MPD expert invents bogus-coin detector

FROM:
http://www.yomiuri.co.jp/dy/national...26TDY03004.htm

MPD expert invents bogus-coin detector

The Yomiuri Shimbun

The Metropolitan Police Department's research institute
has developed a new method that enables investigators
to identify forged coins in just seconds, instead of
the several minutes needed for conventional forgery
detection methods, it has been learned.

The new method has been developed by Mototsugu Suzuki,
33, a senior researcher at the MPD's Criminal
Investigation Laboratory. He earned a doctorate in
applied physics from Osaka University in 2004, and is
now serving as the institute's senior researcher.

The methodology Suzuki has come up with to detect
bogus coins is fairly simple: A coin slides down a
small chute and collides with a brass plate. A
computer analyzes the sound of the collision and
compares it with the sound made by a genuine coin
to determine authenticity.

To ascertain whether a coin is genuine, the MPD has
thus far either examined it using a microscope or
performed a content analysis using fluorescent
X-rays, which takes investigators at least three
to five minutes to finish.

With coin counterfeiters' techniques becoming more
sophisticated, the new way of detecting fake coins
is expected to be very important if accurate
counterfeit coins circulate in a large quantity at
the same time, the MPD institute said.

The method pioneered by Suzuki can be applied to
designing of a new type of vending machine that
would be very effective in foiling fake coin
users, so the institute has applied to patent
the method.

When dropped down a 30-centimeter-long chute, a
coin falls and strikes a brass plate. The sound
is recorded using a high-performance microphone
and its oscillation is gauged through computer
analysis, since, Suzuki said, the oscillation
frequency differs depending on the quality of
material and the way the material is compressed
in the manufacturing process.

There are considerable differences in the
frequencies of authentic coins and forged ones,
because of differences in the degrees of their
hardness and density, according to Suzuki.

"I hit upon the idea of making the device from my
image of a coin clinking when it is put into a
piggy bank," he said.

It took him about two years to complete the bogus
coin detector as he tested through trial-and-error
various metals to be hit by a coin and which
structure was best.

The newly developed device can distinguish bogus
coins from true ones in a brief time even when
hundreds of suspicious coins have to be examined
at once, Suzuki noted.

The MPD has already started using this method of
detecting fake coins, successfully finding 100
bogus ones last year.

Counterfeiters of coins have been rapidly enhancing
their forgery techniques, to the extent, for example,
that they can make a forged 500 yen coin capable of
revealing a latent image of the figure 500 when
tilted just as an authentic one does, according to
the MPD.

The MPD applied for a patent on the device last year,
because it can probably be applied to vending machines
and coin-identification machines at financial
institutions.

If the patent is obtained, the MPD may launch projects
to develop new coin-identifying devices in collaboration
with private-sector companies, it said.

The National Policy Agency, the central government
organization in charge of police affairs nationwide,
said it may be unprecedented for a police body to
file a patent application for a technique it has
developed by itself.

(Feb. 26, 2009)


...

"Arizona Coin Collector" wrote in message
m...

The methodology Suzuki has come up with to detect
bogus coins is fairly simple: A coin slides down a
small chute and collides with a brass plate. A
computer analyzes the sound of the collision and
compares it with the sound made by a genuine coin
to determine authenticity.


Anyone want to certify some old MS silver dollars this way?

On Feb 25, 10:38*pm, "PC" wrote:
"Arizona Coin Collector" wrote in messagenews:x4GdndnRusTkljvUnZ2dnUVZ_heWnZ2d@earth link.com...



The methodology Suzuki has come up with to detect
bogus coins is fairly simple: A coin slides down a
small chute and collides with a brass plate. A
computer analyzes the sound of the collision and
compares it with the sound made by a genuine coin
to determine authenticity.

Anyone want to certify some old MS silver dollars this way?

Perhaps, like Wagner operas, this technique is, "better than it
sounds".

"Peter" wrote in message
...
On Feb 25, 10:38 pm, "PC" wrote:
"Arizona Coin Collector" wrote in
messagenews:x4GdndnRusTkljvUnZ2dnUVZ_heWnZ2d@earth link.com...



The methodology Suzuki has come up with to detect
bogus coins is fairly simple: A coin slides down a
small chute and collides with a brass plate. A
computer analyzes the sound of the collision and
compares it with the sound made by a genuine coin
to determine authenticity.

Anyone want to certify some old MS silver dollars this way?

Perhaps, like Wagner operas, this technique is, "better than it
sounds".


I have posted this before but Coincraft's catalogue has a photograph of a
Royal Mint employee dropping new gold sovereigns onto an anvil to check for
the correct ring. Billy