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1500 questions
11
votes
1 answer
Why does over-modelling an adaptive AR NLMS filter fix sharp spikes?
I just simulated an auto-regressive second-order model fueled by white noise and estimated the parameters with normalized least-mean-square filters of orders 1-4.
As the first-order filter under-models the system, of course the estimations are…
Andreas
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11
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3 answers
How to measure the agreement between to curves?
I have values (plotted below) of expected RSSI values over time that I would like to compare with my measured RSSI values. What I was looking for was a way to quantify it so I can change parameters and be able to compare/contrast different…
toozie21
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11
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2 answers
Where can we find noises like Gaussian, Rayleigh, Gamma, exponential noises in real world images?
I know that while taking pictures from a camera, noise may appear in the image.
It is often described as Gaussian, but what about the other noises, when do they occur in real world?
Please help!
Animesh Pandey
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11
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5 answers
Why does the derivative of an audio file act like a high-pass filter?
Code: https://github.com/echometerain/sound-derivative/blob/master/sd.py
I wrote a program which would subtract the current audio frame by the former one. Why does this act like a high-pass filter?
Rain
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11
votes
2 answers
High Dynamic Range FIR Filters
Related to this question on using the Windowing method for FIR filter design versus the optimized algorithms such as least squares (firls in MATLAB, Octave and Python scipy.signal, my usual "go-to" for filter design), I ran into another interesting…
Dan Boschen
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11
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2 answers
What is the difference between 'de-noising' and what we commonly know as filtering methods to remove noise?
Pretty simple question - I am trying to figure out what exactly is different between 'de-noising' a signal, and simply filtering it (as we commonly know) to remove noise. Is this a case of lexical overlap or is there something fundamentally…
Spacey
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11
votes
1 answer
Image processing and the Fourier Transform
I am trying to understand how and why the fourier transform is used in image processing / computer vision. Below is what I have gathered so far. Would my understanding of it be correct? If not, could somebody explain it to me in simple, plain…
user1796218
11
votes
4 answers
How can a filter have zero group delay?
If you put a wave packet through the passband of a 1st-order low-pass filter, it will be delayed by the group delay of the filter, and remain the same amplitude, right?
If you put the same wave packet through a complementary 1st-order highpass…
endolith
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11
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6 answers
How can I work on DSP using C/C++?
I have been working on MATLAB for signal processing for a while. Many companies from DSP for a communication background has asked me whether I know C/C++ very well. I am confused as to why the companies are using C/C++ for signal processing. Why not…
Sukshith Shetty
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11
votes
6 answers
Do discrete-time series always have a continuous-time underlying?
Can one argue that discrete time-series coming from stocks or commodities (prices) are derived from a continuous-time process?
One can probably argue that stocks or commodities at any time have a value and therefore a continuous-time price/value…
cifuentesba
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11
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3 answers
Most common modern day Image Segmentation techniques
I was doing some reading up on image segmentation techniques and I was wondering about modern day, state-of-the-art segmentation algorithms.
What current segmentation techniques that are a 'must-read', i.e. currently most commonly used in the…
GamingX
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11
votes
3 answers
How to tell if a high-res flac file has been upsampled from a CD-quality file?
Because I might encode my music in lossy format for other devices or edit them, I prefer to keep a high-res copy of my music. However, I know that it is possible to upsample a file using ffmpeg and it would appear the same as an authentic high-res…
Joy Jin
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11
votes
1 answer
Removing noise from F2F signal
(This question relates to Extracting Binary Magnetic-Strip Card Data from raw WAV)
I am extracting the binary sequence from the magnetic strip on a credit card.
As you can see, the signal is degraded clearly in one place. also there is a minor…
P i
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11
votes
2 answers
Does the Nyquist frequency of the cochlear nerve impose the fundamental limit on human hearing?
The bandwidth of human hearing by empirical data is $20 \; Hz$ to $20 \; kHz$. A cochlear implant stimulates the auditory or acoustic or Cochlear nerve directly so that the hearing can be improved in the case of stimulation mechanism upstream of…
kbakshi314
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11
votes
2 answers
Explanation on Haarlets
Would someone be able to give me some info or a link etc ... regarding haarlets aka Haar wavelet-like features. I'm reading several papers for my master dissertation and several of these papers briefly mention haarlets. I can't seem to really get…
Olivier_s_j
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