Questions tagged [peak-detection]

Questions on peak detection algorithms and problems, including applications of the built-in FindPeaks, PeakDetect, MaxDetect and MinDetect.

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1answer
52 views

Selecting data around peak position

I'm trying to write code that imports experimental data, finds peaks in it and cuts data around specific peak for further analysis (Fourier transform & model fitting of spectra). Currently, I'm ...
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1answer
57 views

What is the best way to detect constant or periodic amplitude of the spectrogram?

Suppose I get interpolating function in the solution of the complicated differential system. I plot a solution for various input values that control the outcome of the solution. Some give exponential ...
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1answer
70 views

Fitting data by linear combination of distribution [closed]

I have data ...
6
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2answers
224 views

Inflection point coordinates of peaks in data

Using the following data, which I have used before in other posts (the y-axis is heat flow (mW) and x-axis is Temperature in °C (not time)): ...
6
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1answer
465 views

Find onset and peak temperatures

If I have the following data (which is temperature in the x-axis and heat flow in the y-axis): Import["https://pastebin.com/raw/SMKZUtbQ", "Package"] which ...
8
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2answers
239 views

Remove a specific element of a TimeSeries?

If I have a TimeSeries, how do I remove an element if that element is another TimeSeries? Let's say I have: ...
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2answers
102 views

Track a moving peak on a periodic ListAnimate plot

I have a ListAnimate plot and I want to track the position of the peak as it moves. Is there any way to do this which takes into account the fact that the peak of the wave moves past the window of ...
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0answers
68 views

How to perform a 2D-multi-peak fitting?

I am wondering how to decompose the data[x,y] into several elliptic-shaped functions, i.e. $f[x,y]=\frac{H}{(1+(\frac{x-x1}{a1})^2+(\frac{y-y1}{b1})^2)^{3/2}}$. I could follow in 1D case, ...
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1answer
77 views

Sort and extract values in a nested list

I want to sort the following nested list of peak points by the y values while keeping the dimensions consistent. I then want to extract the x value of the largest and second largest y values (if the ...
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0answers
87 views

Simultaneous Peak and Background Fit

I'm not sure if this is the proper way to do this, but I have a question related to another open question of mine. In this post, I'm looking at analyzing some quantum dot UV-Vis absorbance spectra (...
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0answers
74 views

Quantum Dot Absorbance Data Peakfinding

I work in a lab making quantum dots, and was recently tasked with finding a way to extract some figures of merit from old data in an automated way. In particular, I'm looking to extract the peak ...
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0answers
56 views

Fitting CauchyDistribution to data list to determine peak

I have a list of data in the form like this {{-3,12},{-3.01,13.4},{-3.04,13.6},...} where the x value is time and the y value is current. FindPeak gives me peaks for everydata point i have and ...
2
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1answer
107 views

PeakDetect Function Behavior and Parameters

I am currently using PeakDetect for a project, but I'm not sure how the sharpness parameter works. I can qualitatively tell what it's doing, but is there a more analytical/mathematical way to define ...
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1answer
85 views

Removing Extra Points When Finding an Audio Envelope

I am trying to reproduce Camtasia's way of displaying audio signals which is a strictly positive envelope of the audio signal and very easy for me to identify some sounds visually. These are displays ...
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0answers
139 views

Optimize Use of PeakDetect in Mathematica

I am quite new to Mathematica and I am looking for some advice in order to improve and optimize my code. Here is what I am trying to do: Open a stream Read the stream line by line and store it in "...
2
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3answers
284 views

Finding minimum from ListPlot

I have Table with 10000 elements in it and I plot a graphic using ListPlot. I need find minimum in graph. Here is a .txt file with data. I tried to use ...
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3answers
268 views

Find peaks in data set and correlate variables [closed]

I have a data set composed of a X variable (col 1) and two Y variables. Y1 shows roughly 40 peaks while Y2 is a linear function. Is it possible to find the approximated 40 Y2 values for which Y1 is a ...
2
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2answers
255 views

How to find second,third,etc maximum peak of list

I need to find all values of peaks. I have Table with 10000 elements in it and I plot a graphic using ListPlot. Then I tried to ...
5
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2answers
84 views

Find the base vectors of a point set

I have a list of coordinates that fits into a 2D periodic lattice, with some error ( $\vec{R}=n\vec{i}+m\vec{j}+\vec{\varepsilon}$). Is there a way to find the base vectors of the lattice? I guess the ...
5
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3answers
465 views

Efficient way to detect peak value changes in a list

ListPlot[list, Joined -> True, PlotRange -> Full] I would like a simple method to get the positions within the list where the values deviate a lot from ...
6
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3answers
770 views

Multi-peak fitting for peak position

I have a {x,f} data-set featuring multiple peaks. The peaks evolve with a second variable y. I would like to fit the multiple ...
5
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1answer
311 views

Find centroids and average intensities of regions in an image

The image below shows an approximately triangular array of bright spots. The intensity falls off towards the edges (Gaussian decay). There are some defects (the elongated smudge and the sharper ...
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1answer
295 views

Finding peaks/maxima while extracting the range of x-values

I have read similar questions about finding peaks on the web (Finding peaks of data) as well as the FindPeaks function but I'm struggling to put them into proper context for my case. I am still a new ...
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3answers
367 views

Multi-peak fitting

I am starting, and still learning with Mathematica. I really wonder how to solve my problem : I have a broad peak composed by two peaks actually, and I would like to separate them. Data come from an ...
3
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2answers
180 views

Find peak decibel level (or some measure of peak loudness) from audio sample

So a shotgun range opened near my house and I've been tasked by the HOA to do some nuisance analysis. I've got a quick sample of audio and want to find the peak noise levels at the places where the ...
4
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2answers
946 views

Find positions and values of peaks

FindPeaks only works on a single dimension list and returns the position as an index, however, there are cases when it can return non-integer value as a position, ...
5
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0answers
522 views

Detect and measure smooth peaks in a 2D image

I have multiple grayscale images where I want to identify elevations: I have to find the convex hull that encloses the base of each hill. An example image: The images are already normalized, ...
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1answer
54 views

Plot terminating early

I have a function K3T[2][2 r0 l, g2, z, c, T, p] that is acting weird when evaluated for different p: ...
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0answers
118 views

How to draw local trend lines and divergence lines?

Here are two lists as lstClose and lstCCI, the lstCCI is computed from ...
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1answer
573 views

Mysterious "not a consistent list of real values" error from FindPeaks

I am working with temporal data objects and experimenting with FindPeaks. I find that the function sometimes fails with the error FindPeaks::arg: The argument ...
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1answer
269 views

Plotting a general ZigZag curve with possible threshold value

I want to use zigzag curve to describe the trend of simple data. here is a list as ...
4
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0answers
169 views

FindPeaks confused by initial zeros?

I think that there is something wrong with the FindPeaks algorithm. It seems to get confused when the data starts with some zeros. Here is works well: ...
4
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2answers
789 views

Integrating curve peaks

I have curve with a set of peaks (black line in the figure below) and I have to calculate the area of each peak. At the end of each peak there is a short linear region. So to calculate peaks' area ...
3
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1answer
595 views

Filtering Background with resonance or Peaks

I have some data, the blue curve which I want to filter out the background to get a flat signal with dips(Idea is to divide signal (except the dips) by the background). The orange curve is my best ...
5
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2answers
1k views

Finding very weak peaks

I measured 1d particle oscillations. The particle is oscillating with a certain frequency, whereby its motion is disturbed. Now I would like to to find all peaks of the particles trajectory. One ...
8
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1answer
686 views

Finding peaks of curve with small values

I have 2d data of which I want to find the peaks. data << "http://pastebin.com/raw/EQFz1KFn"; peaks = FindPeaks[data[[All, 2]], 0, 0, -Infinity] // N The ...
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1answer
225 views

Extracting Features from a List

Data: https://drive.google.com/file/d/0B7G3oUuZG1TwYWhMVUhSQzNwTEk/view?usp=sharing Here I have 20 datasets collected from custom built EMG sensors monitoring a users face. I am particularly just ...
3
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3answers
848 views

Finding the width of a bell-shaped curve at half its peak value dynamically in a Manipulate

Kind of new to Mathematica. I am plotting a function that produces a bell-shaped curve in Mathematica within a Manipulate so that I can change its parameters easily....
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2answers
668 views

How do I extract peak frequencies? [closed]

Suppose I have large text file filled with numerical data. Then I do Fourier operation with this file and plot the result: ...
14
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2answers
1k views

How to detect loops in a vector field?

Given a vector field and I'd like to detect if there are streamlines in closed patterns. For example, if the input is a vector field like this: ...
2
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1answer
275 views

How to find the local minimum points in the multi-dimensional numerical data?

I am trying to get some local minima of an n-dimensional function (which only has numerical form). For two-dimensional function data, we can find the local minimum points from the contour plot easily. ...
2
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1answer
223 views

Still more problems with Fitting, please help

I'm in a little over my head here and I'm fully aware of it, so I'm hoping for some help. I've been assigned to a project where I am given data: http://www.pastebin.ca/3061136 (Example Data) I then ...
13
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2answers
8k views

Estimating the full width half maximum of a peak

I have a dataset of which I'm attempting to determine the full width at half maximum. A picture of the data is given below, and the dataset itself can be found here (pastebin). Now, this set has a ...
8
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2answers
386 views

Cutting away points that are not resonances

My situation is as follows. I have a whole bunch of data that I need to fit, which tends to look like this picture: As can be seen, there's three dips (resonances) and a whole bunch of noise around ...
5
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1answer
4k views

Finding peaks of data

I want to find peaks in my data. My code in a reduced form so far: ...
3
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0answers
582 views

FindPeaks finds Minima, but not all of them [closed]

I have 10 sets of data, which are the result of measuring the way of a mass falling down over time, bringing a wheel into rotation when the mass hits the ground and then the wheel lifts the mass up ...
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1answer
841 views

Finding Coordinates of a Peak on a Plot

I have plotted a graph from a CSV file which consists of two columns of data Time and Intensity. I simply want to find the time where the intensity is largest. This code: ...
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3answers
2k views

How to find local minima of data using PeakDetect

One of the great new function in v10 is PeakDetect. It can detect peaks (local maxima) according to desired sharpness as shown in this example: ...
56
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6answers
20k views

How to perform a multi-peak fitting?

I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3). The ...
40
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5answers
19k views

Finding Local Minima / Maxima in Noisy Data

I'm trying to find local minima / maxima in noisy data, consisting of data values taken at certain time intervals. Ideally, the function should take a pair of lists (one containing time values and one ...