The gradient tag has no wiki summary.
4
votes
0answers
70 views
Banding in the derivative of a lock-in amplifier signal
I'm analysing several measurements taken with a SR830 lockin amplifier.
These measurements look similar to this one.
Since I'm interrested in the derivative of the signal I took the numerical ...
3
votes
2answers
133 views
How do convolutions become matrix multiplications?
I know this question may not be very relevant to programming, but if I don't understand the theory behind image processing I'll never be able to implement something in practice.
If I got it right ...
0
votes
1answer
80 views
Downsampling and Gradient filtering
Are the following sequence of operations the same -
Down-sampling filtering followed by gradient filtering with kernel [-1 0 1]
Gradient filtering with kernel [-1 0 1] followed by down-sampling
...
3
votes
0answers
60 views
Gradient Domain Reconstruction - Scaling Problem
I am implementing reconstruction of image from gradient domain. This requires solving the following partial differential equation (a Poisson equation) on a 2D grid:
$$\nabla^{2}I=\mathbb{div} G$$
...
6
votes
1answer
192 views
Gradient of total variation of magnitude of complex function for denoising
Say I have a complex function $f^*$ (e.g. a MRI image) that has a near piece-wise constant magnitude, but a non constant phase.
If I have an optimization problem to find $f^*$ and set up an objective ...
6
votes
2answers
216 views
Shape of structuring elements for morphological gradients
I am looking to understand recommended shapes of structuring elements used in calculating morphological gradients. According to Pierre Soille: Morphological Image Analysis:
Only symmetric ...
12
votes
3answers
409 views
How to detect gradients in images?
I want to be able to find points in images that are the centre of a radial gradient like the one shown in the left picture below. Any ideas on how I could use a Hough transform or some other computer ...
