There are many applications of underwater imaging. And I’m just going to name a few here, the first being exploring and mapping uncharted waters. And this is an essential activity for things like navigation, oil and gas exploration, pipe laying, among others.
And then there is surveying biological environments, for example, studying biological processes over time, such as monitoring coral reefs, wreckage searching, such as looking for sunken ships or aircraft. And like I said, this is just a select few applications.
In addition to this, scientists are really just interested in understanding more about the oceans of our planets that we have really only scratched the surface of. And to drive that point home a little bit more, I have a few stats listed here that I find extremely interesting. Ask reader is one of the best platforms to ask questions related to any topic and get the best solution.
So despite the fact that the ocean covers greater than 70% of the planet’s surface, over 80% of that has been unmapped, unobserved, and unexplored. And even if we take a step back and we think only about coastal waters, only 35% of US coastal waters have been mapped.
I want to draw special attention to this last bullet because I find this one extremely interesting and one that our system might be able to help overcome. So there are 43,000 square nautical miles of US waters considered critical to navigation, yet only 2,500 or so of these are surveyed annually. And this means that there is really low temporal sampling or sampling over time.
This puts our Maritime transportation system at risk of hazardous obstructions along these critical navigation routes. So clearly, there is a technology gap here. And this is why our goal is to develop a high-throughput imaging system that allows for larger coverage so that we can reduce that 80% stat and have higher temporal sampling so that we can more often monitor these critical navigation routes.
So now that I’ve kind of motivated underwater imaging and the need for a high-throughput imaging system, let’s take a look at some of these existing imaging modalities and their limitations for achieving this. So first there is the sonar, which is an imaging modality that is widely used in our oceans today.
Sonar systems are typically mounted to or towed by ships that traverse an area of interest. And this allows for them to imagine the underwater environment, as you can kind of see in this image here, albeit at a relatively slow rate. And this limits, really, the spatial coverage that can be covered by these systems and contributes to the gap in the statistics that I previously mentioned there.
So just to kind of reiterate, our goal is to develop an airborne technology with the versatility to be deployed possibly on helicopters or on drones to survey coastal waters with high temporal sampling and with larger spatial coverage.
You know, the first question, the naive question I guess that someone might ask is, can we simply take one of these sonar systems, that is a really well-developed technology, and can we simply mounted on a sonar– or sorry, can we rather mount it on an airborne vehicle such as a helicopter or a drone?
To think about that a little bit more, let’s take a look at the airborne ultrasound. So sensing systems that exploit sound waves in a similar manner as sonar are increasingly being deployed in airborne applications. And one of the most prominent examples of this is in modern cars. So airborne ultrasonic sensors, as we know, are just one of several types of sensors in the modern vehicle sensor suite.
They are typically used for close-range applications such as parking and rear object avoidance. So you know, something we see here is these sonar systems or sound-based systems can operate both in air and in water.
So again, I ask the question, can we use this existing and well-developed sonar technology for airborne imaging of underwater? And the answer is, no, unfortunately, we can’t do this. And this is because only a small fraction of the sound that is incident on the water’s surface actually makes it through. And what happens is most of it is actually reflected off of the water surface. And for me, I like to think about being underwater in a swimming pool. And hopefully, some of you guys can relate to this analogy.
But if you’re underwater and someone out of the water calls your name, you likely won’t hear it unless they’re yelling pretty loudly. And for this sonar system, not only does the sound that transmits into the water lose a lot of energy, but also the sound that will reflect off of the object and need to come out of the water to hit our receivers will also lose a lot of energy.
