A group of projective invariants was derived based on the cross ratio of five coplanar points, and used to recognize planar polygons. Experimental results show that the invariants have projective invariance and can be used to recognize planar polygons effectively.
陈燕新 戚飞虎.一组用于识别平面多边形的射影不变量[J].红外与毫米波学报,1998,17(2):99~106]. CHEN Yan Xin QI Fei Hu. A GROUP OF PROJECTIVE INVARIANTS FOR RECOGNITION OF PLANAR POLYGONS[J]. J. Infrared Millim. Waves,1998,17(2):99~106.]