opencv学习笔记8 高斯金字塔，拉普拉斯金字塔，调整大小

一。图像金字塔

高斯金字塔用来向下降采样图像

拉普拉斯金字塔用来从金字塔底层图像中向上采样重建一个图像

1.像上采样

void pyrUp(InputArray src, OutputArraydst, const Size& dstsize=Size(), int borderType=BORDER_DEFAULT )

2.向下采样

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

 1 #include<opencv.hpp>
 2 using namespace cv;
 3 int main()
 4 {
 5     Mat src = imread("F:/opencv/lena.jpg");
 6     Mat pyrup,pyrdown;
 7     pyrUp(src, pyrup, Size(src.cols * 2, src.rows * 2)); //图片放大
 8     pyrDown(src, pyrdown, Size(src.cols / 2, src.rows / 2)); //图片缩小
 9     imshow("src", src);
10     imshow("pyrup", pyrup);
11     imshow("pyrdown", pyrdown);
12     waitKey();
13     return 0;
14 }

二。调整图像大小

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

 1 #include<iostream>
 2 #include<vector>
 3 #include<opencv2/opencv.hpp>
 4 using namespace std;
 5 using namespace cv;
 6 int main() 
 7 {
 8     Mat src = imread("E:/test.jpg");
 9     Mat dst1, dst2 = Mat::zeros(1000, 1000,CV_8UC3);
10     imshow("src", src);
11     resize(src, dst1, Size(), 0.5, 0.5);
12     imshow("dst1", dst1);
13     resize(src, dst2, dst2.size());
14     imshow("dst2", dst2);
15     waitKey();
16     return 0;
17 }