usual error diffusion algorithms is completely different from the image dependent traversal described in this paper.
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