The second first pass was skipped where the measured centre sat within three times the fit's own
sigma of the file's - a quarter of the non-SLS corpus, eight of thirty-two runs. That is a decision
taken at a threshold before the evidence is in, and the evidence here costs a median 0.55 s: the
spots are already found and cached, and their positions do not depend on the centre, so a second
first pass is a median 20 % of what the first one costs.
Worse, the gate removed exactly the case worth asking about. A centre error ALONG the spindle does
not fail - it holds 96-100 % of frames indexed and quietly returns an axis harmonic - and the scale
it turns on is a fraction of a pixel: measured on real data, 0.12 px of centre is the whole
difference between the deposited cell and a halved axis. No sigma small enough to gate on would
notice that, so the gate could only ever hide the question, never answer it.
The three-sigma test stays where it belongs, in the report: it says whether the difference is a
measurement or noise, which is what a reader wants to know. It no longer decides whether to look.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3yNBXk4wKdMZy1ak2NY7f
leonarski_fandClaude Opus 5
bf41b1fab1