Questions tagged [gaussian]

For issues related to any of the uses of the Gaussian function. Don't forget to add additional tags to clarify the context.

The graph of a Gaussian is a characteristic symmetric "bell curve" shape that quickly falls off towards plus/minus infinity. The 1-D Gaussian is defined as (taken from wikipedia):

gaussian function from wikipedia

The parameter a is the height of the curve's peak, b is the position of the centre of the peak, and c controls the width of the "bell".

In multiple dimensions, the Gaussian is defined as the product of 1D curves along each dimension.

Gaussian functions are widely used in statistics where they describe the normal distributions, in signal processing where they serve to define Gaussian filters, in image processing where two-dimensional Gaussians are used for Gaussian blurs, in mathematics and physics where they are used to solve heat equations and diffusion equations, to formulate the propagation of optical beams (Gaussian beams), to from a basis set of wavefunctions, to define the Weierstrass transform, and many more.

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Adding gaussian noise to rgb image opencv python

I tried adding gaussian noise to rgn image, m=0 s=3. Tried this: m=(0,0,0) S=(3,3,3) cv2.randn(img, m, s) The result is a black image with white dots... What may be the problem ?
Maroun Sassine
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ICDF function in Matlab for Inverse Gaussian distribution

I am trying to generate an inverse gaussian distribution using the ICDF function in matlab. The parameters are: mu = 4.68 lambda = 12286 I get the following error: Warning: Divide by zero. This warning will be removed in a future release. Consider…
user3533691
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Is that the expected result on ndimage.gaussian_filter?

I'm trying to calculate the discrete derivative using gaussian_filter from scipy.ndimage and so the output is presenting some strange behavior with boundary conditions. The code is below: from scipy import ndimage import numpy as np import…
iury simoes-sousa
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python iminuit attribute error

I like to keep the syntax in its most general form, by giving iminuit its parameters using *: import iminuit import numpy as np x_data = np.array([0,1,2,3,4,5,6,7,8,9]) y_data = np.array([0,1,2,3,4,5,4,3,2,1]) def fit_function(x, *p): return…
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Need Help Python Fitting Gaussian to data that doesn't lie along x-axis at y=0

I have searched a decent amount and have yet to find a clear solution to my question. I currently can fit a Gaussian to any data that lies along the x-axis, the typical set of data you see when looking a Gaussian fitting tutorial. Now I have data…
dciampa
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Fitting gaussians to close peaks in MATLAB

I have a data set that has two peaks close together. I'd like to fit these peaks with gaussians so that I come up with a new data set that replicates the original one. To this end, I am using MATLAB's "findpeaks" function, and using the heights and…
naomig
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Old (sklearn 0.17) GMM, DPGM, VBGMM vs new (sklearn 0.18) GaussianMixture and BayesianGaussianMixture

In previous scikit-learn version (0.1.17) I used the following code to automatically determine best Gaussian mixture models and optimize hyperparameters (alpha, covariance type, bic) for unsupervised clustering. # Gaussian Mixture Model try: …
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Making progress on MATLAB fitgmdist for Gaussian Mixture models, but still getting error :(

Hello stack overflow fam. I have been trying to figure out how to use this pesty fitgmdist on MATLAB for fitting Gaussian Mixture models. I have made progress, but I am still getting an error when trying to set initial parameters. I get the…
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How to do smoothing of 3D images based on millimeter?

I am simulating a paper that the scale of smoothing of images is based on millimeter. The format of 3D images is DICOM. For example, normally the smoothing of image X with window size and scale s, is being done as follows: f1 =…
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How to Replace Value in an arraylist that is itself a Hashmap value

I'm looking for a method to overwrite/ replace a value in an arraylist, the arraylist itself is a value in a hashmap. Here is a bit of the code that was provided for us. public Equations(Double[][] matrix) { // save input matrix into M -- it…
CabooseMSG
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Creating a subsample using a weighted distribution

I have two samples of cookies. Sample 1 has 51 cookies and sample 2 has 47 cookies. They have different mass distributions, D1 and D2, and I have fit gaussians to them via python. The plot below shows the samples' mass distributions, as well as the…
Kelly Ford
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Java convert two integers to a double from 1 to 0

I am working with an ISAAC implementation which generates random integers. I need to create a Gaussian value with these integers. First, I need to change them to a double from 0 to 1 though. How can I do this in Java? Here is what I have so far to…
Colby
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Upsampling and downsamling of 3D-volume in all 3 dimensions

Is there any function for computing expansion and reduction for 3D images in matlab? For example, something to reduce 3D-volume from 170*240*240 to 85*120*120 or to expand from 85*120*120 to 170*240*240. 'impyramid' in matlab does similar but only…
Tee
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Inverse of Laplacian and Gaussian Noise

Given a set of data points, I modify the data points by adding a Laplacian or a Gaussian Noise to them. I am wondering if there exist mathematical inverse functions able to derive the original data points from the ones with noise. My understanding…
Giuseppe
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How to use input features with the same target value with Scikit Learn's Gaussian Processes

I am new to Scikit Learn and am trying to learn how to use Gaussian process regression. I am attempting to use a data-set that has repeated numbers, for example: array(x,y) = [[10, 10, 20, 20, 15, 17], [30, 40, 50, 60, 50, 40]] When following the…
Calum
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