# 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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### Fitting data to peaks visually with manipulate - how to compactly implement for many peaks

I am trying to create a visual aid for peak fitting. There should be a background profile and on top, I want to place peaks. So far, I am stuck with the following issue. For simplicity, I am using a ...
• 3,874
141 views

### FindPeaks in a 2d list and half values

FindPeaks is a nice little help. But it only works on 1D lists and tends to return half integer values for positions of the peaks which are ultimately very useless ...
• 3,874
1 vote
106 views

### Find local maximum

What instruction could I use to obtain the local maximum point of the red circle in the graph? I tried using the $FindMaximum$ instruction, but couldn't get the desired result. The curve generation ...
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198 views

### Separating two peaks in a 2D array of data

I have a 2D array of count values and the data presents two peaks separated by a valley of low counts. I want to be able to separate each peak signal from the other so that I can analyse the ...
• 93
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### Generalise ImageLines to Image3DPlanes?

Context I am interested in detecting (multiple) planes in a cube. Test case Let me first define a test case: ...
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56 views

### Plot the peak frequency of a ShortTimeFourirer Transformation and convert bin # to frequency

I did the ShortTimeFourier(stf) Transformation of the following signal. And got the results as shown in this Spectrogram. Then I wanted to find the peak frequency of this each turn using PeakDetect ...
1 vote
189 views

### FindPeaks of elevation data

I've been reading many posts about how to use FindPeaks. I am working with some GPX data and was looking to plot an elevation profile with points at the peaks and troughs, potentially with those ...
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135 views

### Functions can graph but can't solve for partial derivatives

First I got a function g[xo,yo] by solving a system of partial differential equations ...
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### 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 ...
1 vote
83 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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1 vote
96 views

I have data ...
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511 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)): ...
• 1,611
1k 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 ...
• 1,611
376 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: ...
120 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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1 vote
114 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, ...
1 vote
156 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 ...
• 93
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### 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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1 vote
100 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 ...
• 490
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### 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 ...
175 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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1 vote
119 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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### 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 "...
• 103
452 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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353 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 ...
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310 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 ...
• 573
92 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 ...
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### 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 ...
• 3,023
942 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 ...
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524 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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385 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 ...
• 375
1 vote
409 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 ...
367 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 ...
• 145
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### 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, ...
• 3,874
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### 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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1 vote
63 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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157 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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728 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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402 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 ...
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200 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: ...
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959 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 ...
• 3,461
804 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 ...
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 ...
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753 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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1 vote
238 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 ...
987 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....
• 433
1 vote
908 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: ...
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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: ...
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415 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. ...
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