Overview of quality assessment for visual signals and newly emerged trends

Quality assessment is not only essential on its own for testing, optimizing, benchmarking, monitoring and inspecting related systems and services, but also plays an essential role in the design of virtually all visual signal processing and communication algorithms, as well as various related decision making processes. In the paper, we provide an overview of the quality assessment approaches for traditional visual signals, as well as the newly emerged ones, which covers the subjective quality evaluation and objective quality metrics of scalable and mobile videos, high dynamic range (HDR) images, image segmentation results, 3D images/videos, and retargeted images. Also the challenges for designing effective quality metrics and corresponding applications are discussed.

I. Introduction

The explosion in the number of computers and digital systems connected by networks such as the Internet has brought a flow of instant information into an increasingly large number of homes and businesses. Most of the information is in the form of digital visual signals (including image, video, etc.), as the most intuitive and faithful depiction of things in life and work. As a result, products (e.g. phone cameras) and services (e.g. YouTube) based upon visual signals have grown at an exponential rate.