Improvement of data visualization based on ISOMAP

  • Authors:
  • Chao Shao;Houkuan Huang

  • Affiliations:
  • School of Computer and Information Technology, Beijing Jiaotong University, Beijing, China;School of Computer and Information Technology, Beijing Jiaotong University, Beijing, China

  • Venue:
  • MICAI'05 Proceedings of the 4th Mexican international conference on Advances in Artificial Intelligence
  • Year:
  • 2005

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Abstract

Using the geodesic distance metric instead of the Euclidean distance metric, ISOMAP can visualize the convex but intrinsically flat manifolds such as the swiss roll data set nicely. But it's well known that ISOMAP performs well only when the data belong to a single well-sampled manifold, and fails when the data lie on disjoint manifolds or imperfect manifolds. Generally speaking, as the data points are farer from each other on the manifold, the approximation of the shortest path to the geodesic distance is worse, especially for imperfect manifolds, that is, long distances are approximated generally worse than short distances, which makes the classical MDS algorithm used in ISOMAP unsuitable and thus often leads to the overlapping or ”overclustering” of the data. To solve this problem, we improve the original ISOMAP algorithm by replacing the classical MDS algorithm with the Sammon's mapping algorithm, which can limit the effects of generally worse-approximated long distances to a certain extent, and thus better visualization results are obtained. As a result, besides imperfect manifolds, intrinsically curved manifolds such as the fishbowl data set can also be visualized nicely. In addition, based on the characteristics of the Euclidean distance metric, a faster Dijkstra-like shortest path algorithm is used in our method. Finally, experimental results verify our method very well.