When does automatic blurring miss a bystander's face, and which filming platform is conspicuous?

research/capture-bystander

When does automatic blurring miss a bystander's face? On an assumed size-recall model a face detector leaves 5% of identifiable faces unblurred per frame, blurring the head of any detected body under 0.1%, and independent per-frame misses show a face in some frame of a 5 s shot 100% of the time; an offline whole-track blur leaves 0 to 5%. No real footage or detector.

11 tests

What it found

An assumed size-to-recall model of blurring strangers' faces while filming in public. A face detector that is 50% reliable at 20 px leaves a face-on face of at least 32 px unblurred 5% of the time per frame (8% at 5 m on an 8K 360 camera); blurring the head region of any detected body instead drops it under 0.1%, because a body is 11× taller than a face. A telephoto frame resolves about 10 identifiable people at once against 2.5 for an 8K 360 view. Per-frame blur is worse than it looks: with independent misses a person filmed for 5 s at the edge of range shows unblurred in some frame 100% of the time, 25% if misses last the whole shot, and an offline edit that blurs a whole track after one detection is left with 0–5%. Size alone does not separate the tall platforms. All detector curves, sizes and angles are assumptions; no real detector or footage; blurring is not legal compliance.

A figure from its own output

Figure produced by research/capture-bystander: leak — capture-bystander/experiments/leak.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.