cross-correlation Questions
4
I have two signals which are related to each other and have been captured by two different measurement devices simultaneously.
Since the two measurements are not time synchronized there is a small ...
Bed asked 5/1, 2017 at 19:13
1
If I have two arrays that are identical except for a shift:
import numpy as np
from scipy import signal
x = [4,4,4,4,6,8,10,8,6,4,4,4,4,4,4,4,4,4,4,4,4,4,4]
y = [4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,6,8...
Aorta asked 13/5, 2022 at 13:38
2
I try to implement the spatial spectrum from the above equation (attached)
Where kX, kY are the grid points in k space,
C(w,r) - cross spectral densities between the i'th and j'th sensor(here it i...
Janik asked 19/1, 2022 at 9:47
4
Solved
I have been struggling the last days trying to compute the degrees of freedom of two pair of vectors (x and y) following reference of Chelton (1983) which is:
degrees of freedom according to Chelt...
Pirri asked 22/11, 2018 at 18:4
2
Solved
I am having some trouble with the ccf() method in the (Python) statsmodels library. The equivalent operation works fine in R.
ccf produces a cross-correlation function between two variables, A and ...
Copperplate asked 19/8, 2020 at 17:20
1
Solved
Say the two series are:
x = [4,4,4,4,6,8,10,8,6,4,4,4,4,4,4,4,4,4,4,4,4,4,4]
y = [4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,6,8,10,8,6,4,4]
Series x clearly lags y by 12 time periods.
However, using the fol...
Cystic asked 9/9, 2021 at 11:46
2
Solved
I have recently started using Mathdotnet Numerics statistical package to do data analysis in c#.
I am looking for the cross correlation function. Does Mathdotnet have an API for this?
Previously ...
Tallis asked 26/9, 2017 at 6:33
2
Solved
Basically I wanted to ask two things:
Why does this happen? (negative zero in Matlab)
When does this happen?
I came up with this. Octave has some similarities with Matlab, so the usefulness of th...
Ruck asked 30/4, 2016 at 15:11
2
Solved
I am struggling with template matching in the Fourier domain in Matlab. Here are my images (the artist is RamalamaCreatures on DeviantArt):
My aim is to place a bounding box around the ear of ...
Mather asked 19/9, 2015 at 5:10
8
I am learning numpy/scipy, coming from a MATLAB background. The xcorr function in Matlab has an optional argument "maxlag" that limits the lag range from –maxlag to maxlag. This is very useful if y...
Chinquapin asked 5/6, 2015 at 23:25
3
I have various time series, that I want to correlate - or rather, cross-correlate - with each other, to find out at which time lag the correlation factor is the greatest.
I found various questions...
Rumph asked 16/10, 2015 at 13:12
2
How can I calculate pearson cross correlation matrix of large (>10TB) data set, possibly in distributed manner ? Any efficient distributed algorithm suggestion will be appreciated.
update:
I rea...
Rebba asked 17/2, 2017 at 17:30
3
I have two irregular lines as a list of [x,y] coordinates, which has peaks and troughs. The length of the list might vary slightly(unequal). I want to measure their similarity such that to check oc...
Sarabia asked 16/9, 2015 at 5:53
1
Solved
I am trying to look at astronomical spectra using Python, and I'm using numpy.correlate to try and find a radial velocity shift. I'm comparing each spectrum I have to one template spectrum. The pro...
Borroff asked 9/4, 2018 at 22:26
0
This is similar question to the other questions but not a duplicate one. However, I am still not able to get the correct result.
I am basically trying to record two Wav files (1 - Base File 2 -Te...
Sickness asked 19/10, 2016 at 23:39
2
Solved
I want to find the offset between two arrays of timestamps. They could represent, let's say, the onset of beeps in two audio tracks.
Note: There may be extra or missing onsets in either track.
I ...
Bengali asked 5/10, 2016 at 15:9
3
Solved
I've two signals, from which I expect that one is responding on the other, but with a certain phase shift.
Now I would like to calculate the coherence or the normalized cross spectral density to ...
Cytoplasm asked 8/2, 2014 at 14:18
1
Solved
I have a reference signal (s1) of length = 5 and another signal (s2) of length = 25 samples (containing a shifted version of the same 5 sample signal s1).
I want to find the normalised cross corre...
Djerba asked 25/8, 2016 at 12:19
1
Solved
I have looked at this question but it hasn't really given me any answers.
Essentially, how can I determine if a strong correlation exists or not using np.correlate? I expect the same output as I g...
Extraordinary asked 7/5, 2016 at 20:29
1
Solved
I have a large number of cross-correlations to calculate and I'm looking for the fastest way to do it. I'm assuming vectorizing the problem would help rather than doing it with loops
I have a 3D a...
Hafiz asked 31/7, 2015 at 7:3
1
Solved
I'm doing some C++ optimization work and have need of the plain vanilla version of cross correlation without any mean offset or normalization scaling operations. I know that under normal circumstan...
Lofty asked 23/7, 2015 at 23:47
2
Solved
I am trying to implement a 2d phase correlation algorithm in R using a recipe from Wikipedia (http://en.wikipedia.org/wiki/Phase_correlation) in order to track the movement between 2 images. These ...
Filly asked 3/6, 2015 at 21:1
1
Solved
My boss and I disagree as to what is going on with the CV_TM_CCORR_NORMED method for matchTemplate(); in openCV.
Can you please explain what is happening here especially the square root aspect of...
Headrace asked 13/2, 2015 at 18:53
2
Solved
The image below shows two circles of same radius, rendered with antialiasing, only that the left circle is shifted half pixel horizontally (notice that the circle horizontal center is at the middle...
Danelledanete asked 5/12, 2012 at 19:28
1
Solved
I can't find a reason why calculating the correlation between two series A and B using numpy.correlate gives me different results than the ones I obtain using statsmodels.tsa.stattools.ccf
Here's ...
Wellesz asked 7/7, 2014 at 17:48
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