Image Zooming: Use of Wavelets
Narasimha Kaulgud, U.B. Desai · Kluwer Academic Publishers eBooks · 2005
Here we propose a method to zoom a given image in wavelet domain. We use ideas from multiresolution analysis and zerotree philosophy for image zooming. Wavelet coefficient decay across scales is calculated to estimate wavelet coefficients at finer level. Since this amounts to adding high frequency component, proposed method does not suffer from smoothing effects. Zoomed images are (a) sharper compared to linear interpolation, and (b) less blocky compared to pixel replication. Performance is measured by calculating signal to noise ratio (SNR), and the proposed method gives much better SNR compared to other methods.