Chroma Replacing and adaptive Chroma Blending for subpixel-based downsampling

Ketan Tang, Oscar C. Au, Lu Fang, Yuanfang Guo, Jiahao Pang

Abstract: Subpixel-based downsampling generates images with higher apparent resolution with the expense of annoying color-fringing artifacts near strong edges. In this paper we propose two methods that find a balance in the tradeoff of apparent resolution and color-fringing artifacts. The first method is called Chroma Replacing in which the color-fringing artifacts are completely removed but the subpixel rendering effect is also removed. The second one is called Chroma Blending in which only the color-fringing artifacts that are strong enough to be noticed are removed, and also the subpixel rendering effect is retained. We also propose two objective measures for measuring the similarity of downsampled image to the original image. Experiment results show that the proposed methods are effective in removing color-fringing artifacts, without harming the high apparent resolution.