opencv 实现人脸检测（harr特征）

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我这里用的是已经训练好的haar级联分类器。

眼睛检测 haarcascade_eye_tree_eyeglasses.xml 人脸检测 haarcascade_frontalface_alt2.xml 检测思路：先把图片转为灰度，接着将图片直方均匀化，在上面处理后的图片矩阵中检测脸的区域，然后把脸这一块圈出来去检测眼睛。检测函数代码如下：

#include <opencv/cv.h>
#include <opencv/highgui.h>
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
using namespace std;
using namespace cv;
void DetectFace(Mat, Mat);
CascadeClassifier faceCascade;
CascadeClassifier eyes_Cascade;
int main(int argc, char** argv) {
VideoCapture cap;
if (!cap.open(0)) {
cout << "摄像头打开失败!!" << endl;
return -1;
}
if (!faceCascade.load("E:\\VS2015Opencv\\opencv3.2\\opencv\\build\\etc\\haarcascades\\haarcascade_frontalface_alt2.xml")) {
cout << "人脸检测级联分类器没找到！！" << endl;
return -1;
}
if (!eyes_Cascade.load("E:\\VS2015Opencv\\opencv3.2\\opencv\\build\\etc\\haarcascades\\haarcascade_eye_tree_eyeglasses.xml")) {
cout << "眼睛检测级联分类器没找到！！" << endl;
return -1;
}
Mat img, imgGray;
int fps = 60;
while (true) {
cap >> img;
cvtColor(img, imgGray, CV_BGR2GRAY);
equalizeHist(imgGray, imgGray);//直方图均匀化
DetectFace(img, imgGray);
waitKey(1000 / fps);
}
return 0;
}void DetectFace(Mat img, Mat imgGray) {
namedWindow("src", WINDOW_AUTOSIZE);
vector<Rect> faces, eyes;
faceCascade.detectMultiScale(imgGray, faces, 1.2, 5, 0, Size(30, 30));
for (auto b : faces) {
cout << "输出一张人脸位置：(x,y):" << "(" << b.x << "," << b.y << ") , (width,height):(" << b.width << "," << b.height << ")" << endl;
}
if (faces.size()>0) {
for (size_t i = 0; i<faces.size(); i++) {
putText(img, "ugly girl!", cvPoint(faces[i].x, faces[i].y - 10), FONT_HERSHEY_PLAIN, 2.0, Scalar(0, 0, 255));rectangle(img, Point(faces[i].x, faces[i].y), Point(faces[i].x + faces[i].width, faces[i].y + faces[i].height), Scalar(0, 0, 255), 1, 8);
cout << faces[i] << endl;
//将人脸从灰度图中抠出来
Mat face_ = imgGray(faces[i]);
eyes_Cascade.detectMultiScale(face_, eyes, 1.2, 2, 0, Size(30, 30));
for (size_t j = 0; j < eyes.size(); j++) {
Point eye_center(faces[i].x + eyes[j].x + eyes[j].width / 2, faces[i].y + eyes[j].y + eyes[j].height / 2);
int radius = cvRound((eyes[j].width + eyes[j].height)*0.25);
circle(img, eye_center, radius, Scalar(65, 105, 255), 4, 8, 0);
}
}
}
imshow("src", img);
}