Current Methods of Measuring Visibility

[alewar]

Hello,

I've been watching some of the videos of the Project Baseline and it caught my attention the way they're measuring uw visibility.
Instead of a traditional Secchi or black disks, they use a laminated sheet of paper with some parallel lines on them that you have to illuminate with a light, like this one:

how does this method compare to the traditional ones?

 

[lowviz]

Can't answer your question, but the problem (as I see it) is that nobody accurately corrects for ambient light level. The human eye's response is massively non-linear. Shining a light onto the bars will give you visibility normalized to your light at your given distance. Too many variables...

What I would like to see is the light manufacturers adding a photodiode, transconductance amplifier, and an inexpensive digital display to their high-end lights. Then you can turn the light off, measure the ambient light and reduce the variables to how well the diver can see at a given ambient illumination. So the final step would be to image the target with a "standard imaging device" at a standard distance for the given level of illumination. Could be done...

 

[Steve_C]

There is buddy viz which is the distance at which I can just make out my buddy.

There is sight seeing viz which is the distance at which I can see something fairly clearly

There is camera viz which is the distance I will shoot a flash picture at.

Buddy > sight seeing > > > camera.

Note that buddy viz can depend on colors worn by buddy. Yellow or bright orange add a bit to buddy viz.

 

[DiveNav]

....What I would like to see is ....... a photodiode, transconductance amplifier, and an inexpensive digital display ..... Could be done...

Interesting...... interested...

 

[lowviz]

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