Labeling pixels in images for classification - c++

Question

I would like to know more on how to label pixels in images. I want to use the algorithms in Caffe in order to come up with an edge detection program. So far I have filtered the image to get the edges and successfully wrote code to detect whether a pixel is an edge or not(relying on its neighboring pixels). All I want to do now is label these as edges so I can feed them as training data in my algorithm(s). I am a beginner in C++ and Caffe. What I really need is someone to explain how labeling exactly works, would I say go to every pixel It considers to be an edge and give it the value 1 for edge and 0 for non-edge ? IF so how do I do this ? References and step by step guides are well appreciated since I have been struggling for some time on this task.
Ok for example I reached this code :
Mat pixelComparisonAlg(Mat img){
Mat img_gray;
img_gray = navigateImage(img.clone());
for(int x=0; x < img_gray.cols-1 ; x++){
for(int y=0; y < img_gray.rows-1; y++ ){
Vec3b value1 = img_gray.at<Vec3b>(Point(x+1,y+1));
Vec3b value2 = img_gray.at<Vec3b>(Point(x+1,y));
Vec3b value4 = img_gray.at<Vec3b>(Point(x,y+1));
Vec3b value = img_gray.at<Vec3b>(Point(x,y));
if( value1 != value || value != value2 || value!= value4){
//EDGE!
value.val[0] = 0;
value.val[1] = 0;
value.val[2] = 255;
value1.val[0] = 0;
value1.val[1] = 0;
value1.val[2] = 255;
img_gray.at<Vec3b>(Point(x,y)) = value;
}
else{
value;
}
}
}
return img_gray;
}
int main( int argc, char** argv )
{
Mat img = cv::imread("...", CV_LOAD_IMAGE_COLOR);
if(! img.data){
cout << "could not open or find the image" << endl;
return -1;
}
imshow("edges", pixelComparisonAlg(img.clone()));
cv::waitKey(0);
return 0;
}
is there a possibility to label these pixels as edges ? Lets say I take the code that changes the colors of the edges to red(after the if statement) modify it to label the pixel as edge or not. Thus I have a vector carrying information about the pixel : color (3 vector elements) and label ( 1 vector element)
Thank you