stitcher doesn't remove the black area #44

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1. saudet

   added

   help wanted

   question

   on Mar 4, 2019
2. indra365 commented on Mar 8, 2019

   

   indra365

   on Mar 8, 2019

   Last edited by saudet

   Author

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   Need to convert this code to Java, since javacv doesn't have an easy way to access the pixel ..

   //find largest roi
   bool cropLargestPossibleROI(const cv::Mat& gray, cv::Mat& pano, cv::Rect startROI)
   {
       // evaluate start-ROI
       Mat possibleROI = gray(startROI);
       bool topOk = checkRow(possibleROI, 0);
       bool leftOk = checkColumn(possibleROI, 0);
       bool bottomOk = checkRow(possibleROI, possibleROI.rows-1);
       bool rightOk = checkColumn(possibleROI, possibleROI.cols-1);
       if(topOk && leftOk && bottomOk && rightOk)
       {
           // Found!!
           LOGE("cropLargestPossibleROI success");
           pano = pano(startROI);
           return true;
       }
       // If not, scale ROI down
       Rect newROI(startROI.x, startROI.y, startROI.width, startROI.height);
       // if x is increased, width has to be decreased to compensate
       if(!leftOk)
       {
           newROI.x++;
           newROI.width--;
       }
       // same is valid for y
       if(!topOk)
       {
           newROI.y++;
           newROI.height--;
       }
       if(!rightOk)
       {
           newROI.width--;
       }
       if(!bottomOk)
       {
           newROI.height--;
       }
       if(newROI.x + startROI.width < 0 || newROI.y + newROI.height < 0)
       {
           //sorry...
           LOGE("cropLargestPossibleROI failed");
           return false;
       }
       return cropLargestPossibleROI(gray,pano,newROI);
   }
   
   /check row
   bool checkRow(const cv::Mat& roi, int y)
   {
       int zeroCount = 0;
       for(int x=0; x<roi.cols; x++)
       {
           if(roi.at<uchar>(y, x) == 0)
           {
               zeroCount++;
           }
       }
       if((zeroCount/(float)roi.cols)>cutBlackThreshold)
       {
           return false;
       }
       return true;
   }
   
   //check col
   bool checkColumn(const cv::Mat& roi, int x)
   {
       int zeroCount = 0;
       for(int y=0; y<roi.rows; y++)
       {
           if(roi.at<uchar>(y, x) == 0)
           {
               zeroCount++;
           }
       }
       if((zeroCount/(float)roi.rows)>cutBlackThreshold)
       {
           return false;
       }
       return true;
   }
3. saudet commented on Mar 8, 2019

   

   saudet

   on Mar 8, 2019 via email

   Member

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   Yes we can easily access the pixel values using indexers: http://bytedeco.org/news/2014/12/23/third-release/
4. begiflow commented on Nov 18, 2022

   

   begiflow

   on Nov 18, 2022

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   Hi @indra365 Are you done with this things, Can you share the code crop the black area,.. Thanks