CSE445Computer Vision
ModulesLocal FeaturesCorners & Structure Tensor

Corners and the Structure Tensor

From a windowed SSD to the second-moment matrix, its eigenvalues, and the Harris and Shi-Tomasi responses.

Key Terms

Windowed SSDTaylor ExpansionStructure TensorEigenvaluesHarris ResponseShi-Tomasi

Python Tools

OpenCVNumPyMatplotlib

Textbook Reference

Szeliski Ch.7

Topics Covered

  1. 1Windowed sum-of-squared-differences under a small image shift
  2. 2First-order Taylor expansion of the shifted patch
  3. 3The second-moment matrix M and its accumulation over a window
  4. 4Eigenvalue analysis: flat, edge, and corner regimes
  5. 5Harris response, Shi-Tomasi minimum-eigenvalue criterion, thresholding, and non-maximum suppression

Learning Outcomes

  • Derive the structure tensor from a Taylor expansion of the windowed SSD
  • Classify local image structure from the eigenvalues of M
  • Compare the Harris and Shi-Tomasi corner criteria and their parameters

Lecture Infographics

2 image files

Lecture PDFs

Corners and the Structure Tensor

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