Merging two 1d histograms into one - c++

Question

I got two histograms which I created with standard openCV function calcHist:
int getModels(string filename) {
Mat src = imread(filename, 1);
if(!src.data) { return -1; }
Mat imageHSV;
cvtColor(src, imageHSV, COLOR_BGR2HSV);
vector<Mat> bgr_planes;
split(imageHSV, bgr_planes);
int histSize = 256;
float range[] = { 0, 256 } ;
const float* histRange = { range };
bool uniform = true; bool accumulate = false;
Mat g_hist, r_hist;
calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate );
calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate );
cv::Mat combined_hist = g_hist + r_hist;
int hist_w = 512; int hist_h = 400;
int bin_w = cvRound( (double) hist_w/histSize );
Mat histImage(hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) );
for( int i = 0; i < histSize; i++ )
{
line( histImage, Point( bin_w*(i-1), cvRound(combined_hist.at<float>(i-1)) ) ,
Point( bin_w*(i), cvRound(combined_hist.at<float>(i)) ),
Scalar( 19,90,87), 2, 8, 0 );
}
/// Display
namedWindow(filename, CV_WINDOW_AUTOSIZE );
imshow(filename, histImage );
return 0;
}
Is there any way to merge them into one combined_hist histogram?

Answer 1

Yes, you can. OpenCV has cv::add which can be used like this:
cv::Mat combined_hist;
cv::add(g_hist, r_hist, combined_hist);
However, since cv::Mat has overloaded operators, you can just do this:
cv::Mat combined_hist = g_hist + r_hist;
Hope that helps you.