Image restoration combining a total variational filter and a fourth-order filter

In this paper, a noise removal algorithm based on variational method and partial differential equations (PDEs) is proposed. It combines a total variational filter (ROF filter) with a fourth-order PDE filter (LLT filter). The combined algorithm takes the advantage of both filters since it is able to preserve edges while avoiding the staircase effect in smooth regions. The existence and uniqueness of a solution to the minimization problem is established. Experimental results illustrate the effectiveness of the model in image restoration.