Kinoform Generated Combined with the Error Diffusion Method and the Dynamic Random Phase

In this paper, we propose a method for halftoning color images based on an error diffusion technique, a color design criterion and Neugebauer models for expressing colors. For a natural extension of the conventional method for grayscale error diffusion to its color version, we first reformulate grayscale error diffusion with a one-dimensional Neugebauer model. Then we increase the dimension of the model to derive a color error diffusion method based on a three-dimensional Neugebauer model in RGB (red, green and blue) color space. Moreover, we propose a sparse Neugebauer model based on a color design criterion, or the minimal brightness variation criterion (MBVC), from which we derive a sparse Neugebauer model-based error diffusion method. Experimental results show that color halftone images produced by the proposed methods preserve the color contents in original continuous-tone images better than that by conventional color error diffusion methods. We also demonstrate that the proposed sparse method reduce halftone noise better than the state-of-the-art method based on MBVC.

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Texture-aware Error Diffusion Algorithm for Multi-level Digital Halftoning

Journal of Imaging Science and Technology ◽

10.2352/j.imagingsci.technol.2020.64.5.050410 ◽

2020 ◽

Vol 64 (5) ◽

pp. 50410-1-50410-9

Author(s):

Donghui Li ◽

Takuma Kiyotomo ◽

Takahiko Horiuchi ◽

Midori Tanaka ◽

Kaku Shigeta

Keyword(s):

Digital Printing ◽

Diffusion Method ◽

Error Diffusion ◽

Digital Halftoning ◽

Halftone Image ◽

Processing Theory ◽

Raster Image ◽

Continuous Tone ◽

Multi Level ◽

Halftone Images

Abstract Digital halftoning is a technique for converting a continuous-tone image into a quantized image to reproduce it on a digital printing device. Error diffusion (ED) is an algorithm that has proven to be effective for the halftoning process, and it has been widely applied to digital printing tasks. However, in images reproduced using conventional ED algorithms based on the signal processing theory, the texture of objects is often lost. In this study, we propose a texture-aware ED algorithm for multi-level digital halftoning. First, we generate multiple mapped images with different brightness levels through nonlinear transformation. For each mapped image, we adopt a texture-aware binary error diffusion method to obtain multiple halftone images. Finally, we generate a multi-level halftone image from the multiple halftone images. We test the algorithm on an actual printer, compare the results with those of the current raster image processor software and classical ED algorithms, and observe that our algorithm outputs better results.

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