Using perceptual organization to extract 3D structures

The authors describe an approach to perceptual grouping for detecting and describing 3-D objects in complex images and apply it to the task of detecting and describing complex buildings in aerial images. They argue that representations of structural relationships in the arrangements of primitive image features, as detected by the perceptual organization process, are essential for analyzing complex imagery. They term these representations collated features. The choice of collated features is determined by the generic shape of the desired objects in the scene. The detection process for collated features is more robust than the local operations for region segmentation and contour tracing. The important structural information encoded in collated features aids various visual tasks such as object segmentation, correspondence processes, and shape description. The proposed method initially detects all reasonable feature groupings. A constraint satisfaction network is then used to model the complex interactions between the collations and select the promising ones. Stereo matching is performed on the collations to obtain height information. This aids in further reasoning on the collated features and results in the 3-D description of the desired objects.>