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Question

I have a photograph (shown below - quality reduced to meet upload size limit) of a paraglider with an inflated wing. I would like to extract the paraglider, wing, and the many thin lines (approximately 2-5px wide in most places) between the two for use in another composition. The paraglider and wing themselves are simple enough matters, but how can I select/reproduce the lines while minimizing my selection of the sky?

Original image

Background

Ignoring the region where the lines are in front of trees/ocean (but bonus points if your answer covers these regions!), my thoughts were to use color selections to cut out chunks of the sky - and this works in some capacity, but seems messy - there's lots of semi-transparent remnants that I have to remove and clean up by hand.

I've also tried using a black-to-white gradient layer on top of the image with an overlay or soft-light blending mode in order to normalize the lens-flare, then amping up the contrast to really give the lines definition, producing decently consistent black silhouettes that I feel may be good foundation for a mask - but I still struggle to isolate even the thin black silhouettes from the background.

My final thought is to hand-trace each line with vectors and either use the resulting path for a selection, or stroke it and play with blending in the new composition to reproduce the lines from scratch. Normally this would be my first course of action for encountering such a problem, but I was hoping there might be less time-intensive techniques that I'm unaware of!


Solution

As per the comments and Kurtis Beavers' answer below, I ended up tracing each line by hand, adjusting a contrast layer to make the lines stand out against the background of the region I was tracing as needed. My final vector-path took about three hours to produce, primarily owed to the lack of contrast between the lines and the wing itself - they become essentially invisible, and required some guess-work to approximate:

Final line-trace path

The lines' anchor points on the wing aren't entirely accurate, but it was more than sufficient for my proceeding composition.

  • It occurs to me that this question may be considered off-topic as I feel it fits the format of a 'Simple "How to" question'. Is there another SE site at which my question may be more appropriate? – bosco Jan 26 '15 at 23:07
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    This seems on topic enough to me :) Welcome to GD.SE! – Zach Saucier Jan 26 '15 at 23:13
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    No matter what the method used, it'll take some zoomed-in human painting to do it properly. I think I'd just recreate the lines. – Scott Jan 26 '15 at 23:31
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    I'd move over the person and the wing. Then I'd manipulate the contrast/curves to the point where the wires become essentially a line drawing. I'd then move those over to the new composition and re-apply with some layer blending. – DA01 Jan 28 '15 at 18:30
  • Hey awesome - thanks for the input, all! Sounds like I was on the right path with the vector-tracing/contrast nudging... I'll give it a week or so to see if any other approaches pop up before I select an answer, or write a more comprehensive summary of the suggested techniques. Thanks again! – bosco Jan 30 '15 at 1:45
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Because of the lighting in your photo, I would probably hand trace as vector paths. You can do this in Photoshop or Illustrator.

You could try to Select > Color range. then pick the black of the lines. My guess would be that the darkness of the trees will throw your selection off though.

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