I’ve noticed lot of subsea cameras with water corrected optics use Ivanoff style correctors, which give a flat port on the outside. An ivanoff adapter will correct the distortion from the water from behind the flatport (and it’s much easier to protect a flatport than a domeport).
Optical distortion correction
Optical distortion correction is really only important for photogrammetry.
Software distortion correction isn’t ideal, as the k distortion values change with distance from the subject when not optically corrected.
The only ways to correct optical distortion seem to be with a dome port or an Ivanoff-Rebikoff style corrector.
The acrylic domes are good, but people say they add aberration, and if you want to add a decent camera and lens, you might need a 6 inch dome to get the virtual image far enough from the lens to allow good depth of focus (the dome creates a virtual image of the subject).
Glass domes offer the sharpest corrected image (over both ivanoff correctors and acrylic domes), but a dome that size on the ROV makes me nervous that it would be easily scratched (or even smashed).
I’m very keen to create a camera that would use an Ivanoff lens to correct the optics, and a box camera inside a blue robitics 4 inch enclosure. But it’s difficult to find somebody to create the lens, especially for a low budget one-off build.
If anybody knows of somewhere these can be ordered or bought from, or any kind of commercially available product, that can be used instead, I’d be keen to know about it.
Also, if anybody knows of any alternatives to optically correcting distortion caused by water, I’d be keen to know more about it.
Happy to share my experience here, to help grow the community.