如何使用OPENCV获得最小包围圈? [英] How can I get the minimum enclosing circle with OPENCV?
问题描述
我正在使用cv::minEnclosingCircle(...)
来获得恰好使我的轮廓逐渐发展的最小圆,但是我得到的圆要大一些.
I'm using cv::minEnclosingCircle(...)
in order to get the minimum circle that exactly evolves my contour, but I'm getting a circle a little big bigger.
换句话说,我正在尝试得到这样的东西:
In other words, I'm trying to get something like this:
https://upload.wikimedia.org/wikipedia/commons/thumb/3/35/Simple_concave_polygon_Min_Enclosing_Circle.svg/441px-Simple_concave_polygon_Min_Enclosing_Circle.svg.png
但是我得到了这个(圆圈):
But I'm getting this (the circle):
请注意,圆圈比要围封的项目要大一点.
Note how the circle is a little bigger than the item to enclose.
我需要将对象围成一个圆圈,而不是一个椭圆形.
I need to enclose my object into a circle, not an ellipse.
谢谢.
这是我的代码:
cv::vector<cv::Point> allPixels;
int columnas = img.cols, filas = img.rows;
cv::Point pt;
for(int col = 0; col < columnas; col++){
for(int row = 0; row < filas; row++){
int val = img.at<uchar>(row,col);
if(val == 255){
pt.x = col;
pt.y = row;
allPixels.push_back(pt);
}
}
}
cv::Mat dispImage = img.clone();
cv::Point2f center;
float radius;
cv::minEnclosingCircle(allPixels,center,radius);
cv::circle(dispImage,center,radius,cv::Scalar(128),1);
cv::circle(dispImage,center,1,cv::Scalar(128),1);
cv::imwrite("Enclosing_Result.png",dispImage);
带有'img'的cv :: Mat大小为(760,760),格式为CV_8UC1.最终结果("Enclosing_Result.png")是下一个:
With 'img' a cv::Mat with size (760,760) and format CV_8UC1. The final result ("Enclosing_Result.png") is next:
我的目标是(绘制)如下:
And my target is which follows (drawn):
推荐答案
我的结果很好.
## only one region
cnts = cv2.findContours(threshed, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[-2]
(x,y), r = cv2.minEnclosingCircle(cnts[0])
## more than one region
mask = threshed.copy()
## find centers
for cnt in cnts:
(x,y), r = cv2.minEnclosingCircle(cnt)
pt = (int(x), int(y))
centers.append(pt)
## connect the `centers`
for i in range(1, len(centers)):
cv2.line(mask, centers[i-1], centers[i], 255, 2)
## find the center
cnts = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[-2]
(x,y), r = cv2.minEnclosingCircle(cnts[0])
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