Keynote speech 3: Visual quality evaluation for images and videos

Visual quality assessment of images and videos has become important nowadays with the demand of high-definition and high-quality viewing experience. The standards bodies, i.e., ITU-T VCEG and MPEG, now require subjective tests to be performed on all proposals. This talk will give an introduction on subjective and objective visual quality assessments, with focus on the latter. For subjective visual quality assessment, a short review will be given on the standard subjective evaluation procedure and the subjective score analysis methods. For objective visual quality assessment, its applications, its classifications, and the different techniques used in image and video quality metrics, both from existing literature and from our works, will be discussed. The general framework used by the classical HVS-model based image quality metrics (IQMs) will be briefly introduced first, followed by some new methodologies which do not rely on the HVS models, e.g., ones used in SSIM (Structural SIMilarity) and VIF (Visual Information Fidelity) quality measures. For video quality assessment, how temporal/motion information is used to measure the subjective video quality will also be presented.