Disclosed is a method of determining a 3D trajectory of an object from at least two observed trajectories of the object in a scene. The observed trajectories are captured in a series of images by at least one camera, each of the images in the series being associated with a pose of the camera. First and second points of the object from separate parallel planes of the scene are selected. A first set of 2D capture locations corresponding to the first point and a second set of 2D capture locations corresponding to the second point are reconstructed to determine an approximated 3D trajectory of the object.