Resolution enhancement of aerial image using wavelet transform

The resolution of aerial digital image is low because of atmosphere's swaying and the Image Motion Compensation's error while imaging. In view of the limitation of ordinary interpolation an approach of image magnifying based on two-dimension discrete wavelet is proposed in this article. At beginning the original image is magnified using tri-spline sampling interpolation. Then we perform two-dimension discrete wavelet transformation to the magnified image. Subsequently the inverse transformation of wavelet to recombine digital image is carried out utilizing the acquired three high-frequency images as high-frequency part of the inverse transformation and utilizing the original image as its low-frequency part, and the obtained image is double to original image in the direction of length and width. In the end we completed the proposed approach in MATLAB. The same aerial image is magnified with above-mentioned wavelet-based algorithms, conventional bilinear interpolation and tri-spline sampling interpolation algorithm separately After comparing the magnified image's value of mean gradient, the conclusion is deduced that the wavelet-based approach can not only magnify aerial image and enhance its resolution better, but also retain the minutia of original image, through which the aerial image is ready for the further aerial image interpretation and processing.