Ultrasound images are degraded due to a multiplicative noise also known as speckle which not only deteriorates the edges but also brings about unfaithful indications about the nature of the image. Ideal de-speckling algorithms should preserve the edges as well as the texture of the image. In the proposed scheme, the frequency components in the image are obtained using wavelet decomposition and the noise in the high frequency components is estimated by incorporating a bayesian framework. The low frequency noise components are de-speckled by passing through a guided bilateral filter. The proposed scheme was compared with some existing works which include Bayesian non local means filter (OBNLM), wavelet estimation based on non-parametric model and fast bilateral filtering. Quantitative assessments proved that the proposed scheme performed better both in edge preservation and visual quality. Experiments were conducted both on natural images and ultrasound images and both gave good results.
展开▼
