Improving Depth Perception Using Edge Highlighting in Transparent Stereoscopic Visualizations of Laser-Scanned 3D Point Clouds

Digital archiving is the activity of digitizing cultural heritage to preserve and utilize it. Visualizing these data helps us to understand the complicated internal structure of the cultural heritage. Transparent stereoscopic visualization based on 3D point clouds is effective for understanding the complex structures of cultural heritage. However, the position and depth information often become unclear when three-dimensional data are rendered transparently. We examined whether perceived depth of transparently and stereoscopically visualized objects can be improved by highlighting 3D edges of the structure. We also investigated the effect of edge opacity on perceived depth. We tested two types of figures: vertically and horizontally combined shapes and diagonally combined shapes, which is extracted from the point cloud data of cultural heritage. We conducted psychophysical experiments, and the results suggest that edge highlighting improves the accuracy of perceived depth. Moreover, the effect of edge highlighting was more significant when binocular disparity and motion parallax were available.