Sobel derivative in OpenCV

Question

I have been tasked with making my own Sobel method, and not use the cv::Sobel found in OpenCV. I tried implementing one I found at Programming techniques

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Answer 1

thanks for the post, I was able to generate gradiant map using the above kernel, and using openCV code filter2D getting from Using custom kernel in opencv 2DFilter - causing crash ... convolution how?

to convolve the image with the kernel. the code that I used is

    #include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include 
#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

    //Loading the source image
    Mat src;
    //src = imread("1.png");
    src = cv::imread("E:\\Gray_Image.bmp", 0);
    //Output image of the same size and the same number of channels as src.
    Mat dst1,dst2,grad;
    //Mat dst = src.clone();   //didn't help...

    //desired depth of the destination image
    //negative so dst will be the same as src.depth()
    int ddepth = -1;

    //the convolution kernel, a single-channel floating point matrix:


    //Mat kernel = imread("kernel.png");

    Mat kernel_x = (Mat_(3, 3) << -1, 0, 1, -2, 0, 2, -1, 0, 1);

    Mat kernel_y = (Mat_(3, 3) << -1, -2, -1, 0, 0, 0, 1, 2, 1);
    kernel_x.convertTo(kernel_x, CV_32F);  kernel_y.convertTo(kernel_y, CV_32F);   //<