Signal Processing Stack Exchange Community Digest

Top new questions this week:

Developing Lead Compensator to Decrease Settle Time

This is a follow up to this question. I've approximated the transfer function for a system to be H = zpk([0.012 -1.05 18],[-0.22 -0.22 -45 -1000],10000);. My goal ...

matlab filter-design transfer-function control-systems pid  
asked by cicey60307 4 votes
answered by Dan Boschen 0 votes

Wave Digital Filter Bridge-T Resonator implementation, gives expected cutoff frequency but incorrect gain and roll-off

Trying to implement the WDF in Fig 5(a) of this publication. The response of the ideal op-amp implementation is given by the black curve in Fig 7: Here is the plot I get when trying to implement the ...

filters python digital matrix wave  
asked by Nick Nagy 3 votes

Digital demodulator (SDR) for receiving legacy analog modulated wave

I understand that in SDR, after the ADC the signal processing is fundamentally based on I/Q modulated waves where any discrete value that can be transmitted corresponds to a symbol which is ...

digital-communications sdr polar  
asked by DevBee 3 votes
answered by MBaz 3 votes

Proof of Bedrosian's theorem

I was looking for a straightforward proof for Bedrosian's theorem which says the Hilbert transform of the baseband signal times the passband signal is the original baseband signal times the Hilbert ...

fourier-transform hilbert-transform proof  
asked by Elias 3 votes
answered by Matt L. 2 votes

Frequency-domain deconvolution: "Direct" filtering vs "Wiener" filtering

Can someone help with clarifying the difference between two approaches to frequency domain "deconvolution: For the frequency domain problem: We want to find a filter $F(\omega)$ which will ...

frequency-domain deconvolution least-squares  
asked by telemeister 2 votes
answered by ZR Han 2 votes

calculate or decompose a Fourier transform signal amplitudes with unknown weights on sources

migrated from math-se... I am trying to calculate , or approximate the solution of following Fourier-sine transform problem that can be expressed as a contributions of periodic sources $f_i(x)$ and ...

fourier-transform deconvolution decomposition approximation svd  
asked by dpdp 2 votes

How to calculate Local Spatial Variance of an image?

For those who work often on image processing, I'm facing an algorithm of Non-Uniformity Correction (NUC) that requires the calculation of a parameter called "Local Spatial Variance". I can't ...

image-processing matlab statistics background-subtraction  
asked by tbs1996 2 votes
answered by Laurent Duval 1 vote

Greatest hits from previous weeks:

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 ...

convolution linear-systems  
asked by Sturm 12 votes
answered by Hilmar 7 votes

Difference Between Correlation and Convolution in the Context of Image Processing

Could you please clearly explain what is the difference between correlation and convolution that is done by a filter on an image? I mean in terms of signal processing definition I know that ...

image-processing convolution image correlation  
asked by the_naive 19 votes
answered by Dima 42 votes

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: ...

fft filters python lowpass-filter  
asked by Haroon Rashid 8 votes
answered by jojek 10 votes

How to understand Kalman gain intuitively?

The Kalman filter algorithm works as follows Initialize $ \hat{\textbf{x}}_{0|0}$ and $\textbf{P}_{0|0}$. At each iteration $k=1,\dots,n$ Predict Predicted (a priori) state estimate ...

asked by Tim 31 votes
answered by Jav_Rock 21 votes

Gaussian Blur - Standard Deviation, Radius and Kernel Size

I've implemented a gaussian blur fragment shader in GLSL. I understand the main concepts behind all of it: convolution, separation of x and y using linearity, multiple passes to increase radius... I ...

image-processing gaussian blur  
asked by LodeRunner 24 votes
answered by Tarin Ziyaee 24 votes

Why is the FFT "mirrored"?

If you do an FFT plot of a simple signal, like: t = 0:0.01:1 ; N = max(size(t)); x = 1 + sin( 2*pi*t ) ; y = abs( fft( x ) ) ; stem( N*t, y ) 1Hz sinusoid + DC ...

asked by bobobobo 42 votes
answered by Jim Clay 46 votes

Peak Signal to Noise Ratio (PSNR) in Python for an Image

How do I calculate the maximum signal to noise ratio (PSNR) in Python? Is there any library that can calculate PSNR for Image?

image-processing noise python  
asked by Sudip Das 6 votes
answered by Himanshu Tyagi 7 votes

Can you answer these questions?

what is the FFT logic in calculating far field defraction matlab implemetation

there is an expression shown bellow that we need to plot in 2D grid plot as shown bellow. X and Y are 2D matrices going from -0.5 to 0.5 the Code uses an FFT function FFT takes as input the func_in ...

asked by rocko445 1 vote

Application of the spherical Radon transform property in tomography

Let function $f$ be even and continuous on the unit sphere $S^n$. Let $R$-be a spherical Radon transform. There is a known property: $R(f^n)=f$ whenever $f$=constant. What would this property mean in ...

signal-analysis fourier-transform continuous-signals signal-detection transform  
asked by User 12345 1 vote

Question about a demonstration of the autocorrelation theorem

I’m stuck on this demonstration. It says: If $x'$ is held constant, $dx=dy$ How can $x’$ be constant? Shouldn't $x’$ be a variable?

asked by Luca Mirtanini 1 vote
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