OpenCV计算灰度图像的峰值信噪比（PSNR）

我用两种方法实现了灰度图像的PSNR的计算，如下。代码虽说是针对灰度图像的，但能很容易扩展到多通道图像的PSNR的计算。

 

代码之一,完全靠自己的代码实现PSNR的计算：

#include
#include
#include
#include
#pragma comment( lib, "cv.lib" )
#pragma comment( lib, "cxcore.lib" )
#pragma comment( lib, "highgui.lib" )
int main()
{
    IplImage* img = cvLoadImage("lena.jpg",0);
    int height=img->height;
    int width=img->width;
    int step=img->widthStep;
    uchar *data=(uchar *)img->imageData;
    int i,j;
    double sum=0;
    for(i=0;i
    {
        for(j=0;j
        {
            sum+=data[i*step+j];
        }
    }
    double mean=0;
    mean=sum/(width*height);
    double mse=0;
    for(i=0;i
    {
        for(j=0;j
        {
            mse+=(data[i*step+j]-mean)*(data[i*step+j]-mean);
        }
    }
    mse=mse/(width*height);
    double psnr=0;
    psnr=10*log10(255*255/mse);
    printf("%lf/n",sum);
    printf("%lf/n",mean);
    printf("%lf/n",mse);
    printf("%lf/n",psnr);
    cvNamedWindow("Lena", CV_WINDOW_AUTOSIZE);
    cvShowImage("Lena", img );
    cvWaitKey(0);
    cvDestroyWindow("Lena");
    cvReleaseImage(&img );
    return 0;
}

#include #include #include #include #pragma comment( lib, "cv.lib" ) #pragma comment( lib, "cxcore.lib" ) #pragma comment( lib, "highgui.lib" ) int main() { IplImage* img = cvLoadImage("lena.jpg",0); int height=img->height; int width=img->width; int step=img->widthStep; uchar *data=(uchar *)img->imageData; int i,j; double sum=0; for(i=0;i

 

代码之二，使用了许多OpenCV库提供的函数，代码要精炼一些：

#include
#include
#include
#include
#pragma comment( lib, "cv.lib" )
#pragma comment( lib, "cxcore.lib" )
#pragma comment( lib, "highgui.lib" )
int main()
{
    IplImage* img = cvLoadImage("lena.jpg",0);

    CvScalar sum=cvSum(img);
    CvScalar mean=cvAvg(img);
    CvScalar stddev;
    cvAvgSdv(img,NULL,&stddev);
    double psnr=20*log10(255/stddev.val[0]);
    printf("%lf/n",sum.val[0]);
    printf("%lf/n",mean.val[0]);
    printf("%lf/n",stddev.val[0]);
    printf("%lf/n",psnr);
    cvNamedWindow("Lena", CV_WINDOW_AUTOSIZE);
    cvShowImage("Lena", img );
    cvWaitKey(0);
    cvDestroyWindow("Lena");
    cvReleaseImage(&img );
    return 0;
}

#include #include #include #include #pragma comment( lib, "cv.lib" ) #pragma comment( lib, "cxcore.lib" ) #pragma comment( lib, "highgui.lib" ) int main() { IplImage* img = cvLoadImage("lena.jpg",0); CvScalar sum=cvSum(img); CvScalar mean=cvAvg(img); CvScalar stddev; cvAvgSdv(img,NULL,&stddev); double psnr=20*log10(255/stddev.val[0]); printf("%lf/n",sum.val[0]); printf("%lf/n",mean.val[0]); printf("%lf/n",stddev.val[0]); printf("%lf/n",psnr); cvNamedWindow("Lena", CV_WINDOW_AUTOSIZE); cvShowImage("Lena", img ); cvWaitKey(0); cvDestroyWindow("Lena"); cvReleaseImage(&img ); return 0; }

经lena图检验，上面两份代码计算的结果是一样的。

说明：上面的PSNR的定义参考了维基百科的相关条目。疏漏之处，欢迎拍砖！