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arsenal9971 / Shearlab.jl

Shearlab is a Julia Library with toolbox for two- and threedimensional data processing using the Shearlet system as basis functions which generates an sparse representation of cartoon-like functions.
https://arsenal9971.github.io/Shearlab.jl/
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Strange space shift relative to shearlab.mat #15

Closed dsweber2 closed 6 years ago

dsweber2 commented 6 years ago

baseDomainShearletExampleTmp.pdf Hi Hector,

@BoundaryValueProblems and I were attempting to plot the shearlets in the space domain, and noticed that there is a shift (see the image for an example, though it is somewhat difficult to see). When comparing relative to the results from shearlab.mat, this led to a relative error of 1.4 or so in the frequency domain. I'm wondering if you've done a comparison like this, and what you got.

Additionally, I believe that the shearing indexing is in the opposite order for the matlab and julia codes.

arsenal9971 commented 6 years ago

Dear David,

Thanks a lot for catching the bugs, you are being of great help. When I first implemented Shearlab I did it in parallel with some experiments in matlab to see if the results were the same (or similar up to a very small error). I am not sure weather the change to v0.6 brought some changes in the generating functions. I am suspecting that the fftshift and ifftshift may be different than the matlab version. I will check this as soon as possible. The shearing indexing could be different thant the matlab version, but the variable shearletSystem.shearletIdxs gives you the right indices for the shearlet elements.

dsweber2 commented 6 years ago

Hi Hector,

Have you had any time to investigate this?