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Light Cable too short

Need to have my four lights extend out from the ROV frame at least two to three meters. Want to have my two cameras somewhat near the lights. Setting up for underwater photogrammetry test run …Suggestions welcomed …Thanks

A bit unclear what you’re describing here. Are you wanting one 2-3m cable to extend out and control 4 close together daisy-chained lights, or are your lights going out 2-3m each side? If it’s the former I’m assuming you’re trying to do something like stick a pole with some cameras and lights in a hole and map out stuff the ROV can’t see? And if it’s the latter you’re presumably trying to do photogrammetry on a huge scale (in which case you’ll need super clear water)?

I do not have firm configuration of the arraignment of lights and camera must do some test first, just wanted to find out if possible to increase the wire length. i.e. size of wire, type of wire and best method of sealing connections etc.

There are many technical issue with photogrammetry and clear water is one of them. A woman at MIT is working on how to remove unwanted noise/sediment from photos. Anyways, there are plenty of good examples of photogrammetry underwater…it is a new growing area of photography making 3D meshes of reefs, shipwrecks etc.

Bluerobotics sell the cable for lumen lights by the meter, which is likely helpful for you. You can also have a look at their guides for potting cables in penetrators for the connection into the main electronics hub.

Indeed, there are many challenges. My point about the clear water was more that if your cameras are far apart from each other you’ll need to be far back from the target to get enough common points to make a disparity-map (which photogrammetry is based on). Since visibility in water reduces quite significantly with distance, you’d need very clear water (and also very strong lights) in order to actually detect the target with your cameras from far back. I imagine stiffness of the support structure could also be problematic with cameras that are over a meter apart, due to vibrations that vary the distance between the cameras.

That’s definitely true, and I’m not trying to dissuade you from underwater photogrammetry, just identifying particular issues you may face depending on how you choose to go about the process and what your particular requirements are.