Suyoung Seo

Extraction of Boundaries of Rooftop Fenced Buildings From Airborne Laser Scanning Data Using Rectangle Models

We propose a building boundary modeling method using rectangles to overcome the zigzag boundary shapes of rooftop fenced buildings that are inherent in light detection and ranging (LiDAR) data. The method first finds 3-D patches through building detection using a morphological opening filter and histogram mode analysis. Then, rectangles that encase the traced boundaries of the 3-D patches are adjusted adaptively based on traced boundary coordinates and perpendicular constraints among the sides of the rectangles. The boundary of each 3-D patch is remodeled by subtracting void region rectangles from the parent rectangle. The superstructures of rooftops are also modeled with perpendicularity and adaptive constraints.

Estimation of edge displacement against brightness and camera-to-object distance

This study proposes a systematic method to estimate edge displacement (ED) from ground truth edges. To obtain ground truth edges and test edges, a series of target sheets containing the reference regions and brightness contrast regions were designed. Further, the brightness contrast regions were designed to contain foreground and background brightness between which the image edges occur. By varying the foreground brightness (FB), the influence of the FB on the edge locations was tested. Moreover, the influence of camera-to-object distance on the edge locations was tested. A simple least-squares method using slope profiles and a slope-based weighting scheme is proposed for calculating the edges occurring in contrast regions with subpixel accuracy. The experiment results revealed that a bright foreground moves the edge location towards the dark side of the edges in the range of 0-0.6 pixels with strong relationships between the FB and magnitude of ED.