Wavelet-based resolution enhancement methods improve the image resolution by estimating the high-frequency band information. In this paper, we propose a new resolution enhancement method using inter-subband correlation in which the sampling phase in DWT is considered. Interpolation filters are designed by analyzing correlations between subbands having different sampling phases in the lower level, and applied to the correlated subbands in the higher level. The filters are estimated under the assumption that correlations between two subbands in the higher level are similar to that in the lower level in DWT. The experimental results show that our proposed method outperforms the conventional interpolation methods including the other wavelet-based methods with respect to peak signal-to-noise-ratio (PSNR) as well as the subjective quality.

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A new intra-frame coding method based on H.264/AVC is proposed. In the proposed method, every other pixel is sampled either in a horizontal or vertical direction without any anti-aliasing filtering, and two subframes of the even-pixel and odd-pixel are then generated. The even-pixel subframe is coded as a conventional intra frame whereas the other is coded by utilizing the reconstructed information of the even-pixel subframe. The experimental results show that our proposed scheme outperforms the conventional intra-frame coding in H.264/AVC and reduces the bit rate by 11.67% on average at the baseline profile, and by 4.53% at the high profile of H.264/AVC.

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AVS2 video standard is the next-generation video coding standard under the development of Audio Video coding Standard (AVS) workgroup of China. In this paper, the design of Sample Adaptive Offset (SAO) in AVS2 is presented. Considering the implementation issues, a shifted structure in which the SAO parameter region is shifted from the Largest Coding Unit (LCU) to the upper-left is adopted to make the SAO parameter region consistent with the processing region in implementation. Moreover, the category dependent offset is introduced in the edge type based on the statistical results to improve the offset coding and non-consecutive offset bands are adopted in the band type to optimize offset bands. The test results show that SAO achieves on average 0.3% to 1.4% luma coding gain in AVS2 common test conditions. Index Terms-SAO, AVS2, shifted structure, category dependent offset, non-consecutive offset bands