Knowledge Discovery in an Oceanographic Database

  • Authors:
  • Susan Bridges;Julia Hodges;Bruce Wooley;Donald Karpovich;George Brannon Smith

  • Affiliations:
  • Mississippi State University, Department of Computer Science, Mississippi, 39762-CA 9637, USA. bridges@cs.msstate.edu;Mississippi State University, Department of Computer Science, Mississippi, 39762-CA 9637, USA. hodges@cs.msstate.edu;Mississippi State University, Department of Computer Science, Mississippi, 39762-CA 9637, USA. bwooley@cs.msstate.edu;Mississippi State University, Department of Computer Science, Mississippi, 39762-CA 9637, USA. dkarpov@cs.msstate.edu;Mississippi State University, Department of Computer Science, Mississippi, 39762-CA 9637, USA. smithg@cs.msstate.edu

  • Venue:
  • Applied Intelligence
  • Year:
  • 1999

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Abstract

Knowledge discovery from image data is a multi-stepiterative process. This paper describes the procedure we have usedto develop a knowledge discovery system that classifies regions ofthe ocean floor based on textural features extracted from acousticimagery. The image is subdivided into rectangular cells calledtexture elements (texels); a gray-level co-occurence matrix (GLCM) iscomputed for each texel in four directions. Secondary texturefeatures are then computed from the GLCM resulting in a featurevector representation of each texel instance. Alternatively, aregion-growing approach is used to identify irregularly shapedregions of varying size which have a homogenous texture and for whichthe texture features are computed. The Bayesian classifier Autoclassis used to cluster the instances. Feature extraction is one of themajor tasks in knowledge discovery from images. The initial goal ofthis research was to identify regions of the image characterized bysand waves. Experiments were designed to use expert judgements toselect the most effective set of features, to identify the best texelsize, and to determine the number of meaningful classes in the data.The region-growing approach has proven to be more successful than thetexel-based approach. This method provides a fast and accuratemethod for identifying provinces in the ocean floor of interest togeologists.