On Semi-implicit Splitting Schemes for the Beltrami Color Image Filtering

  • Authors:
  • Guy Rosman;Lorina Dascal;Xue-Cheng Tai;Ron Kimmel

  • Affiliations:
  • Department of Computer Science, Technion, Israel Institute of Technology, Haifa, Israel 32000;Department of Computer Science, Technion, Israel Institute of Technology, Haifa, Israel 32000;Department of Mathematics, University of Bergen, Bergen, Norway 5007 and Division of Mathematical Sciences, School of Physical Mathematical Sciences, Nanyang Technological University, Singapore, S ...;Department of Computer Science, Technion, Israel Institute of Technology, Haifa, Israel 32000

  • Venue:
  • Journal of Mathematical Imaging and Vision
  • Year:
  • 2011

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Abstract

The Beltrami flow is an efficient nonlinear filter, that was shown to be effective for color image processing. The corresponding anisotropic diffusion operator strongly couples the spectral components. Usually, this flow is implemented by explicit schemes, that are stable only for very small time steps and therefore require many iterations. In this paper we introduce a semi-implicit Crank-Nicolson scheme based on locally one-dimensional (LOD)/additive operator splitting (AOS) for implementing the anisotropic Beltrami operator. The mixed spatial derivatives are treated explicitly, while the non-mixed derivatives are approximated in an implicit manner. In case of constant coefficients, the LOD splitting scheme is proven to be unconditionally stable. Numerical experiments indicate that the proposed scheme is also stable in more general settings. Stability, accuracy, and efficiency of the splitting schemes are tested in applications such as the Beltrami-based scale-space, Beltrami denoising and Beltrami deblurring. In order to further accelerate the convergence of the numerical scheme, the reduced rank extrapolation (RRE) vector extrapolation technique is employed.