This might help you describe how different frequencies of an acoustic wave produces different imaging, especially resolution and distinguishing between objects in close proximity. The key component is actually the horizontal beam width (for a tow fish system) that a transducer produces. Higher frequencies use different, more directional, transducers which produce more narrow beam widths. Think of the horizontal beam width as a knife, cutting into an object. The more narrow, the more cuts or slices of the object, the more you're going to see of that object. This is also how objects that are near each other can be separated and displayed. The down side to higher frequencies is reduced scan range. All frequencies from the time they're generated through a medium (like water), will dissipate power over time. The higher the frequency, the more rapid the power loss...hence less range. Sonar systems are regulated in the amount of power they can generate. I think Mark Atherton may have described this a bit in his book, Echos And Images.
Absolutely, But you are getting way to technical for this "Basics" video. Mark does a good job in his book. It's sad that its no longer available. It was one of the best resources for side scan users. Mark's a good friend of mine and I have been trying to convince him to revamp the book and put it back on the market. I get into the depths of the technical side in my more advanced classes, but those agencies have to pay for. (Insert Plug Here) So if anyone reading is interested in more advanced classes please contact me. Im the Training Director for Marine Sonic Technology and you can find my contact on MarineSonic.com
Wow, love that image of the pickup truck at 9:56 in your video. BTW, that's a Ford Ranger..part of a homicide investigation in Cincinnati. It was taken using a technique that we developed using Marine Sonic HDS 900Khz. My name is Ken Purcell. There still might be a few at Marine Sonic that remember me. When I say we developed it... we did. In fact, this is a vertical scan. Now, Marine Sonic did have a method and a clamp system to allow rotation of the tow fish, but the way they describe to do it was not correct. After sending images of bridge piers and a car, using our way...John DeMille and others asked me to write up an article on this. It was published in Ocean News and Technology, August 2012 edition. In fact, it was the feature story on page 10. Now today, many cheaper systems can do the same, but most have the transducers mounted to the vessel. But, with a tow fish, you control the depth and the scan range which is big advantage. By getting the tow fish closer to the object, you can reduce the scan range, which increase the size and (believe or not) the resolution of the image. The one car image we did, you can see the door handles, window rolled down...almost the lug nuts on the wheels. Not kidding.
How to get a better quality in this sonar?
This might help you describe how different frequencies of an acoustic wave produces different imaging, especially resolution and distinguishing between objects in close proximity. The key component is actually the horizontal beam width (for a tow fish system) that a transducer produces. Higher frequencies use different, more directional, transducers which produce more narrow beam widths. Think of the horizontal beam width as a knife, cutting into an object. The more narrow, the more cuts or slices of the object, the more you're going to see of that object. This is also how objects that are near each other can be separated and displayed. The down side to higher frequencies is reduced scan range. All frequencies from the time they're generated through a medium (like water), will dissipate power over time. The higher the frequency, the more rapid the power loss...hence less range. Sonar systems are regulated in the amount of power they can generate. I think Mark Atherton may have described this a bit in his book, Echos And Images.
Absolutely, But you are getting way to technical for this "Basics" video. Mark does a good job in his book. It's sad that its no longer available. It was one of the best resources for side scan users. Mark's a good friend of mine and I have been trying to convince him to revamp the book and put it back on the market.
I get into the depths of the technical side in my more advanced classes, but those agencies have to pay for. (Insert Plug Here) So if anyone reading is interested in more advanced classes please contact me. Im the Training Director for Marine Sonic Technology and you can find my contact on MarineSonic.com
Wow, love that image of the pickup truck at 9:56 in your video. BTW, that's a Ford Ranger..part of a homicide investigation in Cincinnati. It was taken using a technique that we developed using Marine Sonic HDS 900Khz. My name is Ken Purcell. There still might be a few at Marine Sonic that remember me. When I say we developed it... we did. In fact, this is a vertical scan. Now, Marine Sonic did have a method and a clamp system to allow rotation of the tow fish, but the way they describe to do it was not correct. After sending images of bridge piers and a car, using our way...John DeMille and others asked me to write up an article on this. It was published in Ocean News and Technology, August 2012 edition. In fact, it was the feature story on page 10. Now today, many cheaper systems can do the same, but most have the transducers mounted to the vessel. But, with a tow fish, you control the depth and the scan range which is big advantage.
By getting the tow fish closer to the object, you can reduce the scan range, which increase the size and (believe or not) the resolution of the image. The one car image we did, you can see the door handles, window rolled down...almost the lug nuts on the wheels. Not kidding.
Yes, I was there when John got the image. It's definitly a great image and good article. Range is Step 3 and will be out soon.