Searching image for similar features.

[zackyd]

I have a question I would like to throw out there. I am looking at this image: https://planetgate.mps.mpg.de/Image_of_the_Day/public/NAC_2016-06-01T17.17.27.058Z_ID10_1397549002_F22.jpg

And I am interested in selecting just the stars in the image. The star trails are all the same length more or less, different diameters, and more or less in the same vector depending on the rotation of the comet.
any thoughts?

Thanks!

[Carlos Milovic]

Use MorphologicalTransform on a duplicate. 11x11 structuring element, with just a single horizontal white line. Use  "Closing" as the operation. Then multiply this result by the original image. This will give you all the star candidates, along with some other structures that are easily removed. Use Binarize to create a binary mask that selects all the stars.