Donoho et al have proposed a method for denoising by thresholding based on wavelet transform, and indeed, the
application of their method to image denoising has been extremely successful. But this method is based on the
assumption that the type of noise is only additive Gaussian white noise, which is not efficient to impulse noise. In this
paper, a new image denoising algorithm based on wavelet cone of influence (COI) analyzing is proposed, and which can
effectively remove the impulse noise and preserve the image edges via undecimated discrete wavelet transform
(UDWT). Furthermore, combining with the traditional wavelet thresholding denoising method, it can be also used to
restrain more widely type of noise such as Gaussian noise, impulse noise, poisson noise and other mixed noise.
Experiment results illustrate the advantages of this method.