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40 votes
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Remove noise from data

You could try BilateralFilter: ...
Niki Estner's user avatar
  • 36.1k
26 votes

Can we use Mathematica to design an electronic active filter?

Here I would like to share with this great community by offering an example of active filter design. Introduction This Mathematica code determines the component values for a low-pass active filter ...
David Keith's user avatar
  • 4,604
24 votes

Deleting noisy data from a plot (manually) and export the best remaining data

One simple way of "filtering" your data is to treat the points as a graph, and search for the shortest path from left to right: ...
Niki Estner's user avatar
  • 36.1k
21 votes
Accepted

Finding outliers in 2D and 3D numerical data

The question title poses a good question, although the question formulation is somewhat specialized and misplaced (as mentioned in a comment). This answer provides data and a method description ...
Anton Antonov's user avatar
21 votes
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Removing outliers from data

You could take a look at the built-in functions FindAnomalies and DeleteAnomalies. We can use ...
Carl Lange's user avatar
  • 13.1k
20 votes
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Extracting signal from gaussian noise

The procedure below assumes that the original distribution $X$ (the "signal") is non-Gaussian, and $Y$ is Gaussian (normally distributed noise.) General procedure The procedure is as follows: Find ...
Anton Antonov's user avatar
20 votes

Remove noise from data

I would suggest using a median filter with small radius to eliminate the large spikes, then a mean filter to smooth the remaining signal. @Xavier essentially combines these two filters by using ...
KennyColnago's user avatar
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19 votes

What's the correct way to shift zero frequency to the center of a Fourier Transform?

I am writing this answer to put on record how to do the equivalent of fftshift() in MATLAB, for both the one- and two-dimensional cases. In Mathematica, the ...
J. M.'s missing motivation's user avatar
16 votes
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How fast is my fidget spinner spinning? A sound experiment!

First, import the audio and extract usable data from it: ...
Miladiouss's user avatar
  • 1,883
12 votes

Why the BandpassFilter is different than applying LowpassFilter then HighpassFilter

The difference between the low-high/high-low/bandpass filters is clearer plotting them all together: ...
bill s's user avatar
  • 69.1k
12 votes

Remove noise from data

I am not sure what is called "noise" in the question, from the description, I think it is about removing outliers. This solution uses Quantile regression twice: to detect the outliers, and then to ...
Anton Antonov's user avatar
11 votes
Accepted

How to get a smooth derivative graphic

I think one issue is that your initial data is not evenly sampled and thus filtering it directly is not going to do much good in regards to differentiating it. I propose resampling of the data, ...
Sascha's user avatar
  • 8,469
11 votes

How can I generate pink noise using Mathematica?

The approach below is still somewhat brute-force, but it was greatly improved by Carl Woll's suggestion to look into AudioData, which was the link I was missing here. It works to generate a pink ...
MarcoB's user avatar
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11 votes

Processing images from NASA's Juno Jupiter Orbiter

You might find the functions ColorToneMapping and BrightnessEqualize useful, as well as modifying gamma in ...
Carl Lange's user avatar
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10 votes
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Problem with Spectrogram

You should get the old result back by setting MaxPlotPoints -> Infinity in the Spectrogram call, eg ...
carlog's user avatar
  • 301
9 votes
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Computing FundamentalFrequency

You can use Cepstrum,Wiki says It was originally invented for characterizing the seismic echoes resulting from earthquakes and bomb explosions. It has also been used to determine the fundamental ...
partida's user avatar
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9 votes

high pass filter without losing detail

Here is my take on how to do filtering for a time series. The HighpassFilter you used is I think for image processing. Import the data and find the sample rate ...
Hugh's user avatar
  • 16.5k
9 votes

How fast is my fidget spinner spinning? A sound experiment!

Using Fourier Discrete Transform. Let's start by observing the Fourier content of the beginning of the signal: ...
anderstood's user avatar
  • 14.3k
9 votes

Sample rate severely influences quality of ButterworthFilterModel?

I have had a look at your problem. Starting afresh ...
Hugh's user avatar
  • 16.5k
9 votes

Deleting noisy data from a plot (manually) and export the best remaining data

Here's an alternate approach that takes the data into an image that you can edit in a Paint program, and then back into data. Presumes you have "insider knowledge" about the data set that allows you ...
MikeY's user avatar
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9 votes
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Deleting noisy data from a plot (manually) and export the best remaining data

Introduction It seems to me that this question should be answered using more "traditional" time series methods than the already provided interesting solutions (with graphs and image processing.) The ...
Anton Antonov's user avatar
8 votes

high pass filter without losing detail

How about LowpassFiltering the signal and subtracting the result from the original? ...
einbandi's user avatar
  • 4,024
8 votes
Accepted

high pass filter without losing detail

The default kernel length of HighpassFilter seems to be too small, after modifying it to Round[Length@a/10], the result is ...
xzczd's user avatar
  • 66.8k
8 votes
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Why doesn't HighpassFilter fully remove the DC component?

I don't like LowpassFilter and HighpassFilter. Somewhere there is a discussion on how to make them work, but I can't find it now....
Hugh's user avatar
  • 16.5k
7 votes

How to do deconvolution in spectrum with some peaks?

I don't think deconvolution is what you are really after. For example, there is a function called ListDeconvolve. Let's apply it to your data. First you need to ...
bill s's user avatar
  • 69.1k
7 votes
Accepted

Applying filters to data of the form {{x1,y1},{x2,y2},...}

The answer I came up with is ...
Sascha's user avatar
  • 8,469
7 votes
Accepted

Frequency of ticks in mechanical watches

Third, much better answer This is a bit easier to understand graphically, so I put a Manipulate together. ...
Carl Lange's user avatar
  • 13.1k
7 votes

Frequency of ticks in mechanical watches

The data looks like periodic pulses of incoherent noise, familiar to an old pulsar astronomer. So, use a method sometimes used for pulsars. Start by working in intensity rather than amplitude. That's ...
John Doty's user avatar
  • 13.7k
7 votes

how to plot the amplitude and phase spectrum of a Fourier Transform in this specific pattern?

I'll show the easy way, then the hard way. Easy way Since the Fourier transform is the Laplace transform when real of s is zero, then you can use ...
Nasser's user avatar
  • 145k
6 votes
Accepted

Problem with Sin and ListPlot

You haven't defined the x-Axis value for the ListLogLinearPlot and therefore the peak-position is dependent of the duration, which is proportional to the number of values. If you define the ...
Gypaets's user avatar
  • 577

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