64 source pixels was too strict: it threw away 70% of everything the detector
finds, and plenty of what it took were faces a person could name.
Lowering it is not a one-line change, because the two floors are coupled. A face
under 112 pixels is *upsampled* to reach the embedder and upsampling invents no
edges, so a small face scores low on sharpness however crisp the original was.
Re-measured over the reference library with `face_index --quality`:
min crop min sharp size cut blur cut kept
32 0.000 44% 0% 56%
32 0.002 44% 3% 53%
32 0.005 44% 8% 48%
32 0.010 44% 16% 40%
32 0.020 44% 27% 30%
64 0.020 70% 7% 23%
Holding the blur floor at 0.020 while dropping the size floor to 32 would have
rejected a further 27% — for being small rather than for being blurred — and
kept only 30%, barely more than the 23% the strict pair kept. Most of the point
of lowering the size floor would have gone straight back out through the other
gate.
0.005 removes 8% of what the size floor leaves, which is the same job 0.020 was
doing at 64 (7%): the large-but-soft face this gate exists for. Together they
now keep 48% of what the detector finds, against 23% before.
The box pre-filter follows down to 24, staying below what the real floor accepts
so it cannot reject a face that would have cleared 32.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
dtourolleandClaude Opus 5
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