A hybrid filter for image despeckling with wavelet-based denoising and spatial filtering

Noise is one of the most common problems found in different imaging applications. Even a high resolution photo is bound to have some noise in it. Image denoising algorithms may be the oldest in image processing. Many methods, regardless of their implementation, share the same basic idea: noise reduction through image blurring. However, a universal “best” approach has yet to be found. Wavelet transform has been studied extensively in recent years and it has been widely used for noise reduction. In this paper, we propose a novel technique for image despeckling that combines wavelet denoising and an enhanced adaptive version of the old Kuan filter, which results in a significant gain with respect to speckle noise filters and the simple wavelet denoising technique.