In article <
slrnr1un6p.68e.zebeej@gmail.com>,
Zebee Johnstone <
zebeej@gmail.com> wrote:
In uk.rec.cycling.moderated on 15 Jan 2020 11:37:05 +0000 (GMT)
Ian Jackson <ijackson@chiark.greenend.org.uk> wrote:
Here is a program to calculate passing distances. You give it a photo
and mark the vanishing point and some references, and it tells you how
close to your camera the car is.
https://wiki.fricklers.org/abstand.html
It's a JavaScript program to run in your browser. It's FLOSS. Source
is here:
https://github.com/hollma/abstandrechner
Not having a suitable photo to play with... any idea what the numbers
mean? And what the ref points are?
You adjust the yellow spots so that:
Blue and white lines mark the edges of a thing of known with.
"Referenzbreite". You can use a road marking. The TS&GD in
legislation.gov.uk has the nominal sizes for lots of road markings.
Red line corresponds to the line on the ground beneath the widest part
of the passing car.
Distant yellow spot is the vanishing point.
The dotted yellow line is free for your own use when eg finding the
vanishing point. In the example they've set it to the other edge of
the road. The solid yellow line just runs along the ground from
underneath the camera (image centre) to the vanishing point.
The horizontal blue lines are not of much consequence.
The output ("Abstant zwischen...") is the distance (horizontally)
between the camera and the car.
Any handlebar cam freeze frame should do, although you may need to
straighten it if it's not level.
--
Ian Jackson <
ijackson@chiark.greenend.org.uk> These opinions are my own.
If I emailed you from an address @fyvzl.net or @evade.org.uk, that is
a private address which bypasses my fierce spamfilter.
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