3D model generation for cities using aerial photographs and ground level laser scans

In this paper we describe techniques for 3D textured model construction of urban areas using acquisition devices such as intensity cameras, as well as 2D laser scanner. Our experimental set up consists of a truck equipped with one camera and two fast, inexpensive 2D laser scanner, traveling on city streets under normal traffic conditions. The horizontal laser scans are used to determine the approximate component of motion along the movement of the acquisition vehicle. The vertical scanner is used to build 3D models of the facade of the buildings. To improve the accuracy of localization of the truck and hence our resulting 3D models of the city, two different methods are developed and compared: the first method employs a correlation technique and the second method is based on Markov Monte Carlo localization. Both techniques use digital road maps and aerial photographs in conjunction with laser scans. A fairly accurate textured, 3D model of downtown area has been acquired in a matter of few minutes, limited only by traffic conditions during the data acquisition phase.