Mat imgthreshold; Mat imgsrc = cv::imread("C:/Users/Dell/Pictures/Camera Roll/6.png",0); imshow("imgsrc", imgsrc); threshold(imgsrc, imgthreshold,50, 110, THRESH_BINARY); imshow("imgthreshold", imgthreshold); vector<vector<Point>> contours; findContours(imgthreshold, contours, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE); cv::Mat imgdraw = imgsrc.clone(); drawContours(imgdraw, contours, -1, (0, 0, 255),0); imshow("imgdraw", imgdraw); waitKey(0);为什么这块输出的是白色边框而不是红色

在绘制边框时，你应该传入一个 Scalar 类型的参数作为边框颜色，而不是一个元组或者一个数组。修改 drawContours 函数的第四个参数，将其改为 Scalar(0, 0, 255) 即可绘制红色边框，代码如下：

Mat imgthreshold; 
Mat imgsrc = cv::imread("C:/Users/Dell/Pictures/Camera Roll/6.png",0); 
imshow("imgsrc", imgsrc); 
threshold(imgsrc, imgthreshold,50, 110, THRESH_BINARY); 
imshow("imgthreshold", imgthreshold); 
vector<vector<Point>> contours; 
findContours(imgthreshold, contours, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE); 
cv::Mat imgdraw = imgsrc.clone(); 
drawContours(imgdraw, contours, -1, Scalar(0, 0, 255), 1); // 修改这里
imshow("imgdraw", imgdraw); 
waitKey(0);