Take the cv::Mat object as a parameter, and pass in a function as a reference, which will affect the original image

cv::Mat image;
OperateMat(image);   		// 函数OperateMat，对image操作，image会同步改变。省略了定义
OpreateMat(image.clone());  // 不会改变image。

OperateMat(image); If the image is not of cv::Mat type, it is pass-by-value according to the c++ value transfer principle, and the image operation in OperateMat will not affect the image; while the incoming parameter is a cv::Mat object
. Not the same, at this time in the OperateMat function to operate on the image, it will change the image synchronously . You can use clone() to avoid changing the original image.