The tag has no wiki summary.

learn more… | top users | synonyms

1
vote
1answer
31 views

Suitable metrics for summarizing or visualizing the spatial activation of components after temporal Independent Component Analysis (ICA)

I will first describe the Independent Component Analysis (ICA) steps, so that the question becomes clearer, and more relevant to similar questions. Assume we have $N$ sensors distributed in space. ...
1
vote
0answers
70 views

Optimal filter bank from SVD/PCA

Given a million data points in say 100d, is there a way to generate an optimal filter bank of say 20 filters from an SVD of the data ? Call the 100d space $F$ (as in Frequency), with coordinates ...
1
vote
3answers
97 views

How would I represent an image using a basis $A$, given a sparse or compressible image?

Looking for a Basis representation: Given a sparse or compressible image M, how would one represent this image using a basis A? If I let m = vec(M) m = Ax where A is my "representation" basis and ...
1
vote
1answer
109 views

Calculating an incoherence property from sub-optimal sampling patterns

EDIT (after comments and subject matter review) CS is based on a choice of a sensing basis $\Phi$ relative to a representation basis $\Psi$. Using an "Incoherence Property" $\mu$ that measures the ...
1
vote
1answer
143 views

Decomposition of **3D** structuring elements for morphological operations

I am struggling to implement a mathematical morphology toolset in an image processing package. I base my implementation on what I saw in MATLAB, and on several papers on the subject. There seems to ...
1
vote
2answers
138 views

How do I perform the sifting process in empirical mode decomposition?

I am programming a voice activity detection algorithm and I found a paper that recommends the use of HHT. I have been trying to program it and understand how to calculate $m1(x)$, but the shifting ...
0
votes
0answers
93 views

Problem with decomposition from wavelet transform in Java

I need reconstruct the detail singnal of 9th decomposition from wavelet transform. My program is in java, and I found library colded jvawe that implements WPD(description is at the bottom of the ...
2
votes
0answers
47 views

wavelet transform boundary

I am doing 1D wavelet decomposition and I am particularly interested in parts at the border of the signal. These parts are affected by boundary effects. I know that some of the methods to extend the ...
2
votes
0answers
57 views

Can Cholesky outer product version result in negative square roots?

Say A is symmetric positive definite matrix , which means one necessary condition is diagonal entries of A are positive. If I do cholesky factorisation using outer product form, Can there be any ...
4
votes
1answer
1k views

I and Q Channels

My understanding of I and Q channels is as follows (please correct me if I am wrong): I = In-phase, or real component Q = ...
1
vote
1answer
362 views

Time-frequency analysis of non-sinusoidal periodic signals

Given the history of the sum of a time-varying mixture of periodic signals, say square waves, how would you efficiently estimate the number and frequencies of components active at a particular time? ...
3
votes
1answer
199 views

Empirical Mode Decomposition and Sparsity

In what sense does empirical mode decomposition (EMD) bring out the sparsity in a signal? For instance, if I had a signal $f$ and I broke it down into $n$ intrinsic mode functions (IMF), what should ...
3
votes
1answer
371 views

Mathematics / Signal theory behind billiard ball 'wave pendulum' effect

This YouTube video shows a very interesting effect. What is the underlying science? I have recently started studying Fourier theory and DSP, and and trying to understand what is going on in terms of ...