Skip to main content
2 votes

Which technique to use for signal/image processing or noise removal?

You may start with median or Gaussian filters. There are many libraries that implement them and they are simple to use. That said, I think this approach may be not enough because from what I've seen ...
KjMag's user avatar
  • 121
2 votes

Is the inverse radon transform considered a linear operation?

For an operator $R$ to be linear, it has to satisfy two conditions: $R(f+g) = Rf + Rg$ for any two operands $f,g$; $R(\alpha f) = \alpha Rf$ for any operand $f$ and (real or complex) number $\alpha$. ...
Wolfgang Bangerth's user avatar
2 votes
Accepted

Power spectrum incorrectly yielding negative values

This is due to an implicit time shift, which corresponds to a phase shift, perceived here as a sign inversion. The signal you are Fourier transforming is symmetric around t=0 and this is why you ...
zap's user avatar
  • 220
2 votes

identifying peaks in data

Fitting the peaks of gamma spectra is a typical task in non-destructive analysis of spent fuel or neutron activation analysis. Since these applications are already "quite old", there is some standard ...
GertVdE's user avatar
  • 6,159
2 votes

Solving numerically a linear ODE

It seems like your goal is to get an accurate numerical solution for you differential equation, which likely does not require you to code your own ODE solver. In that case, it is likely more efficient ...
whpowell96's user avatar
  • 2,636
2 votes
Accepted

Fourier Transform with logarithmic spacing?

This problem can be addressed by using a Constant Q transform instead of the ordinary Fourier transform. This functionally is provided, for example, by the python library Librosa. The constant Q ...
KF Gauss's user avatar
  • 171
1 vote

Cauchy Lorentzian simulation on FFT with oscillation

Welcome to scicomp! If I remember correctly, then in order to Fourier transform a function it has to be a periodical so that you can use the sine and cosine functions as base for it. In your case the ...
MPIchael's user avatar
  • 2,985
1 vote

Is the sine function periodic in $x$ or $y$?

Don't get hung up on these details of language. One might argue that because $x$ is the independent variable, it moves in arbitrary ways (can be chosen arbitrarily) and so it would make sense to say &...
Wolfgang Bangerth's user avatar
1 vote

Find shift in high resolution noisy signal if only local argmax data are available

If I understand you correctly, you have a periodic reference signal with pulses, and a list of the local maxima. From every local max, search for the nearest reference signal pulse and measure the ...
MPIchael's user avatar
  • 2,985
1 vote

Cyclic Deconvolution

Since convolution can be written as a matrix-vector product $Ax=b$ of a circulant or Toeplitz matrix $A$ acting on a vector $x$, you can invert or pseudoinvert via SVD $A$ to obtain $x=A^{-1}b$. That ...
smh's user avatar
  • 673
1 vote

Amplitude at a given frequency in a wide band signal

If you want the amplitude at a single frequency $f_0$ then you can multiply your signal by $e^{-j 2\pi f_0}$ and then use a simple moving average filter to remove other frequency components. This is ...
Hooman's user avatar
  • 121

Only top scored, non community-wiki answers of a minimum length are eligible