Robust Satellite Image Resolution Enhancement using Double Density Dual Tree Complex Wavelet Transform

Image Resolution enhancement (RE) schemes which are based on wavelets have an advantage over conventional methods which suffer from the losing of high frequency contents which causes blurring. The discrete wavelet transform-based (DWT) RE scheme generates artifacts due to a DWT shift-variant property. A wavelet-domain approach based on double density dual-tree complex wavelet transform (DDDT-CWT) is proposed for RE of the satellite images and compared with dual-tree complex wavelet transform(DT-CWT). A satellite image is decomposed by DDDT-CWT to obtain high-frequency subbands. The high frequency subbands and the low-resolution (LR) input image are interpolated and the high frequency subbands are passed through a low pass filter. The filtered high-frequency subbands and the LR input image are combined using inverse DT-CWT to obtain a resolution-enhanced image. Objective and subjective analyses reveal superiority of the proposed technique over the conventional and state-of-the-art RE techniques.