X-Ray Image Analysis

LeeG

Just received the March PENNY-WISE a couple day's ago. There is a super article written by Mark Hoffmeyer titled "Evaluation And Attribution Of Coins Encapsulated In Certified Grading Service Holders Using X-Ray Image Analysis. For a snapshot, Mark states:

In general, radiography (X-ray analysis & imaging) methods reveal density variations present in both organic and inorganic materials. In many applications, radiography is commonly used to identify the presence and location of objects that are embedded, or hidden from optical view within a composite body of materials. Overall, a coin slab is a composite materials set that provides a close match to this general X-ray imaging scenario, where the high density metal coin and its rims are readily revealed and distinguished from the light weight, low density plastics comprising the certified grading service holder.

In addition, because density variations also exist from presence or absence of metal at specific areas along coin rims where edge devices are present, virtually any edge device type, whether created by Castaing machine, striking, casting, or post achining method can be detected and identified using X-ray image analysis.

In summary, X-ray imaging analysis is a viable method to non-destructively evaluate, identify, and verify coin rim characteristics, and attribute edge device details on coins encapsulated in certified grading service holders. When set up properly, the described analysis method can be applied to any encapsulated coin and can be provided using generally inexpensive, compact, non-state of the art, X-ray imaging equipment typically used for quality control inspection of small electronic components.

This is eight pages of information, including images, that was very well done.

Nic

Just look at mgoodm3's icon using an ultra high relief saint. . K

19Lyds

Off the bat I wonder how many times a coin can be x-Rayed before it becomes something you'd rather not hold in your hand but becomes something you would rather view from a distance?

Any comments on that in the book?

adamlaneus

X-Rays do not render a coin radioactive. Not one bit.

The reason you want to limit your exposure is that it will 'cook' you ever so slightly by damaging molecular bonds. X-Rays knock electrons around.

Shoot enough X-Rays at plastic and it might embrittle. You also want to keep plastic out of UV light too.

In something like metal...a sea of electrons...X-Rays just cause them to slosh around. No lasting changes detectable.

Now, I did see once a picture of a 'neutron activated mercury dime' on this site. That one probably is radioactive. Neutrons will go into the nucleus, and potentially change it into something that is unstable, releasing that energy later.

messydesk

X-ray your Kennedies enough and he'll start looking like Ike.

Coxe

I played around with objects in an xray diffraction apparatus back in grad school and always thought the unique signatures for particular coin specimens could be made using something along those lines, perhaps with a couple separate tuned wavelengths. As for authentication, the compression might be revealed to show a coin was minted and not cast. However, that is overkill as cast counterfeits are discriminated easily enough by simple optical analysis....that is, just by looking at them.

mgoodm3

I like x-rays.

23Pairer

Used one of my machines at the office to make this; guess what series?

Lakesammman

Were the illustrations convincing?? I'm having a hard time visualizing how you could detect edge details. I've used it to tell thick vs thin planchets on patterns, etc, but details??

BECOKA

Seems kind of expensive, would it not be cheaper to crack the coin out, look at the rims and then have it re-slabbed?

Type2

<< <i>Used one of my machines at the office to make this; guess what series?

>>

A 1983-DDR

messydesk

<< <i>Were the illustrations convincing?? I'm having a hard time visualizing how you could detect edge details. I've used it to tell thick vs thin planchets on patterns, etc, but details?? >>


The device used will matter. While you might be able to see edge details with dental x-rays, you're not going to with a detector in the average cardiac cath lab.

mgoodm3

I would doubt that using medical x-ray devices will do you much good. They are not designed for looking at metal.

LindeDad

X-Rays machines have been used for non destructive inspections of aircraft parts and other metals for over twenty years. I know they were using them before I retired from the Air Force and that hits the twenty plus time frame.

LeeG

The images are black and white and a little grainy. Looking at the images, then descriptions, I can make out what is being discussed. As LindeDad stated about NDI in the Airforce, the Navy has done this for many years on Aircraft Engines and other electronic applications. Different set up from the Medical Application.

19Lyds

<< <i>X-Rays do not render a coin radioactive. Not one bit.

The reason you want to limit your exposure is that it will 'cook' you ever so slightly by damaging molecular bonds. X-Rays knock electrons around.

Shoot enough X-Rays at plastic and it might embrittle. You also want to keep plastic out of UV light too.

In something like metal...a sea of electrons...X-Rays just cause them to slosh around. No lasting changes detectable.

Now, I did see once a picture of a 'neutron activated mercury dime' on this site. That one probably is radioactive. Neutrons will go into the nucleus, and potentially change it into something that is unstable, releasing that energy later. >>



Thanks!