Opencv learn read images videos and webcams

Catalog

One 、 Import image

Two 、 Import video

3、 ... and 、 camera

---

One 、 Import image

 

#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <iostream>

using namespace cv;
using namespace std;

// Import image 
int main()
{
	string path="C:\\Users\\Rong\\Desktop\\Resources\\test.png";
	Mat img = imread(path);
	imshow("Image", img);
	waitKey(0);
}

notes ： The image path should be double backslash ！

Two 、 Import video

A video is a picture frame by frame , Use while Loop through each frame

// Import video 
int main() {
	string path = "C:\\Users\\Rong\\Desktop\\Resources\\test_video.mp4";
	VideoCapture cap(path);
	Mat img;

	while (true) {
		cap.read(img);
		imshow("Video", img);
		waitKey(20);
	}

}

3、 ... and 、 camera

Change the path of that video into 0 Because there is only one camera on my computer （ If write 1 Will report a mistake ！）

// camera 
int main() {
	
	VideoCapture cap(0);
	Mat img;

	while (true) {
		cap.read(img);
		imshow("Webcom", img);
		waitKey(20);
	}

}