Efficient Pose Clustering Using a Randomized Algorithm

  • Authors:
  • Clark F. Olson

  • Affiliations:
  • Department of Computer Science, Cornell University, Ithaca, NY 14853, USA. E-mail: clarko@cs.cornell.edu

  • Venue:
  • International Journal of Computer Vision
  • Year:
  • 1997

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Abstract

Pose clustering is a method to perform object recognition bydetermining hypothetical object poses and finding clusters of theposes in the space of legal object positions. An object that appearsin an image will yield a large cluster of such poses close to thecorrect position of the object. If there are m model features and n image features, then there are O(m^3n^3) hypothetical posesthat can be determined from minimal information for the case ofrecognition of three-dimensional objects from feature points intwo-dimensional images. Rather than clustering all of these poses,we show that pose clustering can have equivalent performance for thiscase when examining only O(mn) poses, due to correlation between the poses, if we are given two correct matches between model features and image features. Since we do not usually know two correct matchesin advance, this property is used with randomization to decompose thepose clustering problem into O(n^2) problems, each of whichclusters O(mn) poses, for a total complexity of O(mn^3). Furtherspeedup can be achieved through the use of grouping techniques. Thismethod also requires little memory and makes the use of accurateclustering algorithms less costly. We use recursive histogramingtechniques to perform clustering in time and space that is guaranteedto be linear in the number of poses. Finally, we present resultsdemonstrating the recognition of objects in the presence of noise,clutter, and occlusion.