Does the epipolar gate still help when mismatches have the mix and rate a real SIFT matcher produces?

research/sensing-gatemix

With the mismatch rates and mixes measured from SIFT on a real stereo pair, a ratio test of 0.8 to 0.6 (10% to 5% wrong) leaves gate + Cauchy adjustment at 0.008 to 0.003 object radii against 0.013 to 0.004 for the RANSAC start, and the all-random-pixel assumption overstated plain Cauchy's error 1.3 to 59 times; with no ratio test (56% wrong) every method fails

4 tests

What it found

sensing-epigate assumed random-pixel mismatches; sensing-matchreal measured what SIFT actually produces. Here the measured mismatch rate and the measured along-epipolar / near / far mix, per ratio-test threshold, drive the epigate bundle-adjustment trial (synthetic 12-view rig, 300 features, wrong poses, 8 seeds). At a ratio test of 0.8, 0.7 and 0.6 (10%, 6%, 5% wrong) gate + Cauchy adjustment gives 0.0082, 0.0032, 0.0027 object radii (clean floor 0.0014) against 0.0132, 0.0049, 0.0036 for the RANSAC pair start without a gate; at 0.9 (23% wrong) they tie (0.095 vs 0.087); with no ratio test (56% wrong) every method exceeds 0.6. The gate removes about 83–86% of the measured mix against 95–97% of uniform mismatches, because the along-epipolar share passes pairwise tests, yet the adjustment is harmless to those. Treating all mismatches as random pixels overstated the error of plain Cauchy adjustment from the all-view start by 1.3 to 59 times. Limits: the geometry is synthetic and only the rate and mix are measured, from one stereo pair and one detector; rate is applied per observation; two isolated cells (mutual check, ratio 0.9 and 0.6) show one-seed spikes in 8 seeds.

A figure from its own output

Figure produced by research/sensing-gatemix: error_vs_rate — sensing-gatemix/experiments/error_vs_rate.svg, written by the project's own experiment code.

Paper, code and results

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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.