Ultrasound image denoising using median-anisotropic diffusion

A denoising algorithm using multidirectional median filtering and improved anisotropic diffusion was proposed for ultrasound images corrupted with speckles. Multidirectional median filtering was used to remove the speckles and preserve edge details by its promising edge-preservation capability. A diffusion coefficient incorporated with unitary local variance and image gradient was introduced to obviate poor robustness introduced by the constant gradient threshold in the traditional anisotropic diffusion algorithms. Compared with Perona-Malik model and Speckle Reducing Anisotropic Diffusion model, experiments show that the proposed algorithm has better performance for noise removal, edge-preservation, and iteration speed.