Image Resolution Enhancement using Inter-Subband Correlation in Wavelet Domain

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.