A Comprehensive Review of Deep Learning-based Single Image Super-resolution

Image super-resolution (SR) is one of the vital image processing methods that improve the resolution of an image in the field of computer vision. In the last two decades, significant progress has been made in the field of super-resolution, especially utilizing deep learning methods. This survey is an effort to provide a detailed survey of recent progress in the field of super-resolution in the perspective of deep learning while also informing about the initial classical methods used for achieving super-resolution. The survey classifies the image SR methods into four categories, i.e., classical methods, supervised learning-based methods, unsupervised learning-based methods, and domain-specific SR methods. We also introduce the problem of SR to provide intuition about image quality metrics, available reference datasets, and SR challenges. Deep learning-based approaches of SR are evaluated using a reference dataset. Finally, this survey is concluded with future directions and trends in the field of SR and open problems in SR to be addressed by the researchers.