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1500 questions
19
votes
1 answer
What are the proper pre-processing steps to perform Independent Component Analysis?
What are the proper steps for preprocessing my waveforms in order to perform an independent component analysis (ICA) later? I understand the how, though further explanation of that doesn't hurt, but I'm more interested in the why.
jonsca
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19
votes
1 answer
Help calculating / understanding the MFCCs: Mel-Frequency Cepstrum Coefficients
I've been reading bits and pieces online but I just can't piece it all together. I have some background knowledge of signals / DSP stuff which should be enough prerequisites for this. I'm interested in eventually coding this algorithm in Java but I…
YoungMoney
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19
votes
9 answers
Efficient Magnitude Comparison for Complex Numbers
Is there a more efficient algorithm (or what is the most efficient known algorithm) to select the larger of two complex numbers given as $I + jQ$ without having to compute the squared magnitude as
$$I^2+Q^2$$
In particular binary arithmetic…
Dan Boschen
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19
votes
3 answers
Show others how I hear myself
Sooo .. I've been thinking about this stuff. We all know that we sound different from what we hear of our own voice. It is easy to find out how others hear us by recording oneself and listen to it.
But what about the other way around?
Is there a way…
Dunkingdev
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19
votes
5 answers
Finding polynomial approximations of a sine wave
I want to approximate the sine wave given by $\sin\left(\pi x\right)$ by applying a polynomial waveshaper to a simple triangle wave, generated by the function
$$T\left(x\right)=1-4\left|\tfrac{1}{2}-\operatorname{mod}(\tfrac{1}{2}x+\tfrac{1}{4},\…
Guest
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19
votes
6 answers
Filter design by distributing poles and zeros on parametric curves
An $N$th order Butterworth low-pass filter of cutoff frequency $\omega_c$ can be designed by distributing $N$ poles uniformly with respect to parameter $0 < \alpha <1$ on an s-plane parametric curve $f(\alpha) = \omega_c e^{i(\pi/2+\pi\alpha)}$,…
Olli Niemitalo
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19
votes
1 answer
Kalman filter in practice
I have read the description of the Kalman filter, but I am not clear on how it comes together in practice. It appears to be primarily targeted at mechanical or electrical systems since it wants linear state transitions and that it is not useful for…
John Robertson
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19
votes
3 answers
How to Resample Audio Using FFT or DFT
I'm down sampling voice audio by first performing an FFT, then only taking the parts of the result that I need, and then performing an inverse FFT. However, it's only working properly when I'm using frequencies that are both power of two, say…
thr
19
votes
5 answers
How do I optimize the window lengths in STFT?
I have many EEG signals and I want to analyze them using linear methods such as STFT (Short Time Fourier Transform). In STFT , How can I optimize the analysis window length, to reflect the frequency spectrum of each analysis window in a proper way?
Maen
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19
votes
2 answers
Terminology: spectrum, spectrogram, spectrograph, sonogram, etc
In term of proper or accepted naming conventions of DSP graphics or instrumentation output, what is the difference between the words spectrum, spectrogram, spectrograph, and similar terms, and what type of chart, graph, CRT display, or etc. does…
hotpaw2
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19
votes
4 answers
Applicability of compressed sensing / compressive sensing
From what I have heard, compressed sensing can only be utilized for a sparse signal. Is this correct?
If that is the case, how can a sparse signal be distinguished from any bandlimited signal? Every signal can be expanded to include a sparse or…
user2346
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19
votes
2 answers
What Does Make an Error Surface Convex? Is It Determined by the Covarinace Matrix or the Hessian?
I am currently learning about least-squares (and other) estimations for regression, and from what I am also reading in some adaptive algorithm literatures, often times the phrase "... and since the error surface is convex..." appears and any depth…
Spacey
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19
votes
3 answers
Help understanding Hough transform
I'm trying to get a Hough transform to work in MATLAB, but I'm having problems. I have a really bad way of detecting peaks that needs to be fixed, but before that I need to be able to reverse the hough transform to create the lines again properly.…
waspinator
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19
votes
1 answer
Who is Barbara?
In recent years, I have started doing work in image analysis and have used the Barbara and Lena images. Early on, I became aware of the interesting history surrounding the Lena image and that got me wondering:
Who is Barbara?
Where was the…
Paul
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19
votes
4 answers
What Are the Limitations of a Canny Edge Detector?
Broadly a majority of the literature on edge detection algorithms and applications that uses edge detection, references Canny's edge detector. So much so that it looks like almost "the solution" to edge detection. Certainly, it would do the best…
Dipan Mehta
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