Trajectory triangulation: 3D reconstruction of moving points from a monocular image sequence

Shai Avidan, Amnon Shashua

Research output: Contribution to journalArticlepeer-review

148 Scopus citations


We consider the problem of reconstructing the 3D coordinates of a moving point seen from a monocular moving camera, i.e., to reconstruct moving objects from line-of-sight measurements only. The task is feasible only when some constraints are placed on the shape of the trajectory of the moving point. We coin the family of such tasks as `trajectory triangulation.' We investigate the solutions for points moving along a straight-line and along conic-section trajectories. We show that if the point is moving along a straight line, then the parameters of the line (and, hence, the 3D position of the point at each time instant) can be uniquely recovered, and by linear methods, from at least five views. For the case of conic-shaped trajectory, we show that generally nine views are sufficient for a unique reconstruction of the moving point and fewer views when the conic is of a known type (like a circle in 3D Euclidean space for which seven views are sufficient). The paradigm of trajectory triangulation, in general, pushes the envelope of processing dynamic scenes forward. Thus static scenes become a particular case of a more general task of reconstructing scenes rich with moving objects (where an object could be a single point).

Original languageEnglish
Pages (from-to)348-357
Number of pages10
JournalIEEE Transactions on Pattern Analysis and Machine Intelligence
Issue number4
StatePublished - 2000
Externally publishedYes


FundersFunder number
U.S. Army Research LabsDAAL01-97-R-9291
Defense Advanced Research Projects Agency


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