如何在OpenCV中旋转轮廓的像素或轮廓的近似多边形？

1 回答

• 0

  这是您在图像中旋转对象的方法

  这是具有已知物体/轮廓位置的输入图像（那里有颜色的东西）

  

  int main()
  {
      cv::Mat input = cv::imread("rotateObjects_input.png");
  
      std::vector<cv::Point> myContour;
      myContour.push_back(cv::Point(100,100));
      myContour.push_back(cv::Point(150,100));
      myContour.push_back(cv::Point(150,300));
      myContour.push_back(cv::Point(100,300));
  
      cv::Point2f cog(0,0);
      for(unsigned int i=0; i<myContour.size(); ++i)
      {
          cog = cog + cv::Point2f(myContour[i].x, myContour[i].y);
      }
      cog = 1.0f/(float)myContour.size()*cog;
  
      std::cout << "center of gravity: " << cog << std::endl;
  
  
      // create and draw mask
      cv::Mat mask = cv::Mat::zeros(input.size(), CV_8UC1);
      cv::fillConvexPoly(mask,myContour,255);
  
      // create rotation mat
      float angleDEG = 45;
      cv::Mat transformation = cv::getRotationMatrix2D(cog,angleDEG,1);
      std::cout << transformation << std::endl;
  
      // rotated mask holds the object position after rotation
      cv::Mat rotatedMask;
      cv::warpAffine(mask,rotatedMask,transformation,input.size());
      cv::Mat rotatedInput;
      cv::warpAffine(input,rotatedInput,transformation, input.size());
  
      cv::imshow("input",input);
      cv::imshow("rotated input",rotatedInput);
      cv::imshow("rotated mask",rotatedMask);
  
      // copy rotated object to original image:
      cv::Mat output = input.clone();
      rotatedInput.copyTo(output, rotatedMask);
  
      cv::imwrite("rotateObjects_beforeHolefilling.png", output);
  
      // now there are pixel left from the old object position.
      cv::Mat holePixelMask = mask & (255-rotatedMask);
      // we have to fill those pixel with some kind of background...
      cv::Mat legalBackground = (255-mask);
      //cv::erode(legalBackground,)
  
      // fill holes. here you could try to find some better background color by averaging in neighborhood or sth.
      cv::Vec3b lastLegalPixel(0,0,0);
      for(unsigned int j=0; j<mask.rows; ++j)
          for(unsigned int i=0; i<mask.cols; ++i)
          {
              if(holePixelMask.at<unsigned char>(j,i))
              {
                  output.at<cv::Vec3b>(j,i) = lastLegalPixel;
              }
              else
              {
                  if(legalBackground.at<unsigned char>(j,i))
                      lastLegalPixel = input.at<cv::Vec3b>(j,i);
              }
          }
  
  
  
      cv::imshow("holes before filling", holePixelMask);
      cv::imshow("legal background", legalBackground);
  
      cv::imshow("result", output);
  
      cv::waitKey(-1);
      return 0;
  }
  

  这是填孔前的输出

  

  这是在填孔之后

  

  回复于 2024-05-02T15:54:18+08:00