离散傅里叶变化

傅里叶变换

对傅里叶变换了解不是很清楚的朋友推荐一下这个帖子，讲得很详细 傅里叶变换

源码

先看源码链接

#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
 
#include <iostream>
 
using namespace cv;
using namespace std;
 
static void help(char ** argv)
{
   
    cout << endl
         << "This program demonstrated the use of the discrete Fourier transform (DFT). " << endl
         << "The dft of an image is taken and it's power spectrum is displayed." << endl << endl
         << "Usage:" << endl
         << argv[0] << " [image_name -- default lena.jpg]" << endl << endl;
}
 
int main(int argc, char ** argv)
{
   
    help(argv);

    const char* filename = argc >=2 ? argv[1] : "lena.jpg";

    // 读取灰度图像
    Mat I = imread(samples::findFile(filename), IMREAD_GRAYSCALE);
    if(I.empty()){
   
        cout << "Error opening image" << endl;
        return EXIT_FAILURE;
    }

    // 扩展输入图像到最优尺寸
    Mat padded; 
    int m = getOptimalDFTSize(I.rows);
    int n = getOptimalDFTSize(I.cols); 
    copyMakeBorder