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法律如何使用 C++ 中的 OpenCV 实时检测人脸？
实时检测人脸与在静止图片中检测人脸类似。 实时人脸检测唯一的区别在于，我们必须采用视频流方式运行程序。在此程序中，我们使用了 'VideoCapture()' 函数。此函数从其他摄像头捕获视频，并将帧临时存储在分配给它的矩阵中。此函数从默认摄像头捕获视频，并将帧临时存储在 'real_time' 矩阵中。
以下程序对实时人脸进行检测：
示例
#include<iostream>
#include<opencv2/highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
//This header includes definition of 'rectangle()' function//
#include<opencv2/objdetect/objdetect.hpp>
//This header includes the definition of Cascade Classifier//
#include<string>
using namespace std;
using namespace cv;
int main(int argc, char** argv) {
Mat video_stream;//Declaring a matrix hold frames from video stream//
VideoCapture real_time(0);//capturing video from default webcam//
namedWindow("Face Detection");//Declaring an window to show the result//
string trained_classifier_location = "C:/opencv/sources/data/haarcascades/haarcascade_frontalface_alt.xml";//Defining the location our XML Trained Classifier in a string//
CascadeClassifier faceDetector;//Declaring an object named 'face detector' of CascadeClassifier class//
faceDetector.load(trained_classifier_location);//loading the XML trained classifier in the object//
vector<Rect>faces;//Declaring a rectangular vector named faces//
while (true) {
faceDetector.detectMultiScale(video_stream, faces, 1.1, 4, CASCADE_SCALE_IMAGE, Size(30, 30));//Detecting the faces in 'image_with_humanfaces' matrix//
real_time.read(video_stream);// reading frames from camera and loading them in 'video_stream' Matrix//
for (int i = 0; i < faces.size(); i++){ //for locating the face
Mat faceROI = video_stream(faces[i]);//Storing face in the matrix//
int x = faces[i].x;//Getting the initial row value of face rectangle's starting point//
int y = faces[i].y;//Getting the initial column value of face rectangle's starting point//
int h = y + faces[i].height;//Calculating the height of the rectangle//
int w = x + faces[i].width;//Calculating the width of the rectangle//
rectangle(video_stream, Point(x, y), Point(w, h), Scalar(255, 0, 255), 2, 8, 0);//Drawing a rectangle using around the faces//
}
imshow("Face Detection", video_stream);
//Showing the detected face//
if (waitKey(10) == 27){ //wait time for each frame is 10 milliseconds//
break;
}
}
return 0;
}输出
更新时间: 2021-03-10
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