A VRML Based 3D Visualization and Sonification Environment

Complex biomedical phenomena require sophisticated data presentation methods. Topographic maps of different parameters of brain electrical activity have been commonly used in research and clinical practice to represent spatial distribution of activity. First applications used topographic maps representing the activity on two dimensional scalp projections. Their main indication is to aid to determine the presence of brain tumours, other focal diseases of the brain (including epilepsy, cerebrovascular disorders and traumas), disturbances of consciousness and vigilance, neuropsychopharmacology, psychiatry, etc.

Animation on 3D models gives insight into spatio-temporal patterns of activity. Development of virtual reality technology made possible additional presentation modalities, such as sonification, haptic interface, etc. New immersive environments are particularly appropriate to improve insight into complex biomedical phenomena, which are naturally multidimensional.

The software system is integrated into the Web based medical information system DIMEDAS, developed by Professor Jovanovic and his team, as a set of Virtual Medical Devices (VMD). The VMD set provides different views on the same medical record, such as standard EEG plot, animated 3D topographic maps, etc. The multi modal viewer mmViewer is based on a VRML head model, animated with Java applets. Acoustic presentation (sonification) is used to emphasize temporal dimension of selected visualized scores. A novel method of sonification, based on modulation of natural sound patterns, has been implemented.

The Virtual Reality Modeling Language (VRML) is a file format for describing interactive 3D objects and worlds. VRML is capable of representing static and animated dynamic 3D 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.

The proposed VRML based visualization and sonification environment requires only a standard Web and VRML browser, and therefore it is applicable both to stand-alone workstations and distributed telemedical applications. Implemented sonification improves temporal resolution or introduces the presentation of new parameters. For a picture of the multi modal mmViewer, we refer to the University of Belgrade Web site.