Signal Processing Stack Exchange
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1500 questions
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3 answers

Real discrete Fourier transform

I am trying to understand the real DFT and the DFT and why the distinction exists. From what I know so far the DFT uses $e^{i2\pi kn/N}$ for basis vectors and gives the representation $$x[n]=\sum_{k=0}^{N-1}X[k]e^{i2\pi kn/N}$$ The sum is written…
user782220
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Find similar Music using FFT Spectrums

I have been experimenting some weeks to find a way to match/find similar Songs in a Library containing different Genres of Music. My first try was to Detect Features like Tempo or how much Bass there is in Songs to form groups, but I didnt get far…
gfg
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How to extract traffic signs from a photograph?

What image analysis techniques can I use to extract the traffic signs from an image such as the one below? Edit: After Anisotropic diffusion: The background that i don't want gets cleared a little After Dilation : Thresholding after Diffusion :…
vini
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How do I find a system's impulse response from its state-space repersentation using the state transition matrix?

Suppose we have a linear represented in the standard state space notation: $$ \dot{x}(t)=Ax(t)+Bu(t)$$ $$y(t) = Cx(t) + Du(t)$$ In order to get its impulse response, it is possible to take its Laplace transform to get $$sX=AX+BU$$ $$Y=CX+DU$$ and…
Phonon
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16
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How do I recover the signal from an ECG image

In my project, I have to digitize an ECG image taken with a normal camera (jpeg). For example, I have the following camera captured image: and I want to get something like this:- and then the digitized data (x,y points), like in this video on…
Deepak
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How do you measure "detail" of a signal?

I have an image and I would like to measure the amount of detail in it. Another way to look at it is to measure how blurry an image is. One way is to analyse the high frequency components in the Fourier transform of the image. Are there any…
Patrik
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How can I plot frequency vs magnitude of wavelet transform?

I am running Morlet continuous wavelet transform. I have got wscalogram of signal and now I want to plot freq-magnitude like the following picture., but I don't know how to do it: I've used scal2freq MATLAB function to convert scales to pseudo…
SAH
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System identification packages

I've been hunting around for an alternative to Matlab's System Identification Toolbox, but the commonality of the terms "system" and "identification" are confounding the search. Are there any standalone libraries that are written for this purpose?…
jonsca
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How do I determine if a discrete signal is periodic or not?

I want to know how I can determine whether a series of data is periodic or not. I want to use Fourier transform/series. My data looks either aperiodic [111100001111000110010101010000101] or periodic [11001100110011001100] and I need to decide…
safzam
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could anybody explains me why IIR filters do not have linear phase?

Please tell me. Also I dont know why phase is linear with FIR filters. I would like quantitative analysis. And why linear phase is not achieved by IIR filters ?
hafsa
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Reading the Wavelet transform plot

I am having trouble understanding on how to read the plot plotted by a wavelet transform, here is my simple Matlab code, load noissin; % c is a 48-by-1000 matrix, each row % of which corresponds to a single scale. c =…
Sufiyan Ghori
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Measuring length of DNA fibers from an image of single molecules

I am a biologist with very little experience with image processing but have sufficient knowledge of MATLAB and have the image processing toolbox. Ideally I am looking for a MATLAB based solution, but an approach outlining how to go about it would…
Lee Sande
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Does the determination of the ergodicity of a signal force any changes in methodology?

In mathematics, the term ergodic is used to describe a dynamical system which, broadly speaking, has the same behavior averaged over time as averaged over space. -from wikipedia From the perspective of engineering a signal processing system, does…
jonsca
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What is the first derivative of Dirac delta function?

Could you please help me in a simple way, what is the first derivative of a Dirac delta function? I found this answer: The informal answer is a positive Delta function immediately followed by a negative-going Delta function. Could you please…
Amro Goneim
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Profile Matching in a Point Cloud

A point cloud is generated using uniform random function for (x,y,z). As shown on the following figure, a flat intersecting plane (profile) is being investigated that matches as the best (even if not the exact one) a target profile i.e., given at…
Developer
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