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Questions tagged [signal-processing]

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What does the Jackson Kernel measure?

A certain filter I'm writing uses two different kernels. The Fejer kernel (which is common) and the Jackson kernel: $$ \Delta_T(x) = T \,\left( \frac{\sin \pi T x}{\pi T x}\right)^2 \quad\text{and}...
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1answer
34 views

Cyclic Deconvolution

Suppose I want to generate a vector y which when circularly convoluted with a vector h gives me a vector ...
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0answers
21 views

Can Mallat's pyramidal algorithm be extended to non-power of 2 input sizes?

Mallat's pyramidal algorithm for the discrete wavelet transform operates of power of 2 vector lengths. Can it be extended to work on inputs of any size without resorting to zero padding?
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41 views

Fourier Transform Scaling the magnitude

I have a set of signals S1, S2, ....,SN, for which I am numerically computing the Fourier transforms F1, F2, ,,,,FN. Where Si's and Fi's are C++ vectors (my computations are in C++). My Computation ...
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2answers
69 views

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

I have an image that looks like this (it might appear low res in a browser because it is 16 MB). This image was taken with a scanning electron microscope, but because the equipment is outdated there ...
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1answer
62 views

Is the inverse radon transform considered a linear operation?

I wanted to know if practically the inverse radon transform operation is considered linear and would be a good candidate for the application of compressed sensing. To my understanding it should be ...
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1answer
136 views

Hankel transform from paper works only for certain functions

I implemented an algorithm for solving the Hankel transformation based on a paper. My problem is: It works very good for the functions suggested in the paper (as test functions), it works pretty ok ...
2
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1answer
133 views

Power spectrum incorrectly yielding negative values

I have a real signal in time given by: And I am simply trying to compute its power spectrum, which is the Fourier transform of the autocorrelation of the signal, and is also a purely real and ...
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0answers
41 views

Best way to to find fitting parameters for time series of decaying-growing oscillator type

I have discrete time series emerging from the numerical simulations. It means that the time series can be slightly noisy. The time series should "obey" to the following formula: $$ \psi(t) = \sum_{i=1}...
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3answers
159 views

Amplitude at a given frequency in a wide band signal

Could anyone suggest the most computationally efficient method for finding amplitude at a given frequency having a noisy wide band signal. To be more specific about a task. I have some physical ...
3
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1answer
94 views

Estimating Regions of Flow in Grayscale Video

I am looking to find an algorithm/method by which I can detect regions of flow in a video. The video is that of a grayscale heatmap where the majority of the image is not in motion. The areas that are ...
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0answers
193 views

Fast Forward Laplace transform

There are examples for fast numerical inversion of the Laplace transforms. For example here: http://www.mathworks.com/matlabcentral/fileexchange/32824-numerical-inversion-of-laplace-transforms-in-...
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124 views

Am I using the incorrect implementation of the fast Chebyshev transform?

I was told that the fast Chebyshev transform has superior spectral convergence, but I am unable to verify its rumored convergence. I was given plots of its spectral convergence, where the signal's ...
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0answers
35 views

Concatenating small windows of EEG signals over trial

My question is regarding the mathematical implications of concatenating very small windows from different trials, of the same size and for the same period in time after a stimuli. In other words, ...
1
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1answer
1k views

Creating Periodic Noise in Matlab and then adding it to a signal

I am not sure if this is the correct forum for this question but here it goes. If this is not the correct forum please direct me to the appropriate forum. I wish to add some periodic noise to a 1-D ...
2
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2answers
575 views

Parametric spectrum estimation using aryule: difference between Python and Matlab

I have some code illustrating my problem below. As you can see from the results- Matlab is significantly faster than python. It seems that the function which performs the levinson durbin recursion in ...
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1answer
122 views

How can we compute statistics of the DFT of a random signal?

I would like to know how to compute the statistics of the discrete Fourier transform of a noise signal. To illustrate what I mean, I will first explain in detail a computation I have managed to do ...
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0answers
57 views

Error in treating non-uniformly spaced data as uniform

In discussing smoothing filters, Numerical Recipes p. 772 says ... irregularly sampled data, where the values $f_i$ are not uniformly spaced ... one can simply pretend that the data points are ...
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1answer
338 views

Calculate large and small frequency separation for the Sun

I want to determine the big and small frequency seperation from timeseries data for the sun. An excerpt of the data (timeseries and power series) is plotted below. The power series is calculated in ...
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1answer
129 views

Use Butterworth and Chebychev filters

I need to calculate frequency response, phase response and apply to signals the Butterworth, Chebychev1 and Chebychev2 band-pass filters. I'm developing in C++ with Qt, and I'm looking for algorithms ...
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4answers
4k views

What is the best way to find discontinuities of a black-box function?

It was suggested that this might be a better place for this question than Mathematics Stack Exchange where I asked it before. Suppose one has a black-box function which can be evaluated anywhere (...