OpenCV C ++:按轮廓区域对轮廓进行排序 [英] OpenCV C++: Sorting contours by their contourArea
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问题描述
如何根据轮廓区域的大小对轮廓进行排序?
How can I sort contours by the size of their contour areas? And how can I get the biggest/smallest one?
推荐答案
You can use std::sort
with a custom comparison function object
// comparison function object
bool compareContourAreas ( std::vector<cv::Point> contour1, std::vector<cv::Point> contour2 ) {
double i = fabs( contourArea(cv::Mat(contour1)) );
double j = fabs( contourArea(cv::Mat(contour2)) );
return ( i < j );
}
用法:
[...]
// find contours
std::vector<std::vector<cv::Point> > contours;
std::vector<cv::Vec4i> hierarchy;
cv::findContours( binary_image, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE, cv::Point(0, 0) );
// sort contours
std::sort(contours.begin(), contours.end(), compareContourAreas);
// grab contours
std::vector<cv::Point> biggestContour = contours[contours.size()-1];
std::vector<cv::Point> smallestContour = contours[0];
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