OpenCV : Image synthesis (ROI, Mask, Binary)

Today we will make Image synthesis by using ROI, Masking, binarization.

The full code is like that.

#include <iostream>
#include "opencv2/opencv.hpp"
using namespace std;
using namespace cv;

int main() {
    Mat me = imread("./res/pic/mh.jpg");
    Mat animal = imread("./res/pic/animal_head.png");
    Mat animalGray;
    Mat mask_ani;
    Mat mask_ani_inv;
    imshow("me origin", me);
    imshow("animal", animal);
    cvtColor(animal, animalGray, CV_BGR2GRAY); // color to black and white    

    threshold(animalGray, mask_ani, 10, 255, 0); // make binary    

    bitwise_not(mask_ani, mask_ani_inv);
    imshow("mask ani inv", mask_ani_inv);
    imshow("mask ani", mask_ani);

    Mat imgRoi;
    imgRoi = me(Rect(50, 50, animal.cols, animal.rows));
    imshow("imgRoi", imgRoi);
    Mat me_back;
    Mat ani_for;

    bitwise_and(animal, animal, ani_for, mask_ani); // mask with mask_ani    

    bitwise_and(imgRoi, imgRoi, me_back, mask_ani_inv); // mask with mask_ani_inv    

    imshow("ani_for", ani_for);
    imshow("me_back", me_back);

    Mat dst;
    add(me_back, ani_for, dst); //add background of roi , foreground of animal    

    dst.copyTo(imgRoi); // result copy to imgRoi    imshow("dst", dst);
    imshow("result", me);
    waitKey(0);
    return 0;
}

• Make binary images for masking background and foreground images

cvtColor(animal, animalGray, CV_BGR2GRAY); // color to black and white

threshold(animalGray, mask_ani, 10, 255, 0); // make binary

bitwise_not(mask_ani, mask_ani_inv);

• Make image ROI and fit to the synthesis position.

Mat imgRoi;
// start at x:50, y:50, size width: animal.cols, height: animal.rows

imgRoi = me(Rect(50, 50, animal.cols, animal.rows)); 
imshow("imgRoi", imgRoi);

• Remove animal image background and the part of the image ROI that will contain the animal picture by using bitwise operation.

Mat me_back;
Mat ani_for;
bitwise_and(animal, animal, ani_for, mask_ani); // remove background

bitwise_and(imgRoi, imgRoi, me_back, mask_ani_inv); // remove foreground

imshow("ani_for", ani_for);
imshow("me_back", me_back);

• Finally add background of ROI, foreground of animal image.

Mat dst;
add(me_back, ani_for, dst); //add background of roi , foreground of animal

dst.copyTo(imgRoi); // result copy to imgRoi

imshow("dst", dst);
imshow("result", me);
waitKey(0);