Questions tagged [variational-methods]
6 questions
5
votes
1 answer
Laplacian of Gaussian Approximation and Gaussian Blur as the Solution of Heat Equation
While I was reading SIFT paper(Lowe, 2004), I came across the method that he apply "heat diffusion equation" to Gaussian function to derive that
$$ \frac{∂G}{∂σ}
= σ∇^2G
$$
I searched Wikipedia and found that original heat equation is
$$…
alryosha
- 153
- 2
4
votes
1 answer
How to Solve an Image Deblurring Problem by Variational Methods Using ADMM?
Following up on a previous question, I wanted to understand how to solve an image deblurring problem using Variational methods in matlab or julia.
Given some original blurry image $f$, I would like to find the deblurred version $u$. $K$ is a…
krishnab
- 237
- 1
- 7
4
votes
2 answers
Justification for Squared $ {L}_{2} $ Data and Smoothness Term as an Error Bound
Often in variational methods (and not only) we have an energy that is of the form:
$$E(u) = \frac{1}{2}\|f-u\|^2_2 + \frac{\alpha}{2}\|\psi(u)\|^2_2,$$
where the first term is referred to as the data term, and the second as the smoothness term. I…
lightxbulb
- 165
- 4
3
votes
1 answer
Variational Regularization Method in Image Processing
I would like to understand better variational regularisation methods in image processing. In particular, the formulas in this image:
Why formula (3.13)? In the notes that I read I cannot find anything about its background, why is the solution of…
Novak Djokovic
- 269
- 1
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2
votes
1 answer
Why Does the Rudin Osher Fatemi (ROF) Method Use Variational Methods for Image Denoising When Denoising Problems Are Not Boundary Value Problems?
I was reading the recent book Variational Methods in Image Processing by Vese and Guyader which is quite interesting. In the book the authors discuss different types of image processing problems, from denoising and deblurring problems to image…
krishnab
- 237
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1
vote
0 answers
Is the behaviour of the following filter plausible?
I've designed a filter based on this equation
$$
E(u) = \frac{1}{2}\int_{\Omega} \left[(u-f)^2 + g(\lVert \nabla u \rVert)\right]dxdy
$$
Euler-Lagrange equations in this case are (should be) given by
$$
u - f - \frac{1}{2}\nabla^T \cdot \left(…
user8469759
- 375
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