1 void resize( InputArray src, OutputArray dst,
2                           Size dsize, double fx = 0, double fy = 0,
3                           int interpolation = INTER_LINEAR );

 1 #include<opencv2/opencv.hpp>
 2 #include<iostream>
 3 
 4 using namespace cv;
 5 using namespace std;
 6 
 7 int main(int argc, char** argv) {
 8     Mat srcImage = imread("C:\\Users\\Nelsoner\\Desktop\\Camera Roll\\05.jpg", 1);
 9     
10     Mat tmpImage, dstImage1, dstImage2;
11     tmpImage = srcImage;
12 
13     imshow("【原图】", srcImage);
14     
15     resize(tmpImage, dstImage1, Size(tmpImage.cols / 2, tmpImage.rows / 2), (0, 0), (0, 0), 3);
16     resize(tmpImage, dstImage2, Size(tmpImage.cols * 2, tmpImage.rows * 2), (0, 0), (0, 0), 3);
17 
18     imshow("【效果图一】", dstImage1);
19     imshow("【效果图二】", dstImage2);
20 
21     waitKey(0);
22 
23     return 0;
24 }

 void pyrUp( InputArray src, OutputArray dst,
             const Size& dstsize = Size(),
　　　　　　　 int borderType = BORDER_DEFAULT );

 1 #include<opencv2/opencv.hpp>
 2 #include<iostream>
 3 
 4 using namespace cv;
 5 using namespace std;
 6 
 7 int main(int argc, char** argv) {
 8     Mat srcImage = imread("C:\\Users\\Nelsoner\\Desktop\\Camera Roll\\05.jpg", 1);
 9     
10     Mat tmpImage, dstImage;
11     tmpImage = srcImage;
12 
13     imshow("【原图】", srcImage);
14     pyrUp(tmpImage, dstImage, Size(tmpImage.cols * 2, tmpImage.rows * 2));
15     imshow("【效果图】", dstImage);
16     
17     waitKey(0);
18     return 0;
19 }

1 void pyrDown( InputArray src, OutputArray dst,
2               const Size& dstsize = Size(), int borderType = BORDER_DEFAULT );