Retraction Based Three-Dimensional Tracking of Object Movements

摘要

The technology disclosed relates to tracking movement of a real world object in three-dimensional (3D) space. In particular, it relates to mapping, to image planes of a camera, projections of observation points on a curved volumetric model of the real world object. The projections are used to calculate a retraction of the observation points at different times during which the real world object has moved. The retraction is then used to determine translational and rotational movement of the real world object between the different times.

主权项

1. A system of tracking movement of an object's portion in a three-dimensional (3D) space, the system including:
one or more processors coupled to memory, the memory loaded with computer instructions that, when executed on the processors, implement actions including:
selecting five observation points on a sphere model fitted to a portion of a real world object, wherein one of the observation points is at a center of the sphere model and the other four observation points are along a perimeter of the sphere model;capturing at times t0 and t1 projections of at least the four perimeter observation points in at least a first image plane of at least one camera, wherein the object moved between t0 and t1;calculating a retraction of the four perimeter observation points at time t1 to their positions at to, including using the four perimeter observation points to:
map the captured projections of the perimeter observation points at t0 to a first image plane; andcalculate orientation of a second image plane such that the captured projections of the perimeter observation points at t1 to the second image plane are collinear with respective projections in the first image plane with respect to the retracted center observation point; anddetermining at least translation of the sphere model between the times t0 and t1 using the calculated orientation of the second image plane.