#include "opencv2/core/core.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <iostream>
using namespace cv;
using namespace std;
void convolution(cv::Mat src, cv::Mat kernel, cv::Mat& dst)
{
dst.create(abs(src.rows - kernel.rows)+1,
abs(src.cols - kernel.cols)+1, src.type());
cv::Size dftSize;
dftSize.width = getOptimalDFTSize(src.cols +
kernel.cols - 1);
dftSize.height = getOptimalDFTSize(src.rows +
kernel.rows - 1);
cv::Mat tempA(dftSize, src.type(), Scalar::all(0));
cv::Mat tempB(dftSize, kernel.type(), Scalar::all(0));
cv::Mat roiA(tempA, Rect(0,0,src.cols,src.rows));
src.copyTo(roiA);
cv::Mat roiB(tempB, Rect(0,0,kernel.cols,kernel.rows));
kernel.copyTo(roiB);
dft(tempA, tempA, 0, src.rows);
dft(tempB, tempB, 0, kernel.rows);
mulSpectrums(tempA, tempB, tempA, DFT_COMPLEX_OUTPUT);
dft(tempA, tempA, DFT_INVERSE + DFT_SCALE, dst.rows);
tempA(Rect(0, 0, dst.cols,dst.rows)).copyTo(dst);
}
int main()
{
cv::Mat srcImage = cv::imread("..\\images\\flower3.jpg", 0);
if( srcImage.empty())
return -1;
cv::Mat kernel = (cv::Mat_<float>(3,3) << 1, 1, 1,
1, 1, 1,
1, 1, 1);
imshow("srcImage", srcImage);
srcImage.convertTo(srcImage, CV_32F);
cv::Mat resultImage;
convolution(srcImage, kernel, resultImage);
normalize(resultImage, resultImage, 0, 1, CV_MMX);
cv::imshow("resultImage", resultImage);
cv::waitKey(0);
return 0;
}