CSE445Computer Vision

Homography and Image Alignment

Estimating a planar projective map with DLT and SVD, stabilized by Hartley normalization.

Key Terms

HomographyDLTSVDHartley NormalizationWarpingDegeneracy

Python Tools

OpenCVNumPyMatplotlib

Textbook Reference

Szeliski Ch.8Hartley & Zisserman Ch.4

Topics Covered

  1. 1Planar correspondences and the homography as a projective map
  2. 2DLT construction and homogeneous least squares via SVD
  3. 3Hartley normalization and its effect on conditioning
  4. 4Forward and inverse warping, resampling, and interpolation
  5. 5Degenerate configurations: collinear points and near-planar scenes

Learning Outcomes

  • Derive and solve the DLT system for a homography using SVD
  • Apply Hartley normalization and explain why it improves accuracy
  • Warp and align images with an estimated homography and detect degeneracy

Lecture Infographics

9 image files

Step-by-step walkthrough · Stage 1 of 7

How a homography is estimated and used

Follow one concrete example from four point pairs to a warped image. Every number shown is computed live from the same data. Use ← → keys or the buttons.

SOURCE IMAGEDESTINATION IMAGEposter
step 1 / 26

Two views of one flat surface · Source view

Camera 1 sees a flat poster head-on. Every pixel (x, y)(x,\,y) lies on the poster plane.

Lecture PDFs

Homography and Image Alignment

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