Trilateral filter using rank order information of pixel value for mixed Gaussian and impulsive noise removal

The bilateral filter can remove Gaussian noise while preserving edges of the objects in an image. However the bilateral filter can not remove impulsive noise due to its edge preservation property. Therefore some robust bilateral filters have been proposed in order to also deal with impulsive noise. To make the bilateral filter more robust, this paper proposes a trilateral filter which incorporates a third weighting function based on the rank order information of pixel values into the bilateral filter. The effectiveness of the proposed method is verified in comparison with other conventional methods in experiments using the natural digital images corrupted by mixed Gaussian and impulsive noise.