整理何凯明去雾算法代码优化

持续记录中~~~

这个函数求取三个通道中最小值，然后以最小值组成一幅灰度图-darkchannel,并返回大气强度A

double darkChannel(const cv::Mat &src,cv::Mat &dst){
    cv::Mat rawtemp;
    rawtemp.create(src.size(),src.type());
    for (int i = 0; i < height; i++) { 
        const uchar* imgP = src.ptr<uchar>(i);
        uchar* dstP = rawImage.ptr<uchar>(i); 
        for (int j = 0; j < width; j++) { 
            int b=imgP[3*j]; 
            int g=imgP[3*j+1]; 
            int r=imgP[3*j+2];
            dstP[j] = IMAGE_MIN(IMAGE_MIN(b,g),r);
        } 
    } 
    //把图像分成patch,求patch框内的最小值,得到dark_channel image//range 0-255 center(i,j),every pixel (i,j) of rawtemp's value is Rect minvalue// dx is patchSize/2//rawtemp is the return of function of minChannel
    cv::Mat rect_img; 
    for(int j=0;j<height;j++){ 
        for(int i=0;i<width;i++){
            cv::getRectSubPix(rawtemp,cv::Size(patchSize,patchSize),cv::Point(j,i),rect_img);
            double min_value = 0; 
            cv::minMaxLoc(rect_img,&min_value,0,0,0); //using saturate_cast to set pixel value [0,255] 
            dst.at<uchar>(j,i)= cv::saturate_cast<uchar>(min_value); 
        } 
    }
    //求大气强度A,并没有分开求各个通道的A,取了整体的A值double maxval;
    int minAtomsLight = 220;//经验值 
    minMaxLoc(dst,NULL,&maxval); 
    double A = min(minAtomsLight, (int)maxval);return A;}
///////////////////////////////////////////////////////////////////////////
//当然如果你对opencv比较熟悉的话,可以看出,上面那段代码的后半部分,也就是图像patch块的那部分可以简单的用中值滤波来代替,也就是上面那段代码可以这样写
 double darkChannel(const cv::Mat &src,cv::Mat &dst){
      Mat rawtemp;
      rawtemp.create(src.size(),CV_8UC1); 
     for(int i=0; i<src.rows; i++)
     {       
        const uchar* imgP = src.ptr<uchar>(i); 
        uchar* dstP = rawImage.ptr<uchar>(i);
        for(int j=0; j<src.cols; j++)
        {     
            int b=imgP[3*j];
            int g=imgP[3*j+1];
            int r=imgP[3*j+2];
            dstP[j] = IMAGE_MIN(IMAGE_MIN(b,g),r); 
       }
   }
  // GaussianBlur(rgbmin, MDCP, Size(patch,patch),0);
   //imshow("DCP",MDCP);
   medianBlur(rawtemp, rawtemp, patchSize);

//求大气强度A,并没有分开求各个通道的A,取了整体的A值
   double maxval;
   int minAtomsLight = 220;//经验值
   minMaxLoc(dst,NULL,&maxval);
   double A = min(minAtomsLight, (int)maxval);
   return A;
}

用查找表求粗透射率
    cv::Mat image_trans;
    image_trans.create(nHeight,nWidth,CV_8UC1);
    cv::Mat look_up;
        look_up.create(1,256,CV_8UC1);
        uchar* look_up_ptr = look_up.data;
    //reservation_factor =0.95
      for (int k = 0;k < 256; k++)
        {
            int value = 255*(1- w * k / A);
            look_up_ptr[k] = cv::saturate_cast<uchar>(value);
        }
        cv::LUT(rawtemp,look_up,transmission);

如果不考虑细介质透射率,直接用上面求出的粗透射率来求去雾图,则

//dehazing image
//t 是得到的transmission
//al是大气强度
 Mat getDehaze(Mat source, Mat t, int A)
{
 double tmin = 0.1;
    double tmax;

    Scalar tran;
    Vec3b src;
    Mat dehazed = Mat::zeros(source.rows, source.cols, CV_8UC3);      
//    Mat lookup;
//    look_up.create(1,256,CV_8UC1);
//    uchar* look_up_ptr = look_up.data;
    for(int i=0; i<source.rows; i++)
    {
        for(int j=0; j<source.cols; j++)
        {
            tran = t.at<uchar>(i,j);
            src = source.at<Vec3b>(i,j);
            tmax = (tran.val[0]/255) < tmin ? tmin : (tran.val[0]/255);
            //(I-A)/t +A
            for(int k=0; k<3; k++)
            {
                dehazed.at<Vec3b>(i,j)[k] = abs((src.val[k] - A) / tmax + al) > 255 ? 255 : abs((src.val[k] - A) / tmax + al);
            }
        }
    }
    return dehazed;
}