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快速且误差受控的空变双边滤波

Fast and Error-Bounded Space-Variant Bilateral Filtering

  • 摘要: 由于传统的双边滤波器(BF)使用了固定的各项同性空间核,加权平均窗口中包含了大量的外点,常常会导致滤波结果出现边缘模糊和梯度反转缺陷。然而,如何高效、准确地估计出适应图像结构的空变核,并且快速实现相应的空变双边滤波则是一个具有挑战性的问题。为了解决这些问题,我们提出了一种空变双边滤波器(SVBF)及其具有线性时间复杂度其误差受控的加速方法。首先,我们通过结构张量和最小生成树在线性时间内对随图像结构变化的空变各向异性核进行精确估计。其次,利用两种误差有界的逼近方法:基于高阶奇异值分解的低秩张量近似与指数和近似得到了空变双边滤波器的线性时间复杂度加速算法。因此,本文所提出的空变双边滤波器能够快速获得较好的保边滤波结果。我们验证了所提出的滤波器在图像去噪、图像增强和图像焦点编辑等应用中的优势。实验结果表明,该快速且误差受控的空变双边滤波方法好于已有方法。

     

    Abstract: The traditional space-invariant isotropic kernel utilized by a bilateral filter (BF) frequently leads to blurry edges and gradient reversal artifacts due to the existence of a large amount of outliers in the local averaging window. However, the efficient and accurate estimation of space-variant kernels which adapt to image structures, and the fast realization of the corresponding space-variant bilateral filtering are challenging problems. To address these problems, we present a space-variant BF (SVBF), and its linear time and error-bounded acceleration method. First, we accurately estimate spacevariant anisotropic kernels that vary with image structures in linear time through structure tensor and minimum spanning tree. Second, we perform SVBF in linear time using two error-bounded approximation methods, namely, low-rank tensor approximation via higher-order singular value decomposition and exponential sum approximation. Therefore, the proposed SVBF can efficiently achieve good edge-preserving results. We validate the advantages of the proposed filter in applications including:image denoising, image enhancement, and image focus editing. Experimental results demonstrate that our fast and error-bounded SVBF is superior to state-of-the-art methods.

     

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