Edge-based Image Coding at Low Bit-rate

We propose a novel edge-based low bit-rate image codec. Although being edge based, the codec does not explicitly code the edge geometry. To avoid spending high bit budget on edges, a background layer of the image is first coded and transmitted, from which the decoder estimates the trajectories of significant edges. The edge regions are then refined by a residual coding technique based on edge dilation and sequential scanning in the edge direction. Experimental results show that the new image coding technique outperforms existing ones in both objective and perceptual quality, particularly at low bit rates.