How Sonar is revealing the secrets of the sea, lakes and rivers.
ฝัง
- เผยแพร่เมื่อ 30 ต.ค. 2023
- Get NordVPN’s 2 year plan + four months extra for free here: nordvpn.com/curiousdroid It's risk-free with Nord's 30-day money-back guarantee!
We live on a planet that 70% of is covered in water but if anything falls in to deep water it becomes increasingly difficult to find. However, Sonar technology originally developed to find submarines in wartime is being used to map the seabed and find things that have been lost for years if not decades. This is the story of sonar and how it is now being used to find not only submarines but also anything from WW2 planes to missing persons cold cases.
To give one off tips and donations please use the following :
www.buymeacoffee.com/curiousd...
or paypal.me/curiousdroid
/ curiousdroid
This video is sponsored by nordvpn.com/curiousdroid
Written, Researched and Presented by Paul Shillito
Images and footage: Images and footage : NASA, ESA, ESO, Annelie on Tour, SB C,Chandra X-ray Observatory, caltech, Jade Timelapse
SOLVED 21 Year Old Missing Persons Case (Erin Foster & Jeremy Bechtel)
• SOLVED 21 Year Old Mis...
And as always a big thank you also goes out to all our Patreons :-)
Eριχθόνιος JL
Adriaan von Grobbe
Alex K
Alipasha Sadri
Andrew Gaess
Andrew Smith
Bengtstromberg
Brian Kelly
Carl Soderstrom
Charles Thacker
Collin Copfer
Daniel Armer
erik ahrsjo
Florian Müller
George Bishop II
Glenn Dickinson
inunotaisho
Jesse Postier
John & Becki Johnston
John Zelinka
Jonathan Travers
Ken Schwarz
L D
László Antal
Lorne Diebel
Mark Heslop
Matti J Malkia
Patrick M Brennan
Paul Freed
Paul Shutler
Peter Engrav
Robert Sanges
Ryan Emmenegger
SHAMIR
stefan hufenbach
Steve Ehrmann
Steve J - LakeCountySpacePort
tesaft
Tim Alberstein
Tyron Muenzer
Will Lowe - วิทยาศาสตร์และเทคโนโลยี
Get NordVPN’s 2 year plan + four months extra for free here: nordvpn.com/curiousdroid It's risk-free with Nord's 30-day money-back guarantee!
i alsways thought the oceans are bodies of water that extens all the way down to the bottom of the sea, so if sth is 4 km beneath the indian ocean, wouldnt it be 4 km deep in the ground under the seafloor?
Great work Paul. I was in the Hydrographic Survey division in the Navy. As an engineer, supporting the Hydrographer's who were mapping the seabed and gathering data to produce charts, it was quite an interesting time, although we spent months at sea working 7 days a week.
I would be interested if you were able to do a similar video, based on the mapping of the sea bed using LIDAR. These were fitted to planes, along with large data collection hard drives and effectively put our method of chart making obsolete. I would think that we know a lot about our off shore sea bed, but very little further out to sea.
My last stint at surveying was to help update charts, produced by Captain Cook!
Water - penetrating LIDAR surveys (sometimes also called LADS) are fantastic for shallow and clear water regions - and a worthy topic for a video (along with other lidar applications). But LADS is limited to coastal regions of less than about 30m depth due to light attenuation, which is a function of water clarity. They also don't work in the surf zone. A fun way of using high resolution SAR from satellites is to use information from the waves and how they change through the image to 'inverse model' the sea floor bathymetry based on observed wave refraction, dispersion and accompanying measurements of the wave spectrum.
@@benwilliams8387 Loved that detail on the sea floor bathymetry. Thanks a million. Faster than running the boats, with echo sounders, along the transponder transmission lines into shore, then backing out. Taking the tide gauge readings, then marking the echo sounder paper charts for low tide, then transferring the readings on to a chart by hand! Ha ha, those were the old ways. And we also had an Elliot 905 computer with 8k core memory, yes 8,000 bits. And programmed with paper tape with holes punched in it and reel to reel tape.
@@David-yo5wsthat sounds.... time consuming 😅
Some good stories to tell, I'm sure?
I'm curious, does the navy make their scans of the seabed available to other organisations? Or is it secret information
@@benwilliams8387 So itrs not so much depth as the limiting factor because as long as use can make a housing that can withstand the pressure you can use LIDAR sensors to scan the seafloor pretty much anywhere where the water conditions are clear enough. So it is still very much limited by attenuation of the beam to roughly the altitude above the seea flor that you mentioned 30m at the absolute max but usually less than 20m but really this also applies for the potential swath with of the scan itself meaning that really your not going to get that wide coverage area per each pass maybe 30-45m wide. While the resolution is pretty much the highest you can get for any sort of larger scale mapping it becomes really impractical really quick. Multibeam sonars are become pretty advanced these days and ones geared to AUVs and ROVs for smaller surveying are more commonly sold together as a package. But really ot much can match up to multibeam sonar for both resolution and coverage.
I do wish he went into a few more of the more current or interesting methods being used for higher resolution mapping, and really with how structure from motion programs are these days and hw accurate they can be its fast becoming a more common thing to use for deep sea surveys/ science. I really also hoped he might've brushed up on Synthetic Aperture Sonar (SAS) because it really is becoming more prevalent and viable with the computing power we have available today. SAS or more commonly used interferometric SAS (InSAS) is a process similar to SAR but uses sound and can be used to get sub millimeter resolution 3d mapping that is almost on par with the scans you can get from LIDAR. It still is limited in the regards to the coverage and efficiency you can get with multibeams alone because you still need to be relatively close to the target/ seafloor and you can not move too quickly along the sea floor. It is starting to being looked at for things like science exploration or other surveys where they might be close to the seafloor with some sort of vehicle already.
Figured id mention it since you mentioned SAR and i was kinda hoping that i would see it mentioned in the video. Theres actually an Science expedition that is investigating just this technology and applying it to mapping hydrothermal vents, happening right now and they live stream their ROV dives here on youtube. Its called Schmidt ocean institute if you wanna check it out , can even live chat wit the scientists onboards.
I'd *love* to see marine archaeologists scan the sites of ancient naval battles like the Battle of Actium or Cape Ecnomus!
Ok, it's possible that most of the ships may have rotted away but you'd think there must be *something* down there, even if only a few of the metal rams they had on the bows of their ships.
I'd *love* to see a sonar scan of the seabed in the area of these battles!
That missing jetliner is also probably in a thousand pieces, too, even if you find it you might not know what it is at first.
Not likely, aluminum is ductile and will not shatter. It COULD be in 3 or 4 main pieces (two wing sections and a broken back fuselage, though, and be crushed to an unrecognizable set of blobs, not unlike big rocks, especially if it went straight in so you are very correct in your point. Four rocks look like a few billion others. The greatest breakthrough in this research is to get a tool, similar to a spectograph in capability, that could have the parameters of, say, Aluminum (7075?) or steel and search and only alert on those materials. Of course, the ultimate would be if it could differentiate the 'subtle' difference of Aluminum and Aluminium. 🙂
I've seen experiments with dolphins that support the theory that a dolphin can recreate what the returns sounded like when it "saw" something interesting previously and wants to "show" another dolphin.
It would be like us recreating a tree or a landscape by projecting a hologram of what we saw for someone.
Also, they were recording the sounds that drove Chladni plates. Not with a bow but with a transducer.
They threw a hoop, a square, a four bladed propeller shape and s star made of plastic tubing into the pool and then played the sound that jostled the sand on the plate into a square.
The dolphin swam to the square hoop and bought it back!
So the dolphin was turning the sound into shapes in its brain!
I was thinking that to recreate the returns from an object too show another dolphin it would have to recreate what it sent as well as the returns otherwise the second dolphin wouldn't be able to tell exactly how the object modified the sound, distorting the "image".
Fascinating stuff!
I think a more direct analogy than a hologram would be the way we can also emulate sounds for each other. Everyone knows how to sound like a helicoptor or a motorcycle. Though the sounds don't quite create pictures in human brains in the way you're describing for dolpins.
@@johnladuke6475 Yup, indeed.
Super interesting!Thanks
We missed you, TechnoVarys
Man, seeing that ship rollover, brought about some anxiety. I couldn't fathom still being inside that ship when it rolled and went belly up. Had to have been absolutely terrifying.
Did you see the men running along the sides against the roll? Jarring. Imagine if it were filmed with today's cameras.
There was a ship that capsized near sweden i think. The ss estonia if i remember correctly. Many died, but quite a few survived too. And somebody wrote a short story on what went on, based on eyewitness reports. Harrowing stuff.
Water isn't actually incompressible, at oceanic depths, it can be compressed 4 to 5%, which is enough of a spring for explosive decompression (speed of sound in water) instead of just freefall speed. Just an interesting factoid I learned after the whole Oceangate thing.
It's astonishing how much can be heard, even by primitive passive sonar. For anyone interested, take a listen to the sinking of Japanese submarine i-52 in 1944. it's the only recording of a sub being sunk by an acoustic homing torpedo. Despite the quality not being great, the actual detail is chilling. The sounds of inrushing water and subsequent multiple implosion events as internal tanks and piping are crushed by ever increasing sea pressure, is fascinating and horrible at the same time.
Worth a listen, even if to appreciate how much can be heard underwater.
"...JUST 4km down under the ocean." Understatement of the year.
Ty as always for the content!!
In terms of pure distance, it really is quite close. I could take a 4km walk with ease. In the same way that when the space station passes over my head, the astronauts are "just" 400km away... you know, like a long drive.
@johnladuke6475 I understood the analogy but was just highlighting the "easy going" tone of the statement given the pressures involved. Distance is easy otherwise. Ty for thoughts :)
@@sundayridetexas416 Yea the more wildpart is that the average depth of the ocean if roughly 4km and more than 66% of it is deeper than 1km.
I had a similar thought when i read about a ship that sank somewhere and they could hear someone banging from inside but it was in such deep water they couldn't get divers to it. The depth was mentioned and it wasn't mad deep, but a few hundred feet. Then i looked up the length of the ship and found that if it was stood on end, its other end would poke out of the water! My little head went pow!! 😄
In case anyone is interested, Adventures With Purpose is a TH-cam channel about a couple of guys who work with law-enforcement agencies in the US; they use side-scanning sonar to identify possible targets for missing-persons cases, and they then dive the targets to determine exactly what it is they've found.
Hey Paul! Hugely enjoying your presentations. I'm a science and engineering buff and your presentations are brain food for me. Keep going!
And BTW, I find it interesting that we don't know more about our oceans and seas. I do know that they are a large part of what drives Earth's climate and understanding how they interact, and developing technologies that help us understand potential issues is really important.
Several sonar systems are used by subs, a short scatter sonar dectects mines, sea ice, or even dead whales. Sonar systems are so sensitive you can hear shrimps clicking their claws. However there are also massive blind spots, in recent years a sub went to surface and had a massive commercial ship approaching from the rear, the sub came to periscope depth and did a visual sweep and had to do an emergency dive. She got hit and did damage to the conning tower. Amaazing tech but still fundamentally flawed in so many ways...
if sub sims have taught me anything it's that towed arrays are very useful to avoid baffles ^^
You’re talking about two totally different systems. Hydrophones are the ones where you can hear all sorts of wildlife. Sonar is different from hydrophones.
We have all sorts of varying frequencies, data processing techniques, etc… to map the sea floor. 3.5- 12khz for deep water up to 11km depths and even sub bottom profiling. 40-100khz chirps for medium depths up to 3000m. and higher for much shallower (albeit much higher resolution scans).
Higher frequencies also take up a lot of power, and the swath widths are far shallower than the wide swaths one can accomplish with a 12khz system.
But a 12khz system can only yields resolutions of around 1 pixel per maybe 100m^2 at the very best of conditions.
Still, that’s way better than satellite gravimeter data that comes in at around 1-5km^2 per pixel.
Also, each multibeam bathymetric sonar system takes up incredible hull space. You also need a highly specialized hull to install such systems with a ship that’s purpose-built for such purpose. That’s expensive. Ridiculously expensive given that such a ship costs $50k/day to operate.
Source: I’ve lived at sea for 15 years with the US Navy’s oceanographic research vessels.
Out of curiosity, have there been any studies done on the damage a 200db in water sonar system can cause to whales and other marine life?
It does indeed...
en.wikipedia.org/wiki/Marine_mammals_and_sonar
Also, depending on the proximity and sonar intensity, it can kill any animal nearby. Exploding lungs and making animals bleed inside. Not fun. Amazing tech tho.
Great Episode. One of the few TH-cam channels with accurate information, clearly presented and quality audio/video, including rare archival media. Spectacular. Topics are always interesting too!
As someone who spent 20 years being a sonar technician (surface) in the USN, I'd just like to tell you how much I enjoyed this video. Learned a couple of things also. I never knew what they were using for crystals in the early sets, that was one. Also, while the acronym ASDIC was mentioned briefly in our rate training manuals, I can't remember an explanation of what the acronym stood for. Probably because it was so far removed from the time I served (79-99). Another thing I would like to mention is that in 20 years of operating at sea, primarily in the Pacific and Indian Oceans, including every sea contained therein, I never once heard a U.S. submarine go active on sonar. Mostly never heard U.S. subs at all, just a couple of times. The only submarine I ever heard go active was a Charlie class Soviet SSGN who lit us up with his Blocks of Wood fire control. The Charlie was submerged and in company of a couple of Soviet destroyers and the Russians routinely f'd with us by lighting us up with every radar, fire control radar, and whatever else they had. All they really did was provide us with intel on their systems while we remained quiet. Definitely will be sharing this with my sonar group.
'Back in 2010'
Man, how did we even get through the day !
Wonderful work Paul always enjoy your videos.
I am involved in offshore wind and we have to have all our noisy processes including sonar and pile driving approved. We often have marine mammal observers on board with us to ensure that we don’t cause issues. We even use bubble curtains occasionally to shield them.
I find the the side scan mapping data absolutely intriguing to see.
Another great video! Super interesting to learn about the density of water compared to air and how that sows for sound to travel so much further.
What a terrific video about the uses of sonar beyond just the military, with relevant comments about the MH flight. Thank you.
This video is LITERALLY a _"Deep Dive."_ 😊
I guess Pauls feeling better! Well done Paul!
I used to dive in Portland harbour in the 90’s and the dive centre had a huge RN poster with an image of a local wreck done by side-scan sonar. 30 years ago it seemed so impressive considering how bad the vis was. Just imagine the clarity they have to now!… decades later.
IIRC the titanic wasn’t found with sonar. It was found using cameras on a sled looking for debris in the debris trail. The same way the found the Bismark. Can’t remember the name of the sled at the moment. Argos maybe?
Thank you Paul. This was very interesting! Yes, thumbs up, of course!
I appreciate your high end editing and narration, in all of your vids!
TOP NOTCH as always! I love your work!
Still a great channel. Thankyou for another interesting topic
Thanks for another great video sir, I’ve been looking forward to it! 👍
If I had the money or the influence I'd create a heavily funded project to study, map and observe the oceans and the life it contains in methods/scope/detail we've never done before. I'd call it the Bubble Project or the Bubble Oceanescope. The Hubble changed the way we imagine and study the cosmos, it'd be cool to have a landmark program for the ocean that pushes technology and captivates the public as well as researchers and engineers.
Yea for real we need like some excentic billonare to get into ocean exploration like Elon Musk but for the ocean and deep sea exploration.
Thanks 'Curious' (Paul) always interesting, always good !
super informative as always. love it.
FYI it's pronounced TA-LES. My father worked for them for many years :)
Hah, spotted this too. Stupid way to spell it.
@@JMMC1005Thales was a Greek philosopher. You're a bit late to tell him he can't spell.
@@composimmonite3918 I'm sure the way he spelled it made perfect sense in ancient Greek!
It probably does. Many spellings were changed due to the limitations of early typeset. There were certain limited use characters that early typeset couldn't do, so they replaced them with things they can. Like how "Ye" in Ye Olde whatever is spelled. Instead of a Y, it was supposed to use a þ.
I worked alongside Thales and also noticed the mispronunciation.
Wow that was fascinating, thank you for this!
Nice Paisley shirt, mate.😊
I wonder how whales and other sea creatures who use their own 'sonar' are affected by such powerful audio sources?
It really messes them up, it can even kill them
It seems reasonable to assume that sealife is indeed affected
I think it's more telling how we know so much about the world above and around us but not the remaining 70 odd percent of the world that surrounds and lies under us, Not that it's bad, but it's just rather surreal to imagine that.
People always say this, but to be honest it’s because it’s 99% nothing. The ocean is so vast and most of it is simply very uninteresting, as the vid says it’s simply a lot more useful and interesting for us to map space instead
@@jtfc7286 I definitely see this side of the coin too, but with respect to how it's 99% nothing, I wonder how much we're really missing out on considering that 1% still remains an unknown, and looks to remain that way for a long time to come unless something changes with respect to our attitude to exploration of the depths.
"We" may not know but ill tell you there are those who do, Oil/Gas companies. They just dont Share it all with "Us" .
Thats where it lies, in nasa,s imagination
I don't know where these random numbers come from but they are entirely made up percentages. Sort from ice shelves or areas that are difficult to access the entirety of the world's oceans and sees have been surveyed in great detail.
There are a lot of good reasons that the data has not been shared. Some is business related, some for ethical reasons, some for defense reasons, etc. Take these salvage companies as a for instance. If they got access to all the data, they would plunder everything. Vessels and aircraft are now the final resting place of those who lost their lives. There is an ethical reason to leave these sites alone. People need to move on with their lives. Digging up the past for money and salvage is one rung above piracy. It's just the tip of the iceberg, just because we can doesn't mean we should. It's not a giant Subsea Disneyland and we shouldn't look at it like that.
Altruism is nice but it rarely leads to anything good. So, I doubt the data will be shared in my lifetime.
I am a subsea engineer, I know what I'm talking about. I've worked for subsea survey companies, exploration companies, oil companies etc and I assure you that for the best part, we really do know what's down there. It's not just sonar surveys either, we have core samples, seismic date, core samples, ROV surveys and so on. Sharing it all, well no business or institution worth it's salt will share the data just to mollify the public interest and I don't think they should. If folks spent a bit of time thinking about it, they would probably understand and agree. Few things in life are simple and until you understand the ramifications it's best to implement change. Change isn't always good and some things, once done, can not be undone.
There really isn't a lot of mystery left in this world. Sometimes not knowing is ok. Sometimes, it's best we don't. You really need to ask why we need to know and what the knock on effect of that would be.
I don't know what everything is down there any more than I could put a name to every mountain, river, town, city etc. But that doesn't mean it isn't catalogued and hasn't been analyzed. We know than people think or at least more than is portrayed in the media or at school level. It's probably easier that way, that's just the way the world is.
Great as always, hope you're doing well.
Hello! Great video as always, so firstly, thanks! Also I was hoping you might talk about the possible effects of active sonar on sea creatures. Also also, what would LIDAR be able to bring to this field?
Another great job. But water is not incompressable because of its density. It's incompressable because of hydrogen bonding with other water molecules'relatively large oxygen atoms. And... sonobouys can be active or passive.
Great channel Droid.
another great video, thanks. what about a follow-up explaining what seismic data is and how it is acquired, and its uses? I'm thinking about seismic data to see the geology of an area., 2D and 3D (and 4D).
Mr. Curious Droid sir, can you comment on demining techniques including electromagnetic mitigation or modern techniques for detection
Great work.
Thank you very much.
Paul, I wish ALL of your videos were one hour long! Hello from the States.
Dude... You just rock!
Thank you for your videos, I always learn something new! I wanted to make a correction at [9:40] where the quoted statistic is 62dB; that should be 26dB, a simple transposition of digits. This aligns with the 1 vs 20 micropascals SPL difference. Sound power is pressure squared, and log(20^2) =~ 2.60 = 26dB.
Actually, 62dB is the correct amount. While you're correct in that the different reference levels account for 26dB of the difference, there are other considerations like density/impedance which account for the rest--roughly 62dB (actually something like 61.3dB if memory serves) is the correct delta.
I'd love to see a video on LIDAR & the other versions of it & all the unique ways we are using it. As well as UV satellite imagery to see ancient dried up rivers, etc.
Thank you Phil.
Were men on that capsizing ship in that old footage? Holy Moly!
Always so interesting!
Great video, always interesting
I can imagine the task of mapping the ocean floor taking fleets or swarms of AUV's in each ocean basin, more likely mini AUV's in the same way that we now have cubesats where once they were big machines.
great video as usual, my OCD will keep bugging me about the typo "thier ongoing support" in the beginning of the video
I'd be surprised if they ever find MH370. There's no question it completely disintegrated on impact and likely spread out into a pretty sizable debris field of very small pieces. In fact some computer simulation analysis indicates they could hover directly over that field w/a sonar buoy and not even see it if there aren't any sizable pieces left.
Engines remain relatively intact, depending on the speed of the impact. There’s still a chance, but indeed: it’s tiny.
I guess it will be found eventually. The cost of surveys will keep falling forever and it seems likely that ever more seabed imaging will be done for other purposes. One day this century, someone will stumble over it.
1:30 This part, the ocean depth, makes me think of The Core movie, and this line:
General Percell: _"If we can go into space, we certainly..."_
Josh Keyes: _"Well, space is easy. It's empty."_
Ah a video on my area! ... the images you showed are technical synthetic aperture sonar, basically side scan sonar but with successive pings combined to give a larger aperture size than would be practical to fit on a vehicle.
Nice im glad someone at least knows whats up and yea i was kinda bummed he didn't go into some of the newer stuff becoming more common and viable to use with the advances in technology and processing power that's available to the general public. Just some cursory details on synthetic aperture sonar(SAS) or even interferometric (SAS) or (InSAS) would've been super cool cause really not a lot of people know about it at all and the capabilities. Also would've been nice to touch a bit on the different international efforts into mapping the seafloor at a reasonably high resolution.
I didn't realize I clicked on a Curious Droid video. But I know that voice as distinct as David attenborough's. Immediately, I pictured Christian Von Koenigsegg in a flamboyant shirt. Good to be here, my friend.
Great video, thank you.
14:09 what is causing that "shadow" on the scanner image?
"ASDIC" - whoever came up with that acronym - well done Sir
yep, also DICASS (Directional Command Activated Sonobuoy System)
Could that ad be any longer?
Great video
3:35 NordVPN ad has ended.
Nice batik that you wear
Thanks for adding actual captions for the Deaf
Thank you.
"Back-scatter has been bringin things up from around here for some time now. I'd say the ice it's buried in is 100,000 years old.... at least"
Where did you get those underwater pictures of boats and planes ?
I love your videos.
I became obsessed with mh370 when it went missing, after months of searching I thought theyll find it within the year surely.
I can't believe it's never been found. I feel this aircraft being lost is so tragic, almost humbling in a sad way, reminding us we have a long way to go in terms of technology
Nearly every video fails to to explain how Sonar truly works. Yes, it does use sound return, but how do they get spacial information ? You get bounce from everywhere. How can you know where it came from (angle) ? You can't focus sound. Frequency modulation based on angle ? Or just a lot of microphones searching for "parallax" in bounced front ? Can you make a detailed video about it ?
Thanks !
Of course you can focus sound! How do you know who's speaking to you, or which direction a car's coming from?😅
@composimmonite3918
You can limit angle, but can you do perfect 1degree sound separation with no crosstalk ? My problem is that you can create lots of same length reflections, and this needs to be processed correctly
@@Kilohercas you're not going to understand sonar by watching TH-cam videos and reading TH-cam comments.
@composimmonite3918 Don't worry, I already have a good idea how it works,
I do like the American pronunciation of "buoy" - BOO-ee is just a nicer expression than being pronounced "boy"
Amazing informative concise information especially regarding the level of sounds and distances or range. I understand the the focus of the channel is all tech, but may I ask if any information reg the sound volume used by the various scanning devices with particular attention to the military or Navy use of these technologies because the volume used by military is off the chart, so to speak, compared to the civilian side, which is also troublesome to the fauna of the oceans, particular attention to marine mammals who communicate ie can make and hear sounds, the drone of ocean going cargo vessels make mammal communication next to impossible and the scanning sonars esp those used by the mining industry are possiblity responsible for marine mammals deaths esp large beaching events. Whales esp are so diminished in numbers, isolated from species by sound walls from shippings lanes that monitored in Japan of illegal whale hunting discovered inter species breeding, eg humpback whale mating with fin whale, that's how desperate it's getting, this inter species breeding is not well documented, if at all.
Those sonar pics of the sunken ship and the plane have great detail. My question is, if soft surfaces are light and denser surfaces are darker and the combined side-scan gives us a "3D" image, why do those pics have dark shadows? With vertical and side-scan there should be no shadows.
That was a misleading statement. It is in fact the opposite.
Intensity is a function of material properties and angle. These images should be seen more like shining a weak flashlight on a surface in darkness. If surface normal (axis perpendicular to it) bisects angle between the loght source and observer, then return would be higher - lighter color. If the material scatters a lot, then it would be lighter. Darks mean little to no return - surfaces facing away or not that reflective.
Secondly, the sonar image in these sidescans is like a perpendicular scanline (w/r to motion) collage, plotting intensity (pixel color) against time (distance from center. If there is an obstruction, then there is no return at later times - black color. Later on there is a place on seafloor that is illuminated and there are returns - lighter color. The shadows are really shadows, just acoustic.
Look up side scan sonar on youtube.
Amazing
I knew you were into synths before I knew you were into synths - it's something about the shirts
06:57 Thales is pronounced more like Tal-iss. A French company that bought Racal out (via Thomson) decades ago.
Racal Vodafone is still going, it was seen as too much of a target for a takeover bid for the group and was spun off, you nay recognise the name, but without the prefix.
You did not mention synthetic aperture sonar. Like in synthetic aperture radar used in satellites to get much better images.
1:50 at the top "their" is spelt incorrectly
...for *their* ongoing support 👀
It seems in regards to searches for missing people data should be saved for reprocessing with better software as it becomes available
I love your videos! Keep going! Don’t stop!!! Proud of you!
Bass fisherman have been using side scan and multiband sonar for a long time.
And what is the impact on sealife of all this sonar?
Not too good...
en.wikipedia.org/wiki/Marine_mammals_and_sonar
@@chromaticAberration Exactly, that was glossed over in the video.
A pressure factor of 20 is 26dB not 62dB.
6:55 "Thales" is pronounced "Tallis" or "Thay-lees", named after an ancient Greek philosopher.
Was there a Lockheed Electra found?
Man somethinf happened because I used to watch all the time and then TH-cam started hiding all these! Hopefully we can get the algorithm kicking again
1 ping only
1 Ping Sir ?
03:35 saved you the ad read.
Ive found 2 cars in my local area already. Police told me to keep it up as they don’t have the technology to do it lol
Is it possible to create a sattelite that can send and recieve sonar singnals/images from orbit?
As he explained, the problem is the intervening atmosphere, attenuating the sound. A more appropriate method would be to have a robotic ship (or Sub) doing a raster scan, unattended, with enough speed to match the scan resolution, and build a map over time. BUT as mentioned, it's always the operational and maintenance cost, less the hardware investment and it is always losing money until it finds 'the needle'. The only other major issue would be the time factor. The seabed is fluid with underwater currents redistributing silt and debris over time, so as with picturing the earth, a month later, all could be changed, OR hidden/exposed.
@@paulholmes672 hmm what about a somewhat cheap air drop sonar wich is made to desolve after a few months but sends a signal to a sattelite(think a simple ping not a map but to find anomalies to scan later)
Just for the information, Thales from Thalesgroup is pronounced more like Taless
Content starts at 3:36
Why are you not on nebula yet
How does this affect sea life
Another very interesting mini-documentry.
Keep up the good work 👍
Hopefully the British government will stop giving away our cutting edge technology to the Americans. Like they did with our supersonic plane technology and many others.
imagine all the bodies in Lake Mead.
The ones that haven't already turned up from drought, anyway.
I love your channel but I cannot stand sensortube any longer. Do you use any other platforms where I might watch your videos? Thanks, Dustin Blanchard