Monoscopic method for the automatic determination of height of buildings in air photos

Abstract

This paper proposes a monoscopic method for automatic determination of
building’s heights in digital photographs areas, based on radial displacement of
points in the plan image and geometry at the time the photo is obtained.
Determination of the buildings’ heights can be used to model the surface in urban
areas, urban planning and management, among others. The proposed methodology
employs a set of steps to detect arranged radially from the system of
photogrammetric coordinates, which characterizes the lateral edges of buildings
present in the photo. In a first stage is performed the reduction of the searching area
through detection of shadows projected by buildings, generating sub-images of the
areas around each of the detected shadow. Then, for each sub-image, the edges are
automatically extracted, and tests of consistency are applied for it in order to be
characterized as segments of straight arranged radially. Next, with the lateral edges
selected and the knowledge of the flight height, the buildings’ heights can be
calculated. The experimental results obtained with real images showed that the
proposed approach is suitable to perform the automatic identification of the
buildings height in digital images.