Discovering High-level Parameters for Visualization Design

In most graphics and visualization applications, the effects of the mapping parameters on the output domain are multidimensional, non-linear and discontinuous. The complexity of such mapping often makes it difficult for a user to manually explore and manipulate the design parameter space to produce the desired output. Computer assistance is therefore useful in setting the mapping parameter values to generate desired outputs. Existing systems rely on exploring the entire input parameter space, which can be time and resource-intensive, particularly if the number of input parameters is large. We introduce a new approach to handling a large number of mapping parameters more efficiently. The basis for our approach is the identification of a small and effective set of highlevel parameters that can be associated directly with the characteristics of the outputs. Users will have a better understanding of this small set of high-level parameters and can easily modify their values interactively to produce the desired outputs. We demonstrate this technique in manipulating mapping parameters for a non-photoreastic volume rendering application.