Make the example self-sufficient

[ghost]

Hi, first of all, thanks for sharing the library! I would like to as you if it is possible to renew this link to get the example image?

imageio.imread('https://dl.dropboxusercontent.com/u/1463853/images/chelsea_morph1.png')

[GenevieveBuckley]

I'd like to second this request. If the test images were available, it would be relatively easy to check whether pyelastix is installed correctly or not.

[almarklein]

It looks like I no longer have that image :)

Can either of you please provide a morphed version of chelsea, and post it here? Then I can update the example.

[GenevieveBuckley]

I'm sure we could, if there was any information on what kind of morphing was done to the image originally. Do you remember what you did to it?

In test_register_affine_gray the moving image is rotated by 15 degrees. That seems a little too simplistic though, so I'm guessing the morphed chelsea image had something different done.

[GenevieveBuckley]

Trying it anyway, the example script gives a poor result. I think the number of iterations is too low (the unit test uses 1000 iterations, instead of 500).

Top row: fixed image, moving image Bottom row: registered image, field[0], field[1]

Increasing the number of iterations to 1000 produces a much better result for this simple example. (EDIT: Actually, I'm having more trouble than you would expect reliably reproducing outputs, so it may not be solely to do with the number of iterations)

[almarklein]

Do you remember what you did to it?

No I don't, but I think it would have been a morph. E.g. a displacement defined by a Gaussian blob.

I think the problem with the rotated image is that since the edges of the image are not attached its harder to get a good result.