OpenCV获取和设置图像的平均亮度

1. OpenCV1.0中C方式：

 double getAvg(IplImage *img)
 {
     IplImage *gray = cvCreateImage(cvGetSize(img),IPL_DEPTH_8U,1);
     cvCvtColor(img,gray,CV_RGB2GRAY);
     CvScalar scalar = cvAvg(gray);
     cvReleaseImage(&gray);
     return scalar.val[0];
 }

 void setAvg(IplImage *img,IplImage *out,double avg_gray)
 {
     double prev_avg_gray = get_avg_gray(img);
     cvConvertScale(img,out,avg_gray/prev_avg_gray);
 }

2. OpenCV2.0中C++方式：

 double getAvg(Mat img)
 {
  Mat gray;
     cvtColor(img, gray, CV_RGB2GRAY);
  Scalar scalar = mean(gray);
     return scalar.val[0];
 }

 void setAvg(Mat scr,Mat dst, double avg)
 {
     double fpreAvg = getAvg(scr);
     scr.convertTo(dst,scr.type(),avg/fpreAvg);
 }