一、介绍
findContours() ：The function retrieves contours from the binary image。
二、代码
void main()
{Mat src = imread("match00.bmp", IMREAD_GRAYSCALE);Mat mask;threshold(src, mask, 128, 255, cv::THRESH_BINARY_INV);Mat element = cv::getStructuringElement(cv::MORPH_RECT, cv::Size(3, 3));cv::morphologyEx(mask, mask, cv::MORPH_CLOSE, element, cv::Point(-1, -1), 1);vector<vector<Point>> conts;cv::findContours(mask, conts, cv::RETR_LIST, cv::CHAIN_APPROX_NONE);cout << "RETR_LIST = " << conts.size() << endl;for (int i = 0; i < conts.size(); i++){double len = cv::arcLength(conts[i], false);double area = cv::contourArea(conts[i]);cout << "len = " << len << ", area = " << area << endl;}
}三、说明
1、原图
2、闭运算后的二值图像
3、RETR_EXTERNAL模式下计算的轮廓个数（只提取外轮廓）
4、RETR_LIST模式下计算的轮廓个数（提取内轮廓和外轮廓）
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