Padikkal, P.George, S.2026-02-052012Computers and Electrical Engineering, 2012, 38, 5, pp. 1262-1277457906https://doi.org/10.1016/j.compeleceng.2012.03.017https://idr.nitk.ac.in/handle/123456789/27098In 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. © 2012 Elsevier Ltd. All rights reserved.DiffusionAnisotropic propertyDiffusion functionsDirectional diffusionFourth order diffusionQuantitative resultSecond ordersStaircase effectState-of-the-art methodsImage enhancement