Segmentation fault (core dumped) with OpenCV

Question

I am trying to code a program that eliminates some of the connected components and keep the rest. However, at some point in the code, the program exits with error message "Segmentation fault (core dumped)".

I have narrowed down the error to the statement: "destinationImage.at(row, column) = labeledImage.at(row, column);" using the checkpoints you'll find the code below.

I have tried all the solution I found, especially this one, with no luck.

Please Help!

One more thing, the program reads the image correctly but does not show the original image as per the code. Instead, it prints a message "init done opengl support available". Is this normal? Does the implementation of the imshow take place at the end of the program with no errors?

/* Goal is to find all related components, eliminate secondary objects*/

#include <opencv2/core/utility.hpp>
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>

using namespace cv;
using namespace std;

//Declaring variables
Mat originalImage;
int conComponentsCount;
int primaryComponents;

//Declaring constants
const char* keys =
{
    "{@image|../data/sample.jpg|image for converting to a grayscale}"  
};

//Functions prototypes, used to be able to define functions AFTER the "main" function
Mat BinarizeImage (Mat &, int thresh);
int AverageCCArea(Mat & CCLabelsStats,int numOfLabels, int minCCSize);
bool ComponentIsIncludedCheck (int ccArea, int referenceCCArea);

//Program mainstream============================================
int main (int argc, const char **argv)
{
    //Waiting for user to enter the required path, default path is defined in "keys" string
    CommandLineParser parser(argc, argv, keys);
    string inputImage = parser.get<string>(0);

    //Reading original image
    //NOTE: the program MUST terminate or loop back if the image was not loaded; functions below use reference to matrices and references CANNOT be null or empty.
    originalImage = imread(inputImage.c_str(), IMREAD_GRAYSCALE);// or: imread(argv[1], CV_LOAD_IMAGE_GRAYSCALE)
    cout << " 1) Loading image done!" << endl;//CHECKPOINT
    if (originalImage.empty())
    {
        cout << "Nothing was loaded!";
        return -1; //terminating program with error feedback
    }

    cout << " 2) Checking for null Image done!" << endl;//CHECKPOINT

    namedWindow("Original Image", 0);
    imshow("Original Image", originalImage);

    cout << " 3) Showing ORIGINAL image done!" << endl;//CHECKPOINT

    //Image Binarization; connectedcomponents function only accepts binary images.
    int threshold=100; //Value chosen empirically.
    Mat binImg = BinarizeImage(originalImage, threshold);

    cout << " 4) Binarizing image done!" << endl;//CHECKPOINT

    //Finding the number of connected components and generating the labeled image.
    Mat labeledImage; //Image with connected components labeled.
    Mat stats, centroids; //Statistics of connected image's components.
    conComponentsCount = connectedComponentsWithStats(binImg, labeledImage, stats, centroids, 4, CV_16U);

    cout << " 5) Connecting pixels done!" << endl;//CHECKPOINT

    //Creating a new matrix to include the final image (without secondary objects)
    Mat destinationImage(labeledImage.size(), CV_16U);
    //Calculating the average of the labeled image components areas
    int ccSizeIncluded = 1000;
    int avgComponentArea = AverageCCArea(stats, conComponentsCount, ccSizeIncluded);

    cout << " 6) Calculating components avg area done!" << endl;//CHECKPOINT

    //Criteria for component sizes
    for (int row = 0; row <= labeledImage.rows; row++)
    {
        cout << " 6a) Starting rows loop iteration # " << row+1 << " done!" << endl;//CHECKPOINT
        for (int column = 0; column <= labeledImage.cols; column++)
        {
            //Criteria for component sizes
            int labelValue = labeledImage.at<int>(row, column);
            if (ComponentIsIncludedCheck (stats.at<int>(labelValue, CC_STAT_AREA), avgComponentArea))
            {
                //Setting pixel value to the "destinationImage"
                destinationImage.at<int>(row, column) = labeledImage.at<int>(row, column);

                cout << " 6b) Setting pixel (" << row << "," << column << ") done!" << endl;//CHECKPOINT
            }
            else
                cout << " 6c) Pixel (" << row << "," << column << ") Skipped!" << endl;//CHECKPOINT
        }
        cout << " 6d) Row " << row << " done!" << endl;//CHECKPOINT
    }

    cout << " 7) Showing FINAL image done!" << endl;//CHECKPOINT

    namedWindow("Final Image", 0);
    imshow("Final Image", destinationImage);

    cout << " 8) Program done!" << endl;//CHECKPOINT

    waitKey (0);
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++
Mat BinarizeImage (Mat & originalImg, int threshold=100) //default value of threshold of grey content.
{
    // Binarization of image to be used in connectedcomponents function. 
    Mat bw = threshold < 128 ? (originalImg < threshold) : (originalImg > threshold);
    return bw;
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++
int AverageCCArea(Mat & CCLabelsStats,int numOfLabels, int minCCSize) //calculates the average area of connected components without components smaller than minCCSize pixels..... reference is used to improve performance, passing-by-reference does not require copying the matrix to this function.
{
    int average;

    for (int i=1; i<=numOfLabels; i++)
    {
        int sum = 0;
        int validComponentsCount = numOfLabels - 1;
        if (CCLabelsStats.at<int>(i, CC_STAT_AREA) >= minCCSize)
        {
            sum += CCLabelsStats.at<int>(i, CC_STAT_AREA);
        }
        else
        {
            validComponentsCount--;
        }
        average = sum / (validComponentsCount);
    }
    return average;
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++
bool ComponentIsIncludedCheck (int ccArea, int referenceCCArea)
{
    if (ccArea >= referenceCCArea)
    {
        return true; //Component should be included in the destination image
    }
    else
    {
        return false; //Component should NOT be included in the destination image
    }
}

Answer 1

change this:

for (int row = 0; row <= labeledImage.rows; row++)

to this:

for (int row = 0; row < labeledImage.rows; row++)

and this:

 for (int column = 0; column <= labeledImage.cols; column++)

to this:

 for (int column = 0; column < labeledImage.cols; column++)

any good?

(remember that in C++ we start counting from 0, so if e.g. labeledImage.cols == 10, the last column is the one with the index 9)