Rotationally Invariant Wavelet Shrinkage
نویسندگان
چکیده
Most two-dimensional methods for wavelet shrinkage are efficient for edge-preserving image denoising, but they suffer from poor rotation invariance. We address this problem by designing novel shrinkage rules that are derived from rotationally invariant nonlinear diffusion filters. The resulting Haar wavelet shrinkage methods are computationally inexpensive and they offer substantially improved rotation invariance.
منابع مشابه
Rotationally Invariant Texture Features Using the Dual-Tree Complex Wavelet Transform
New rotationally invariant texture feature extraction methods are introduced that utilise the dual tree complex wavelet transform (DT-CWT). The complex wavelet transform is a new technique that uses a dual tree of wavelet filters to obtain the real and imaginary parts of complex wavelet coefficients. When applied in two dimensions the DT-CWT produces shift invariant orientated subbands. Both is...
متن کاملCorrespondences between Wavelet Shrinkage and Nonlinear Diffusion
We study the connections between discrete one-dimensional schemes for nonlinear diffusion and shift-invariant Haar wavelet shrinkage. We show that one step of (stabilised) explicit discretisation of nonlinear diffusion can be expressed in terms of wavelet shrinkage on a single spatial level. This equivalence allows a fruitful exchange of ideas between the two fields. In this paper we derive new...
متن کاملInterpreting translation-invariant wavelet shrinkage as a new image smoothing scale space
Coifman and Donoho (1995) suggested translation-invariant wavelet shrinkage as a way to remove noise from images. Basically, their technique applies wavelet shrinkage to a two-dimensional (2-D) version of the semi-discrete wavelet representation of Mallat and Zhong (1992), Coifman and Donoho also showed how the method could be implemented in O(Nlog N) operations, where there are N pixels. In th...
متن کاملOn the Equivalence of Soft Wavelet Shrinkage, Total Variation Diffusion, Total Variation Regularization, and SIDEs
Soft wavelet shrinkage, total variation (TV) diffusion, TV regularization, and a dynamical system called SIDEs are four useful techniques for discontinuity preserving denoising of signals and images. In this paper we investigate under which circumstances these methods are equivalent in the one-dimensional case. First, we prove that Haar wavelet shrinkage on a single scale is equivalent to a sin...
متن کاملWavelet shrinkage of itch response data
This article addresses the problem of denoising piecewise constant functions by using both an jump-tolerant moving average and Haar wavelet shrinkage. The piecewise constant functions are contaminated with Poissonlike noise and are measurements of perceived itch by human subjects in an experiment to relate perceived itch to blood ow in response to histamine iontophoresis. We show that the trans...
متن کامل