Gradient Mosaic problem

[lorenzi]

Dear all, I am having problems creating mosaics using gradient Mosaic function. In fact the script merges my images but always create strange halos and black "holes" for the stars that are in proximity of the border of one of the two images. See the attached image for a clear example. I tired to change the order of the images to merge, to change the Shrink radius value from 0 to 10, the feather radius from 0 to 30 or more, all without success, always having these kind of strange artifacts. Is anybody experiencing the same? Any suggestion?

Thanks
Marco

[georg.viehoever]

This should no longer happen with the latest version. Can you share the data so I can analyze the problem?
Thanks,
Georg

[lorenzi]

Dear Georg, sure I can share the data. Where can I upload them? Original files are about 4000x4000 pixels, quite large..

Thanks
Marco

[georg.viehoever]

There are a number of possible services. How about dropbox.com, skydrive.com, you name it... Just send me the link.

Georg

[lorenzi]

Hi Georg, thanks for the suggestion. I have uploaded the compressed fits in Skydrive. Below is the link:
https://skydrive.live.com/?cid=632C5BB26F472B64&sc=documents&id=632C5BB26F472B64%21116&group=0&sff=0#

These are the original sums. Let me know if you can get them.

Clear Skies
Marco

[georg.viehoever]

Hi Marco,

I downloaded the data, and can confirm that the problems stays even with feather radius 50. It is the problem I hoped to address with feathering, and for quite a number of images this works fine. It does get smaller though  with increasing feather radius. (see screenshot), so my feeling is that I should increase the current upper limit of Feather radius.

Immediate workaround:

- use the CloneStamp tool to make the critical stars black in one of the contributing images, then merge again. Or:
- use a lower resolution version of the images (where feather radius 50 is sufficient)

I'll release a new version of the module as soon as I have a permanent solution.

Georg

[georg.viehoever]

Hi Marco,

I fixed the problem in the version that I shortly will publish on http://pixinsight.com/forum/index.php?topic=3572.0. I increased the maximum value for Feather Radius from 50 to 250. The attached screenshot shows from left to right the results for Feather Radius 10, 50 and 200. The two rightmost pictures show the overall result with 200, and the generated mask. I initially was a bit worried about the dark region in the center, but that is actually in the original data of VIRGO_AD_L_70m.fit, as can be seen at the bottom.

Enjoy,
Georg

[lorenzi]

Thanks Georg, this was fixed at record speed I will wait now the compiled version by Juan (I suppose).
Great work by the way with your tool, thanks for making it

Clear Skies
Marco