Panoramic Imaging: Sensor-Line Cameras and Laser Range-Finders

9

3D Meshing and Visualization

So far this book has discussed data acquisition and the photogrammetric interpretation of captured data. This chapter deals with fundamentals in 3D modeling and visualization. 3D computer graphics is more diverse, as briefly reported in this chapter. This book is not about 3D computer graphics, and this chapter is not intended as an introduction into this topic. This chapter assumes that the reader is already familiar with (basics of) 3D computer graphics, and discusses those techniques which are in particular used for LRF and panorama data.

9.1 3D Graphics

To visualize 3D objects (by identifying object coordinates) it is necessary to project each 3D point (i.e., if in the regular orthogonal 3D grid, then a voxel) from Euclidean space into a pixel on a 2D surface, which means, in a more general sense, into a point in . This is done by projections. Projections can be comfortably implemented with OpenGL (the Open Graphics Library). OpenGL is an application programming interface which allows the user to render simple 3D primitives (e.g., points, lines, polygons) into a selected buffer; rendering in this context means the projection of each primitive under given geometric and radiometric conditions. The targeted projection manifold is not necessarily the ...