排序2d点数组以找出四个角 [英] Sorting 2d point array to find out four corners

问题描述

我有2d个点的集合，它们可以是任意大小.通过找到原点之间距离的最小值和最大值，我可以找出左上角和右下角的点，但我无法找出右上角和左下角.

Hi I have the collection of 2d points which can be of any size .By finding min and max value of the distance between origin I am able to find out the top left and bottom-right corner point but I am not able to find out top-right and bottom left point.

推荐答案

也许您可以使用cv::approxPoly()查找一组2D点的角.然后，您可以按照以下想要的任何顺序对点进行排序:

Perhaps you can use cv::approxPoly() to find the corners of your set of 2D points. Then you can sort the points in any order you want in the following way:

//Sorts a vector of 4 points into top left, top right, bottomleft, bottomright
vector<Point> sortPoints(vector<Point> unsorted) {
    vector<Point> sorted;
    for (int i = 0; i < 4; i++)sorted.push_back(Point(0, 0));
    int middleX = (unsorted[0].x + unsorted[1].x + unsorted[2].x + unsorted[3].x) / 4;
    int middleY = (unsorted[0].y + unsorted[1].y + unsorted[2].y + unsorted[3].y) / 4;
    for (int i = 0; i < unsorted.size(); i++) {
        if (unsorted.at(i).x < middleX && unsorted.at(i).y < middleY)sorted[0] = unsorted.at(i);
        if (unsorted.at(i).x > middleX && unsorted.at(i).y < middleY)sorted[1] = unsorted.at(i);
        if (unsorted.at(i).x < middleX && unsorted.at(i).y > middleY)sorted[2] = unsorted.at(i);
        if (unsorted.at(i).x > middleX && unsorted.at(i).y > middleY)sorted[3] = unsorted.at(i);
    }
    return sorted;
}

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