Evaluating Certainties in Image Intensity Differentiation for Optical Flow

  • Authors:
  • Affiliations:
  • Venue:
  • CRV '04 Proceedings of the 1st Canadian Conference on Computer and Robot Vision
  • Year:
  • 2004

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Abstract

We use 3 脳 3 脳 3 Sobel operators to compute both spatio-temporal derivatives s_x, s_y and s_t and their certainties (scalar number) in a number of image sequences and then use Lucas and Kanade's weighted least squares framework to compute optical flow (image velocity) in 5 脳 5 image neighbourhoods, where the weights are the derivative certainties. We model the certainties in the derivatives as proposed by Spies [Vision Interface 2003] and analyze them quantitatively by evaluating the flow computed using them. For a number of synthetic image sequences with the correct answer known, we perform a quantitative analysis using either weights of 1.0 or weights computed from the derivative certainties (2 ways) and show that using a good estimation of the derivative quality in an optical flow calculation leads to better quality optical flow (both more dense and more accurate).