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# Questions tagged [gaussian]

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### Generate Complex White Gaussian Noise in MATLAB

n_3=sqrt(0.1)*randn(1,K); n_4=sqrt(0.1)*randn(1,K); beta_NLoS=(n_3+1i*n_4); % CN(0,0.1) I want to create a $CN(0,0.1)$,does my code have any problem?
6k views

### How to Calculate Gaussian Kernel for a Small Support Size?

How to calculate the values of Gaussian kernel? I think I understand the principle of it weighting the center pixel as the means, and those around it according to the $\sigma$ but what would each ...
2k views

### Common Use Cases for 2D Non Separable Convolution Filters

In the image processing world, I've noticed that a lot of the popular convolution filters are separable. Here's a quick list of common separable filters: Sobel Gaussian blur Box filter (all ones, for ...
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### What Are Different Approaches to Realize a Gaussian Blur (Smoothing) Step on an Image? [closed]

Could some review some methods to apply Gaussian Filter (Blur) on an image besides the direct one using Truncated FIR (classic convolution with Truncated Kernel) approximation?
862 views

### Comparison Between Average Kernel (Box Kernel) and Gaussian Kernel

In image processing, we have two kinds of major kernels that are average kernel and Gaussian kernel. For image segmentation, which is difference between average kernel and Gaussian kernel? I found ...
Given a signal $x[n] = A + w[n]$ where $A$ is a Gaussian random variable and $w[n]$ is Gaussian white noise, then the covariance matrix of the signal is given by $[C(\sigma^2_A)]_{ij}=E[x[i-1]x[j-... 1answer 762 views ### Determinant of Hessian approximation (SURF) I have a question regarding formula in SURF article by Bay et al. Theory Given a point$p=(x,y)$in an image$I$, the Hessian matrix$\mathcal{H}$in$x$at scale$\sigma$is defined as follows $$\... 1answer 370 views ### Power spectrum of downsampled image I am not sure if this is the right stackexchange community for this question, but here goes. I am generating a Gaussian Random Field (GRF) of a pre-defined power spectrum. In the image below, the ... 2answers 5k views ### Which IIR filters approximate a Gaussian filter? So it recently dawned on me that Bessel filters, despite being listed along with the other common types, are really an oddball that belongs in a different "class", and I'm trying to learn more about ... 2answers 2k views ### Parameters of Gaussian Kernel in the Context of Image Convolution Hi Everyone i am new at image processing. I copy code from this website, I have image 600 \times 480 gray scale. What will be the value of standard deviation or \sigma? What will be the value of ... 2answers 291 views ### Optimum Filter Signal Detection for Non AWGN Channels I have been reading this question and it confirms that the matched filter is the maximum-likelihood receiver in the presence of additive white Gaussian noise. So in the AWGN channel it maximizes the ... 0answers 202 views ### Noise PSD and sampling rate relation Let's consider generating samples of a random process like white Gaussian noise (AWGN). Let's assume I am generating N samples of AWGN with variance \sigma ^2 in MATLAB by using randn() funtion i.... 0answers 280 views ### frequency spectrum of a sampled signal, PSD and power discussion Before I go into my question, I first want to review the basics of sampling a signal and at the same time I build the basics of my questions so that they make more sense. I know I have asked couple of ... 1answer 869 views ### How Does the RMS of White Noise Change with Sampling Frequency? There is an analog system which includes the continuous-time linear equalizer (CTLE). With some .noise analysis the power-spectral density (PSD) of the noise in that system is provided. So let's not ... 1answer 1k views ### How Does Gaussian Blur Affect Image Variance I am trying to find a way to analytically estimate how the noise (or variance in pixel values) will be affected for a zero-frequency image of random noise after applying a Gaussian blur. In more ... 1answer 1k views ### Applying Gaussian Blur in Frequency Domain Please see second update I'm trying to implement gaussian blur in frequency domain using c#. Those are steps that I'm doing: Load bitmap. Split bitmap into separate color channels. Convert every ... 3answers 51k views ### 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 ... 0answers 147 views ### issue with the MFCC and GMM for audio recognition i am working on a project related to audio events recognition in real time like a door bell, baby crying, footstep, I have 9 categories of sound events so the first step i did was getting many wav ... 1answer 117 views ### Why Does the Odd Multiple of \frac{\pi}{4} on Gaussian Cause Loss in Repeatability Under Image Rotations? I couldn't figure out below paragraph on SURF paper and hope that someone can help me to understand it. Why image rotations around odd multiples of \frac{\pi}{4} lead to a loss of repeatability? ... 1answer 164 views ### What's the relationship between the parameters of this noise generator and the gaussian curve it produces in the frequency domain? This algorithm produces a sequence y having a magnitude spectrum that resembles a normal distribution, peaking at frequency \omega:$$b[n]=(1-\sigma)b[n-1]+\frac{\sigma}{\omega} Cp[n]=p[n-1]+... 0answers 33 views ### Creating realization of 2D Gaussian field in Fourier space I want to generate a 2D Gaussian field with dimensions$L\times L$with$N^2$cells each of size$l = L/N$. I'm doing this by producing a realization of this field in Fourier space by producing ... 0answers 97 views ### What is SNR of Signal with Additive White Gaussian Noise [duplicate] Calculating the power of AWGN should be equal to infinity as PSD is constant and its integration is infinity over all frequencies. Hence for any signal with finite power mixed with AWGN, SNR should ... 1answer 45 views ### Play with a Gaussian random set in the frequency domain to obtain desired effect in the time-domain Please assume we have a set of 100 random numbers obeying Gaussian PDF in time-domain. Let's index them 1-100. Within a time-accurate simulation, I apply four operations on this dynamic set every ... 0answers 47 views ### Does a “chirp”-like generalization of the Gabor or Morlet wavelets definitions exist in the lit somewhere? I have asked this at the Math SE also. Predicating this on the definition of the continuous Fourier Transform preferred by most electrical engineers:$$X(f) \triangleq \mathscr{F} \Big\{ x(t) \Big\}... 1answer 240 views ### Zero padding effect on a FFT of gaussian noise I have a gaussian noise$\nu(t)$with variance$\sigma^2$. After a FFT I get$X(\omega)$. If now I do the IFFT on the$X(\omega)$can I say that the result is still a gaussian noise of variance$\...
I am trying to figure out how to use the matlab gausswin function which constructs a Gaussian window for $N$ samples with a given standard deviation $\sigma$. The function is defined by ...