Data Mining

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The first step in data mining images is to create a distance measure for two images.  In the intro to data mining images, we called this distance measure the “black box.”  This post will cover how to create distance measures based on time series analysis.  This technique is great for comparing objects with a constant, rigid shape.  For example, it will work well on classifying images of skulls, but not on images of people.  Skulls always have the same shape, whereas a person might be walking, standing, sitting, or curled into a ball.  By the end of this post, you should understand how to compare these hominid skulls from UC Riverside1 using radial scanning and dynamic time warping.

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Footnotes
  1. Eamonn Keogh, Li Wei, Xiaopeng Xi, Sang-Hee Lee and Michail Vlachos  ”LB_Keogh Supports Exact Indexing of Shapes under Rotation Invariance with Arbitrary Representations and Distance Measures.” VLDB 2006. (PDF) []

Image processing is one of those things people are still much better at than computers.  Take this set of cats:

Just at a glance, you can easily tell the difference between the cartoon animals and the photographs.  You can tell that the hearts in the top left probably don’t belong, and that Odie is tackling Garfield in the top right.  The human brain does this really well on small datasets.

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