Merging cv::Mat horizontally

Question

I want to merge a few cv::Mat, when I use mat1.push_back(mat2) it add mat2 to the end of mat1 vertically , is there a way to do this horizontally? The only other option I can think of is making every cv::Mat into a cv::RotatedRect, rotate it, creating a new Mat, merging, rotating everything in the end in the same way, but it sound pointlessly long if there is another way

Answer 1

Take a look at hconcat and vconcat.

usage:

Mat M1,M2,HM,VM;
// M1 and M2 - source matrices
// HM,VM - results matrices
 ...

 hconcat(M1,M2,HM); // horizontal concatenation
 vconcat(M1,M2,VM); // vertical   concatenation

Take care, these methods are not documented.

Answer 2

There is a very simple way of displaying two images side by side. The following function can be used which is provided by opencv.

Mat image1, image2;
hconcat(image1,image2,image1);//Syntax->
hconcat(source1,source2,destination);

This function can also be used to copy a set of columns from an image to another image.

Mat image;
Mat columns=image.colRange(20,30);
hconcat(image,columns,image);