OT:ideas for oblique view tide-gauge ?

[N_Cook]

So not directly over tidal water , viewing horizontally the rise and
fall of tidal water over mud flats.
There is a change in light level , excluding fog, between veiwing the
mud and veiwing the water. Night time there is a lot of street-light
spill over , if moonless.
Perhaps a web-cam , with masked off view of a vertical slot with range
of angle from about -2 degrees to the horizontal , to about -50 deg,
with no boats, reed-beds or anything else in the view, just mud or
water. I assume it would be possible to digitally determine the
"terminator" as it moves up and down and initially generate a look-up
table comparing to a proper tide-gauge nearby, for the heights
corresponding to the image.
Any other ideas?

 

[Andy Burns]

N_Cook wrote:

> Any other ideas?

Rotate a polarising filter in front of the camera, look for differences
in the light reflected by water and mud?

 

[N_Cook]

On 01/09/2017 09:40, Andy Burns wrote:

N_Cook wrote:

Any other ideas?

Rotate a polarising filter in front of the camera, look for differences
in the light reflected by water and mud?

Thats an interesting idea, but would that be sunlight only and rather
variable angle during the day?
I'm thinking of that early Viking navigation instrument of 2 slabs of
felspar on a viewing tube, to know the time, by rotating one wrt the other.