Sonar for use in Low vis and confined space ????

Have a look at the Didson sonar camera.

Not sure who supplies them in the UK, but I was very impressed with it during inspection work in the gulf. Allowed us to navigate to specific points on different members in zero viz. Still had to wait for the viz to clear for the 3.4u, but at least we were bang in the right place when it did.

Hi John,

I’ve put up an image from the underwater laser-aided trenching job below; really for illustrative purposes, (but also if someone looks for similar information later on down the line.) In any case, if your visibility is akin to that observed below then perhaps this may be relevant to you after all.

The image below shows a Lumeneye underwater laser profiler mounted on what I presume is the front of a subsea jet trenching unit. I suspect the laser may be pointing downwards towards the seabed beneath the trencher.

I didn’t have a technician out on this job unfortuntely; it was just our unit being used to test whether or not there would be a sufficient detection of the seabed for the pilots during landout onto the lay-product. The imaging would have been much better than achieved below if the operator had placed the video camera in close proximity and offset laterally to the underwater laser projector. (By way of example – the Lumeneye underwater laser shown here is only 30mm diameter so it’s been mounted quite a distance abaft the laser unit). I also suspect if the ROV flood lights had been reduced or directed elsewhere the laser swath would have been easier to observe too.

We have put together a real-time image processing system that to some extent enables the existing camera to improve the detection of the laser swath amidst the scattering, but in this market no one is really paying for it. The human eye does a pretty amazing job at picking up the laser swath amidst the scattering anyway. It’s not a game-changer, just a marginal improvement. The client liked it but they didn’t want to stump up for the LIDAR version of it.

Incidentally; if you are looking at this image on a laptop, you may find that the laser line here becomes easier to see if you move your head a few feet back and move your head around a bit too). I think there’s something to do with the way the brain receives low contrast signals like this from LED monitor screen. I promise this isn’t our attempt to have a few hundred ROV project managers in Aberdeen doing the reverse of the trainee sonar calibration procedure….. OR MAYBE IT IS !!!

Best Regards,

Grant

For more information; please visit our website at http://www.savante.co.uk

savante_subsea_laser_underwater_laser_trenching_underwater_laser_profiler_180.jpg

Description: Herein an image of a Savante Lumeneye subsea laser projector profiler in use during jet trenching operations. This underwater laser profiler was mounted on the front of a jet-trenching unit and was intended to assist in imaging (detection of) the seabed.

afraid not; it’s the start of our silly season now and I’m thin on the ground as it is. give me a call if you need.