OPENCV 检测人脸 不依赖于任何第三方库

效果图：

代码部分 ：涉及不到任何复杂的 机器学习库什么的 opencv几个简单的api就可以跑起来 ，简单的做个入门引导  可以发现 侧脸的检测不出来  正脸的基本上能检测出来 

void do_findface()
{
    string xml_path = R"(E:jasonsoftwareopencvopencvbuildetchaarcascadeshaarcascade_frontalface_alt2.xml)";//类似于模型文件把 opencv自带的
    string img_path = R"(E:/jason/5D4/multi2.png)"; //待检测的图片

    Mat face_img = imread(img_path,IMREAD_COLOR);   //正常彩色图
    Mat face_gray = imread(img_path,IMREAD_GRAYSCALE);//灰度图的方式打开

    namedWindow("gray", WINDOW_NORMAL);
    namedWindow("equalizeHist", WINDOW_NORMAL);

    if (face_img.empty() || face_gray.empty())
    {
        cout<<"Load image failed" << endl;
    }

    imshow("gray", face_gray);

    equalizeHist(face_gray,face_gray); //直方图均衡化 增加对比图 可做可不做 本例子中影响不大 更多的是影响性能估计

    
    //imshow("equalizeHist", face_gray);
    
    CascadeClassifier faceCascade;
    if (!faceCascade.load(xml_path))
    {
        cout << "Load xml path failed :["<faces;  //检测出来的人脸矩形坐标会放到这里

    faceCascade.detectMultiScale(face_gray,faces,1.2,5,0,Size(30,30));

    int index = 0;
    for (auto b:faces)
    {
        index++;
        cout << "Face pos:[" << index << "][" << b.x << "," << b.y <<","< 0)
    {
        for (size_t i = 0; i < faces.size(); i++)
        {
            putText(face_img,"face",Point(faces[i].x-10,faces[i].y-10), FONT_HERSHEY_COMPLEX_SMALL, 1.0, Scalar(0, 0, 255));
            rectangle(face_img, Point(faces[i].x, faces[i].y), Point(faces[i].x+faces[i].width,faces[i].y+faces[i].height), Scalar(0, 255, 0), 2, 8);
            cout << "faces:------------------>" << faces[i] << endl;
        }
        
    }
    imshow("equalizeHist",face_img);
    waitKey();

    destroyAllWindows();
}




int main()
{
    //do_filter();
    //do_addweight();
    //do_sharpen();
    //do_cvtColor();

    //do_findContours();
    do_findface();
    return 0;
}