Model-based conifer-crown surface reconstruction from highresolution aerial images. Photogrammetric Engineering and Remote Sensing 67

Abstract

Abstract Tree crown parameters such as height, shape and crown closure are desirable in forest and ecological studies, but difficult to measure on the ground. The stereoscopic capability of high-resolution aerial images provides a way to crown surface reconstruction. However, existing digital photogrammetry packages designed to map terrain surfaces cannot accurately extract tree crown surfaces, particularly for conifer crowns with steep profiles in the vertical direction. In this paper, we integrate crown features derived from images to stereo matching, and develop a model-based approach to reconstruct crown surfaces for conifers. The idea is based on the fact that most conifer crowns are in a form of solid geometry. We model a conifer crown as a generalized ellipsoid; establish the optimal tree model using a geometric equation; and then apply the optimal tree model to guide a conventional pyramid image matching in crown surface reconstruction. The effectiveness of the proposed- approach is illustrated using an example of a redwood tree on 1:2,400 aerial photographs. 1