cvPointPolygonTest的使用教程。

/* Checks whether the point is inside polygon, outside, on an edge (at a vertex). Returns positive, negative or zero value, correspondingly. Optionally, measures a signed distance between the point and the nearest polygon edge (measure_dist=1) */ CVAPI(double) cvPointPolygonTest( const CvArr* contour, CvPoint2D32f pt, int measure_dist );

这是OpenCV中对其的注释和声明。

 

其中：CvArr* contour可以简单的表示为一个1维N个点的CvMat.于是

 

CvMat* Poly2 = cvCreateMat(1,nPoint,CV_32FC2); for (int i = 0; i < nPoint; i++) { CvScalar Pnt = cvGet1D(Poly,i); cvSet1D(Poly2,i,Pnt); }

nPoint是多边形顶点的数量，

然后：double jl = cvPointPolygonTest(Poly2,待测点坐标,1)

jl > 0表示在内部。jl<0表示在外部。jl=0表示在多边形上。当cvPointPolygonTest最后一个参数设0时。jl只会是-100或者100.