Object detection through magnetic signature [field]?

[pettt]

Hi,

I am trying to figure out if a group of similar objects "A's" can be distinguished from different group of similar objects "B's" without using any means of visual analysis, be it a laser scanning or measurement of dimensions. I want to know if one could analyze or map the magnetic signature of an "A" (for instance a certain brand of casserole) – if such a thing exists – and detect another "A" casserole through comparing the magnetic signature.

Am I getting my question through?

Thanks,
Peter

 

[mikeph]

I'm not sure I know what you mean by magnetic structure, are the objects of interest magnetised? This can be detected in an MRI scanner.

 

[Crazymechanic]

the object you are trying to detect has to have some magnetic properties without them and MRI would be useless.
Magnetic detectors can't detect paper for example and tell if it's different from another paper by color.

 

[pettt]

Thanks for your answers,
I am thinking about by IndoorAtlas (http://www.indooratlas.com) – they utilise the variations in the Earth's magnetic field to navigate.

The objects all consists of a high percentage of metal. In reply to MikeyW they would have to be magnetised unless one uses a MRI scanner.

The Earth's magnetic field is ubiquitous. If I place a metal object in a spot where I know what the Earth's magnetic field looks like, I'm thinking I should be able to detect the interference made by that object, seeing as metals are affected by magnetic fields.

So theoretically, should I be able to distinguish mass produced casseroles from different brands if I place them in the exact same spot? Or is there no truth to almost identical objects having a "magnetic signature?"

 

[mikeph]

If the different objects have different permeabilities, permittivities, and/or conductivities, then it is possible to distinguish them using an excitation coil and a detector, yes. Whether it's practical to do so depends on how different the signal will be for each distinct object. It's also possible (and practical to varying degrees) to image the inside an object, if you have enough coils/detectors.

Is there any more information you can give about what the target is?