Questions tagged [peak-detection]

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24
votes
4answers
17k views

Peak detection approach

What are the peak detection algorithms in existence? I have noisy data, and I would like to implement peak detection for this data. Data is in reverse, actually I am trying to determine the bottom. ...
12
votes
5answers
6k views

Is up-sampling prior to cross-correlation useless?

Consider a simple case where two signals from two different sensors are cross-correlated, and the time-delay-of-arrival computed from the absissa of the peak of their cross-correlation function. Now ...
12
votes
7answers
4k views

Obtain a signal's peak value if it's frequency lies between two bin centers

Please suppose the following: The frequency of a signal's fundamental has been estimated using FFT and some frequency estimation methods and is lying between two bin centers The sampling frequency is ...
12
votes
4answers
4k views

Finding zebra-like pattern in image (Detection of structured-light fringe centerline from photo)

I'm working in a project where fringes are projected against a subject, and a photo is taken. The task is to find the centerlines of the fringes, which represent, mathematically, the 3D curve of ...
11
votes
2answers
3k views

Real-Time Human Pitch Detection

I'm trying to implement a singing game that will analise raw mic input and tell the player how good is he singing. That needs to be done in real-time. I've come across a lot of threads asking the ...
10
votes
2answers
680 views

What is obtained from the cross correlation plot?

Let’s assume that we have two audio signals, x(t) and y(t) affected by the noise as shown below. And we would like to cross-correlate these two signals and the cross-correlation plot is shown as ...
9
votes
2answers
3k views

Finding local peaks in-between samples

I have $n$ discrete samples of a seismic signal $y[n]$: I want to find local maxima in the signal. A naive test for if $y[n]$ is a maximum would be: $$y[n]: maxima \textbf{ if } y[n] > y[n-1] \...
9
votes
1answer
7k views

Real time slope and peak detection and calculation

I have a signal that I sample at 500khz. I am trying to detect a rise, fall and the peak in the incoming data. The base of the peak could be  for 250 usec or 2.5msec, amplitude could be 6db or 15db ...
9
votes
1answer
3k views

How do I use a Savitzky Golay filter to find local maxima (in between samples) in a discretely sampled 1D signal?

I have a seismic signal y(i): Here I have found one maximum: i=152.54, y=222.29 manually and plotted it in red. I want to find all maxima automatically. I read that the Savitzky Golay Filter (SGF) ...
9
votes
1answer
2k views

Derivative calculation

I have a series of data (single array). If I take this data and plot it, I can see that there are multiple peaks. However If I zoom in to a section of data, I see that there is substantial noise. I ...
7
votes
1answer
17k views

How Hessian feature detector works?

I know about Harris corner detector, and I understand the basic idea of its second moment matrix, $$M = \left[ \begin{array}{cc} I_x^2 & I_xI_y \\ I_xI_y & I_y^2 \end{array} \right]$$, edges ...
5
votes
2answers
367 views

What is the uHz-rotator algorithm?

According to this page, the Baudline software tool implements ...the uHz-rotator algorithm that operates in the complex domain to calculate an extremely accurate estimate of the frequency. ...
5
votes
2answers
1k views

Remove negative slopes from signal

I'm very new to signal processing, and have been struggling this far. I've a rather messy signal measuring respiration using some chest bands and would like to focus solely on the inspiratory half of ...
4
votes
1answer
8k views

Taking audio frequency and picking out peaks (Peak Detection)

So I have a unique challenge. I want to take an audio file, and pick out the peaks in the samples and plot that onto a graph. Each point based on the amplitude/pitch(?) will be represented as either a ...
4
votes
3answers
2k views

Removing unwanted peaks from signal

I have a signal which looks something like: The 12 main round peaks is what I'd like to keep. However, the peak detection algorithm I apply is picking up the in-between noisy peaks. Any strategies I ...
4
votes
2answers
423 views

Peak location estimation for a triangle wave in AGWN?

Is there a more optimal peak location estimator specifically for triangle waves in AGWN, compared with peak estimation for generic waveforms? For a "smooth" waveform in noise, a common peak locator ...
4
votes
1answer
1k views

Detecting peaks in a noisy 2D correlation plot

I'm doing pattern matching by means of normalized grey-scale correlation. My input image is noisy and so the peaks in the correlation plot cannot be found just by thresholding. The original ...
4
votes
1answer
1k views

Onset Detection Peak Picking

I have a guitar music signal and I want to detect the onset points via energy. This is the signal example: This is the energy plot: My question is what would be the best method defining the ...
3
votes
4answers
2k views

Auto correlation correspondence to original time domain window

I'm trying to figure out how exactly an auto correlation corresponds to a time domain signal. Now I'm trying to find pitch periods in an audio file and 99% of the time I'm getting it spot on. ...
3
votes
3answers
5k views

Good way to detect pulse with known width with background noise?

I'm dealing with a light sensor tracking a bursting LED. Unfortunately signal is weak and there are other light sources in environment. I've used optical filters on sensor but there is still some ...
3
votes
4answers
244 views

Estimate peak width from a vector that is a superposition of unknown number of identical Gaussian peaks with different heights?

If you have a vector that is a superposition of an unknown number of identical Gaussian shaped peaks/impulses of unknown width (but all the same width) and different amplitudes (with Poisson or ...
3
votes
1answer
110 views

Chromatogram peak detection - bunching vs others?

Reading presentations from existing tool providers I noticed that in order to detect peaks they first use bunching (average N points) and then use slope and curvature to detect peaks. I'm guessing ...
3
votes
2answers
2k views

Algorithms for finding fundamental frequency based on ACF result

I am developing a software for fundamental frequency tracking. For this purpose, I have designed a function which calculates autocorrelation over the signal and a second function which, based on ...
3
votes
3answers
497 views

Filtering data so that only rising edge is left

I have data that looks like this: Sometimes the data has a higher point in the middle of the shallow slope I want to find a way to filter the data such that it smooths it and leaves the first rising ...
3
votes
0answers
338 views

Remove the extra peaks by lag

Suppose that we have some peaks of a signal and we know the time lag between dominant peaks. How is it possible to remove the extra peaks by applying time lag ? Lets say it in MATLAB ...
3
votes
2answers
641 views

DOA estimation 2 sources time delay estimation uniform array

I am new to signal processing, so sorry if the question is superbanal. I have been spending more days than I would admit on this and can't find the error. I have two triangle waves that are emitted ...
2
votes
4answers
4k views

Estimate frequency and peak value of a signal's fundamental

How can I find out frequency and peak value of a signal's fundamental? Please do consider the following: The peak value of some harmonics might be higher than that one of the fundamental The ...
2
votes
1answer
38 views

What does this block operator mean?

What does this block do? It's part of a block diagram for a RMS/Peak detector.
2
votes
1answer
2k views

MUSIC algorithm for peak detection

On Wikipedia, is written that MUltiple SIgnal Classification (MUSIC) is an algorithm used for frequency estimation. One purpose of estimating the spectral density is to detect any periodicities in ...
2
votes
1answer
310 views

How to detect peaks in a microcontroller?

In the context of a microcontroller, I have much less memory and far less processing power. This means, I can only buffer a reasonable window of samples (e.g. 16 or 32), and may not be able to use ...
2
votes
1answer
209 views

How to detect peaks ignoring soft declivity?

I have to detect repetitions in a signal, and I am managing to do it by finding peaks and valleys, and cutting the desired pieces. The following figure shows the pattern wanted, shaded areas are the ...
2
votes
1answer
838 views

O(1) peak segmentation algorithm in matlab?

I have an intensity image, similar to the image below. I would like to very quickly, segment this image, into separate peaks. Where each peak is labelled, and segmented. A notional segmentation of ...
2
votes
0answers
123 views

Peak detection for signals that contain high frequencies

I have an question about peak detection. My purpose is creating a plot with an impulse response and the decay line at / above it. What I see till now is that there are two options for finding peaks: ...
2
votes
0answers
135 views

how to detect number of syllables in a batch of audio recordings?

I have a corpus of short speech samples from Kiswahili speakers, and I want to detect the number of syllables in each audio recording. How should I approach this task? Background: I asked a ...
2
votes
0answers
493 views

Peak detection techniques

I'm using a cell-averaging constant false-alarm rate (CA-CFAR) detector to detect peaks like the first one in the following plot: The magenta line is the adaptive threshold, which is the local ...
2
votes
0answers
230 views

Absolute value vs. power (to make a signal positive-only)

In order to make a signal positive-only, I have the choice between taking the absolute value and multiplying the signal by itself (i.e. taking the signal to the power of two). Obviously, multiplying ...
2
votes
1answer
279 views

Unexpected peaks in spectral analysis

I am doing the spectral analysis of some antenna recorded signals by computing PSD (logarithmic absolute value of the FFT) and the spectrogram of the signal. The problem is that I get some unexpected ...
1
vote
1answer
586 views

What DSP method are consumer products like the game Rocksmith and guitar polyphonic tuners likely to use for multiple f0 detection?

The game Rocksmith and some polyphonic guitar tuners (like the PolyTune) are able to recognize, at least to some extent, multiple fundamental frequencies in single-source audio. I know there are some ...
1
vote
3answers
1k views

How to find peaks and periods?

I am looking at data like this: Source data: http://pastebin.com/raw.php?i=L6cd8d5K The data is quasi-periodic, there is a distinct cycle but it is not an exact repeat, and the period changes ...
1
vote
3answers
1k views

Real-Time peak detection (amplitude)

I capture signal (sound) in 44100hz and I need get response if there is peaks at amplitude, actually. Is this possible? How I can do this in real-time?
1
vote
1answer
204 views

How can I get the uncertainties for peaks on an image?

When pick the peak points on an image, e.g. the matrix made by peak in matlab as this one, I can use max to get the index of ...
1
vote
2answers
942 views

Getting a more accurate frequency read from autocorrelation and peak-detection algorithm

For a project I am attempting to create an automatic tuner for a guitar, which reads the audio from the guitar jack, determines the frequency and adjusts the string by a motor. Using http://www....
1
vote
2answers
64 views

Filtering Surge Signals

I am working on a matlab program which needs me to detect the pattern of surges in a signal and then remove them. I tried out various filters like median, hampel, butterworth etc. but couldn't get an ...
1
vote
1answer
63 views

Intelligent Noise Removal in Data

This question is linked to this question: I have this data: ...
1
vote
1answer
221 views

Filtering and peak finding

I have an observed signal which is the norm of the sum of two 3-vectors: $$ S(t) = || \mathbf{A}(t) + \mathbf{B}(t) || $$ Now, I have full knowledge of the vector $\mathbf{A}(t)$, $$ \mathbf{A}(t) = \...
1
vote
1answer
469 views

Harmonic Product Spectrum algorithm. I dont understand one step

I was looking some Harmonic Product Spectrum algorithm examples and I came up with this: ...
1
vote
1answer
2k views

How do spectrum analyzers detect peaks?

Using peak search, I'm able to put the cursor on any of the several peaks on the spectrum analyzer display. I am trying to do something similar in software, with the output of the FFT of the radio ...
1
vote
1answer
1k views

DFT normalization for amplitude estimation

After an interesting recent answer, I'm doing some research on proper DFT normalization for sinusoidal peak estimation. It's clear that to get the correct amplitude from DFT peaks we need to normalize ...
1
vote
1answer
153 views

reducing MIPS in detecting tones

Currently our software is detecting tones using FFT and checking if there is only a single peak in frequency spectrum. Our software needs to know what kind of input it is before taking action. So we ...
1
vote
1answer
359 views

Uses of peaks in audio auto-correlation

Do you know of any algorithms for audio processing that make use of peaks in auto-correlation function? I am currently involved in research on mapping methodology for dynamic algorithms. I came ...