# Tagged Questions

Correlation or Cross-Correlation is a measure of similarity of two waveforms as a function of a time-lag applied to one of them.

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### Practical advices for applying phase correlation in image registration task

I'm using OpenCV to detect shift between 2 images, here is sample code (based on cv::phaseCorrelate function): ...
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### Windowing the sequence to compute Correlation

I want to compute the Correlation Functions of the input and output time-domain sequence, ...
1answer
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### How to find the time instant where my sent signal and received signal can synchronize?

I am having two .wav files, one is modulated wave that is made into a .wav file and another is a recieved .wav file which is recorded from microphone while playing first modulated .wav file. So now ...
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### Can correlation be used for face recognition?

I read about the use of correlation 1D signals and how can it be used to find if a signal occurs in another signal. Can this principle, used for radar systems, be extended to facial recognition ? ...
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### Synchronization of two audio tracks via Mel-frequency cepstral coefficients (MFCCs)

I am trying to solve the (common) problem of synchronizing (i.e. measuring the delay between) two audio tracks recorded from different sources during a conference talk (about 1h of audio). One track ...
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### correlation vs. coherence of cortical signals

Does anyone have a simple explanation of the difference between the correlation and coherence of cortical signals? From what I understand, they are both a measure of the similarity between two signals ...
3answers
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### Phase shifting a noisy signal

I have a signal of the form $s(t)=A(t) \sum \cos(\omega_i(t)t +\phi_0) + n(t)$, where $n$ is gaussian noise. I can only read the signal+noise and thus can not separate them. I want to phase shift ...
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### Signal correlation vs Pearson correlation between signals

I have some data which are the sets of values uniformly distributed along some measure (simple example - along the time intervals). I tested both the coefficients and found the difference, some times ...
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### Timing synchronization in limited channel

I need measure timing of an signal that is send through a noise band limited channel (wireless). By measure timing, I mean measure as exactly as possible when the signal has arrived at the receiver. ...
3answers
469 views

### What does it mean exactly when two parts of a signal are correlated?

I stumble quite often upon the notion that two or more parts of a signal are correlated to describe semi-formally that they belong together. For example in image processing, two pixels on an edge ...
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### Correlation meter

I have three questions regarding the correlation meters used in audio. How are they calculated? I have heard correlation is performed by convolving one signal with the time flipped version of a ...
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### 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 ...
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243 views

### calculate relative error of two signals [duplicate]

I'm new to dsp.stackexchange and digital signal processing. I'm required to develop an app to measure the similarity of two signals.for an example I need to compare breathing of a man whether it is ...
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### Minimum Samples Per Chip?

Is there a 'Nyquist Criteria' for the minimum samples per chip that are needed for a correlator? I've heard 2, but will 1 work? What are the implications of having less than the minimum (in the ...
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### What type of correlation is this equation?

In a book [1], gives an equation (equation 5.31 in the book) for estimating frequency offset in OFDM systems proposed by Classen. the procedure is: first, two OFDM symbols, $y_l [n]$ and \$y_{l+D} ...
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### Autocorrelation function of a discrete signal

For a certain experiment of which I have data, I want to calculate the autocorrelation of the measurements. For this I used the expression from http://en.wikipedia.org/wiki/Autocorrelation#Estimation, ...