math - Concave and Convex Polygon -

how can identify , remove 4 red points drawn in image alt text

those 4 points make polygon concave polygon that’s why want remove it.

my goal convert concave polygon convex removing kind of point identifying , removing points.

is there way identify , remove these kind of points?

thanks

use convex hull algorithm (such the graham scan), , remove points not part of resulting convex hull.

in example, convex hull consist of p1, p2, p3, p5, p7, p8, p9, p11, p12, p13, p14, p15, p16, p18, precisely points except red ones.

note removing points inner angle greater 180 not result in convex polygon. take polygon example:

enter image description here

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