Introduction to the issue on visual signal processing for wireless networks

RECENT development of mobile computing technology and wireless communications brought into focus a new paradigm of visual signal transmission via wireless channels and networks. With the emergence of smartphones and continued growth of laptops, netbooks, and tablets, there is a huge increase in a number of mobile devices capable of supporting new image and video applications. According to recent estimates, more than two thirds of all communication network traffic is currently consumed by visual signals and this share is still persistently growing with the development of multi-view and 3D video technology. In addition, interactivity of visual content transmission has become an essential ingredient of modern multimedia communication systems, where uplink channel requirements are also augmented to enable real-time connection between users and video encoders. However, conveying visual information to mobile devices over cellular or mobile broadband networks encounters many challenges, such as limited channel bandwidth, constrained computational and energy resources, high required quality and reliability, tight latency requirements, etc. These problems lie at the heart of the ongoing research in wireless video.