Unhandled Exception at Memory Location - c++

Question

I am new at OpenCV and I am trying to write a simple code to get the mean of a block size in an image. I wrote the following code, the build is ok, however, the debug is giving me an unhandled exception at memory location. This exception is at the following line:
mean_img.at<double>(i/block_size, j/block_size) = mean_img.at<double>(i/block_size,j/block_size) + new_img.at<double>(i + x, j + y) / (mean);
So, I will be grateful if anyone give me some hints. Thanks in advance and here is the whole code:
#include "opencv2/highgui/highgui.hpp" // Include Libs for OpenCV and Image Processing
#include <opencv2/opencv.hpp> // check that
#include "opencv2/core/core.hpp" // check that
#include <iostream> // Include Libs for C++
#include "opencv2/imgproc/imgproc.hpp" // Include Libs for OpenCV and Image Processing
#include <math.h>
using namespace cv; // namespace parameters not important in OpenCV2.4.6
using namespace std; // namespace parameters not important in OpenCV2.4.6
int main( int argc, const char** argv )
{
/*This part is to compute the parameters(block size, resize parameter) of the new_img*/
int resize_parameter; // resize parameter must be multiplication of 2
resize_parameter = 500;
int block_size; // block parameter must be divisable by of block size
block_size = 50;
if ((resize_parameter % 2) != 0) resize_parameter = resize_parameter - (resize_parameter % 2);
while ((resize_parameter % block_size) != 0) block_size = block_size - 1;
int mean_size = resize_parameter/block_size; // this is the size of the mean matrix
int mean = block_size * block_size; // this no is ti get the mean of every element in the matrix
//int mean_img [mean_size][mean_size] = {}; // the mean image matrix initialized by zero
/*This part is to allocate the array with dynamic size*/
//int** mean_img = new int*[mean_size];
//for(int x = 0; x < mean_size; x++)
//mean_img[x] = new int[mean_size];
/*Then we can use the array*/
/*This part is to fill all the elements of the mean matrix with zeros*/
//memset(mean_img, 0, sizeof(mean_img[0][0]) * mean_size * mean_size);
/*This part is the definition of the matrices that are used for the images*/
Mat mean_img = Mat(mean_size,mean_size,CV_64FC4, cv::Scalar(0)); // define a new matrix with meansize*meansize elements to compute the mean
Mat mean_img_full = Mat(resize_parameter,resize_parameter,CV_64FC4, cv::Scalar(0)); // define a new matrix with resizeparameter*resizeparameter elements to compute the mean
Mat new_img = Mat(resize_parameter,resize_parameter,CV_64FC4); // define a new matrix with resize_parameter*resize_parameter elements
Mat original_img = imread("Desert.JPG", CV_LOAD_IMAGE_GRAYSCALE); //define a new matrix and read the image data in the file "Desert.JPG" and store it in 'original_img'
// notes: the location of the image must be in the same directory of the C++ file
if (original_img.empty()) //check whether the image is loaded or not
{
cout << "Error : Image cannot be loaded..!!" << endl;
//system("pause"); //wait for a key press
return -1;
}
// explicitly specify dsize=dst.size(); fx and fy will be computed from that.
// resize( src matrix, dst matrix, dst.size to get the size of the dst matrix, 0, 0 "to deal with the dst matrix size, may be 0.5 or any fraction from the src size, "AREA,CUBIC,LINEAR")
resize(original_img, new_img, new_img.size(), 0, 0, CV_INTER_AREA);
/*This part is to compute the mean of each block*/
for ( int i = 0; i < resize_parameter; i = i + block_size) // i represents the index of the raw
{
for ( int j = 0; j < resize_parameter; j = j + block_size) // for the blocks in the same raw with different columns
{
for ( int x = 0; x < block_size; x++) // x represents the index of the raw
{
for ( int y = 0; y < block_size; y++) // y represents the index of the column
{
//cout << i ; //cout << "\n"; //cout << j ; //cout << "\n"; //cout << x ; //cout << "\n"; //cout << y ; //cout << "\n";
mean_img.at<double>(i/block_size, j/block_size) = mean_img.at<double>(i/block_size,j/block_size) + new_img.at<double>(i + x, j + y) / (mean);
}
}
}
}
/*This is the end of the part to compute the mean of each block*/
/*This part is to fill all the resize matrix with the mean value*/
for ( int x = 0; x < resize_parameter/block_size; x++) // x represents the index of the raw in the mean matrix
{
for ( int y = 0; y < resize_parameter/block_size; y++) // y represents the index of the column in the mean matrix
{
for ( int i = 0; i < block_size; i++) // i represents the index of the raw in the mean_full matrix
{
for ( int j = 0; j < block_size; j++) // j represents the index of the column in the mean_full matrix
{
mean_img_full.at<double>((x*block_size)+i,(y*block_size)+j) = mean_img.at<double>(x,y);
}
}
}
}
//cout << cv::getBuildInformation() << endl;
/*This is the end of the part to fill all the resize matrix with the mean value*/
namedWindow("OriginalImage", CV_WINDOW_AUTOSIZE); //create a window with the name "OriginalImage"
imshow("OriginalImage", original_img); //display the image which is stored in the 'original_img' in the "OriginalImage" window
namedWindow("NewImage", CV_WINDOW_AUTOSIZE); //create a window with the name "NewImage"
imshow("NewImage", new_img); //display the image which is stored in the 'new_img' in the "NewImage" window
namedWindow("MeanImage", CV_WINDOW_AUTOSIZE); //create a window with the name "MeanImage"
imshow("MeanImage", mean_img); //display the image which is stored in the 'mean_img' in the "MeanImage" window
namedWindow("MeanFullImage", CV_WINDOW_AUTOSIZE); //create a window with the name "MeanFullImage"
imshow("MeanFullImage", mean_img_full); //display the image which is stored in the 'mean_img_full' in the "MeanFullImage" window
waitKey(0); //wait infinite time for a keypress
destroyWindow("OriginalImage"); //destroy the window with the name, "OriginalImage"
destroyWindow("NewImage"); //destroy the window with the name, "NewImage"
destroyWindow("MeanImage"); //destroy the window with the name, "MeanImage"
destroyWindow("MeanFullImage"); //destroy the window with the name, "MeanImage"
return 0;
}

Answer 1

The problem was at the definition of the type of each matrix. It has to be 8 Bits Unsigned Character. It is working now. Thanks a lot ,,,