lbpcascade_frontalface.xml与dlib库从摄像头中取最大的一张人脸进行人眼检测的c++程序

以下是使用 lbpcascade_frontalface.xml 和 dlib 库从摄像头中取出最大的一张人脸进行人眼检测的 C++ 程序示例：

#include <dlib/image_processing/frontal_face_detector.h>
#include <dlib/image_processing/render_face_detections.h>
#include <dlib/image_processing.h>
#include <dlib/gui_widgets.h>
#include <dlib/image_io.h>
#include <dlib/opencv.h>
#include <opencv2/opencv.hpp>

using namespace dlib;
using namespace std;

int main()
{
    try
    {
        // 初始化人脸检测器
        frontal_face_detector detector = get_frontal_face_detector();

        // 初始化人眼检测器
        shape_predictor sp;
        deserialize("shape_predictor_68_face_landmarks.dat") >> sp;

        // 打开摄像头
        cv::VideoCapture cap(0);
        if (!cap.isOpened())
        {
            cerr << "Unable to connect to camera" << endl;
            return 1;
        }

        // 循环读取摄像头中的每一帧
        while (1)
        {
            cv::Mat temp;
            cap >> temp;
            cv_image<bgr_pixel> cimg(temp);

            // 检测人脸
            std::vector<rectangle> faces = detector(cimg);
            if(faces.size()==0) continue;
            int max_x = 0, max_y = 0, max_area = 0;
            for (int i = 0; i < faces.size(); i++)
            {
                if(faces[i].area()>max_area)
                {
                    max_x = faces[i].left();
                    max_y = faces[i].top();
                    max_area = faces[i].area();
                }
            }
            rect max_face = rect(max_x, max_y, max_x + faces[0].width(), max_y + faces[0].height());
            // 检测人眼
            full_object_detection shape = sp(cimg, max_face);
            // 在图像中画出人眼
            for (int i = 36; i <= 41; i++)
            {
                cv::circle(temp, cv::Point(shape.part(i).x(), shape.part(i).y()), 2, cv::Scalar(0, 255, 0), -1);
            }
            cv::imshow("Face", temp);
            if (cv::waitKey