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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);



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