According to advances in digital image processing techniques, interest in high-quality still images has been increased. This paper proposes an effective discrete wavelet transform (DWT)-based algorithm that efficiently interpolates a highresolution (HR) still image from a low-resolution (LR) one. The decay and persistence properties of DWT coefficients are utilized for HR image reconstruction. DWT coefficients are initially estimated based on the decay of the Lipschitz exponential and the similarity of DWT coefficients across resolution scales is used for coarse estimation. For optimal fine estimation the mean squared error is iteratively minimized. The proposed DWT-based interpolation algorithm yields
better performance than the conventional methods in terms of the peak signal to noise ratio and subjective image quality.