On-the-Fly Extraction of Polyhedral Buildings From Airborne LiDAR Data

This letter presents an on-the-fly method for extracting polyhedral buildings from airborne light detection and ranging (LiDAR) data. By using the gridding method, the planimetric position and elevation of laser footprints (normally treated as points) in the obtained scan line are mapped into a data sequence. Then, discrete stationary wavelet transform is applied to analyze the elevation variation in the sequence. Buildings in the scan line can be obtained from the detail wavelet coefficients of the sequence. Moreover, to improve precision of the extraction, the gradients of grid points in the geometric planes of building roofs along the direction of the scan line are calculated and remedied by using the corresponding gradients acquired from the adjacent scan lines. With the proposed on-the-fly method, polyhedral buildings in the scan area can be accurately extracted from laser points along the scan lines during the scanning process. The new method is validated by using a set of real airborne LiDAR data.