A Helmholtz Principle Approach to Parameter Free Change Detection and Coherent Motion Using Exchangeable Random Variables

  • Authors:
  • Arjuna Flenner;Gary Hewer

  • Affiliations:
  • arjuna.flenner@navy.mil and gary.hewer@navy.mil;-

  • Venue:
  • SIAM Journal on Imaging Sciences
  • Year:
  • 2011

Quantified Score

Hi-index 0.00

Visualization

Abstract

A parameter free technique for finding changes between images is discussed. The technique uses the Helmholtz principle to find changes in an input image in situations where only one or two images are available to build a background model. The Helmholtz principle locates image regions that are unlikely to occur due to an a priori random image generation model, and it assigns a confidence level to each changed region. All previous algorithms based on the Helmholtz principle assumed that the image was generated using independent and identically distributed (IID) random variables. The IID assumption is replaced with the weaker exchangeable assumption, and a simple exchangeable random variable model based on the hypergeometric distribution is investigated. Furthermore, practical calculation methods are discussed. The calculation methods require new nonasymptotic bounds to the hypergeometric distribution, and a major contribution of this paper is the novel proof of this bound and its relationship to large deviation theory. The calculations also incorporate the fast level set transform tree structure of the image to create shape boundaries of changed regions. The algorithm is applied to the problems of change detection and coherent motion. We also illustrate that the exchangeable random variable model yields more consistent results than an equivalent IID random variable model.