Signal Processing Stack Exchange
Signal Processing Stack Exchange

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1500 questions
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Is it customary to correct for the gain of a window?

Consider how the Hanning window is defined: 0.5 - 0.5 * cos(n*2*Pi/(N-1)) By this definition, it has a gain of 0.5, which is simply the average value of the coefficients. By contrast, Flattop windows, as defined, have unity gain, presumably by…
user5108_Dan
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When can we write Heisenberg uncertainty Principle as a equality?

We know that Heisenberg uncertainty Principle states that $$\Delta f \Delta t \geq \frac{1}{4 \pi}.$$ But (in many case for Morlet wavelet) I have seen that they changed the inequality to an equality. Now my question is when are we allowed to change…
SAH
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ICA - Statistical Independence & Eigenvalues of Covariance Matrix

I am currently creating different signals using Matlab, mixing them by multiplying them by a mixing matrix A, and then trying to get back the original signals using FastICA. So far, the recovered signals are really bad when compared to the original…
Rachel
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How to compute camera pose from Homography matrix?

Say I use only one calibrated camera. From this camera, I get images A and B. I know the homography between A and B, computed through OpenCV's findHomography(). I know the pose (rotation matrix R and translation vector t) of image A, and I need the…
Stéphane Péchard
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Detection of circles (ellipses) in 2D point cloud

Given a set of points (2D) i.e., point cloud (PC), the question is about a robust, accurate and computing-friendly method to find circles (or ellipses in advanced version). The intuitive idea is to use Brute-Force Search on all possible points (as…
Developer
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Relationship between entropy and SNR

In general any form of enropy is defined as uncertainty or randomness. In a noisy environment, with increase in noise, I believe that entropy increases since we are more uncertain about the information content of the desired signal. What is the…
Ria George
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List of possible image features for content based image retrieval

I am trying to find a list of possible image features like color, oriented edges and so on for measuring their usability in case of finding same/similar objects in images. Does anyone know such a list or at least some features?
Hans Sperker
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How can I design a very narrow filter?

Suppose I've got an audio signal sampled at $48000$ Hz, and I'd like to design a low-pass filter that isolates everything below ~$60$Hz. In the digital world, this is a low-pass filter with the passband at $[-\frac{\pi}{400} , \frac{\pi}{400} ] $.…
Phonon
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Binary robust independent elementary features ("BRIEF") understanding

How are the descriptors in the BRIEF algorithm matched to each other? How is the template image found in the another image? How do we compare the descriptors? I have read that article but didn't understand how they have done it. They wrote that they…
maximus
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What Are Linear and Circular Convolution?

I have some basic understanding of signals and convolution. As far as I know it shows the similarities of two signals. Could I get some explanation in plain English of: what are the linear and circular convolution why they are important practical…
Sturm
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How to Improve Least Means Squares (LMS) / NLMS Filter Performance?

Are there ways to increase computational performance of a normalized least squares (NLMS) filter? Multidelay block frequency-domain (MDF) filters have been proposed to do this, but they also take away from convergence speed and accuracy, because…
Phonon
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Why convolution is required, or what is the philosophy behind convolution?

I am working in digital image restoration field. I have read all things about convolution, that, for an LTI system, if we know its impulse response, then we can find its output by just using convolution between input and impulse response. Can…
Mayank Tiwari
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How to find the convolution kernel in frequency domain?

I have a two vectors of spatial data (each about 2000 elements in length). One is a convolved version of the other. I am trying to determine the kernel that would produce such a convolution. I know that I can do this by finding the inverse Fourier…
Bowler
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Learning roadmap for the audio signal processing beginner

I would like to start learning audio signal processing. There are numerous books online and academic papers all of which seem to skip the fundamentals of the topic. I would like to know a rough roadmap, so to speak, to follow in order to…
some_id
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How can I build something, like actual implementations of all these things I am learning in signal processing?

I am an undergraduate electronics engineering student taking a signal processing course this semester. I have learned a lot of theoretical things in my lectures, such as how to shift or fold a signal, how to convolve 2 signals, how to take their…
Koustubh Jain
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