Subsea Lights and Lasers: An Overview Guide
Why Subsea Lights and Lasers are Essential for Your Research
Accessories such as subsea lights and lasers are great considerations when looking to enhance your marine research. Each has its own capabilities to complement your current setup and object detection to help elevate your results. Plus, they are easily attached to subsea cameras for marine observation.
The requirements you’ll want to look for when adding additional subsea equipment to your system for ocean imaging will depend on the desired outcome of your mission. In this quick overview, we’ll walk through the benefits of subsea lasers and lights and how they can make your life easier.
What are Underwater Lights?
Ambient light decreases the deeper you go underwater so in order to capture quality subsea videos and images, you’ll need the proper lighting. Without it, you won’t get the results you’re looking for in your marine research or survey, which turns into a waste of time and money.
Why Are Lasers Used For Ocean Imaging?
Subsea lasers are an important tool to have in your arsenal as they can be used in applications such as ROV surveys, 3D modelling, pipeline inspection, and marine research.
Lasers provide a visual reference to objects underwater by determining the scale of an object, taking general measurements, or estimating the distance to a subject.
Common applications where subsea lasers come in handy are when assessing the size of holes or cracks in equipment and structures during offshore energy inspections or when measuring study targets in marine research.
What Features Should I Look For In A Subsea LED?
LED lights are the best for subsea imaging because they are high output, high performance, long-lasting, and rugged so they make a great option for both short- and long-term projects.
Strobing
If you’ll be taking digital stills, you’ll want to select a subsea LED with strobe (or flash) capability which will give you the ability to freeze subjects to remove motion blur by increasing the shutter speed. Some marine species and environments are sensitive to lamps and floodlights, but a strobe has less of an effect on creatures because of its extremely short duration causing minimal disruption or impact. This type of safeguarding measure in marine protected areas is recommended.
Floodlights tend to spread light everywhere whereas directional lights like the SubC Aquorea LED produces less backscatter and can be more intentionally positioned to illuminate the scene when and where you need it. This high-efficiency, TTL synchronized subsea LED can simultaneously operate as a lamp and strobe and easily integrates with subsea ROVs, observatory, drop, tow, and battery-deployed camera systems.
Colour LEDs
Light is absorbed quickly underwater making colours fade away with colours having the longest wavelengths and lowest energy disappearing first:
Red: 5 meters
Orange and yellow: 10-20 meters
Green: 30 meters
Blue: 60 meters
While the human eye will adjust for the loss of underwater colour, those colours may be missing in your photos resulting in dull images. Using a coloured subsea light can help compensate for any colour deficiency.
SubC offers far-red and deep-blue options in our LEDs. Many sea creatures are unable to see in the red spectrum so a red LED is ideal for capturing images of some creatures in their natural state. For bio-fluorescence and leak detection, deep-blue is what you’re looking for.
What About Subsea Lasers?
The first thing to consider when looking at subsea lasers is knowing the outcome you’re looking for because different lasers operate at different wavelengths and produce different light.
Lasers used in ocean imaging commonly have a wavelength of 520nm ± 10nm, which means they show to the eye as green. Green ensures good visibility even at long distances because green light absorbs less in water. Red lasers are also fairly common underwater but red wavelengths get absorbed quicker than green or blue.
There are various types of lasers to choose from depending on your application:
Parallel Dot Laser
A parallel dot laser, like SubC’s MantaRay laser, is one that is most commonly used in subsea imaging and can be incredibly precise. This type of laser, which is usually the lowest cost form factor of laser, is used to give distance and scale by projecting two beams that appear as green dots in images. When attached to a camera, the dots are parallel with the frame of reference and the spacing between the dots gives the distance range and scale information.
Parallel dot lasers work best when the scene is perpendicular to the camera sensor, such as a vertical view of the seafloor. Sizing is determined with the parallel dots using simple methods in photo editors and can be made more accurate with calibrated cameras and specific software.
Line Laser
Another commonly used laser is a line laser, like SubC’s Skate Mk2 line laser option. These types of lasers are used in more precision applications for generating data from images. Often this data is used for creating a 3D model or point cloud. Line lasers are also often used for metrology in pipeline inspections, marine species measurements, or habitat mapping.
Grid Laser
Grid lasers are less commonly used in subsea imaging but are still very useful. Grid lasers, available as an option with SubC’s Skate Mk2 laser, project hundreds of points onto a scene. This allows for multiple redundant data points for more complex geometry as the points spread out at a predictable angle from the laser. Having multiple evenly spaced points on a target gives many data points to help build geometry.
Aside from the type of laser that would work best for your project, you’ll also need to take into account how deep the laser can go, its ruggedness, and how long it’s expected to last.
Conclusion
SubC’s LEDs and lasers are widely used in diverse subsea applications by marine researchers, ROV operators, and others across the globe. For more information on using lights and lasers for ocean imaging check out these additional resources:
