Make library useful to others

[rjw57]

@scf32 notes that the some tasks need to be done for dtcwt to be useful to him. I have reproduced them below:

• Double sampling rate of transform in all 3 dimensions (scale dimension can be handled fairly trivially at a higher level by initial scaling of the input image and interleaving the pyramid outputs, but the spatial dimensions require a modified colfilter).
• Ability to work in RGB colour space. All I've done to achieve this is merge the low-pass outputs from the 3 colour channels at level 1 and assume the colour distances in the RGB cube propagate through the rest of the transform.
• Subsample keypoint refinement using a 4x4 window method. This is not related to the DTCWT itself but just FYI.

[rjw57]

@scf32 Re RGB colour space: I think it is correct to simply transform each colour plane. I suspect the nicest behaviour would be for the 2D transform to accept 3D arrays and simply transform each slice independently. Opinions?

[rjw57]

@scf32 Can you point me at some MATLAB code which does the double sampling rate stuff?

[rjw57]

@scf32 I'm unfamiliar with the 4x4 refinement. TBH, the existing keypoint stuff in dtcwt id a little bit experimental and probably needs a re-write.

[scf32]

Double sampling low level functions are in Tim's git.csx.

The 4x4 refinement is one of Pashmina's creations. The current fastest version of that should also be in Tim's repo.

[rjw57]

Tim's repo being this private one, yes?

[scf32]

Yes. Actually, for reference it's best to look at refineMaxima(), which is
the original we're working from. If that's not there then I can send a copy
your way.

On 8 August 2014 13:38, Rich Wareham [email protected] wrote:

Tim's repo being this
https://git.csx.cam.ac.uk/i/eng-sigproc/u/teg28/MatlabDTCWT.git private
one, yes?

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[rjw57]

On 8 August 2014 13:57, scf32 [email protected] wrote:

Yes. Actually, for reference it's best to look at refineMaxima(), which is
the original we're working from. If that's not there then I can send a
copy
your way.

Super. I'll take a look and I'll open a new issue and update this one with
progress.

Dr Rich Wareham