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1500 questions
64
votes
17 answers
What is the physical meaning of the convolution of two signals?
If we convolve 2 signals we get a third signal. What does this third signal represent in relation to the input signals?
Parag
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64
votes
4 answers
Why is TV static noise always black and white?
Most modern day Cathode Ray Tube (CRT) televisions manufactured after the 1960s (after the introduction of NTSC and PAL standards) supported the circuit-based decoding of colored signals. It is well known that the new color standards was created to…
nabulator
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64
votes
6 answers
What is the distinction between ergodic and stationary?
I have trouble distinguishing between these two concepts. This is my understanding so far.
A stationary process is a stochastic process whose statistical properties do not change with time. For a strict-sense stationary process, this means that its…
Matt
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61
votes
6 answers
What Is the Relationship Between a Kalman Filter and Polynomial Regression?
What is the relationship, if any, between Kalman filtering and (repeated, if necessary) least squares polynomial regression?
hotpaw2
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60
votes
10 answers
Meaning of Hilbert Transform
I understand the Fourier Transform which is a mathematical operation that lets you see the frequency content of a given signal. But now, in my comm. course, the professor introduced the Hilbert Transform.
I understand that it is somewhat linked to…
MathieuL
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58
votes
5 answers
Analogous Library to OpenCV for Audio Processing / Analysis
I understand OpenCV is the de facto library for programming image processing in C/C++; I'm wondering if there is a C or C++ library like that for audio processing. I basically want to filter raw waves from a microphone, and analyze them with some…
Tae-Sung Shin
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57
votes
8 answers
What are some good signal and image processing blogs worth following?
Are there some good sites or blogs where I can keep myself updated on the latest news and papers about image and signal processing research, or I should just check out "classical" providers like IEEE Transactions, Elsevier, etc?
martjno
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55
votes
5 answers
What is the difference between convolution and cross-correlation?
I've found on multiple sites that convolution and cross-correlation are similar (including the tag wiki for convolution), but I didn't find anywhere how they differ.
What is the difference between the two? Can you say that autocorrelation is also a…
Mien
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55
votes
4 answers
What is the sparse Fourier transform?
MIT has been making a bit of noise lately about a new algorithm that is touted as a faster Fourier transform that works on particular kinds of signals, for instance: "Faster Fourier transform named one of world’s most important emerging…
nibot
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55
votes
5 answers
What is the difference between phase delay and group delay?
I'm studying some DSP and I'm having trouble understanding the difference between phase delay and group delay.
It seems to me that they both measure the delay time of sinusoids passed through a filter.
Am I correct in thinking this?
If so, how…
dB'
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54
votes
16 answers
What Resources Are Recommended for an Introduction to Signal Processing (DSP)?
What are some recommended resources (books, tutorials, lectures, etc.) on digital signal processing, and how to begin working with it on a technical level?
Dulan
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54
votes
6 answers
Best way of segmenting veins in leaves?
I have done a lot of research and found out methods like adaptive thresholding , watershed etc that can be used of detecting veins in leaves . However thresholding isn't good as it introduces a lot of noise
All my images are gray image please could…
vini
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53
votes
6 answers
The difference between convolution and cross-correlation from a signal-analysis point of view
I am trying to understand the difference between convolution to cross-correlation. I have read an understood This answer. I also understand the picture below.
But, in terms of signal processing, (a field which I know little about..), Given two…
MathBgu
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51
votes
10 answers
What is the least JPG-compressible pattern? (camera shooting piece of cloth, scale/angle/lighting may vary)
I am trying to design a cloth that, from the point of view of a camera, is very difficult to compress with JPG, resulting in big-size files (or leading to low image quality if file size is fixed).
It must work even if the cloth is far away from the…
Nicolas Raoul
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50
votes
3 answers
Why is the FFT "mirrored"?
If you do an FFT plot of a simple signal, like:
t = 0:0.01:1 ;
N = max(size(t));
x = 1 + sin( 2*pi*t ) ;
y = abs( fft( x ) ) ;
stem( N*t, y )
1Hz sinusoid + DC
FFT of above
I understand that the number in the first bin is "how much DC" there is…
bobobobo
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