Shrey's profile - activity

Thanks LBerger: This solved it.

berak: I have debugged the code. My custom function medFilter works correctly. imshow displays the output which is correct. Error is thrown at the closing curly bracket of the main() function.

LBerger: hist[255] has been changed to hist[256] as you have correctly suggested. Problem still persists though.

berak- The error is happening in the destructor: cv::ImageCodecInitializer::~ImageCodecInitializer(). Which is OpenCV Library code. Cant seem to find whats going on.

LBerger: Line numbers are removed.

berak.. I used gdb: The program executed well till line no. 16; after which just before exiting the main function gave a dump.

I am trying to implement a median filter(for practice). The program showed the output image correctly but it ended with a segmentation fault. The following error occurred just before exiting main(){}

Program received signal SIGSEGV, Segmentation fault. 0x00007ffff78bf789 in cv::ImageCodecInitializer::~ImageCodecInitializer() () from /usr/local/lib/libopencv_imgcodecs.so.3.2

//mainFile.cpp
 #include <opencv2/highgui/highgui.h
 #include <opencv2/core/core.hpp>
 #include "lowp.h"
 //#include <stdlib.h>
 using namespace cv;

 void medFilter(Mat &, Mat &, int);
 int main(){
 Mat img = imread("home.jpg",1);
 Mat out;
 medFilter(img,out,7);
 namedWindow("Example");
 imshow("Example", out);
 waitKey(0);
 destroyWindow("Example");
  }



    //lowp.h
 void medFilter(Mat &img, Mat &out, int size){
      Mat low(img.rows, img.cols, img.type());
      int r = img.rows;
      int c = img.cols;
      const int ch = img.channels();
      int hist[256];   //changed from int hist[255] -- as correctly suggested by LBerger
      int w = 0;
      int *win;
      win = new int(size*size);
      for(int h = 0; h<255; h++){
                  hist[h] = 0;
      }
      for(int i = 0; i<r; i++){
                   for(int j = 0; j<c; j++){
                        for(int chi = 0; chi < ch; chi++){
                                  if(i>=size/2 && i<r-size/2 && j>=size/2 && j<c-size/2){
                                           for(int u = -size/2 ; u<=size/2; u++){
                                                 for(int v = -size/2; v<=size/2; v++){
                                                          win[w] = *(img.ptr<uchar>(i + u) + (j + v)*ch + chi);
                                                          w++;
                                                   }
                                           }
                                          w = 0;
                                         *(low.ptr<uchar>(i) + j*ch + chi) = getMedian(win, hist, (size*size));
                                  }else{
                                         *(low.ptr<uchar>(i) + j*ch + chi) = *(img.ptr<uchar>(i) + j*ch + chi);
                                  }
                         }
                 }
          }
          out = low;
  }

   uchar  getMedian(int* w, int* hist, int size){
        uchar h;
        for(int i = 0; i<size; i++){
              hist[w[i]] ++;
         }
          int sum = 0;
          for(h = 0; h<255; h++){
                  sum += hist[h];
                  if(sum>size/2) break;
          }
         for(int i = 0; i<size; i++){
                  hist[w[i]] = 0;
         }
         return h;
  }