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Jonty Wareing

This paper starts out amazing and just keeps getting better

arxiv.org/abs/2401.06133

A screenshot of a paper on arxiv, it reads:

The possibility of making $138,000 from shredded banknote pieces using computer vision

Every country must dispose of old banknotes. At the Hong Kong Monetary Authority visitor center, visitors can buy a paperweight souvenir full of shredded banknotes. Even though the shredded banknotes are small, by using computer vision, it is possible to reconstruct the whole banknote like a jigsaw puzzle. Each paperweight souvenir costs $100 HKD, and it is claimed to contain shredded banknotes equivalent to 138 complete $1000 HKD banknotes. In theory, $138,000 HKD can be recovered by using computer vision. This paper discusses the technique of collecting shredded banknote pieces and applying a computer vision program.
A screenshot from the paper, it reads "The shredded banknotes were then collected. Surprisingly, three paperweight cylinders were opened, and two of them had stones in them". Three pictures follow.
Screenshot from the paper, it reads: "This cylinder only contained 82.57/138 = 60% of the shredded banknote pieces that the label had claimed. Although this issue is not the focus of this paper, it appears that the Hong Kong Monetary Authority has broken the law."
Screenshot from the paper, it reads: "The idea for this paper was discussed with the staff during my visit to the Hong Kong Monetary Authority visitor center. The paperweight souvenir is currently no longer available."
36 comments
Michael Gemar

@jonty @nev I’m guessing that sticking the pieces together would *not* result in a convincing bill…

Jonty Wareing

@michaelgemar @nev Doesn't need to be convincing - the paper cites The Association of Commercial Banknote Issuers: "banks will only reimburse you with the face value of a damaged banknote if you still have at least half of the banknote and visible serial number".

They might be real mad about it though.

Michael Gemar

@jonty @nev I wonder if a note intentionally shredded by the government to take it out of circulation is legally considered “damaged”…

Natasha Nox 🇺🇦🇵🇸

@michaelgemar @jonty @nev The government would have to proof that. It's not the citizen's job to know whether a note was governmentally shredded before.

Michael Gemar

@Natanox @jonty @nev If you got it from a paperweight sold at the Hong Kong Monetary Authority visitor center, that’s probably proof enough.

Atomic Fox

@jonty @michaelgemar @nev

The real question is, are enough pieces of any single note included to reconstruct a complete serial number?

Martin Jost

@jonty @michaelgemar @nev
Getting a reasonable serial number (IF this is cut in pieces) might be tricky...

Inga stands with Ukraine

@jonty @michaelgemar @nev in this context, "half of the banknote" usually means "half of the banknote in one piece" (and also that's a weird wording because in practice usually a bit more than 50% is required).
Otherwise it would be trivial to convert e.g. two whole banknotes into three damaged ones.
(Also see the infinite chocolate paradox.)

EggCess

@jonty
So wait ... I think the most interesting fact is actually this:

> This cylinder only contained 82.57/138 = 60% of the shredded
banknote pieces that the label had claimed. Although this issue
is not the focus of this paper, it appears that the Hong Kong
Monetary Authority has broken the law

In other words: Someone stole some bank notes before shredding, then filled the container up with stones to make up for the lost weight?

:D

@jonty
So wait ... I think the most interesting fact is actually this:

> This cylinder only contained 82.57/138 = 60% of the shredded
banknote pieces that the label had claimed. Although this issue
is not the focus of this paper, it appears that the Hong Kong
Monetary Authority has broken the law

In other words: Someone stole some bank notes before shredding, then filled the container up with stones to make up for the lost weight?

Jonty Wareing

@GHabiger That was my guess too!

A nice little profit - even the "full" ones were missing 56 notes, which means they were making off with a minimum of $56,000 HKD ($7000 USD) per cylinder!

Tom Forsyth

@jonty This suggests some else came up with this idea first and has been stealing 40% of the notes and making up the weight with stones.

Jonty Wareing

@TomF Given they show that complete notes are in the shreddings it's more likely that the person who shredded them *also* packed the cylinders and just made off with complete notes tucked into their underpants

Psoul 🏳️‍🌈:vbike:🇺🇸

@jonty I read the full paper. This us very funny. Looking forward to seeing the machine assemble the bills back together!

Aphrodite ☑️ :boost_ok:

@jonty dammit- i could’ve used the shredded cash for a project i’ve been working on for over a decade >.<

Necrofancy

@jonty I see a press release on this by the Hong Kong Monetary Authority:

hkma.gov.hk/eng/news-and-media

"It has recently come to the attention of the Hong Kong Monetary Authority (HKMA) that shredded banknote paperweights sold at the HKMA Information Centre contain pebbles to make them heavier and enhance their function as paperweights. Therefore, the number of shredded banknotes inside each paperweight falls short of the approximate number stated on the paperweight label."

@jonty I see a press release on this by the Hong Kong Monetary Authority:

hkma.gov.hk/eng/news-and-media

"It has recently come to the attention of the Hong Kong Monetary Authority (HKMA) that shredded banknote paperweights sold at the HKMA Information Centre contain pebbles to make them heavier and enhance their function as paperweights. Therefore, the number of shredded banknotes inside each paperweight falls short of the approximate number stated on...

martenson

@Necrofancy @jonty There has to be more to this story. I demand the third episode! Maybe with invoices for pebbles bought by the Hong Kong Monetary Authority.

Royce Williams

@Necrofancy
Full text, if you cannot reach the site:

"Notice about shredded banknote paperweights sold by the HKMA

It has recently come to the attention of the Hong Kong Monetary Authority (HKMA) that shredded banknote paperweights sold at the HKMA Information Centre contain pebbles to make them heavier and enhance their function as paperweights. Therefore, the number of shredded banknotes inside each paperweight falls short of the approximate number stated on the paperweight label. If any member of the public who has purchased a paperweight wishes to return the product, they are advised to contact the HKMA Information Centre by calling the Hotline (2878-1111) or by email (info_centre@hkma.gov.hk) to arrange for a refund.

The HKMA apologises for any inconvenience caused.

Hong Kong Monetary Authority
20 October 2023"

@Necrofancy
Full text, if you cannot reach the site:

"Notice about shredded banknote paperweights sold by the HKMA

It has recently come to the attention of the Hong Kong Monetary Authority (HKMA) that shredded banknote paperweights sold at the HKMA Information Centre contain pebbles to make them heavier and enhance their function as paperweights. Therefore, the number of shredded banknotes inside each paperweight falls short of the approximate number stated on the paperweight label. If any member...

John de Largentaye

@jonty In Rainbows End (2006), by Vernor Vinge, one plot arc is about the digitization of a library *by shredding the books* and venting the shreds through an air tunnel surrounded by cameras, which photograph the shreds hundreds of times, to reconstruct the pages kind of like this.

At the time, his concept was based on how DNA was sequenced.

Bread80

@jonty Surely they record the serial numbers of notes in circulation and notes removed from circulation? And cashing a defaced note can only be done at the central bank? In which case they’re guaranteed to check the serial number and attempting to cash would raise a few eyebrows.

mike805

@jonty The spook agencies no doubt have a puzzle solving machine for shredded paper. Even cross cut shredded paper could be reassembled this way.

The Iranians reassembled by hand quite a few documents from the American embassy.

Eric Lawton

@jonty

That reminds me of the machine used to reconstruct the files shredded by the former East German Stasi as the Berlin Wall fell.

'E-Puzzler' ends painstaking manual restoration of torn secret police documents
theguardian.com/world/2007/may

@szescstopni

Tom Tom

@EricLawton @jonty @szescstopni actually, according to the guardian, that e-puzzler machine had already in 2007 been put to use to reconstruct banknotes : "the machine was put to a wide range of uses - [...], and to piece together hundreds of thousands of bank notes shredded by a mother in an attempt to block her estranged daughter from her inheritance".

Paul Turnbull :CApride:

@jonty I’m reminded of Vernor Vinge’s novel “Rainbow’s End” where they decided the most efficient way to digitize books was to run them through shredders and scan the pieces as they tumbled through the air on the other side.

#ScienceFiction #VernorVinge

sollat

@jonty
It isn’t mastodon if nobody complains about the font anarchy.

FONT ANARCHY.

m3t00🌎

@jonty and they don't track destroyed serial numbers? they'll just burn them from now on. AI start reconstructing smoke next

tres tristes tigres

@jonty this money is worth its weight in stones!

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