SAR and Optical Pixel Level Fusion Methods and Evaluations

In the past years, many vital improvements in image fusion have been recognised, particularly in the fusion of Synthetic Aperture Radar (SAR) and optical sensors. Many kinds of research have been published focusing on pixel-level fusion of SAR and optical images. This paper focuses on pixel-level SAR-optical fusion methods, along with performance assessment and applications. Five categories (component substitution, numerical method, model-based, multi-resolution, and hybrid methods) of fusion are presented. Subjective, objective , and comprehensive methods are surveyed to assess fusion. Experimental findings utilising Sentinel-1A and Sentinel-2A data corroborate the assessment. Finally, paper suggests that there is still space for investigation into SAR-optical fusion.