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Nonconvex Haar-TV denoising
Digital Signal Processing ( IF 2.9 ) Pub Date : 2020-09-15 , DOI: 10.1016/j.dsp.2020.102855
Yinan Hu , Ivan W. Selesnick

The anisotropic total variation (TV) denoising model suppresses noise for two-dimensional signals that are vertically and horizontally piecewise constant. However, two-dimensional signals may have sparse derivatives in other directions. We propose a modification of the classical anisotropic two-dimensional TV regularizer from a spectral point of view. In the frequency domain, the TV regularizer can be considered as penalizing the high-frequency component of original signals and promoting only low-frequency components. The classical anisotropic TV, which applies l1-norm on vertical and horizontal differences, suppresses high-frequency components of the signals. The proposed operator, named Haar total variation (Haar-TV), penalizes two-dimensional signals that have more varied high-frequency regions. Furthermore, we propose non-convex penalties based on the Haar-TV operator since non-convex penalties can preserve edges and thus enhance the quality of the estimation. We derive a condition that preserves the strong convexity of the total cost function so the global minimizer can be reached.



中文翻译:

非凸Haar-TV去噪

各向异性总变化(TV)去噪模型可抑制垂直和水平分段恒定的二维信号的噪声。但是,二维信号可能在其他方向上具有稀疏导数。从光谱的观点出发,我们提出了对经典各向异性二维电视调节器的改进。在频域中,TV正则器可被视为对原始信号的高频分量进行了惩罚,而仅提升了低频分量。适用于古典各向异性电视1个-垂直和水平差异的范数,抑制信号的高频分量。提议的运营商名为Haar总变化(Haar-TV),对具有更多变化的高频区域的二维信号进行了惩罚。此外,我们建议基于Haar-TV算子的非凸罚分,因为非凸罚分可以保留边缘,从而提高估计的质量。我们得出一个条件,该条件保留了总成本函数的强凸性,因此可以实现全局最小化。

更新日期:2020-09-29
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