An Effective Illustrative Visualization Framework based on Photic Extremum Lines (PELs)

Xyexuabg Xie, Ying He, Feng Tian, Hock-Soon Seah, Xianfeng Gu and Hong Qin
IEEE Visualization 2007
Conveying shape using feature lines is an important visualization tool in visual computing. The existing feature lines (e.g., ridges, valleys, silhouettes, suggestive contours, etc.) are solely determined by the local geometry properties (e.g., normals and curvatures) as well as the view position. This paper is strongly inspired by the observation in human vision and perception that a sudden change in the luminance plays a critical role to faithfully represent and recover the 3D information. In particular, we adopt the edge detection techniques in image processing for 3D shape visualization and present Photic Extremum Lines (PELs) which emphasize significant variations of illumination over 3D surfaces. Comparing with the existing feature lines, PELs are easy to compute and offer users more freedom to achieve the desired visualization effect. Specifically, the user can fully control the shape visualization by changing the light position, the number of lights, and different light models. More importantly, PELs can deliver the consistent visualization result in the same way of our human perceptual system. We make a thorough comparison between PELs and the existing approaches through extensive evaluations. We demonstrate that PELs enable a flexible and effective tool to illustrate 3D surfaces and volumes for visual computing.