Distinguish True or False 4K Resolution Using Frequency Domain Analysis and Free-Energy Modelling
With the prevalence of Ultra-High Definition (UHD) display terminals, 4K resolution (38402160 pixels) contents are becoming a major selling point for online video media. However, due to the insufficiency of natural UHD contents, a large number of false 4K videos are circulating on the web. Those '4K' contents, usually being upscaled from lower resolutions, often frustrate enthusiastic consumers and are in fact a waste of stringent bandwidth resources. In this paper, we propose to distinguish natural 4K contents from false ones through frequency domain analysis. The basic assumption is that true 4K contents have much more high frequency responses than the upscaled versions. We use the free energy modelling to approximate the Human Visual System so as to minimize the impact of structural complexity of visual contents. We set up a dataset containing more than 1k original 4K frames together with upscaled versions using four widely used interpolation algorithms. Experimental results show that the proposed free-energy-based metric has an accuracy rate higher than 90%.