Focal region-guided feature-based volume rendering

In this paper we advocate the use of a focal region-guided feature-based volume renderer that offers an alternative for visualization of internal structures of volumetric data. We describe this promising technique for communicating the first impression of object shape or contour while at the same time providing detailed information of volumetric data with the use of a lens-like focal region. We designed a method for generating object contours and enhancing volumetric features to depict context information out of the focal region based on gradient volume. In the focal region, we render interesting volume data using the direct volume rendering method. The rendering is guided by the focal region through which we can specify what subset to render. The connection between the structure of the interior and exterior of the focal region gives a better understanding of the spatial relationship. This is to communicate better the existence, form, and location of underlying targets while minimally occluding them.