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1500 questions
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1 answer
General questions on the CMA equalizer
So I recently implemented a CMA equalizer in MATLAB that uses method of steepest descent to converge to the minimal cost. (Im on an equalizer implementation binge).
My questions are the following:
1) It seems to me that the CMA algorithm is only…
Spacey
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11
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3 answers
Understanding the Difference Between MAP Estimation and ML Estimation
There are a number of possible criteria to use in making decisions.
Can someone elaborate on the difference between ML and MAP for a sequence of BPSK symbols impaired by Gaussian noise ?
Abby_DSP
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11
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2 answers
Digital image moments in plain English
I'm studying OpenCV and, in computer vision and image processing, people speak of blobs, contours, connected regions, and I sometimes hear the phrase "image moments".
I know of an article on Wikipedia about it, but I think it is too technical. I…
nkint
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11
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8 answers
How can I generate a sine wave with time varying frequency that is continuous, in C?
How can I generate a sine wave with time varying frequency that is continuous? How can I resolve the following problem? I want a continuous graph.
I'm generating this simply like this:
for(int i = 0; i < pcm_buffer_size - 1; i += 2) {
float…
deltafft
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2 answers
Is a wavelet-based correlation measure worth any additional computational overhead?
I have used both correlation and coherence as measures of correlation between signals. I was thinking that a time-frequency approach would give me the best of these worlds.
My question is whether this extra data adds enough to the overall picture…
jonsca
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11
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2 answers
Understanding the Parameters of the Bilateral Filter
Allow me to show you a snip from Szeliski's Computer Vision book on bilateral filter. I don't know how to interpret these kernel definitions:
In the actual summation what values do the $k$ and $l$ take? E.g For a kernel of size 5x5 does $k$ take…
cannot image process
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11
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4 answers
What's the difference between the Gabor-Morlet wavelet transform and the constant-Q transform?
At a glance, the constant-Q fourier transform and the complex Gabor-Morlet wavelet transform seem the same. Both are time-frequency representations, based on constant-Q filters, windowed sinusoids, etc. But maybe there's a difference that I'm…
endolith
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11
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2 answers
Segmentation of half transparent material, e.g. glass
I'm totally stuck on an issue regarding the segmentation of glassy objects.
I need to get the object as precise as possible.
My approaches were different.
At first I tried to remove the background, so that only some sharp contours are left.
But that…
mchlfchr
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11
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3 answers
Why does the autocorrelation get its peak at zero?
I know that zero shifting in the autocorrelation function is equal to its energy, yet, I would like to understand why the peak is at zero.
itamarb
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11
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3 answers
Why transforming the data to a high-dimensional feature space in which classes are linearly separable leads to overfitting?
I read in my book (statistical pattern classification by Webb and Wiley) in the section about SVMs and linearly non-separable data:
In many real-world practical problems there will be no linear boundary separating the
classes and the problem of…
Gigili
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11
votes
2 answers
Harmonic Product Spectrum limitations in pitch detection
I've made a pitch detection algorithm using HPS and I'm facing a problem. I'm a beginner with signal processing and this site helped me before, so I though I should ask.
For higher pitches ( eg. >C6:1046.50hz ) I'm starting to get garbage data from…
Rad'Val
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11
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1 answer
What are thoughts on best modulation to use for underwater acoustic communications at low frequencies?
I wanted to ping the DSP hivemind for general thoughts on what would be the best modulation type to use for low frequency underwater communications. I have chosen this project since I can learn a lot from it.
Some context:
Low frequency as in <…
Spacey
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11
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1 answer
Cross Correlation Matrix
In my group, we have developed an algorithm which shows abstract information from quantum mechanical systems as images. This way, given a quantum system, we obtain an associated image which has the same information and makes some features…
Javier Rodriguez Laguna
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11
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3 answers
Apply Low pass Butterworth filter in Python
I want to use a low pass Butterworth filter on my data but on applying the filter I don't get the intended signal. Here is the dummy code:
Signal A:
import numpy as np
import matplotlib.pyplot as plt
from scipy import signal
a =…
Haroon Lone
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11
votes
3 answers
Understanding Cb and Cr Components of YCbCr Color Space
I am familiar with additive (RGB), substractive (CMYK), and HSV-like colorspaces, but an article I'm currently trying to understand operates on YCbCr color space for image segmentation / object definition.
I've spend most of my morning looking for…
penelope
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