[OpenCV] C++ OpenCV image annotating

C++에서 opencv를 이용해 이미지에 선, 원 등 다양한 도형을 그리는 방법입니다.

 

 

1.선 그리기  

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

int main() {
    Mat image =imread("../test.jpg");

    Mat imageLine = image.clone();
    Point pointA(200,80);
    Point pointB(450, 80);

    line(imageLine, pointA, pointB, color=Scalar(255,255,0), thickness=3, 8, 0);
    imwrite("line_image.jpg", imageLine);

    return 0;
}

 => line(Input Output array, pt1, pt2, scalar(B,G,R), thickness, lineType, shift)

lineType은 line 안을 채울지 등에 대한 값이며 shift는 무조건 0으로 세팅하면 됩니다.

 

 

2. 원 그리기  

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

int main() {
    Mat image =imread("../test.jpg");

    Mat circle_image = image.clone();
    Point circle_center(415,190);

    int radius = 100;

    circle(circle_image, circle_center, radius, Scalar(0,255, 0), 3, 8, 0);
    
    //안이 채워진 원 그리기
    circle(circle_image, circle_center, radius, Scalar(0,255, 0), -1, 8, 0);

    imwrite("cricle_image.jpg", circle_image);

    return 0;
}

 

 

3. 사각형 그리기  

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

int main() {
    Mat image =imread("../test.jpg");

    Mat rect_image = image.clone();
    Point start_point(300,115);
    Point end_point(475, 225);

    rectangle(rect_image, start_point, end_point, Scalar(0,0,255), 3, 8, 0);

    imwrite("rect_image.jpg", rect_image);

    return 0;
}

 

4.  타원 그리기  

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

int main() {
    Mat image =imread("../test.jpg");

    Mat imageEllipse = image.clone();
    Point ellipse_center(415,190);
    Point axis1(100, 50);
    Point axis2(125, 50);

    ellipse(imageEllipse, ellipse_center, axis1, 0, 0, 360, Scalar(255, 0, 0), 3, 8, 0);
    ellipse(imageEllipse, ellipse_center, axis2, 90, 0, 360, Scalar(0, 0, 255), 3, 8, 0);
    
    imwrite("ellipse_image.jpg", imageEllipse);

    return 0;
}

 

4-1. 반원 반만 채우기

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

int main() {
    Mat image =imread("../test.jpg");

    Mat halfEllipse = image.clone();
    Point ellipse_center(415,190);
    Point axis1(100, 50);

    ellipse(halfEllipse, ellipse_center, axis1, 0, 180, 360, Scalar(255, 0, 0), 3, 8, 0);
    ellipse(halfEllipse, ellipse_center, axis1, 0, 0, 180, Scalar(0, 0, 255), -2, 8, 0);
    
    imwrite("ellipse_image.jpg", halfEllipse);

    return 0;
}

 

5. text 삽입  

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

int main() {
    Mat image =imread("../test.jpg");

    Mat imageText = image.clone();
    putText(imageText, "A beautiful flower!~", Point(50, 350), FONT_HERSHEY_COMPLEX, 1.5, Scalar(250, 250, 100));
    
    imwrite("text_image.jpg", imageText);

    return 0;
}

 

 

 

[참고자료]

https://learnopencv.com/annotating-images-using-opencv/