John, is this for work in an inshore tunnel or offshore?
If I keep my laser hat on one thing I can think of at the moment is actually just taking a few line lasers and project a swath infront of you. It might give slightly better illumination characteristics than flood lit illumination by keeping scattered light source in a thin plane but you may find it's just clutching at straws if the water clarity is just too bad. We did this during some trenching operations in Turkey and it was only a marginal improvement. Obviously not what you want if the situation is more dynamic or you're floating around valves.
Now putting my offshore hat on - I would go for a 3D imaging sonar and mess with the gain ....
If I keep my laser hat on one thing I can think of at the moment is actually just taking a few line lasers and project a swath infront of you. It might give slightly better illumination characteristics than flood lit illumination by keeping scattered light source in a thin plane but you may find it's just clutching at straws if the water clarity is just too bad. We did this during some trenching operations in Turkey and it was only a marginal improvement. Obviously not what you want if the situation is more dynamic or you're floating around valves.
Now putting my offshore hat on - I would go for a 3D imaging sonar and mess with the gain ....