tailieunhanh - Handbook of Multimedia for Digital Entertainment and Arts- P6

Handbook of Multimedia for Digital Entertainment and Arts- P6: The advances in computer entertainment, multi-player and online games, technology-enabled art, culture and performance have created a new form of entertainment and art, which attracts and absorbs their participants. The fantastic success of this new field has influenced the development of the new digital entertainment industry and related products and services, which has impacted every aspect of our lives. | Chapter 6 Digital Video Quality Assessment Algorithms Anush K. Moorthy Kalpana Seshadrinathan and Alan C. Bovik Introduction The last decade has witnessed an unprecedented use of visual communication. Improved speeds increasingly accessible technology and reducing costs coupled with improved storage means that images and videos are replacing more traditional modes of communication. In this era when the human being is bombarded with a slew of videos at various resolutions and over various media the question of what is palatable to the human is an important one. The term quality is one that is used to define the palatability of an image or a video sequence. Researchers have developed algorithms which aim to provide a measure of this quality. Automatic methods to perform image quality assessment IQA has made giant leaps over the past few years 1 . These successes suggest that this field is close to attaining saturation 2 . More complex than IQA algorithms are video quality assessment VQA algorithms whose goals are similar to those for IQA but require processing of dynamically changing images. In this chapter we focus on VQA algorithms for digital video sequences. Digital videos comprise of a set of frames still images played at a particular speed frame-rate . Each frame has the same resolution and the frame is made up of a bunch of picture elements or pixels. These pixels have fixed bit-depth . the number of bits used to represent the value of a pixel is fixed for a video. This definition is valid for progressive videos. Interlaced videos on the other hand consist of a pair of fields each containing alternating portions of the equivalent frame. When played out at an appropriate rate the observer views the videos as a continuous stream. When one defines a digital video sequence as above one is bound to question the necessity for separate VQA algorithms - Can one not apply an IQA algorithm on a frame-by-frame basis or on one of the fields and then average out the .