论文标题
分段恒定图像恢复的两个阶段连续域正则化
Two Stage Continuous Domain Regularization for Piecewise Constant Image Restoration
论文作者
论文摘要
与结构化的低级别基质相对应的信号/图像对应的有限速率(FRI)框架正在成为传统稀疏正则化的替代方案。这是因为这样的离网方法能够减轻连续域中的真正支持与离散网格之间的基础不匹配。在本文中,我们为图像恢复提出了一个两阶段的离线正规化模型。鉴于图像的不连续性/边缘位于带限的周期性函数的零级集合,我们可以得出图像梯度的傅立叶样品满足an灭关系,从而导致低排名的Hankel矩阵。此外,由于低级别Hankel矩阵的奇异值分解对应于可以用稀疏规范系数表示图像的自适应紧身框架系统,因此我们的方法包括以下两个阶段。第一阶段从给定的测量中学习了紧密的小波框架系统,第二阶段通过基于分析方法的稀疏正则化来恢复图像。提出了数值结果,以证明所提出的方法可以与几种流行的离散正则化方法和结构化的低级矩阵方法进行比较。
The finite-rate-of-innovation (FRI) framework which corresponds a signal/image to a structured low-rank matrix is emerging as an alternative to the traditional sparse regularization. This is because such an off-the-grid approach is able to alleviate the basis mismatch between the true support in the continuous domain and the discrete grid. In this paper, we propose a two-stage off-the-grid regularization model for the image restoration. Given that the discontinuities/edges of the image lie in the zero level set of a band-limited periodic function, we can derive that the Fourier samples of the gradient of the image satisfy an annihilation relation, resulting in a low-rank two-fold Hankel matrix. In addition, since the singular value decomposition of a low-rank Hankel matrix corresponds to an adaptive tight frame system which can represent the image with sparse canonical coefficients, our approach consists of the following two stages. The first stage learns the tight wavelet frame system from a given measurement, and the second stage restores the image via the analysis approach based sparse regularization. The numerical results are presented to demonstrate that the proposed approach is compared favorably against several popular discrete regularization approaches and structured low-rank matrix approaches.