OpenCV依據顔色的車牌定位

使用顔色屬性：

Mat srcImage=imread("image/t10.jpg");
  Mat srcShowImage;
  srcImage.copyTo(srcShowImage);
  //imshow("a",srcImage);
  int i,j;
  int cPointB,cPointG,cPointR;
  for(i=1;i<srcImage.rows;i++)
    for(j=1;j<srcImage.cols;j++)
    {
      cPointB=srcImage.at<Vec3b>(i,j)[0];
      cPointG=srcImage.at<Vec3b>(i,j)[1];
      cPointR=srcImage.at<Vec3b>(i,j)[2];
      if(cPointB>80&cPointR<80&cPointG<80)    //提取藍色，将該區域設定為黑色
      {
        srcImage.at<Vec3b>(i,j)[0]=0;
        srcImage.at<Vec3b>(i,j)[1]=0;
        srcImage.at<Vec3b>(i,j)[2]=0;
      }

      else if(cPointB>200&cPointR>200&cPointG>200)  //提取白色，将其設定為黑色
      {
        srcImage.at<Vec3b>(i,j)[0]=0;
        srcImage.at<Vec3b>(i,j)[1]=0;
        srcImage.at<Vec3b>(i,j)[2]=0;
      }

      else
      {
        srcImage.at<Vec3b>(i,j)[0]=255;
        srcImage.at<Vec3b>(i,j)[1]=255;
        srcImage.at<Vec3b>(i,j)[2]=255;
      }

    }
    cvtColor(srcImage,srcImage, CV_BGR2GRAY);  
    threshold(srcImage,srcImage,127, 255,CV_THRESH_BINARY);   
    //使用差分法，去掉不相關的區域。
    for(i=1;i<srcImage.rows;i++)
      for(j=1;j<srcImage.cols-1;j++)
      {
        srcImage.at<uchar>(i,j)=srcImage.at<uchar>(i,j+1)-srcImage.at<uchar>(i,j);

      }

      threshold(srcImage,srcImage,127, 255,CV_THRESH_BINARY_INV);//通過二值化的方式來取反。
      //erode(srcImage,srcImage,Mat(5,5,CV_8U),Point(-1,-1),2);  //腐蝕
      //  dilate(src,src,Mat(5,5,CV_8U),Point(-1,-1),2); //膨脹
      //  morphologyEx(src,src,MORPH_OPEN,Mat(3,3,CV_8U),Point(-1,-1),1);   //開運算
      //   morphologyEx(src,src,MORPH_CLOSE,Mat(3,3,CV_8U),Point(-1,-1),1);  //閉運算
      erode(srcImage,srcImage,Mat(3,3,CV_8U),Point(-1,-1),5);
      threshold(srcImage,srcImage,127,255,CV_THRESH_BINARY_INV);
      imshow("a",srcImage);
      vector<vector<Point> > contours;
      vector<Vec4i> hierarchy;
      findContours(srcImage, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );
      Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
      for( int i = 0; i < contours.size(); i++ )
      {  
        //使用邊界框的方式  
        CvRect aRect =  boundingRect(contours[i]);
        int tmparea=aRect.height*aRect.height;  
        if (((double)aRect.width/(double)aRect.height>2)&& ((double)aRect.width/(double)aRect.height<6)&& tmparea>=2000&&tmparea<=25000)  
        {  
          rectangle(srcShowImage,cvPoint(aRect.x,aRect.y),cvPoint(aRect.x+aRect.width ,aRect.y+aRect.height),color,2);  
          //cvDrawContours( dst, contours, color, color, -1, 1, 8 );  
        }  
      } 


      imshow("da",srcShowImage);      

效果如下：