A TECHNIQUE FOR ESTIMATING THE POSE OF SURFACE SHAPES USING TRIPOD OPERATORS

摘要

A software procedure, with associated hardware, for estimating the pose of an object from a range image containing the object. A range image is a two dimensional array of numbers which represent the distances from a reference point in the range imaging instrument to observed surface points in a scene. All six parameters of the pose of an object are estimated; three translational and three angular parameters. A new technique known as 'non-pose-distinctive placement removal' is combined with of tripod operators (TOs), a method for interpreting range images, and is comprised of two steps. The first is training the system on a new object so that it will later be able to estimate the pose of that object when seen again in some range image (502). The second is the actual pose estimation, where a TO is placed at a random location on a new range image containing the object of interest. Then the nearest neighbor in feature space, the nearpoint, is computed. If the distance to the nearpoint is less than some appropriate threshold (508), then the surface is recognized and pose estimation proceeds by computing the six pose parameters (512) of a central triangle of the new placement in the coordinate system of the range imaging instrument. Then the pose parameters associated with the nearpoint are retrieved. An estimate of the pose of the surface shape in the new image is recoverable using those two pose six-vectors; the pose of the central TO triangle in the new image and the retrieved pose of the central TO triangle in the training image are composed together to determine an estimate where the object actually is with respect to the location of its original model used in training.