Abstract—We present a novel 2-D wavelet transform scheme of adaptive directional lifting (ADL) in image coding. Instead of alternately applying horizontal and vertical lifting, as in present practice, ADL performs lifting-based prediction in local windows in the direction of high pixel correlation. Hence, it adapts far better to the image orientation features in local windows. The ADL transform is achieved by existing 1-D wavelets and is seamlessly integrated into the global wavelet transform. The predicting and updating signals of ADL can be derived even at the fractional pixel precision level to achieve high directional resolution, while still maintaining perfect reconstruction. To enhance the ADL performance, a rate-distortion optimized directional segmentation scheme is also proposed to form and code a hierarchical image partition adapting to local features. Experimental results show that the proposed ADL-based image coding technique outperforms JPEG 2000 in both PSNR and visual quality, with the improvement up to 2.0 dB on images with rich orientation features.

Temporal scalable video coding is a useful feature supported in all existing video coding standards. Though coding efficiency is still the predominant performance metric, buffer requirement is another important factor for assessment of temporal scalable video coding methods. This paper presents analyses of minimum buffer requirement for temporal scalable coding based on the most typical temporal scalable video coding structure, i.e., the so-called hierarchical B picture coding structure. Minimum buffer sizes required for decoding of both the full bitstreams and thinned bitstreams are derived. After that, some reference picture management methods are proposed in order to enable both minimum buffer consumption and maximum coding efficiency. Comparative experiment results showing how different reference picture marking methods affect coding efficiency are also provided.

3D facial extraction from volume data is very helpful in virtual plastic surgery. Although the traditional Marching Cubes algorithm (MC) can be used for this purpose, it could not separate the facial surface from other tissue surfaces. This weakness greatly limited the accuracy of the facial model and its application in plastic surgery. In this paper a volume graph model is proposed, in which the facial surface extraction is formulated as a min-cut problem and can be solved by existing graph cut algorithm. Based on this model, irrelevant tissue surfaces are effectively excluded and a more accurate 3D virtual face can be built for plastic surgery.

In this paper, a video inpainting approach is proposed, which targets at repairing a video containing moving humans that are largely or completely occluded or missing for some of the frames. The proposed approach first categorizes typically periodic human motion in a video into a set of temporal states (called motion states), and then estimates the motion states for the frames with missing humans so as to repair the missing parts using other undamaged frames with the same motion states. This deviates from common approaches that directly repair the pixels of the damaged parts. Experiments demonstrate that the proposed method can well repair the damaged video sequences without introducing strong artifacts that exist in many existing techniques.

In theory, a Wyner-Ziv video codec should achieve the same efficiency as a joint encoding and decoding one. However, existing approaches still exhibit significant gaps. One main reason is the lack of the complete correlation exploitation between source and side information. In this paper, we propose a transform domain classification based Wyner-Ziv video codec, aiming at exploiting additional video statistics. In this proposed new scheme, the encoder exploits additional statistics by performing block classification to differentiate low motion blocks from high motion ones. In general, low motion blocks represent highly correlated regions. Such information is useful when the decoder performs motion-compensated interpolation to obtain better side information, thus improving the performance of Wyner-Ziv coding. Experimental results show that we are indeed able to achieve better rate-distortion performance compared to the existing Wyner-Ziv video codecs at the expense of some additional complexity in frame store and comparisons at the encoder.