The Blind Spot Inside Self-Diagnosis
■ A sensor cannot detect the dirt on its own lens
Hakobukun starts missing people and objects, yet its self-check reports every function normal. The report is not a lie. Dust on the lens clouds the image without ever appearing in it, so the fault shows up in behaviour and never in the diagnostic output.
■ The person who noticed was looking in from outside
Terashima crouches down and looks at what the robot looks through. One wipe, and recognition accuracy returns. The work took seconds; the harder shift was doubting the machine's own report and checking the premise behind its performance.
■ Conclusion: Self-checks work only when paired with outside eyes
Hakobukun cannot detect its own impaired vision and says so. Oshiro answers that the team will wipe the lens on a schedule. Nothing was blamed; an unreachable area was simply divided. A self-check is trustworthy only when its blind range is already someone's routine.
The dust on your eye is always someone else's find.
