Illustrative Visualization

The tutorial presents state-of-the-art visualization techniques inspired by traditional technical and medical illustrations. Such techniques exploit the perception of the human visual system and provide effective visual abstractions to make the visualization clearly understandable. Visual emphasis and abstraction has been used for expressive presentation from prehistoric paintings to nowadays scientific and medical illustrations. Many of the expressive techniques used in art are adopted in computer graphics, and are denoted as illustrative or non-photorealistic rendering. Different stroke techniques, or brush properties express a particular level of abstraction. Feature emphasis or feature suppression is achieved by combining different abstraction levels in illustrative rendering. Challenges in visualization research are very large data visualization as well as multi-dimensional data visualization. To effectively convey the most important visual information there is a significant need for visual abstraction. For less relevant information the dedicated image space is reduced to enhance more prominent features. The discussed techniques in the context of scientific visualization are based on iso-surfaces and volume rendering. Apart from visual abstraction, i.e., illustrative representation, the visibility of prominent features can be achieved by illustrative visualization techniques such as cut-away views or ghosted views. The structures that occlude the most prominent information are suppressed in order to clearly see more interesting parts. Another smart way to provide information on the data is using exploded views or other types of deformation. Illustrative visualization is demonstrated via application-specific tasks in medical visualization. An important aspect as compared to traditional medical illustrations is the interactivity and real-time manipulation of the acquired patient data. This can be very useful in anatomy education. Another application area is surgical planning which is demonstrated with two case studies: neck dissection and liver surgery planning.