Solution of Anisotropic Diffusion Equations

We suggest and analyze the computational method based on Rothe's approximation in time and finite element method in space for solving the modified Perona-Malik anisotropic diffusion equation

u_t - div ( g( |grad G_sigma * u|) grad u ) = f (u_0 - u)

together with zero Neumann boundary conditions and initial condition representing the processed image. Here, g(s) tends to 0 for s tends to infinity. It causes the selective smoothing of the image regions and keeping of the edges on which the 'gaussian gradient' is large (G_sigma is smoothing kernel of the convolution). Such image analysis is included in the so-called nonlinear scale space theory.

We present some results of image reconstructions. The successive coarsening finite element grid strategy which decreases the computational costs is added to the method.


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Figure 1a. Original and noisy images.

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Figure 1b. Reconstruction of the original and final computational finite element grid.


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Figure 2a. Original and noisy images.

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Figure 2b. Reconstruction of the original and final computational finite element grid.


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