如何在OpenCV中最好计算光线线段的交点？并获得其交点和距原点的距离？

Question

我有4条线段，A，B，C和D。每条线表示为两个点。例如。线A表示为点A1和点A2。

我想要的是

1. X点，A线与B线相交的点
2. X和A1（原点）之间的距离

测试相交时，线A射线不应该

1. 与线段D相交
2. 与线段C相交

我该怎么做？

Answer 1

最后使它可以在OpenCV C ++上运行。基于此https://stackoverflow.com/a/32146853/457030。

// return the distance of ray origin to intersection point
double GetRayToLineSegmentIntersection(Point2f rayOrigin, Point2f rayDirection, Point2f point1, Point2f point2)
{
    Point2f v1 = rayOrigin - point1;
    Point2f v2 = point2 - point1;
    Point2f v3 = Point2f(-rayDirection.y, rayDirection.x);

    float dot = v2.dot(v3);
    if (abs(dot) < 0.000001)
        return -1.0f;

    float t1 = v2.cross(v1) / dot;
    float t2 = v1.dot(v3) / dot;

    if (t1 >= 0.0 && (t2 >= 0.0 && t2 <= 1.0))
        return t1;

    return -1.0f;
}

// use this to normalize rayDirection
Point2f NormalizeVector(Point2f pt)
{
    float length = sqrt(pt.x*pt.x + pt.y*pt.y);
    pt = pt / length;
    return pt;
}

// gets the intersection point
Point2f GetRayIntersectionPoint(Point2f origin, Point2f vector, double distance)
{
    Point2f pt;

    pt.x = origin.x + vector.x * distance;
    pt.y = origin.y + vector.y * distance;

    return pt;
}

应该是自我解释。