Shock coupled fourth-order diffusion for image enhancement

In this paper a shock coupled fourth-order diffusion filter is proposed for image enhancement. This filter converges at a faster rate while preserving and enhancing edges, ramps and textures present in the images. The proposed filter diffuses with varying magnitudes in the directions normal to the level-curve and along it. The magnitude of the directional diffusion is controlled by a diffusion function, meant to provide a good response in the direction along the level-curves, than across them. The proposed filter can still preserve the planar approximation of the image, thereby avoiding the discrepancy caused due to the staircase effect, as in the second-order counterparts. The anisotropic property of the filter is thoroughly studied, analyzed and demonstrated with perspective and quantitative results. The performance of the proposed filter is compared with the state-of-the-art methods for image enhancement. The quantitative and perspective measures provided endorse the capability of the method to enhance various kinds of images.

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► We propose a fourth-order shock coupled image enhancing filter to restore the images.
► The filter preserves planar approximation and considerably reduces the staircase effect.
► The anisotropic behavior of the filter was closely analyzed and thoroughly studied.
► The filter converges at a faster rate giving visually and qualitatively impressive results.
► The proposed method is compared with the state-of-the-art image enhancement methods.