Author Topic: Sidescanning in ice (Read 24733 times)

Kimi · « **on:** January 03, 2012, 03:02:03 PM »

Her is my first try to sidescan in water whit ice on. Its taken in an marina and the surface was covered whit a very thin ice that was broken up in small Pieces. Interesting!

Kimi..

Vik3 · « **Reply #1 on:** January 04, 2012, 05:30:27 AM »

This is what I have seen in ice hole:

Vik3 · « **Reply #2 on:** February 20, 2012, 04:57:56 AM »

Some more imagies

sonar2000 · « **Reply #3 on:** February 20, 2012, 10:36:44 AM »

Nice pictures.
Kind of makes you want snapshots or recordings......
Interesting pictures and good scan.
chuck

Double Digit · « **Reply #4 on:** February 20, 2012, 11:10:27 AM »

Yea I agree....That 570 di looks like it takes some nice images for a cheaper unit...

Roddy · « **Reply #5 on:** February 22, 2012, 01:48:06 AM »

Kimi, Nice pix,good work :-) Roddy

Vik3 · « **Reply #6 on:** April 12, 2012, 04:52:04 AM »

Quote from: Double Digit on February 20, 2012, 11:10:27 AM

Yea I agree....That 570 di looks like it takes some nice images for a cheaper unit...

One more screen shot:

vik33 · « **Reply #7 on:** January 11, 2013, 11:53:32 PM »

Humminbird 385 ci DI with two DI transducers: "UFO" - depth is 30ft, 300 ft away of bank, diameter of the object is 20ft. All screenshots were taken in one ice hole"

Rickard · « **Reply #8 on:** January 12, 2013, 05:17:00 AM »

Hi,

That's interesting, the 385 DI can be tweaked so Humviewer accepts and interprets the recorded channels as the 385 would have two SI channels. It would be interesting to see how you have arranged the DI transducers and how you have wired the channels to get this excellent result!?

I myself, and a few other ice-scanning nerds, have experimented with these techniques for some time. You can find a long discussion on this here: http://www.xumba.scholleco.com/viewtopic.php?t=851

We have used dedicated SI units (and an old Matrix 37 in some cases), which made it easier to arrive at viewable results, but I think you have achieved something new with this equipment.

Kind regards,
Rickard

vik33 · « **Reply #9 on:** January 12, 2013, 06:33:25 AM »

Hi!

I made several drives for my DI transducers: first it was mechanical drive and I coud operate it from ice only, then I made electrical drive - using additional 30 feet cable I coud go down under ice for 45 feet and look at underwater things and fish from very short distance. Now I made very simple mechanical drive - one short movement of my hand and it can scan the bottom for bouth sides deep under ice. I just connected one DI cristal of the 570 DI transducer to 2D window of 385 DI sonar, and used its own DI cristall for DI window - they have the same 455 kHz and 4000W.
I hope Humminbird will be interested in my the last version of mechanical drive and will manufcture simple reliable drives

Rickard · « **Reply #10 on:** January 12, 2013, 07:58:54 AM »

That's clever, and brave!! I'm particularly interested in your electrical device with 45 feet with cable. How fast does the transducer head rotate? I use to walk slowly at 1 or 2 RPM around the ice-hole, very slow, that is, to get the best images. But even if I try to walk at a constant speed there use to be problems with varying rotation speed at the transducer end. A hanging electrical device might be easier to control? If one can reach the sea floor there is of course the possibility to use a stationary tripod. As I understand you know, there is also the problem with twisting the cable. I suppose you have to reverse the direction after a few revolutions?

Have you tried to convert the recordings with Son2XTF.exe? If that's possible it will be possible to make "radar" images with very high quality by saving images with SiView, edit with any image editor and convert with e.g. ImageMagick

Rickard

vik33 · « **Reply #11 on:** January 12, 2013, 08:47:48 AM »

There is no any problems with twisting of cable because transducer head does not rotate around the vertical cable: the cable and peace of tube stay still- transducer rotate around horizontal axis ( not vertical) via worm reducer ( taken from old gitar). It is doing only half of revolution from -90 till +90 degree back and forth (like pendulum or swing). This is why I can go under ice as deep as I want without any twisting. The potation speed is 6-9 degree per second or 1-1.5 RPM.
Looks like it is useless to use Son2XTF.exe for such movement. But what is good with this movement it gives DI (profile) and SI pictures at the same time, and sometimes this is much more informative, than just rotating transducer around the cable and getting just SI imagies.

Viktor

Rickard · « **Reply #12 on:** January 12, 2013, 10:31:42 AM »

Ok, now I understand. Your Humviewer image made me a bit confused from the beginning, but now it makes sense! This is truly a new scanning method, at least in this forum! The same thing could be done with a SI transducer, as far as I can understand. I'm sure it's possible to convert these images to something with correct proportions. However, this can't be done out on the ice - too much manual computer work is needed. I think the converted image would look like a half-circle shaped SI image.... but that's only what my spatial intuition tells me. I really like your system, it creates some new challenges!

Rickard

vik33 · « **Reply #13 on:** January 12, 2013, 10:46:06 AM »

Thank you! Yes, I am going to use one SI transducer instead of two DI ones as well. Just one cable is easier to bend than two, and it would be good to use flexible winter cable. I think it is quite possible to straite the picture with computor program ( I am just a piping mechanical engineer). The curve is described by eqviation y=1/cosec. x. I even going to draw this curve on the sonar screen to see the bottom profile on its background

. In summer it will allow to use it in static regardless the waves and get good imagies.
Try it, good luck!
Viktor.

Rickard · « **Reply #14 on:** January 12, 2013, 12:15:53 PM »

Ok, I saved your image from Humviewer, cut out a segment and transformed it. I think I got it right. Since the resolution (it wasn't possible to reach the original image via the link) is low the result could be better. The sea floor is barely visible along the upper edge of the converted image. The object still looks circular, though. I'm sure it's possible to get much better results, this was a quick-and-dirty conversion.

Rickard

vik33 · « **Reply #15 on:** January 12, 2013, 11:09:47 PM »

This is not bad for the first approch

But I think the program for circular scaning can hardly be used for that kind of scaning. Last year I thinked out the name for it - "Globe Scaning". What is good in this scaning that in the central sector up to 90 degree (+/-45) it keeps almost real width of objects without computer treatment and it doesn"t matter how far they are from transducer 10, 20 or 50 feet. You can see on your treated picture that the object in front of the "plate" two times wider than the plate, but actually it is half less. No doubt, that computer treatment can be very helpfull in this case aswell

As a mechanic I will be doing mecanical improvement of that unit

I have already gotten quite even rotation.

Viktor.

Rickard · « **Reply #16 on:** January 13, 2013, 04:02:46 AM »

I agree, only the depth profile and the circular outer shape of the area covered gets (almost) correct with the standard transformation. Structures within the image gets distorted. The image also lacks slant range correction. This is a funny problem that probably has a quite simple solution that still can be tricky to implement with the conversion system I use, ImageMagick.

(Today I will test a new transducer arrangement using the "old" rotation method

. I have combined a high resolution Lowrance LSS-2 structurescan transducer with an old Humminbird Quadrabeam transducer. It will be the first test on ice with the LSS-2. Added: this test was successful and is presented in the topic "Interfacing a HB with the Lowrance LSS-2".)

Rickard

sonar2000 · « **Reply #17 on:** January 13, 2013, 08:55:10 AM »

We certainly look forward to the test and pictures. Great work. Good to have folks like you all on the forum.

chuck

Rickard · « **Reply #18 on:** January 17, 2013, 08:41:35 AM »

Viktor,

What do you think about this procedure? I have transformed your image in several steps to arrive at something I believe is correct...

1. First image is cut from your Humviewer image, "CutViktorSmall.jpg".

2. The second image is a simple change of width. The width is now 2*height. "BredViktorSmall.jpg".

3. In the third image the horizontal scale is transformed from beam angle (-90 to +90 degrees) to a metric scale. "NyBredSmall.jpg".

4. The fourth image shows the final result which is a slant range corrected view of the seabed covered by the rotated beam. "SlantViktorSmall.jpg".

The final image doesn't look very nice. This can be explained by low quality of the original image and sloppy cutting, the repeated transformations of jpg-images and the fact that good slant range correction requires precise rotation, precise cutting and is based on the assumption that the bottom is absolutely flat.

vik33 · « **Reply #19 on:** January 19, 2013, 01:38:21 AM »

Rickard,

the last picture shows what exactly DI beam covers. Central part is more or less correct, but sides are extrimly strached. I do not think that something can be done with them. It is better to fix rectangular view of central part (not sector or semy-circle view) say two depths wide and four depths long - it would be quite real view.

To me to take several Globe Views, keep them on SD card and then view one by one are quite sufficient to undestand what is going on under ice:

Rickard · « **Reply #20 on:** January 19, 2013, 03:00:04 AM »

Viktor,

I think I have arrived at the same conclusion. The great advantage with your scanning method is, like you wrote before, the fairly correct imaging of the bottom within about +-45 degrees from a vertical plane WITHOUT any transformations. This means the system can give prompt information to the fisherman while on ice that is easier to interpret than a sidescan view is. No need for complicated conversions back home.

I hope you will report on further progress with the system!

Rickard

vik33 · « **Reply #21 on:** January 19, 2013, 03:46:53 AM »

Rickard,

I certainly will when I come home after my rotation ( in four weeks)

Viktor

Vik3 · « **Reply #22 on:** March 15, 2013, 10:01:16 PM »

I taught my mini sonar (2”) to read

. I just made it’s beam narrow (Down Imaging) using a slot diaphragm, and pulled vertical word “YXA” under the transducer several times, and the word steadily appeared on the screen

The stripe across the screen is a diaphragm reflection.

Rickard · « **Reply #23 on:** March 16, 2013, 04:27:23 AM »

Hi,

This is really a step forward in sonar technology

! I look forward to a sonar with translation

.

Most fishfinder sonars don't work well in air, is this device designed for use in air?

Rickard

Vik3 · « **Reply #24 on:** March 16, 2013, 07:07:57 AM »

This sonar is mainly used for winter fishing. It is less than half a pound of weight. It’s transducer is very sensitive, like Vexilar’s, and can work in air up to 6 feet just for checking. Translation of that short Russian word is “Fish Soup”

Viktor

Rickard · « **Reply #25 on:** March 16, 2013, 11:17:31 AM »

"Fish soup" or "ear", isn't that correct? Both translations fit this subject well

.

Have you made any further progress with your "vertical rotating DI system"? I'm not sure everyone understands how clever and useful this idea is. I believe this could be developed into a handy standard device.

Rickard

Vik3 · « **Reply #26 on:** April 24, 2013, 08:00:59 AM »

I installed SI transducer on my Humminbird 385 ci DI and sailed over the concrete blocks that I found in ice hole last winter (in blue frame). One can see that winter shapshots looks pretty real. I think I will check other objects that are in green frames using this method soon. And I also are going to check other objects from short distance that I found using Side Imaging on 385 DI.

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Author Topic: Sidescanning in ice (Read 24733 times)

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