Resolution Enhancement of Satellite Images Using Dual-tree Complex Wavelet and Curvelet Transform

Resolution enhancement(RE) methods that are independent of wavelets i.e. interpolation methods leads to blurring as high frequency components are lost.RE scheme based on Discrete wavelet transform(DWT) leads to artifacts due to shift variant property. A complex wavelet-domain image resolution enhancement algorithm based on dual-tree complex wavelet transform (DT-CWT) with non local means(NLM) and curvelet transform is proposed. In this scheme, the low resolution image is undergone curvelet transform for denoising. The high frequency sub bands obtained by DT-CWT of the resultant denoised image are interpolated using Lanczos interpolator. The high frequency sub bands are further passed through an NLM filter to cater for the artifacts generated by DT-CWT.The low resolution input image and the filtered high frequency sub bands are combined using inverse DT-CWT to obtain a resolution-enhanced image. The quantitative peak signal-to-noise ratio (PSNR) and results are presented to reveal the superiority of the proposed technique through comparisons between state-of-the-art resolution enhancement methods. KeywordsResolution enhancement, image interpolation,shift variant, dual-tree complex wavelet transform,curvelet transform, Lanczos interpolation, discrete wavelet transform, satellite image