opencv 频率域滤波实例

来源：互联网发布：新能源就业前景知乎编辑：程序博客网时间：2024/06/01 09:40

先上参考链接：http://blog.csdn.net/qq_19764963/article/details/51209970

http://www.cnblogs.com/TonyHome/p/4010116.html

这里给出高斯滤波器的实例，关于傅立叶变换的详细步骤，可以看上一篇博客，这里不做过多介绍了

#include<opencv2/opencv.hpp>#include<iostream>using namespace std;using namespace cv;int main(int a,char**p){Mat input=imread(p[1],CV_LOAD_IMAGE_GRAYSCALE);        //这是在ubuntu上运行的，p[1]为控制台给出的参数，即图片路径       //如果不知道怎么传入参数，可以直接改为        //Mat input=imread("image.jpg",CV_LOAD_IMAGE_GRAYSCALE);        //image.jpg必须放在当前目录下，image.jpg即为输入图片        imshow("input",input);int w=getOptimalDFTSize(input.cols);int h=getOptimalDFTSize(input.rows);Mat padded;copyMakeBorder(input,padded,0,h-input.rows,0,w-input.cols,BORDER_CONSTANT,Scalar::all(0));padded.convertTo(padded,CV_32FC1);imshow("padded",padded);for(int i=0;i<padded.rows;i++)//中心化操作，其余操作和上一篇博客的介绍一样{float *ptr=padded.ptr<float>(i);for(int j=0;j<padded.cols;j++)ptr[j]*=pow(-1,i+j);}Mat plane[]={padded,Mat::zeros(padded.size(),CV_32F)};Mat complexImg;merge(plane,2,complexImg);dft(complexImg,complexImg);//************************gaussian****************************Mat gaussianBlur(padded.size(),CV_32FC2);Mat gaussianSharpen(padded.size(),CV_32FC2);float D0=2*10*10;for(int i=0;i<padded.rows;i++){float*p=gaussianBlur.ptr<float>(i);float*q=gaussianSharpen.ptr<float>(i);for(int j=0;j<padded.cols;j++){float d=pow(i-padded.rows/2,2)+pow(j-padded.cols/2,2);p[2*j]=expf(-d/D0);p[2*j+1]=expf(-d/D0);q[2*j]=1-expf(-d/D0);q[2*j+1]=1-expf(-d/D0);}}multiply(complexImg,gaussianBlur,gaussianBlur);//矩阵元素对应相乘法，注意，和矩阵相乘区分multiply(complexImg,gaussianSharpen,gaussianSharpen);//*****************************************************************split(complexImg,plane);magnitude(plane[0],plane[1],plane[0]);plane[0]+=Scalar::all(1);log(plane[0],plane[0]);normalize(plane[0],plane[0],1,0,CV_MINMAX);imshow("dft",plane[0]);//******************************************************************split(gaussianBlur,plane);magnitude(plane[0],plane[1],plane[0]);plane[0]+=Scalar::all(1);log(plane[0],plane[0]);normalize(plane[0],plane[0],1,0,CV_MINMAX);imshow("gaussianBlur",plane[0]);split(gaussianSharpen,plane);magnitude(plane[0],plane[1],plane[0]);plane[0]+=Scalar::all(1);log(plane[0],plane[0]);normalize(plane[0],plane[0],1,0,CV_MINMAX);imshow("gaussianSharpen",plane[0]);//******************************************************************//*************************idft*************************************idft(gaussianBlur,gaussianBlur);idft(gaussianSharpen,gaussianSharpen);split(gaussianBlur,plane);magnitude(plane[0],plane[1],plane[0]);normalize(plane[0],plane[0],1,0,CV_MINMAX);imshow("idft-gaussianBlur",plane[0]);split(gaussianSharpen,plane);magnitude(plane[0],plane[1],plane[0]);normalize(plane[0],plane[0],1,0,CV_MINMAX);imshow("idft-gaussianSharpen",plane[0]);waitKey();return 0;}

运行结果如图所示

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