Model-Based Conifer Canopy Surface Reconstruction from Photographic Imagery

Abstract

signed to extract canopy surfaces with high variability in the Canopy surface data are desirable in forestry, but they are vertical direction. difficult to collect in the field. Existing surface reconstruction Sheng et al. (2001) introduced a model-based photogramtechniques cannot adequately extract canopy surfaces, es- metric approach to tree crown surface reconstruction. They expecially for conifer stands. This paper develops an integrated pressed the crown morphology of a tree using 3D geometric model-based approach to reconstruct canopy surface for models and modeled it as a generalized 3D hemi-ellipsoid. conifer stands analytically from the crown level. To deal with They manually established the optimal tree model from aerial dense stands, critical problems are addressed in the process photos, and used the initial crown surface derived from the of model-based surface reconstruction. These include the tree model to guide image matching in crown surface reconocclusion problem in disparity (parallax) prediction from tree struction. The potential of this model-based approach was models, the edge effect of tree models on the disparity map, demonstrated using a single tree. When reconstructing the canand the foreshortening effect in image matching. The model- opy surface of a dense stand of multiple trees, we need to estabbased approach was applied to recover the canopy surface of lish optimal tree models in a more efficient manner and cona dense redwood stand using images scanned from 1:2,400- sider problems such as occlusion. This paper extends the scale aerial photographs. Compared with field measurements, capability of the model-based approach from recovering the crown radius and tree height derived from the reconstructed crown surface of a single tree to reconstructing the canopy surcanopy surface model have an overall accuracy of 92 percent face of a tree stand, and further develops the model-based and 94 percent, respectively. The results demonstrate the method to canopy surface reconstruction for complicated tree approach’s ability to reconstruct complicated stands. stands. The improved method addresses the problems of occlusion, foreshortening, and tree edge effects, and was applied to