Identifying multiple targets simultaneously... Responses no longer allowed. If you have comments concerning multiple targets, please make a new post

[earthmansurfer]

In all fairness, it only benefits everyone to ask questions, even by those who quote don't get it. Many people who "don't get it" are actually quite intelligent as you can see by the content of their posts and I disagree with name calling on the premise that it just subdivides us. To go against the grain is much harder than to go with it. Our society is a reflection of that, and in large part why we are in the mess we are. The more we ostracize people for not "understanding things" or rather seeing them as we do, the less open we are, the less we question overall, the less flexible we are, etc. If done with respect, there is nothing at all wrong with questioning and for the most part I saw much respect for Digger (and I try to show it as well). Had I posted earlier I would have felt a lot of what Critter brought up, as I think I understand VLF technology enough to question terms like "simultaneous". But, after Diggers tests were brought out, a bit more came to lite, quite a bit more. That said...

Minelab is notoriously very secretive with it's patents, probably because a lot of what they do isn't covered by patent. So, we often question things, like "How many frequencies really are being processed on the receiving end?" ;-)

To those of us familiar with VLF technology, to recover finds and use words like simultaneous doesn't make a lot of sense. Generally speaking the coil must be in motion during discriminate and the subtraction of a "target" or "ground", etc from those two fields, gives us an idea of what is there sequentially but not at the same time (traditionally speaking though!). The coils must be in motion according to VLF technology (unless in AM mode). I think that is where the problem lies. FBS has been described as Time Domain technology, which is a phrase usually reserved for PI machines. Even with the FBS machines out now, not being known at all for their recovery speed, they do well in moderate iron+. I always wondered how could this be. My old Omega and V3i were clearly much faster recovery speed wise, but when I tested coins in the ground in iron, the E-Trac with a similar sized coil came out on top. I do think that there is something about FBS (and now moreso with FBS2) that is not exactly VLF technology and think it has to do with a pulsing of sorts, hence the Time Domain terminology. Even VLF is measured in kHz, so there is a pulse so to speak going on. I would love to hear more discussion on that.

Thx,
Albert

 

[targets]

of course people never read the manual ,thats why you lure them in with youtube videos and then they read the manual after getting their interest up....

 

[bfodnes]

This thread really shows what can be the result a few weeks from now.

Sorry the language but you will understand the point. It will possibly blow your socks off.

http://www.youtube.com/watch?v=e5SJpvP6rFw

 

[Bell-Two]

Thanks for your efforts AND incredible patience Randy.-----We are all very fortunate to have you as moderator of this Forum.

I totally agree your efforts have always been beyond expectations, and I KNOW you have helped me immensely. Keep it up and we will continue to follow your lead in learning.

 

[Bell-Two]

In all fairness, it only benefits everyone to ask questions, even by those who quote don't get it. Many people who "don't get it" are actually quite intelligent as you can see by the content of their posts and I disagree with name calling on the premise that it just subdivides us. Thx,
Albert

Thank you so much Albert, I am not very technically savvy when it comes to the electronics of detectors and I try to follow the best I can and if I pick up one glimmer of knowledge from a post I consider it worthy of reading.

I like to read the manual and see it working so I can have better understanding of how it operates. Obviously most of us do not have any hands on experience yet and so the best we can do is read look at the pictures posted...AND THINK ABOUT IT. Then formulate questions. Trying to describe something in just words that is really a visual and audio experience is quite daunting so we must be content with what is explained to us. An example that comes to mind for me is "How would you explain the chromatic smear sound of the clarinets in Gershwins Rhapsody In Blue?" Pretty tough to do I would imagine.

 

[TerraDigger]

Let me give my input. First there is no need for posters to be sarcastic. This is about detectors and their functions. Digger posts some results with CTX. Great!!! That's what we are here to see. I replicate to best of my ability same tests on my machine. I give results. Ask Digger more questions. Digger is gracious enough to do more testing. I do more testing. Results get posted by Digger and myself. Neither myself or Digger are being rude to each other or slamming each others machine. It's simply TESTING. CTX looks very good in this nail over quarter test. That's good. No need to get disrespectful. I would love to have a CTX...but I am also impressed with my machine. Its all about learning. Maybe we should try to keep it on that subject.

 

[CDDZ]

http://www.minelab.com/usa/treasure-talk/ctx-3030-discrimination-advantages

New video up on minelab, has a good bit to do with the thread topic

 

[Digger]

Thanks. I was just going to post it and make it a sticky! HH Randy

 

[Gonehunting]

That is unreal!!!! Should help with some of the Questions for sure!

 

[niterider_58]

THIS IS WHAT I'VE BEEN WAITING FOR AWESOME

 

[GKMan]

Well, it would surely be hard to not to be impressed by the video. The Minelab engineer in the video seemed to make a point of stating the CTX's ability to identify two targets at once. What happens when a third is introduced within close enough proximity to mix things up a bit? Digger?
Thank You.

 

[earthmansurfer]

Nice video and it explains a lot.
Did they just rename fast on with the coin near ferrous setting? Edit - I take this back. Seems like it is an FBS2 function.

 

[Critterhunter]

I really hesitate to ask further questions as I've already made mine clear, but these latest tests raised some further and most importantly different questions I just can't resist in asking. If you feel this is too much, then please shoot me a PM and I'll quickly re frame from the topic...As I certainly don't want to make any kind of trouble for myself.

OK, I *slowly* read the latest posts in this thread and (I'm sorry but) I'm one of those who just "isn't seeing it". For instance, a nail laid directly over a coin can easily be overcome with a DD coil by sweeping with the DD detection line (which runs from tip to tail of the coil) in parallel motion to the nail. In effect, the detection line is off to the side but parallel to the nail and thus you "see" the coin. As you wiggle the coil you then see the nail, and then the coin again, and thus...over and over. *Assuming this is true* (not stating, but supposing), the only difference I can see is that on a conventional detector the ID will alternate from coin to nail and back again as you wiggle, instead of placing one prior and one current target ID on the screen. The detection field still has to see the coin alone, and then the nail alone, and so on as you wiggle.

So I still have to ask (sorry!) if this new feature is simply a previous target history and not really any ability to "see" and track two targets at once? I guess to some that may sound like a play on semantics, but never the less there is a very big distinction between such abilities. From what I understand about coil dynamics the field can only interact with the first thing it sees, and does not have the ability to also see something else deeper in the field unless it has a clear view of it. Meaning no other metal in the field that it first hits, as the magnetic field stops and interacts with the first object is hits...With no further ability to reach any deeper.

This can be witnessed by moving the coil so that the DD detection line is at a 90 degree angle to the nail. In that kind of situation it is MUCH harder to get any kind of ID on the coin. If you move the coil over the nail/coin now and wiggle then the detection field is hitting the nail first, and chances are you'll only get an iron signal, or at best a severely degraded "some kind" of signal. If you do get some kind of severely degraded signal above iron, that's only because the eddy currents due have a somewhat (but very limited) ability to bend and "warp" around the bottom of the target they are first hitting...And thus the detector can in effect "see" something there other than iron. Actually, what happens is the field is being soaked in the properties of both objects to some extent and so if it can produce any kind of above iron response it will more than likely be averaged somewhere on the scale between coin and iron.

With the coin test with both coins laying in horizontal relation to each other and the DD detection line at a 90 degree orientation to that respect, once again it's rather easy for a good machine using a quality DD coil to see the two targets at separate items. Yes, you don't have them both being listed on the screen at once, but as we all know metal detecting requires moving the coil, and thus either coin can easily be isolated and inspected by an experienced hunter.

The picture of both coins being in parallel to the DD detection line...It appears by the picture that one coin is slightly off to the side of the other? If that's the case, once again any good small (such as you are using there) DD coil will have little problem with seeing both coins separately. What I'm anxious to hear is if you can in fact put both coins in perfect alignment with each other and perfect alignment with the DD detection line, with both coins *under the coil at the same time* and still be able to see two distinct targets on the screen. With what I've always heard about coil field dynamics, both targets should be being washed in the field at the same time and thus become "one" target. This test has to be done carefully, because it is possible to raise the coil to a point where it's detection field narrows and thus it's only seeing the coin under the very center of the coil, and not the one at the top or bottom of the coil...And so it may appear that it can in fact pick out one coin and then the other as you move the coil slightly forward or back and then the next coin is seen and not the first.

I really hesitated to jump into this again as I pretty much made my concerns know extensively before. However, this is one of the key things I want to clear up before I decide if I shall buy this machine. Everything I know about coil detection fields tells me that there are rigid laws of physics that just can't be changed. I'll have to see some pretty hard core amazing proof to believe those apparently static laws of nature can be "bent" in some way. At this point in time I still feel that what we are seeing here is just a history of the previous target and the present one on the screen. *If that's the case then* (Saying *IF* here and not FOR SURE), while that could be a nice feature to some, it really doesn't give you any better ability to separate targets under the coil...That proper coil use to investigate targets with any conventional machine and noting the VDI response(s) will also do.

Once again Digger I thank you for your extreme patience and just hope I haven't pushed things to far in order to dig a little deeper into this. I'm just looking for definite answers to things I need to know before making the buying decision, but I fully understand that it's probably becoming a royal pain in the backside to some people. I just can't help but ask these questions in the search for information.

If I have been too redundant in my questions then PLEASE shoot me a PM to let it be and I'll quickly refrain from any further questions in this respect, as I have no wish to cause trouble for myself here.

 

[BarnacleBill]

Well the first thing you are wrong about and keep asserting is that if two objects are in a magnetic field one of them absorbs all of the energy present. The ground itself is a target and absorbs some of the energy depending on makeup, but there is left over energy to detect metallic objects. Just because you ground balance out the receiver portion of the signal does not mean the ground suddenly becomes transparent to the transmitted signal. The second disproof of that concept is a coin spill, with a combination of high and low conductors averages the ID.

HH
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[Critterhunter]

I'm not arguing the point of a coin spill potentially producing a combined averaged target ID, which means the targets are close proximity to each other and at the same depth for all intended purposes so they can even have any chance to both be washed in the field at the same time. That's in a sense exactly what I am saying in fact, and asking if those combined targets, *being both seen at once now* and not isolated, can be separated into two distinct and true target IDs via some form of enhanced processing by the detector? All I've ever heard is that the signal is seen as "one" target when that happens due to the nature of the limits of what a detection field's received signal can tell the machine. The field has a rather limited "vocabulary" in terms of just what it can tell the detector about target interaction.

You helped me stumble onto and boil it down to one key question here...I want to know if Minelab has found a way to in fact be able to get more out of what that signal has to say. Enough to be able to see two distinct targets in the one "word" the coil is telling it. That's it in a nutshell. But even if it can, those targets still have to be at the same depth and very close to each other to have any chance to both being washed in the field at the same time. And with a sharp field a machine can still wiggle over and isolate those as two separate targets with proper coil managment,

Ground matrix interactions with the field are very different than what happens to the field when it encounters the first metal object it sees. What I've read (and tested) is that even a piece of metal as small as a staple will in effect block the field from seeing a deeper target if it hits the staple first. The eddy currents for the most part warp and bend around the first thing they see with no *major* ability to reach much further (if at all) than that.

 

[Gonehunting]

Wow are you guys still talking about this.. Here is some advice.. wait till the machine is out.... borrow, buy, steal, what have you, then test it for yourself.. that is the only way to prove in anyone's own mind that it does what the Tester's are saying.. no offense to anyone, just tired of seeing (in all forums) members continuing to argue a point with a tester, when we all know the tester is a very experienced detectorist. If what they got to say doesn't agree or you find their tests to not be valid, then take it upon your self to prove it.. sorry, just a couple of weeks of this is getting old...in about a month the forums will be flooded with first hand accounts from other members... GH

 

[Digger]

Target Trace, in relation to the Smartsreen, is based on signal strength, the metallic content and size and shape of the target. Therefore, there is no way a coin of one size will pass under the center of the coil at exactly the same as of a larger or smaller coin. The larger coin will either "get there first" or "leave there last". So in reality, the difference between "history" and "real time" could be as little as a nano second. With that said, the only way to duplicate a process in response to your ongoing inquiry would be to place two identical coins at the exact same depth, and perfectly aligned so they would both pass under the center bar of the coil at the exact moment in time. And if I did that, what would the Target Trace show us? One image. Not two. And the reason that you'll only see one Target Trace image is because, as I said, Target Trace images are based on both target's signal strength and metallic composition. Two identical coins with identical ferrous and non-ferrous compositions will be "represented" at the exact same position on the Smartscreen. And, since those two coins have identical signal strengths, the two Target Trace images will be indistinguishable. HH Randy

 

[ExpIInut]

The "bullseye" represents the target you isolated under the coil. If you worked the coil properly, it is probably directly under the center at this point in time. The TID number appearing at the top of the smartscreen represents the ferrous and conductive values of that "bullseye" target. The object at the bottom of the Smartscreen represents another target you passed over, but not currently under the center of the coil. The "Target Trace" tells you that you've passed over one target while getting to the other one. If you want to know the TID number for the other target, move the coil to isolate it, and center the coil over it.

Think of the Smartscreen as a sheet of graph paper that has 35 horizontal columns and 50 vertical columns. The horizontal columns represent ferrous properties and the vertical columns represent conductive properties. The Ferrous columns are numbered 1 - 35, from top to bottom. And the conductive columns are numbered 1 -50, left to right. The grid lines on the screen are in increments of 10.

In the first picture, the isolated target with the bullseye has a TID of 10/36. The ferrous of 10 makes sense because it is right on the first line down from the top. The 36 conductive also makes sense because it is about halfway between the third and fourth vertical line. Since the coil is isolated on that target, it provides a TID of 10/36. The other target is not under the center of the coil, but you just passed it because it left a Target trail. And judging by the grid location, it has a ferrous value of 11 and a conductive value of 12. If you swept back to that target, the TID would change to represet the 11/12 when you centered over it. And you would now have a target trail left to represent the first target. In the second picture, the target directly under the "hot spot" of the coil is providing both a grid location and the TID number of 12/36. If you're in the US, it is likely a penny. The other target that you passed over is likely iron, as the grid location indicates a highly ferrous target. If you moved your coil to center on what appears to be iron, you should get a TID of approx 31/42. And the previous target would be represented by the trace left on the grid only because it is not the one you are centered over. HH Randy

The "bullseye" represents the target you isolated under the coil.

If you worked the coil properly, it is probably directly under the center at this point in time.

The TID number appearing at the top of the smartscreen represents the ferrous and conductive values of that "bullseye" target.

The object at the bottom of the Smartscreen represents another target you passed over, but not currently under the center of the coil.

The "Target Trace" tells you that you've passed over one target while getting to the other one.

If you want to know the TID number for the other target, move the coil to isolate it, and center the coil over it.

Right - I've read - re-read - then read again the above statement/post. I've even broken it down into a line by line passage to make it easier. Surely everything that the "Target Trace" shows you has been "HEARD" in your headphones in the form of an accepted or rejected target?

Which leads me to the question I want to ask before I even consider buying one of these machines - has there been a "substantial" improvement in the recovery speed between targets?

If this question has already been answered elsewhere my apologies but there's that much hype it's unbelievable

 

[Digger]

Recovery speed is not an issue when you can see all the targets at once. It now becomes a matter of target separation, which is a learned skill implementing a combination of audio and visual recognition, not a functionality of the detector. I suppose if you relied strictly on the audio response, you'll not likely hear a substantial improvement on the recovery speed between targets. But with having more than one tool in the toolbox, why not use those that give the best results? HH Randy

 

[BarnacleBill]

So Randy,

Would a fair statement be that with this new viewing capability there is a paradigm shift away from speed to under the coil target mapping? Speed was a good thing to discover close targets but only because the under coil target mapping didn't exist yet. Like the leap from carrying a compass to carrying handheld GPS. The cost went up but the capability exploded what was possible.

HH
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