# Questions tagged [gaussian-kernel]

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### Appropriate Gaussian filter parameters when resizing image

When scaling an image down it is common to first convolve the image with a Gaussian filter. Given a scale factor $0 < s < 1,$ what is an appropriate $\sigma$ to use? For example, if $s = 0.5$ (...
• 243
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### The Effect of the Finite Radius of Gaussian Kernel

Page 168 of Digital Image Processing, Global Edition says: we know that the values of a Gaussian function at a distance larger than 3𝜎 from the mean are small enough that they can be ignored. If we ...
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### How to approximate gaussian kernel for image blur

From wiki, a $3 \times3$ gaussian kernel is approximated as: $$\frac{1}{16}\begin{bmatrix}1&2&1\\2&4&2\\1&2&1 \end{bmatrix}.$$ Applying this kernel in an image equals to ...
• 153
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### Is Unsharp Mask (USM) Equivalent to Applying Laplacian of Gaussian Filter Directly on the Image?

There are some educational materials, like Alex Pan - CS 194-26: Image Manipulation and Computational Photography - Fun With Frequencies and Gradients, which demonstrate the unsharp masking technique ...
• 143
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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?
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### PYTHON Calculating Laplacian of Gaussian Kernel Matrix

I've been trying to create a LoG kernel for various sigma values. But the problem is that I always get float value matrix and I need integer value matrix as it is published on every document. I haven'...
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