Gaussian filtering in OpenCV

We have spent a considerable amount of time understanding the theory behind Gaussian filtering. It is now time to jump into the implementation. The headers will remain the same as in the case of boxFilter(). The functions implementing Gaussian filtering also reside within the imgproc module:

#include <iostream> 
#include <opencv2/core/core.hpp> 
#include <opencv2/highgui/highgui.hpp> 
#include <opencv2/imgproc/imgproc.hpp> 
 
using namespace std; 
using namespace cv; 

Here is the code snippet that actually accomplishes the task of Gaussian filtering:

int main() { 
    Mat input_image = imread("lena.jpg", IMREAD_GRAYSCALE); 
    Mat filtered_image; 
 
    GaussianBlur(input_image, filtered_image, Size(7, 7), 1.0, 1.0, BORDER_REPLICATE); 
 
    imshow("Filtered Image", filtered_image); 
    waitKey(0); 
    return 0; 
} 

One of the first things that you probably...