使用级联分类器实现人脸检测（OpenCV自带的数据）

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char** argv) {
    String cascadeFilePath = "F:/CMake_bulid/install/etc/haarcascades/haarcascade_frontalface_alt.xml";//数据路径
    CascadeClassifier face_cascade;//创建分类器对象
    if (!face_cascade.load(cascadeFilePath)) {
        printf("could not load haar data...\n");
        return -1;
    }

    VideoCapture Capture(0);
    Mat src, gray_src;
    while(Capture.read(src)){    
    
        cvtColor(src, gray_src, COLOR_BGR2GRAY);
        equalizeHist(gray_src, gray_src);//直方图均衡化        

        vector<Rect> faces;
        face_cascade.detectMultiScale(gray_src, faces, 1.1, 2, 0, Size(30, 30));//多尺度查找
        for (size_t t = 0; t < faces.size(); t++) {
            rectangle(src, faces[t], Scalar(0, 0, 255), 2, 8, 0);
        }
        namedWindow("output", CV_WINDOW_AUTOSIZE);
        imshow("output", src);

        uchar key = waitKey(100);
        if(key==27)
        {
            break;
        }

    }
    waitKey(0);
    return 0;
}