Building facade detection, segmentation, and parameter estimation for mobile robot localization and guidance

Building facade detection is an important problem in computer vision, with applications in mobile robotics and semantic scene understanding. In particular, mobile platform localization and guidance in urban environments can be enabled with an accurate segmentation of the various building facades in a scene. Toward that end, we present a system for segmenting and labeling an input image that for each pixel, seeks to answer the question ??Is this pixel part of a building facade, and if so, which one??? The proposed method determines a set of candidate planes by sampling and clustering points from the image with Random Sample Consensus (RANSAC), using local normal estimates derived from Principal Component Analysis (PCA) to inform the planar model. The corresponding disparity map and a discriminative classification provide prior information for a two-layer Markov Random Field model. This MRF problem is solved via Graph Cuts to obtain a labeling of building facade pixels at the mid-level, and a segmentation of those pixels into particular planes at the high-level. The results indicate a strong improvement in the accuracy of the binary building detection problem over the discriminative classifier alone, and the planar surface estimates provide a good approximation to the ground truth planes.