Re: [scikit-image] Image deconvolution ...

2017-11-23 Thread Stefan van der Walt
On 22 November 2017 23:08:17 Jérôme Kieffer wrote: On Thu, 23 Nov 2017 12:33:21 +1100 Juan Nunez-Iglesias wrote: Sounds great! I’ll admit that I’m not confident in this area either, but my reading of the documentation suggests that this is the right approach: the damping controls the square

Re: [scikit-image] Image deconvolution ...

2017-11-22 Thread Jérôme Kieffer
Hi Juan, On Thu, 23 Nov 2017 12:33:21 +1100 Juan Nunez-Iglesias wrote: > Sounds great! I’ll admit that I’m not confident in this area either, > but my reading of the documentation suggests that this is the right > approach: the damping controls the square norm of x. By keeping it > small (with

Re: [scikit-image] Image deconvolution ...

2017-11-22 Thread Stefan van der Walt
Hi Jerome The problem you describe sounds very similar to the one solved for super-resolution imaging. My PhD thesis talks quite a bit about the methods utilized to solve it: http://mentat.za.net/phd_dissertation.html The code is here, but---written by some PhD student in 2009 ;) https://github.

Re: [scikit-image] Image deconvolution ...

2017-11-22 Thread Juan Nunez-Iglesias
Hi Jérôme, Sounds great! I’ll admit that I’m not confident in this area either, but my reading of the documentation suggests that this is the right approach: the damping controls the square norm of x. By keeping it small (with large damping), you force the elements to be non-negative. I hope t

Re: [scikit-image] Image deconvolution ...

2017-11-22 Thread Jerome Kieffer
On Wed, 22 Nov 2017 12:40:50 +1100 Juan Nunez-Iglesias wrote: > Hi Jérôme, > > Can you explain your problem more? You know A and x and want to find > b? Is this an exact solution, or is Ax = b + err? SciPy’s > sparse.linalg module is where you’ll find most of your answers, I > think… If you want

Re: [scikit-image] Image deconvolution ...

2017-11-21 Thread Juan Nunez-Iglesias
Hi Jérôme, Can you explain your problem more? You know A and x and want to find b? Is this an exact solution, or is Ax = b + err? SciPy’s sparse.linalg module is where you’ll find most of your answers, I think… If you want to *build* A from some description, you might find our homography exampl

[scikit-image] Image deconvolution ...

2017-11-21 Thread Jerome Kieffer
Dear all, I have an image which is "blurred" by a kernel which depends on the position on the image. This blurring can be expressed as a sparse matrix (A) multiplication where only the neighboring pixels have non-null contribution. Ax = b where in addition Aij>=0 x >= 0 #non negativity constra