Harris Corner Detector MCQ 15 Questions
Time: ~25 mins Intermediate · Popular

Harris Corner Detector MCQ

Second-moment matrix M, eigenvalue interpretation, response R = det(M) − k·trace²(M), and why edges score low.

Easy: 5 Q Medium: 6 Q Hard: 4 Q
M matrix

2×2 tensor

λ₁, λ₂

Curvatures

Response R

det − k·tr²

Edges

One λ large

Harris corner detector

Harris analyzes local image derivatives summed in a window: both eigenvalues large → corner; one large → edge; both small → flat region.

Response trick

The Harris response avoids explicit eigen decomposition using determinant and trace of M.

Interpretation

det & trace

det(M)=λ1λ2, trace(M)=λ1+λ2—combined into R with empirical k ≈ 0.04–0.06.

Shi-Tomasi

Uses min(λ1,λ2) as corner score—often more stable for tracking.

Window size

Larger windows smooth noise but reduce localization; Gaussian weighting is common.

Not scale-invariant

Classic Harris is not intrinsically scale invariant—multi-scale or blob detectors address that.

Eigenvalue diagram

Corner: both λ high · Edge: one λ high · Flat: both λ low

Pro tip: Non-maximum suppression cleans duplicate responses around the same corner.