Here’s a little question I was wondering about, but let’s give a little context first.
I’m currently setting up an experiment involving the PING-2 echosounder. The idea is to obtain “raw data pictures” from it and then carry out data processing to get rid of the major effects of the transmitter/receiver (specifically, the famous red band on the first few centimetres of the full echo). This manipulation involves numerous implementations and substractions of Green’s Function. The idea is that this processed image should enable me to perform an inversion manipulation and recover the physical characteristics of objects previously placed in the bottom of a large water container (24m³). These objects are 3D-printed manta and rockan watermines, which I first lay out on the sand and then gradually embed.
The problem now is that I’m using a mechanical arm (which moves on the x, y and z axes) inside the tank. Before setting up this experiment, I need to know if there’s a way of increasing the cable length (between my pc and the 2D ping) by several meters without compromising signal quality. Is this possible and how would you go about it? I’d like a simple opinion. I’ve got a lot of male-to-female small wires, but I can’t see myself connecting them all together to give me more headroom.
Hi @Lulu -
Sounds like a neat idea! However the 25 degree beam width of the sonar is unlikely to make your application feasible… You may need something like an Omniscan FS or Sonoptix Echo if you’d like to resolve imagery with sound!
The Ping2 sonar also doesn’t output as raw a data as you may wish, you can find details in the documentation.
I’m not sure if you’re referring to the “red band” as the top of the sonar picture (ringing from the transducer) or the region past the surface that gives the return?
As noted in the technical details on the Ping2 product page, you can extend the cable, perhaps with our wetlink splice kit, up to 8m.
As I understand it, the profile_data command retrieves an array of return force measurements at different distances, plus a confidence index. Can this take the form of a csv. table with this data? If so, that’s what I’m looking for, simple return force measurement values that I correct afterwards. I also welcome your reference to other devices, but the challenge of my dissertation is to use sonar at lower frequencies than normal. So I’m not expecting to make any major discoveries, but simply to deduce a few parameters such as an approximation of the object’s impedance (like for example: ok, this is a layer of fine sand and there’s something sitting on it, a fish, a stone, a mine, a piece of plastic or anything, just a tiny distinction).
I had come across this comment made on Ping1D on the forum: “That said, if I remember correctly, the “material types” I had in mind when I originally made that comment were probably ones with obvious differences (for example, vegetation usually has a rather fuzzy response compared to metal, stone or concrete, so it may be possible to estimate things like the thickness of vegetation on a concrete wall from quite standard echo sounder profiles).”
So I’m just trying to detect small differences in responses, not something big, but in a controlled environment, I can maybe push that aspect.
Ps : I was in fact talking about the ringing from the transducer (it has been done with GPR data previously, pretty similar process).
Hi @Lulu -
You may be able to determine how hard the bottom is based on the return. You could transfer the data to a csv format, but you’re likely best off staying in python. This example may help . You could modify this example to receive the full profile.
It’s worth noting that the Ping2 has a fixed frequency, it would require a hardware change to use the system at lower frequencies…
