A fourth-order PDE-based non-linear filter for speckle reduction from Optical Coherence Tomography images

摘要

In this paper, a fourth-order PDE-based non-linear filter for speckle reduction from Optical Coherence Tomography (OCT) images is proposed in a variational framework. The speckle noise pattern in OCT images is distributed according to Rayleigh's Probability Distribution Function (pdf). The initial condition of the proposed PDE-based filter is the speckle noised OCT images and the output is the better quality speckle reduced image. For digital implementations, the proposed scheme is discretised using the finite difference scheme. The performance comparison of the proposed scheme with other standard speckle reduction techniques such as the Lee filter, the Frost filter, the Kuan filter, the SRAD filter, the homomorphic Wiener filter and homomorphic versions of the anisotropic diffusion based filter, the non-linear complex diffusion-based filter and the fourth order PDE-based filter is also presented. The obtained results justify the applicability of the proposed scheme.