Signal Processing Stack Exchange
Signal Processing Stack Exchange

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Fast DCT implementation

I'm having trouble figuring out how to follow the fast 8x8 DCT algorithm diagrams found in the following two papers: (1) A Fast Computational Algorithm for the Discrete Cosine Transform by Chen et al. and (2) Practical Fast 1-D DCT Algorithms With…
Mokosha
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Complex conjugate and IFFT

I asked a question over on stack overflow. I'm having a slight problem however. As suggested by Paul R I am mirroring my lower $n/2$ bins into the upper $n/2$ bins. I have a few questions however. I'm assuming $n$ is $2^{fftOrder}$? Thus for an…
Goz
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Log-Polar DFT Based Scale-Invariant Image Registration

I'm trying to do image registration using phase correlation as described in the Reddy Chatterji paper. In my case, the images may be scaled and translated relative to each other. The algorithm for finding the relative scale, as I understand it, is…
Drew Cummins
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Noise removal in medical segmented image

Can anyone suggest methods for removing the noise (indicated inside the red square) from every where in the following image, while keeping the white lines?
crack_addict
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How to perform a Rubberband-Correction on spectroscopic data?

I basicaly understood how the Rubberband/Baseline-correction works. The given spectrum is divided into (N) ranges. The lowest points in every range are determined. The initial baseline is built out of those points. Now all the points on the…
チーズパン
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Convert a FIR to an equivalent IIR

Is there a way to convert a FIR to an IIR filter with the most similar behavior?
Andrea
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Is the Kalman Filter a Best Linear Unbiased Estimator (BLUE) for Heteroscedastic Noise?

According to the Gauss-Markov Theorem, a ordinary least squares estimator is BLUE if the noise entering a system is uncorrelated with zero mean and is homoscedastic (has a constant finite variance). I am aware that a Kalman Filter applied to a…
sid
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Difference between Nyquist rate and Nyquist frequency?

So I've been searched online and can't seem to find a clear cut answer to this question. From my understanding, the Nyquist rate is double of the maximum frequency of a signal which Nyquist frequency is half of the Nyquist rate. Which would conclude…
QQStack
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Is concept of "bit" in computer programming similar to the concept of "bit" in information theory?

until today I knew that one bit is a variable, or a space in memory that can hold a value of either One (high) or Zero (low). This is the concept I learned from studying computer programming, microprocessor or DATA bus etc. But after starting the…
benjamin
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How does auto focus in cameras work?

I am just wondering how does camera auto focus work. What kind of processing does it do on images in order to adjust the focus? Is there freely available code that detects the focus level of an image or video?
Cory
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How to estimate octave and size for visual features positioned at Harris corners

I am currently working with and comparing the performance of several feature detectors provided by OpenCV as basis for visual feature matching. I am using SIFT descriptors. I have accomplished satisfactory matching (after rejecting bad matches) when…
penelope
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Designing a feature vector for discriminating between different sonic waveforms

Consider the 4 following waveform signals: signal1 = [4.1880 11.5270 55.8612 110.6730 146.2967 145.4113 104.1815 60.1679 14.3949 -53.7558 -72.6384 -88.0250 -98.4607] signal2 = [ -39.6966 44.8127 95.0896 145.4097 144.5878 …
Andy
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A few questions about Slepian and generalized gaussian windows

I'm trying to add documentation for all the window functions in scipy.signal, and I'm stuck on the Slepian (same as DPSS?) and Generalized Gaussian windows, which I'd never heard of before. There are two variables that are shape parameters of some…
endolith
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Conceptually, how does a Fourier transform differ from an autocorrelation?

I realize the two are derived using different algorithms, and the units are different, but from a conceptual standpoint of the information they provide how do they differ? I'm thinking here about the more or less specific (yet general) case of a…
Daniel R Hicks
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What Kind of Features Can I Extract from a Signal

I want to monitor (automatic-)gearbox failures on some vehicles. For each vehicle I have a captured signal representing the selected gear at each one millisecond. An example of two signals are shown on the figure bellow. I would like to compute…
eLearner
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