Near-optimal model-based halftoning technique with dot gain

• 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.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Annan teknik -- Mediateknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Other Engineering and Technologies -- Media Engineering (hsv//eng)

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