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A Technique for Estimating the Pose of Surface Shapes Using Tripod Operators

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Patent Application, Filed 8 Dec 1999

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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. 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 near point, is computed. If the distance to the near point is less than some appropriate threshold, then the surface is recognized and pose estimation proceeds by computing the six pose parameters of a central triangle of the new placement in the coordinate system of the range imaging instrument. Then the pose parameters associated with the near point 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.

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  • Computer Programming and Software

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