Inner/outer edge division

Problem

1. old method: look at an edge point-of-interest; find its angular peers; see if among the peers, inner-more points exceed outer-more points compared to this POI, true-> this an outer point
2. this one is too rough to handle situations where there are significant angular overlap among such angular groove, then the number stats will be messed up instead of clear-cut 1-on-1 inner/outer pair.

Solution

1. angular analysis: still take angular groups; at each azimuth, find in the original top area a random non-edge point, all points outer-more are outer edge, and inner-more are inner edge.