Abstract: Denoising is an important issue in image processing. However, in the classical approaches there is often a tradeoff between reducing the noise level and preserving the high-frequency edges of the image. Denoising with wavelet transform has been acknowledged as one of the most promising methods for image denoising, as the method can not only remove the noise of the image but also preserve the edges of the image. The paper reviews the literature on denoising methods with wavelet transform, with emphasis on MR images denoising with wavelet transform. The future trend of wavelet image denoising is also discussed.

Key words: wavelet transform, magnetic resonance image, threshold, noise reduction