earticle

영어

Image enhancement is a process of improving the quality of digital image without knowledge about the source of degradation. A method to enhance the quality of given low resolution image is presented in this paper. The enhancement is made in both wavelet and spatial domain. The upsampling scheme is used to enhance the edge information in the spatial domain. To get a sharp high resolution image, the proposed method uses Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT) which decompose the input image into four sub-bands denoted by LL, LH, HL and HH. Then the high frequency sub-bands of DWT as well as the input image are interpolated separately by using bicubic interpolation. The high frequency sub-bands produced by SWT are added into the interpolated high frequency sub-bands to correct the estimated high frequency coefficients. After that, the corrected high frequency sub-bands and interpolated input image are combined by using inverse DWT (IDWT). Consequently, the support of filters to model the regularity of natural images is exploited in the wavelet domain. To minimize the reconstruction error, iterative back projection method is employed. The objective and subjective qualities show that the proposed algorithm over-performs the conventional and state-of-the-art image resolution enhancement techniques.