Signal Processing Stack Exchange
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1500 questions
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4 answers

Estimating period of low frequency oscillations: autocorrelation vs. Frequency approaches

I have a noisy signal around $15\text{s}$ long sampled a $32\,\text{Hz}$. I am trying to estimate the peak frequency or period for a low frequency component with expected frequency in between $0.08\,\text{Hz}$ and $0.2\,\text{Hz}$. Empirically I…
00__00__00
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Can you represent an audio signal in any other domains besides time and frequency?

Maybe a stupid question, but if there is a time-domain representation of audio signal, and also frequency-domain, so is there any other domain that signal can be represented in?
apocalypse
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Levinson's algorithm and QR decomposition for complex least-squares FIR design

I'm studying Mathias's thesis Algorithms for the Constrained Design of Digital Filters with Arbitrary Magnitude and Phase Response. In section 2.1.2 the complex LS approximation problem is defined by an overdetermined linear…
ZR Han
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FFT of random binary data

I am trying to make sense of FFTs and binary data. Say I have a series of random binary data, which is measured with a repetition rate of 400Hz (interval time of 0.0025s). I have a total of 12489 points, which corresponds to a total measurement time…
ElizabethPor
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2 answers

What is the state-of-the-art method for dealing with illumination issues in background subtraction?

I have been struggling to find a well-cited approach to this. Essentially, I am experimenting with different background subtraction algorithms, but none seem to perform well when there are significant lighting changes (say, from a window in the…
charlie
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2 answers

Gesture recognition with Hidden Markov Models

I am currently working on a gesture recognition system (for an Android Application). I think that I have completed the Image processing stage, where I am able to extract the contour of the hand (I am wearing a glove to avoid background subtraction…
test
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How to Tell How Likely a Signal Is Present in Another One (Variance Unknown)?

I know this is probably a simple question, but I haven't been able to find a satisfactory answer anywhere... Say you have a time series signal of finite length N. Call it $y[n]$. It looks like a sine-gaussian perhaps but with some random effects. …
bill_e
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What sensors can be fused using the Kalman Filter framework

I was recently introduced to the concept of Kalman filtering in the context of projectile tracking. A classmate recommended this to me, and what intrigued me most was its ability to fuse different types of information from sensors. Are there types…
batlike
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Proof that the rectangular window has the best resolution

The resolution of a window is typically defined by the width of its spectral mainlobe (3dB-width or null-to-null width). It is often stated that the rectangular window has the best resolution among all windows. In my work, I'd be looking for a…
Lukas
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Distinguish vowels from consonants

Problem of processing speech. Required to determine the phonemes and identify vowels and consonants. Anyone involved in this? Please advise what work on the subject is worth reading?
ekruten
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Why complex numbers are represents as a+ib and can't be as (a,b)?

I am confused as why do we need to represent the complex numbers with the imaginary y-axis if we can simply represent them as (x,y) ? I've read that Multiplication by i is an anti-clockwise rotation of a quarter-circle over y-axis. Multiplying 1 by…
Sufiyan Ghori
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Advantage of STFT over wavelet transform

I have learned about STFT and wavelet transform recently, and wavelet transform seems better than STFT in my opinion. So, I wonder if there is any advantage of using STFT than WT, and if so, what are practical applications of STFT?
lemoncake
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Image / Video Upscaling (Super Resolution) Algorithm Explanation (Image and Video Upscaling from Local Self Examples)

So, I'm trying to implement the classical algorithm described in this paper Image and Video Upscaling from Local Self-Examples and this presentation to serve as a baseline for comparison with AI/NN-based approaches for the same problem. My issue is…
Br4veSt4rr
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Fixed point multiplication with negative numbers

I am stumped on a simple problem. Let's say I have two 4 bit numbers in Q0.3 format. One sign bit and three fractional bits. So I can represent $-1$ through to $0.875$. Let's now say I wish to do this calculation: $-0.25 \times 0.875$. Which…
benjwy
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Median Filter one after another

Operate on an image by performing Median Filtering in a 3x3 window. Operate on the resulting image by performing, again, Median Filtering in a 3x3 window. Can the resulting image be obtained from a single Median filtering? my initial thought is that…
Gilad
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