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1500 questions
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Directly compare subpixel shifts between two spectra — and get believable errors

I have two spectra of the same astronomical object. The essential question is this: How can I calculate the relative shift between these spectra and get an accurate error on that shift? Some more details if you are still with me. Each spectrum will…
JBWhitmore
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What is the type of noise in this image?

what reason could make the noise/effect in this image? Below is the original Thanks!
raboof
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Different state-space representations for Auto-Regression and Kalman filter

I see that there are different ways to write an AR model into a state-space representation, so that we can apply Kalman filter to estimate the signal. See Example 1, 2 and 3 here. I wonder what differences are between the different state-space…
Tim
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Weighted Nuclear Norm Minimization for Image Denoising

Recently, I saw new published papers like Shuhang Gu, Lei Zhang, Wangmeng Zuo, Xiangchu Feng, Weighted Nuclear Norm Minimization with Application to Image Demonising [pdf]. about denoising images using Weighted Nuclear Norm Minimization (WNNM)…
user2987
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best implementation of a real-time, fixed-point iir filter with constant coefficients

I have implemented IIR filter in direct form, parallel form, and cascade form. The input in all the cases is a kronecker delta function. How to judge which implementation is better is in real time and why? What are the factors to be considered while…
sai priya
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Algorithm to pan audio

I'm looking for a way to pan the PCM audio I have. At the moment the audio is in a stereo format and I would like to pan it to the desired side (or more/less to a side). I've recently figured out how to do mixing here so I guess it would be…
Dries
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Choosing Drive Signals for System Identification?

(I'm just learning a little about system identification so apologies in advance if this question is badly worded) How do you go about choosing drive signals for system identification? I've seen PRBS signals used but it seems like that's going to…
Jason S
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Duration of unknown rectangular pulse with additive white Gaussian noise

Problem. There is a discrete signal $f[i]$ (example below). It is known, that $f[i]$ have a form of rectangular pulse with additive white Gaussian noise. $f[i] = s[i] + n[i]$, $s[i] = \alpha(\theta[i - i_{1}] - \theta[i - i_{2}]) + c$, $i_{2} >…
Nikolai Popov
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How to recognize colors from the color chart?

I am developing a vision application that is using the color chart below and camera to extract color of each patch in the chart. In order to do that, I have to first detect the chart area in an image and match the area with existing template which…
Tae-Sung Shin
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Detecting tennis courts in aerial images?

Possible Duplicate: How to find tennis courts in aerial imagery I am trying to detect tennis courts that are present in aerial images .. I have the following image: I tried color image segmentation on it but no success it gives a bad result…
vini
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How to shift the frequency spectrum?

Lets say we have a spectrum ranging from -X MHz to +X MHz. I would need to correct the frequency error in the spectrum by shifting the zero component to the middle (0 Hz). If the output (the frequency spectrum) is calculated via FFT, as far as I…
user1166780
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Is it possible to hack camera calibration without having access to the camera?

Many times we have a stream of video to process without access to camera. Having access to camera matrix would be beneficial for various processing techniques. Is it possible to hack camera calibration without having access to the camera? I have a…
Manav Kataria
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Improving Digitization by Adding White Noise Before Oversampling

I was reading a physics book and it said that when digitizing a signal white noise was added to improve the process. I don't understand how this works. Therefore my question is: When digitizing an analogue signal, how can adding noise be…
SiberianSloth
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Why do we deal with the eigenvectors of the autocorrelation instead of the data itself?

How intuitively to understand why eigenvectors of the autocorrelation matrix are used, but eigenvectors of the matrix constructed from temporal samples have no sense and aren't used? For example, in detection of a harmonious signal in additive…
Timur
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Low pass filtering on short int (16 bit PCM) samples

I am writing software for processing audio given as 16-bit PCM samples. The first stage of the processing involves calculating the energy (or total variation) in a certain frequency range (above a certain cut-off frequency). What I am currently…
smichak
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