Check if 2d polygon has "loops" inside

[karolek]

Hi

I'm trying to make an envelope around a shape that is not convex. When envelope width is too big, the shape that is created contains "loops", like that red one:

The problem is that I want to use Point In Polygon.vi to remove all outliers and artifacts out of the envelope, but this vi will give me incorrect result inside those "loops" (points are marked Outside of polygon instead of Inside)

Is there some smart way of finding and removing those "loops"?

I can use all the functions from vision library if needed.

[shoneill]

Check to see if any line intersects with any other.  For N line segments, this requires (N-1)! comparisons.  Easiest way to do it.

Once you know which lines intersect, you can remove the in-between lines and move the start / end point of the two directly affected lines to the intersection point.

[MikaelH]

Here is a quick hack that does the job.

I hope you have the Vision Sub VI, to find the Line Intersection point.
I use that in combination with a OpenGDS VI to see if 2 lines intersect, sorry didn't have time to document it nicely.

//Mike

 

 

OpenGDS_LineIntersectLine.zip

[MikaelH]

BTW this is the end result with the VI above:

[karolek]

Perfect!  that's what i needed

It seems like I'd spend too much time on this.

Thanks!