[HN Gopher] Noise Filtering Using EUR1 Filter (2020)
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Noise Filtering Using EUR1 Filter (2020)
Author : dsego
Score : 75 points
Date : 2024-12-09 07:31 UTC (15 hours ago)
(HTM) web link (jaantollander.com)
(TXT) w3m dump (jaantollander.com)
| rzzzt wrote:
| Patient following of links resolves the mystery I'm sure everyone
| is asking: The '1EUR' name is an homage to the
| $1 recognizer [10]: we believe that the 1EUR filter can
| make filtering input signals simpler and better, much
| like the $1 recognizer did for gestures
|
| https://dl.acm.org/doi/10.1145%2F2207676.2208639?cid=8110016...
| JusticeJuice wrote:
| But now I gotta know why it's called the $1 recognizer! One
| question solved, another opened.
|
| Edit: > It's because the algorithm is easy to implement and
| efficient in terms of compute usage to match a gesture. It's a
| "cheap and easy" recognizer, a $1 recognizer.
| dvh wrote:
| But if they wanted to do the homage to $1 recognizer, shouldn't
| they call it EUR0.95 filter?
|
| Edit: nvm, just realized they included the VAT
| danbruc wrote:
| Paper [1] and home page [2] of the $1 Unistroke Recognizer.
|
| [1] https://www.microsoft.com/en-us/research/wp-
| content/uploads/...
|
| [2] https://depts.washington.edu/acelab/proj/dollar/index.html
| echoangle wrote:
| The title on HN includes ,,EUR1", the original uses the ,,1EUR"
| (which makes more sense I think, even when considering the
| reference to $1).
| locallost wrote:
| In English the currency symbol is typically before the number,
| whereas especially in Europe (with exceptions e.g. Switzerland)
| it is typically after the number. The title here is kind of
| correct in English I'd say, but the author is Dutch who happens
| to write in English.
| Leif24 wrote:
| At least with American currency it varies, e.g. one dollar is
| $1 while one penny is 1C/.
| tristor wrote:
| This actually is useful, because it allows the symbols to
| visual indicators when reading currency figures and can be
| used in a programmatic way. $ becomes a start marker for
| the beginning of a currency figure where the most
| significant digit is immediately after the marker and
| anything remaining after flows from that, and the same is
| true for cents where the symbol acts as an end marker and
| infers a lower bound. They can almost be thought of as
| start and end markers in regex, although they are not used
| together so not exactly that way.
|
| It makes a sort of rational sense, at least to me.
| dmonitor wrote:
| The rationale I've always heard for having the $ at the
| beginning of the number was so that a handwritten value
| on, say, a check couldn't be modified by sticking a
| number at the beginning. 1.00$ could be forged into
| 91.00$, but not so with $1.00.
| tristor wrote:
| That rationale makes sense, and pretty much aligns with
| what I mean by a visual marker.
| agmater wrote:
| In Dutch the currency symbol always comes before the number
| as well, so this is intentional of the author.
| locallost wrote:
| Except he wrote in English, not Dutch :-)
| agmater wrote:
| Yes exactly, my point was that it works the same in
| English and Dutch. But other comments mentioned how its
| based on a French paper, where they do place the currency
| after the amount.
| locallost wrote:
| Ah, I'm sorry, I totally misread that.
| echoangle wrote:
| Interesting, I knew that it was written $1 for dollar but
| thought it depends on the currency, not the language.
| locallost wrote:
| My best answer is it depends on the language and country.
| E.g. Germans will write it after the number, whereas Swiss,
| who also officially speak German, will write it before the
| number. And yes, I needed to display some prices on a page
| recently, that had versions for Germany and Switzerland
| :-).
| sigio wrote:
| In the before-times (before the euro), we dutch used to write
| fl123,45 So putting the euro symbol in front comes naturally.
| locallost wrote:
| I wonder if it's because of the proximity to the UK, and
| that it influenced the choice of where to put it.
| blainelewis1 wrote:
| Dan was my masters advisor and he's Canadian, they used the
| French "spelling" because it's a French paper.
| notpushkin wrote:
| Euro sign can be used before the amount, depending on the
| language and local norms, although I've seen it mostly after,
| separated by a space (150 EUR).
| wiether wrote:
| The original algorithm[1] comes from people working at a French
| university. In France we put the currency directly after the
| amount, without space : 1EUR.
|
| [1]: https://gery.casiez.net/1euro/
| dsego wrote:
| It was moderated I think, the year 2020 was added as well.
| roger_ wrote:
| A normal EWMA filter is a special case of a Kalman filter and I
| bet this could be re-cast as one too. Might need an extra state
| or adaptive process noise though.
| wyager wrote:
| How is EWMA a special case of Kalman? I typically frame it in
| terms of laplace/Z transform, in which case it's just a 1-pole
| LPF
| roger_ wrote:
| It's actually shown in the Wikipedia article:
| https://en.wikipedia.org/wiki/Kalman_filter#Details
| Tade0 wrote:
| I "invented" this filter in middle school when I was deep into
| audio processing but didn't have the theoretical foundations yet.
|
| Adding a bX_{i-2} term allows for a filter with sharper cutoff,
| but makes determining the parameters more difficult.
|
| The Z-transform is helpful here:
|
| https://en.wikipedia.org/wiki/Z-transform
| WithinReason wrote:
| Me too, playing with Microsoft Excel as a child, creating
| series where the next cell depends on the previous one.
| meindnoch wrote:
| Ok. And where's the Bode plot?
| duped wrote:
| Why are we reinventing wheels and giving them bad names
|
| This is an exponential moving average aka first order average and
| has been used for decades. It's introductory material in any DSP
| class.
|
| There are multiple varying derivations of the coefficients that
| have different meanings, the best one for this example would be
| as an approximation of an N-point moving average (derivation of
| that is an exercise to the reader, but it's like five minutes of
| whiteboarding)
| spookie wrote:
| Your criticism is the reason for the name though
| dsego wrote:
| But an N-point moving average isn't adaptive, no? It has lag,
| this filter can adjust the smoothing effect to reduce lag. The
| exponential moving average is just one part of the presented
| filter, that's not the innovation here.
| CasperH2O wrote:
| We've been happily using this algorithm for motion sensor (IMU,
| gyroscope and accelerometer) filtering to game control input for
| some time in the open source application Handheld Companion [1].
|
| There's also another nice page with explanation on how to tune
| the parameters [2] and there's a great visual with your mouse
| [3].
|
| [1] https://github.com/Valkirie/HandheldCompanion
|
| [2] https://gery.casiez.net/1euro/
|
| [3] https://gery.casiez.net/1euro/InteractiveDemo/
| tobinfricke wrote:
| This has the same vibes as "Tan's method", wherein someone
| managed to rediscover and publish the well-known trapezoidal rule
| for integration from Calculus in a medical journal
|
| https://academia.stackexchange.com/questions/9602/rediscover...
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