W for the shift [u, v]: E(u, v) = (x,y)∈W [I(x + u, y + v) − I(x, y)]2 • First-order Taylor approximation I(x + u, y + v) ≈ I(x, y) + Ix (x, y)u + Iy (x, y)v • Let’s plug this into E(u, v) E(u, v) ≈ (x,y)∈W [I(x, y) + Ix (x, y)u + Iy (x, y)v − I(x, y)]2 ≈ (x,y)∈W I2 x u2 + 2Ix Iy uv + I2 y v2 NHSM - 4th year: Computer vision - Keypoints (Week 3-4) - M. Hachama (
[email protected]) 9/20