Perceptualization of Biomedical Data

Abstract

Virtual reality technology (VRT) enabled a new environment for biomedical applications. Increased computing performance emphasizes the importance of human-computer interface, bound by characteristics of human perception. VR technologies shift the human-computer interaction paradigm from a graphical user interface (GUI) to a VR-based user interface (VRUI). The main characteristic of VRUI is extension of visualization with acoustic and haptic rendering. New interface technology and natural interaction make possible perceptual data presentation. Immersive environments are particularly appropriate for improving insight into complex biomedical phenomena, which are naturally multidimensional. The technique of data presentation using variable sound features is called sonification. The authors employed sonification to improve insight into spatiotemporal patterns of brain electrical activity. Animation on three-dimensional (3-D) models gives insight into spatiotemporal patterns of activity. Visualization is based on topographic maps projected on the scalp of a 3-D head model. Presented here is the use of sonification for refining temporal cues or introducing new information channels in the human-computer interface. In addition to visualization, which gives predominantly spatial distribution, acoustic rendering improves temporal cues. A novel method of sonification implements modulation of natural sound patterns to reflect certain features of processed data, and creates a pleasant acoustic environment. Global vigilance index is used as a warning signal for drowsiness during EEG analysis. This feature is particularly important for prolonged system use. The multimodal interactive environment for biomedical data presentation described here is based on a VRML head model with sonification used to emphasize temporal dimension of selected visualized scores. VRML langu age is applied as a standard tool for VR applications in the Internet environment. The Virtual Reality Modeling Language (VRML) is a file format for describing interactive 3-D objects and worlds, applicable on the Internet, intranets, and local client systems. VRML is also intended to be a universal interchange format for integrated 3-D graphics and multimedia. VRML is capable of representing static and animated dynamic 3-D and multimedia objects with hyperlinks to other media such as text, sounds, movies, and images. VRML browsers, as well as authoring tools for the creation of VRML files, are widely available for many different platforms. Therefore, VRML was chosen as the platform for Internet-based information systems. In the system described, the VRML world is controlled by Java applets.