closed polyline

hallo everyone,

I am trying to get an outline or closed polyline from a fisheye picture that i produced. attached is the jpeg. Is there a way to get a closed outline where only the sky can be seen ( i.e: without the surrounding building).

thank you in advance.

fe_02.eg_00_f.jpg

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Comment by Mostapha Sadeghipour Roudsari on November 20, 2013 at 10:29pm: Hi Nass,

Did you produced this image in Rhino? If the answer is yes how did you setup a fisheye camera in Rhino?

Thanks,

Mostapha

Comment by Richard Schaffranek on September 27, 2013 at 3:09am: If you want to do it in Grasshopper you would need to look into Image Processing a little bit.

A starting point could be :

http://en.wikipedia.org/wiki/Sobel_operator

This should give you the position of the outlines.

So if you would like to filter the sky than you would need to make a black and white image first.

Get the Edges with e.g the sobel operator and then connect the points using something like:

http://de.wikipedia.org/wiki/Marching_Squares which is similar to Marching Cubes where there is a lot of discussion in Grasshopper forum and you can find some nice implementations there:

http://www.grasshopper3d.com/page/search-results?cx=007664031582976...

Have fun.

Comment by Piotr on September 26, 2013 at 5:10pm: This image is very simple and honestly saying you can draw it in Rhino in just two minutes.

Comment by Piotr on September 26, 2013 at 4:59pm: Import image to Photosop, make a mask with a magic wand, save selection as path, export path as AI file, open it in Rhino as vector graphic.