A method for representing 3D tree objects using chain coding

Abstract

We describe a method for representing 3D (three-dimensional) tree objects by means of a chain code. These 3D tree objects correspond to natural existing 3D tree structures, such as: blood vessels, plants, live trees, and so on. Thus, trees are digitalized and represented by a notation called the unique tree descriptor. The unique tree descriptor is invariant under translation and rotation. Furthermore, this descriptor is starting vertex normalized via the unique path in the tree. Also, it is possible to obtain the mirror image of any tree with ease. This unique tree descriptor preserves the shape of trees (and the shape of their branches), allows us to know their geometrical and topological properties. To determine if two 3D tree objects have the same shape, it is only necessary to see if their descriptors are equal. In this manner, graph comparisons and tree searches are eliminated. Also, the proposed tree descriptor is a good tool for storing of 3D tree objects. Finally, in order to prove our method for representing 3D tree objects, we obtain some tree descriptors of objects on real images.