Information Services and Use

Distributed multimedia computing is seen as the next generation of information technology. This new technology has both the potential to create new application areas and augment those that already exist. This paper introduces multimedia and describes the characteristics of multimedia information. Those application areas where this new technology is having a significant impact are also discussed along with an evaluation of the current state of the art.

The popular portrayal by the media of Virtual Reality is that of enthusiastic games participants indulging in strange whole-body movements whilst wearing bulky head-mounted stereoscopic displays, interactive gloves, head and hand tracking systems and even whole-body suits. The purpose of this equipment, one is informed, is to give the user an effective means by which he or she can become “immersed within” a virtual world, interacting with features in much the same way as one might in the real world—by walking around, making gestures, talking, listening and looking at the computer generated scene.

This paper traces the history of Virtual Reality as it has driven the development of equipment in use today. A brief description of some of the commercially available technologies is presented, together with some of the emerging concepts and problems which require urgent addressing before the technology can find its way cheaply and safely into a wide range of serious applications.

Unlike textual databases, image databases are fairly new. This is largely because image processing is a highly computationally intensive activity. Storage overhead for an image database is also considerable. Despite these problems significant progress has already been made because of advances in VLSI technology. This paper will describe how we successfully harnessed the parallelism offered by a transputer network, which is a product of VLSI technology, in providing the necessary processing power for creating an image database. The database consists of a collection of historical museum photographs. It is implemented on an IBM compatible PC equipped with the necessary image processing and mass storage facilities and linked to a network of four transputers. The user interface is provided through a serial mouse and a menu of keywords. Users will be able to retrieve individual images in three different modes: (i) the browse mode will allow the user to display a set of up to 12 photographs in miniature “stub” format at one go: a click on a stub will select it for display in full size, (2) the search mode involves the selection of a keyword from the menu of subject or location index in order to retrieve a specified image, (3) users can also retrieve a photograph by typing-in the unique museum reference number. The paper will also discuss the results of our image processing experiments—enhancement, compression and decompression—very briefly.

Traditional databases use simple data types chiefly numbers and strings—to represent information such as payroll records or scientific data. Queries commonly take the form of relational calculus or relational algebra expressions and the results require little more than a textual terminal for presentation. The natural successor to a traditional database is the Multimedia Information System which also uses richer data types—images, text, sound and so on—to describe some application domain. This calls for more advanced technologies such as graphical workstations for data creation and presentation, high-bandwidth networks for fast access to distributed data and large repositories for the storage of objects. These technologies are now widely available.

Ideally, queries put to a Multimedia Information System should refer to the content of stored objects—content retrieval—and results should be able to contain complex as well as simple data types. Manual entry of content descriptions is time-consuming, error-prone and subjective; a better approach is to draw on the emerging fields of image interpretation, text interpretation, speech interpretation and knowledge representation to provide automatic content retrieval.

This article serves as an introduction to Multimedia Information Systems and related fields and describes in detail a pilot system with automatic content retrieval built by the Multimedia Group at Manchester University.