Images can be combined(结合) in different ways. Since they are regular(一般) matrices, they can be added, subtracted, multiplied, or divided.

1. Example analysis　

　　可以使用cv::add函数来实现相加功能。如想得到加权和，可使用更精确的cv::addWeighted函数。

#include 
     
      #include 
      
       #include 
       
        #include 
        
         using namespace cv;int main(){    Mat image1;    Mat image2;    image1 = imread("test.jpg");    image2 = imread("test_b.jpg");    namedWindow("Image 1");    imshow("Image 1", image1);    namedWindow("Image 2");    imshow("Image 2", image2);    Mat result;    /*    add two images:    cvAddWeighted( const CvArr* src1, double alpha,  const CvArr* src2, double beta,  double gamma, CvArr* dst );    dst(I)=src1(I)*alpha+src2(I)*beta+gamma    */    addWeighted(image1, 0.7, image2, 0.5, 0., result);    namedWindow("result");    imshow("result", result);    waitKey();    return 0;}
        
       
      
     

 1.2 Overloaded image operators(重载图像运算符)

　　Most arithmetic functions(运算函数) have their corresponding operator（相应操作） overloaded in OpenCV 2. Consequently(因此), the call to cv::addWeighted can be written as follows:

　　result = 0.7*image1 + 0.9*image2;

　　The preceding(前面的) code is a more compact form(紧凑的形式) that is also easier to read.

1.3 Splitting the image channels（分割图像通道）

　　use the cv::split function that will copy the three channels of a color image into three distinct（不同） cv::Mat instances（实例）. Suppose we want to add our rain image to the blue channel only. The following is how we would proceed:

　　// create vector of 3 images

　　std::vector<cv::Mat> planes;

　　// split 1 3-channel image into 3 1-channel images

　　cv::split(image1, planes);

　　// add to blue channel

　　planes[0] += image2;

　　// merge the 3 1-channel images into 1 3-channel image

　　cv::merge(planes, result);