Skip to content
Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

ratio test

Rejecting a descriptor match unless its best candidate is meaningfully closer than its second-best.

Lowe's ratio test rejects an ambiguous descriptor match by comparing the distance to its best-matching descriptor against the distance to its second-best: if the ratio of best to second-best distance exceeds a threshold (commonly 0.7-0.8), the two candidates are too close together to trust, and the match is discarded before it ever reaches a geometric fit.

Examples

  • A descriptor whose best match is 0.9\times as close as its second-best match gets discarded -- the two candidates are too ambiguous to trust.

See also

descriptor matching
Read the full section →
Graph settings

Calculator