Mixed pulse-Gaussian denoising algorithm for improving image quality in assembly inspection of nuclear power plants
Visual inspection for nuclear fuel assemblies is necessary during outages of nuclear power plants. These inspections can be used to identify fuel assemblies' anomalies that endanger the reactor's running. However, intense radiation of fuel assembly sensitively degrades the image quality through a mixture of impulse and Gaussian noise. To solve this problem, an image denoising algorithm based on Non-Local Dual Denoising (NLDD) and Rank-Ordered Absolute Differences (ROAD) is proposed here. It consists of two steps. The detector ROAD is first used to find noisy pixels in an image damaged by impulse noise and replace them with neighborhood values. Then, NLDD filter is applied to image corrupted with Gaussian noise and retains the details. The proposed approach has been successfully tested on assembly inspection of nuclear power plants. The results reveal that our approach is effective to noise suppression and crucial detail preservation.