# Questions tagged [gaussian]

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### Implementing a 1-D Kalman Filter Regression, Missing the smoothing action (getting the opposite)

I am implementing the 1D Kalman Filter in Python on a fundamentally noisy set of measurement data, and I should be observing a large amount of smoothing...but, instead, my Kalman Filter is doing the ...
481 views

### How do I calculate the autocorrelation of a train pulse having only the pdf?

I have a pulse train of a fixed period, but a random amplitude following a Gaussian distribution $(\mu=0,\sigma=1)$. I know how to work with a random period or delay, but how do I proceed to calculate ...
790 views

### How to make a 2D gaussian Blur terms?

I want to make a 2D gaussian Blur coeffients. Now I am making 1D gaussian Blur term as following. ...
68 views

### Curve fitting to distorted Gaussian

I have to measure the distance between two pulse trains, each of which looks like a slightly long tailed Gaussian distribution. Is there a relatively easy curve fitting method for this? I can do it ...
222 views

### Mutual information of $\infty$-PAM

I'm trying to compute using matlab the mutual information for an $\infty$-PAM input (the limit of a very dense PAM constellation) for a range of snr and I got stuck. I'm working with a real-valued ...
57 views

### How to derive the $\log$ of fraction of two Gaussian distribution

I am designing a function $A(x)$ that map $x\to \{0,1\}$. The function $A$ can be expressed as $$A(x)=\begin{cases} 1 \text{ if p_1(x) \ge p_2(x)}\\ 0 \text{ otherwises} \end{cases}$$ where $p_1$...
87 views

### What is the equivalent smoothing function to running the same Gaussian 8 times?

Suppose there is an image which is to be smoothed by convolving it with a Gaussian kernel with standard deviation $\sigma$. If the image is then smoothed with this kernel 8 consecutive times, is the ...
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 ...
600 views

I have a gaussian signal $x$ with zero mean and unit variance. I am quantizing it by using a uniform quantizer of step size $q$ calculated by $$q = \frac{x_\mathrm{max} - x_\mathrm{min}}{2^{M_\mathrm{... 1answer 190 views ### Plotting uniform and Gaussian random variables I want to create uniform and Gaussian (normal) random variables in MATLAB via rand and randn syntax. And I would like to plot ... 1answer 206 views ### What is the most efficient way to perform Gaussian blurs for varying sizes of Gaussian kernels in an image? I have detected corner points of images using Harris corner detector in GLSL and now, I intend on using Fast Retina Keypoint(FREAK) as keypoint descriptor to later match the keypoints between images. ... 2answers 81 views ### How does gaussian convution stacking work? If I first convolve an image with a Gaussian filter with σ = 1, and then convolve the output of that image with a Gaussian with σ = 2 Does this give the same effect as convolving the original image ... 1answer 136 views ### Multiscale Shape and Detail Enhancement from Multi-light Image Collections I have been working on a practical implementation in Matlab of the algorithm Raanan Fattal suggested in the following paper. I couldn't understand the meaning of eq. 11 on page 5: g is a gaussian, ... 1answer 133 views ### How can I implement image widowing in my image in Java? My initial image is a medical image and my main objective is finding directionality. The original size of my image was 8X8 and I have rescaled the image to 32X32 to increase my accuracy. My input ... 1answer 365 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 4k views ### Gaussian Filter Close to Image Border When applying Gaussian filters close to the borders of an image, algorithms usually zero-pad or replicate/mirror/wrap the borders. This is not good enough for my case, so I wonder if there is ... 2answers 309 views ### equations to calculate coefficients of recursive IIR Gaussian blur filter I am reading the implementation of IIR Gaussian blur filter from this link. In the source code, the coefficients are generated by the following code ... 1answer 460 views ### Complex Gaussian Channel + AWGN noise If I define a channel to have complex Gaussian coefficients, do I still need to add noise to the signal passing through this channel using the command "awgn" or would that be redundant? 4answers 2k views ### filter coefficients to know high pass and low pass filter Looked on few questions already there in dsp.stackexchange and couldn't get the direct answer. Basically I have a kernel of a gaussian separable filter. ... 1answer 904 views ### Complex normal Gaussian noise I would like to create complex normal Gaussian noise with dimensions (M,N). The noise should be zero mean and the variance should be equal to one. How can I do so? 1answer 5k views ### Question about Difference of Gaussian (DoG) algorithm I am recently learning about Computer Vision and I am having a trouble understanding Difference of Gaussian (DoG) algorithm. I get how the algorithm works in high level idea, but I am trying to ... 1answer 1k views ### Downsampling and Gaussian filtering in the context of scale space pyramids In the context of scale space image pyramids using Gaussian filters I noticed that it's common to downsample the image after blurring with \sigma = 2*\sigma_{init} . My question is: What is the ... 1answer 190 views ### Gaussian in matlab I have written a function that implements a gaussian filter. I use fft2 to transform my image and my filter to 2d fourier transform. Then I multiply them and then use ifft2. The resulting image is ... 3answers 455 views ### SURF feature extractor and descriptor I am trying to understand how SURF extracts features using a Hessian matrix. What I am a bit confused about, is why a second derivative Gaussian filter is used, rather than a standard Gaussian filter?... 1answer 566 views ### FFT function of Gaussian pulse I need gaussian pulse fft. I set the sigma of gaussian pulse 1e-10 and define the gaussian function in time and use the fft. as you know the amplitude of should be unit in frequency domain. but my ... 2answers 5k 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 ... 2answers 1k views ### Why/How a Gaussian Channel is both band-limited and Power limited? All physical channels are band-limited, such that, X(f) = 0 for |f| > W A Gaussian Channel is limited in both power and bandwidth. For this reason we encounter phrases, such as, "A band-limited ... 1answer 101 views ### Can we decompose a correlated random variable into correlated plus uncorrelated? Assume a random sequence  Y_k = X_k \cdot H_k + W_k  where X_k is a deterministic quantity, H_k is a correlated random sequence, W_k is Additive White Gaussian random sequence. Can we ... 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 ... 1answer 417 views ### Is there a closed form expression for noise other than white noise? For white noise, where the PSD is constant, we can model that as a simple Gaussian. Is there any way to model the probability density function of other types of noise (pink noise, red noise, blue ... 1answer 74 views ### What type of sensors have complex Gaussian noise? What type of sensors have complex Gaussian noise? Do strain gauges also exhibit such noise? 0answers 132 views ### Effect of Gaussian Smoothing to mean image intensity I am implementing Perona-Malik Diffusion in using the formulas: Creating image at time k+1 using equation This is my implementation: ... 1answer 46 views ### How to determine stopband of discrete Gaussian, stdev sigma, support N I would like to analyse a gaussian smoothing kernel with a set standard deviation and support (let's say, in MATLAB, fspecial('gaussian', [5 1], 1.3) so sigma is 1.3 and support is 5) in the DTFT ... 0answers 56 views ### Relation between Gaussian and Savitsky-Golay kernels I would like to make a mathematical comparison between two methods in my field. One smooths with a Gaussian filter, and one smooths using a second-order Savitsky-Golay filter. Let's say the window ... 2answers 739 views ### Gaussian noise generator algorithm trouble I stumbled upon the following algorithm for Gaussian noise generation and I just can't figure out how this is supposed to work at all. The algorithm is as follows: First of all: j = \arg\min_i (q_1 ... 2answers 287 views ### imshow command for Gaussian function I'm trying to plot 2D gaussian function using "imshow" in MATLAB. However I could not see any white points in image. I tried to change sampling values and limits of x and y values. In addition to this,... 2answers 808 views ### carrier frequency difference Papers use wireless device-dependent radio-metrics as fingerprints. A radio-metric is a component of radio signal, amplitude, frequency and bandwidth. Each device creates a unique set of radio-metrics ... 1answer 338 views ### use scale space representation to filter one image Currently I hope to use scale space representation to filter one image. Features in one image can be filtered using an Gaussian smooth filter with one optimal sigma. It means different features in one ... 1answer 534 views ### Introduction to IP : Laplacian of Gaussian? I am very new to the concept of computer vision (and image processing), and trying to understand the algorithm used for edge detection. One thing I'm currently struggling to figure out is the ... 0answers 7k views ### Horizontal banding (flickering) due to electronic rolling shutters It is a well-known artifact that in CMOS cameras with electronic rolling shutter, horizontal banding (flickering), i.e. brightness intensity variations, are observed when the image is recorded under ... 1answer 290 views ### Spacing between gaussian windows for STFT I'm computing discrete short time Fourier transform. Data is split into overlapping chunks and gaussian window is used for each chunk. However, I'm not sure how much overlap there should be between ... 1answer 54 views ### Different results for seperable filtering v/s direct filtering on 2-D image in MATLAB I compared the difference between seperable and direct filtering for MATLAB's cameraman image. The difference is huge. I would like to understand the reason for this. Code below. ... 2answers 4k views ### Discrete approximation to Gaussian filter One method of producing a discrete approximation kernel to a Gaussian filter of variance \sigma^2 is to assume a cutoff of 5\sigma. This seems to suggest the following procedure: Create a uniform ... 1answer 7k views ### Simple fft to Gaussian pulse with MATLAB trying simply to create femtosecond pulse in MATLAB exactly like in the attached image, the carrier frequency is around 374THz, and my sampling frequency is 10 times the carrier. The results of the ... 1answer 925 views ### Fixed SNR with unitary noise variance I've just one question : How can I write a model like y = x + w,( with w a white gaussian noise) with a fixed SNR and a noise variance equal to 1. What coefficient may I have before x ? Thanks ! 2answers 796 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 ... 0answers 148 views ### What is purpose of correlation kernel? IIs it high pass filter or low pass filter? I am research about correlation kernel and I have some questions that need your help. Let see the pp. 3302-3303 in the paper: Changyang Li, et al., Robust Model for Segmenting Images With/Without ... 1answer 3k views ### What is correlation kernel and compare with gaussian kernel I read a paper that said about correlation kernel that defined:$$W(x-y)=(α/1+d(|y − x|)) where $α = (\int(1+d(y − x)dy)^{-1}$, $(d(|y − x|))$ is spatial Euclidean distance from the central pixel. ...
I would like to simulate a sensor that provides range and direction of a beacon. This is for EKF localization, so the noise must be Gaussian (i.e. $\mathcal{N}(0, \sigma^{2})$. Also, I would like to ...