4D tree geometry 4D registration Statistical analysis 4D tree generation Extended SRVF
This paper introduces a novel computational framework for modeling and analyzing the spatiotemporal shape variability of tree-like 4D structures whose shapes deform and evolve over time. Tree-like 3D objects, such as botanical trees and plants, deform and grow at different rates. In this process, they bend and stretch their branches and change their branching structure, making their spatiotemporal registration challenging. We address this problem within a Riemannian framework that represents tree-like 3D objects as points in a tree-shape space endowed with a proper elastic metric that quantifies branch bending, stretching, and topological changes. With this setting, a 4D tree-like object becomes a trajectory in the tree-shape space. Thus, the problem of modeling and analyzing the spatiotemporal variability in tree-like 4D objects reduces to the analysis of trajectories within this tree-shape space. However, performing spatiotemporal registration and subsequently computing geodesics and statistics in the nonlinear tree-shape space is inherently challenging, as these tasks rely on complex nonlinear optimizations. Our core contribution is the mapping of the tree-like 3D objects to the space of the Extended Square Root Velocity Field, where the complex elastic metric is reduced to the L2 metric. By solving spatial registration in the ESRVF space, analyzing tree-like 4D objects can be reformulated as the problem of analyzing elastic trajectories in the ESRVF space. Based on this formulation, we develop a comprehensive framework for analyzing the spatiotemporal dynamics of tree-like objects, including registration under large deformations and topological differences, geodesic computation, statistical summarization through mean trajectories and modes of variation, and the synthesis of new, random tree-like 4D shapes.
Details
Title
A Riemannian Framework for the Elastic Analysis of the Spatiotemporal Variability in the Shape and Structure of Tree-like 4D Objects
Authors/Creators
Tahmina Khanam
Hamid Laga
Mohammed Bennamoun
Guanjin Wang
Ferdous Sohel
Farid Boussaid
Guan Wang
Anuj Srivastava
Publication Details
ArXiv.org
Publisher
Cornell University
Identifiers
991005813642207891
Murdoch Affiliation
Centre for Biosecurity and One Health; Centre for Crop and Food Innovation; School of Information Technology; Centre for Healthy Ageing