如何使用C++在OpenCV中檢測眼睛?


本文介紹如何在 OpenCV 中檢測眼睛。我們使用位於“C:/opencv/sources/data/haarcascades”中的haarcascade_eye.xml分類器來檢測眼睛。為檢測眼睛,我們需要新增這些標頭檔案。

第一個標頭檔案是<iostream>,它是C++程式語言的標頭檔案。在“highgui”標頭檔案中定義了讀取寫入影像和使用者介面功能。我們需新增“imgproc”標頭檔案來增強影像質量,我們還使用“objdetect”標頭檔案來檢測人臉和眼睛。

以下程式演示瞭如何在 OpenCV 中檢測和跟蹤眼睛。

例項

#include<iostream>
#include<opencv2/highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
#include<opencv2/objdetect/objdetect.hpp>
using namespace cv;
using namespace std;
int main() {
   Mat frame;//declaring a matrix to video frame in it//
   namedWindow("Detect");//Declaring a window to show our work//
   VideoCapture image(0);//capturing video from default camera//
   if (!image.isOpened()){ //Error message if video source is not found//
      cout << "Couldn't load video from the source.Make sure your camera is working properly." << endl;
      system("pause");
      return 0;
   }
   double height = image.set(CAP_PROP_FRAME_HEIGHT, 480);//setting up height of each frame//
   double width = image.set(CAP_PROP_FRAME_WIDTH, 640);//setting up width of each frame//
   CascadeClassifier face_cascade, eyes_cascade;//declaring a CascadeClassifier object//
   face_cascade.load("C:/opencv/sources/data/haarcascades/haarcascade_frontalface_alt.xml");//loading the cascade classifier//
   eyes_cascade.load("C:/opencv/sources/data/haarcascades/haarcascade_eye.xml");
   while (true) {
      bool temp = image.read(frame);//loading video frames from source to our matrix named frame//
      vector<Rect>faces;//Declaring a vector named faces//
      face_cascade.detectMultiScale(frame, faces, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(100, 100));//detecting the face
      for (int i = 0; i < faces.size(); i++){ //for locating the face
         Point center(faces[i].x + faces[i].width * 0.5, faces[i].y + faces[i].height * 0.5);//getting the center of the face//
         ellipse(frame, center, Size(faces[i].width * 0.5, faces[i].height * 0.5), 0, 0, 360, Scalar(255, 0, 255), 4, 8, 0);//draw an ellipse on the face//
         Mat faceROI = frame(faces[i]);//Taking area of the face as Region of Interest for eyes//
         vectoreyes;//declaring a vector named eyes//
         eyes_cascade.detectMultiScale(faceROI, eyes, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(5, 5));//detect eyes in every face//
         for (size_t j = 0; j < eyes.size(); j++){ //for locating eyes//
            Point center(faces[i].x + eyes[j].x + eyes[j].width * 0.5, faces[i].y + eyes[j].y + eyes[j].height * 0.5);//getting the centers of both eyes//
            int radius = cvRound((eyes[j].width + eyes[j].height) * 0.25);//declaring radius of the eye enclosing circles//
            circle(frame, center, radius, Scalar(255, 0, 0), 4, 8, 0);//drawing circle around both eyes//
         }
      }
      imshow("Detect", frame);//showing result in window named 'Detect'//
      if (waitKey(30) == 27){ //wait time for each frame is 30 milliseconds//
         break;
      }
   }
   return 0;
}

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更新時間:2021 年 3 月 10 日

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