Signal Processing Stack Exchange
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Where did Arnold Tustin first introduce the bilinear transform?

It's well known that the bilinear transform is also known as Tustin's Method. As far as I know, Arnold Tustin really did introduce the idea into the control systems literature, so the name isn't just a case of Stigler's Law. For example, I managed…
datageist
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Image Registration by Segmentation

Image registration algorithms are usually based on point features such as SIFT (Scale-Invariant Feature Transform). I saw some references to line features, but I was wondering if it would be possible to match image segments instead of points. For…
Libor
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Kalman Filter - Optimal Way to Handle "Derived" Measurements?

Ie, if you have as state variables position (p) and velocity (v), and I make low-frequency measurements of p, this also indirectly gives me information about v (since it's the derivative of p). What is the best way to to handle such a…
Paul Molodowitch
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How to demodulate an AFSK signal in software

I am trying to transmit binary data from one device to another over an audio channel (speaker/mic). I use AFSK (Audio Frequency Shift Keying) as in Packet Radio, with $1200 \text{ Baud}$ and two frequencies $f_{mark} = 1200 \text{ Hz}$ and…
Patrick Oscity
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Image Processing: How to detect a quadrialteral signboard in image?

How can I detect a quadrilateral signboard from an image captured using a mobile phone? How can i detect shapes like rectangle? rounded rectangle (rounded corners instead of shape corners)? I am using opencv.wrapper but i am new to it. Thanks. Here…
user364295
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1 answer

Will an Unscented Kalman Filter Be "As Good" as Other Optimization Algorithms for This Problem?

I want to calibrate a tri-axis magnetometer when a tri-axis gyroscope is also available. I am fairly certain I can solve this problem using various optimisation algorithms, but I would prefer to use an unscented Kalman filter for a number of reasons…
Benjohn
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Detecting meandering rivers in images

I have $n$ surfaces: $z_i(x,y)$ with a measured attribute (variable) on each surface: $a_i(x,y)$. Most of the surfaces will have a random distribution of the attribute across the surface, but some surfaces (the interesting ones) will show a…
Andy
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Connecting edges detected by an edge detector

I have a binary image obtained from a canny edge detector. The edges are not nicely detected in the center and I need to join them. The connection of edges is orientation and neighborhood dependent. I need to connect the vertices if they are below a…
Naresh
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Is up-sampling prior to cross-correlation useless?

Consider a simple case where two signals from two different sensors are cross-correlated, and the time-delay-of-arrival computed from the absissa of the peak of their cross-correlation function. Now let us further assume that due to the…
Spacey
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Differences between filtering and polynomial regression smoothing?

What are the differences between classical low-pass filtering (with an IIR or FIR), and "smoothing" by localized Nth degree polynomial regression and/or interpolation (in the case of upsampling), specifically in the case where N is greater than 1…
hotpaw2
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Why is telephone audio sampled at 8 kHz?

When did we decide to sample telephone at $8$ kHz? Has this always been the case? Why did we do that? Is it because higher bit rates can't be transferred as quick? And do these reasons still count? And if not, why isn't there a new standard yet? Is…
Lewistrick
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How to deal with a negative pole (unstable) in the pre-filter of a control system?

So while answering how to design a PI controller for a first order time delayed system (Question Here ) Here is the closed loop equation to a control system: $$ G_C(s) = \frac{\frac{K}{T}(1-sT)(s)} { s^3 + (\frac{1}{T} + a - KK_p)s^2 +…
CyberMen
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Time delay estimation of oscilloscope signals using cross correlation

I have recorded 2 signals from an oscope. They look like this: I want to measure the time delay between them in Matlab. Each signal has 2000 samples with a sampling frequency of 2001000.5. The data is in a csv file. This is what I have so far. I…
Nick Sinas
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Analytical expression for the eigenvectors of a 3x3 real, symmetric matrix?

I am writing an algorithm that process 3D images based on the local moment of inertia. I have a 3x3 real symmetric matrix, from which I need to find the eigenvalues. I have found a variety of generic algorithm for the diagonalization of matrices…
Jean-Yves
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Why is a negative exponent present in Fourier and Laplace transform?

could anyone explain why there is a need of negative exponent in fourier and laplace transform.I looked through the web but I couldn't get anything.Does anything happen if a positive exponent is placed in these transforms. While looking through…
justin
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