We propose an elevation-based approach to parking lot structure analysis from aerial imagery. In contrast to image-based methods, the new approach treats parked vehicles as 3-D microstructures and attempts to locate them in the elevation domain. The STME (Surface Texture and Microstructure Extraction) system is applied to the elevation map to extract the 3-D microstructures. A hybrid application of this system to both intensity and elevation maps results in a complete extraction of individual vehicles. Based on a comparison of texture exploitation techniques, a WCC (weighted combination criterion) algorithm is presented to generate a clean parking lot ground surface, which facilitates visualization and simulation of parking lot activities with a high degree of visual realism.

We study the reliability of a set of stereo-based 3-D textural features in classification in response to different training data. Two types of training data, "labeling-based" and "chip-based," are investigated. Experiments have been carried out to compare the 3-D features with a set of 2-D features based on co-occurrence analysis. Results show that the 3-D features consistently outperform the 2-D features in terms of classification accuracy under various configurations of training data.

We present a surface texture and microstructure extraction system to provide added realism in visualization and virtual reality applications. The system uses multiple images, 3-D models and camera information, in addition to knowledge about man-made structures, to cope with problems such as perspective distortion, data deficiency, and corruption caused by shadows and occlusions. Combined with the Ascender site modeling system and scene rendering algorithms, the system is typically useful for urban site model refinement and visualization.

Texture has long been regarded as spatial distributions of gray-level variation, and texture analysis has generally been confined to the 2-D image domain. Introducing the concept of "3-D world feature", this paper considers texture as a function of 3-D structures and proposes a set of "3-D textural features". The proposed 3-D features appear to have a great potential in terrain classification. Experiments have been carried out to compare the 3-D features with a popular traditional 2-D feature set. The results show that the 3-D features significantly outperform the 2-D features in terms of classification accuracy.

This paper addresses the general 3-D rigid motion problem, where the point correspondences and the motion parameters between two sets of 3-D points are to be recovered. The existence of missing points in the two sets is the most difficult problem. We first show a mathematical symmetry in the solutions of rotation parameters and point correspondences. A closed-form solution based on the correlation matrix eigenstructure decomposition is proposed for correspondence recovery with no missing points. Using a heuristic measure of point pair affinity derived from the eigenstructure, a weighted bipartite matching algorithm is developed to determine the correspondences in general cases where missing points occur. The use of the affinity heuristic also leads to a fast outlier removal algorithm, which can be run iteratively to refine the correspondence recovery. Simulation results and experiments on real images are shown in both ideal and general cases.

A system has been developed to acquire, extend and refine 3D geometric site models from aerial imagery. This system hypothesizes potential building roofs in an image, automatically locates supporting geometric evidence in other images, and determines the precise shape and position of the new buildings via multiimage triangulation. Model-to-image registration techniques are applied to align new, incoming images against the site model. Model extension and refinement procedures are then performed to add previously unseen buildings and to improve the geometric accuracy of the existing 3D building models.>