opencv - 找出一个圆的所有点

Question

我画一个带有固定输入点的圆。现在，我真的想得到该圆圈中所有点的 vector ，其中包括内部填充区域。我尝试了下面的代码，但它只能得到边框。我不能使用轮廓函数，因为我已经使用了很多次，所以它将非常复杂。请给我建议，非常感谢

 vector<Point> allpoints;
 Point center = Point(370, 200);

void getPoints()
{
   Size axes(20, 20);
   ellipse2Poly(center, axes, 0, 0, 360, 1, allpoints);
}

void draw(Mat &BGR_frame)
{
    circle(BGR_frame, center, 20, Scalar(0, 255, 0),CV_FILLED ,2);
    getPoints();
}

Answer 1

一种简单的方法是在初始化为黑色的蒙版上绘制圆，然后从那里检索非黑点:

void draw(Mat &BGR_frame)
{
    circle(BGR_frame, center, 20, Scalar(0, 255, 0),CV_FILLED ,2);

    // Black initialized mask, same size as 'frame'
    Mat1b mask(frame.rows, frame.cols, uchar(0));

    // Draw white circle on mask
    circle(mask, center, 20, Scalar(255), CV_FILLED, 2);

    // Find non zero points on mask, and put them in 'allpoints'
    findNonZero(mask, allpoints);
}

另外，您可以扫描矩阵的所有像素，并保留满足以下条件的点作为圆的内部点:

Point c(370, 200);
int r = 20;

void draw(Mat &BGR_frame)
{        
    circle(BGR_frame, c, r, Scalar(0, 255, 0),CV_FILLED ,2);

    for (int y = 0; y < mask.rows; ++y) {
        for (int x = 0; x < mask.cols; ++x) {

            // Check if this is an internal point
            if ((x - c.x)*(x - c.x) + (y - c.y)*(y - c.y) <= (r*r)) {
                allpoints.push_back(Point(x,y));
            }
        }
    }
}