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The enlargement method is a partial technology in many application including medical imaging, satellite imaging, and video applications. Due to the wavelet representation has characteristics of the efficient time-frequency localization and the multi-resolution analysis, the wavelet transforms are suitable for processing the image resolution enhancement. Therefore, this method focuses on wavelet-based image resolution enhancement and proposes a framework of enlargement method. This proposed method is based on the estimation of detail wavelet coefficients at high resolution scales. The method exploits shape function according to wavelet coefficient correlation in a local neighborhood and employs undecimated discrete wavelet transform to estimate the unknown detail coefficients. The simulation results objectivity show that the proposed method is considerably superior to conventional image interpolation techniques.

Blocking effect is the major drawback in DCT-based (discrete cosine transformation) codecs at low bit-rates. In this paper, a post-processing filter is proposed in DCT frequency domain. The proposed algorithm uses a shift block within four adjacent DCT blocks to reduce computational complexity. By slightly modifying several DCT coefficients in the shift block, the artifacts that result from quantization and dequantization process are alleviated. The simulation results show that both visual perception and objective image quality are improved noticeably.