Yik-Hing Fung

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Multiscale error diffusion (MED) is superior to conventional error diffusion algorithms as it can eliminate directional hysteresis completely and possesses a good blue noise characteristic. However, due to its filter design, it is not suitable for systems with poor isolated dot generation and instable dot gain. In this paper, we propose a MED algorithm to(More)
A good halftoning output should bear a blue noise characteristic contributed by isotropically-distributed isolated dots. Multiscale error diffusion (MED) algorithms try to achieve this by exploiting radially symmetric and noncausal error diffusion filters to guarantee spatial homogeneity. In this brief, an optimized diffusion filter is suggested to make the(More)
The advance in printing technology makes multilevel halftoning become important as printers can now print inks of different intensities. This letter presents a multilevel halftoning algorithm that is based on multiscale error diffusion. This algorithm takes care of the constrained pixels before handling the unconstrained pixels and diffuses errors with a(More)
– Elimination of directional hysteresis – Use of predefined scanning path and causal filter – Computational complexity is comparatively high ‹ Fast MED algorithm – Reduction of computational complexity – Preservation of the image quality – Support of parallel processing ‹ Analysis and simulation Abstract Abstract 3 3 /34 /34 ‹ Error diffusion for digital(More)
This paper studies the restoration of images which are color-quantized with error diffusion. Though there are many reported algorithms proposed for restoring noisy blurred color images and inverse halftoning, restoration of color-quantized images is rarely addressed in the literature especially when the images are color-quantized with halftoning. Direct(More)
To reliably and efficiently deliver media information to diverse clients over heterogeneous networks, the media involved must be scalable. In this paper, a color quantization algorithm for generating scalable color-indexed images is proposed based on a multiscale error diffusion framework. Images of lower resolutions are embedded in the outputs such that a(More)