Fast iterative image restoration algorithms

The goal of image restoration is to reconstruct the original image from a degraded model. This recovery process is very important in many image processing applications. In the present paper we propose two methods which improve the conventional iterative restoration algorithms. One is to accelerate convergence of the steepest descent method using the improved search directions. The other accelerates convergence by using preconditioners. It is also shown that the proposed preconditioned algorithm can accelerate iteration-adaptive iterative image restoration algorithm. The preconditioner in the proposed algorithm can be implemented by using the FIR filter structure, so it can be applied to practical application with manageable amounts of computation.