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- Minutes - ASTM E12.11.05 WG on Flashing Lights
- Third Meeting, Salt Lake City, 8:30 AM to 9:45 AM, June 27,
2002
- Run by Dennis Couzin
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- Attendance
- Dennis Couzin
- Carl Andersen
- Richard Austin
- Justin Rennilson
- James Worthey
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- Ian Tutt sent a well illustrated historical report. Andersen
contributed
- more fascinating lighthouse stories.
-
- Brief presentation on Rashbass' (1970) result for double
flashes.
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- Determination that barricade lights at 200m are about 150 x
safe threshold.
- Based on Broca-Sulzer result, can't expect threshold formulas
to apply to
- these, or any other practical flashing warning lights.
Nevertheless, WG
- will stick to threshold, as Effective Intensity concept
requires.
-
- Couzin distributed his"2, 3, many Blondel-Reys" and briefly
explained its
- results:
- extends the Blondel-Rey equation to multi-peak flashes.
- shows Blondel-Rey-Douglas equation mathematically
incoherent
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- Brief discussion of literature on flashing lights and 1970
bibliography.
- Couzin didn't think he could write a post-1970
bibliography.
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- Andersen was optimistic that FHWA can copy the Berkeley
Maxwell view
- apparatus and establish visual lab. He envisioned many
experiments beyond
- those of this WG. He requested experimental requirements from
the group.
-
- Proposed that the committee limit its formula to
- white light
- foveal view
- low photopic adaptation
- as suggested by Prof. Vienot, and also that the viewing
apparatus overfill
- the subject's pupil.
-
- Proposition floated that committee accept the convolutional
model (closely
- agreeing with Blondel-Rey for rectangle flashes) provided that
experiments
- with oddball flashes (like the Rashbass 40 ms separated double
flash) do
- not find errors greater than 2 x. This may be safer than
trying to modify
- the q(t) to accomodate oddball flashes.
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