C++：opencv 人脸检测

问题描述：

要求

输入一张图片；输出圈出人脸的图片；vs； opencv3.4.6；

效果

输入：

输出：

代码实现：

#include "opencv2/objdetect.hpp"#include "opencv2/highgui.hpp"#include "opencv2/imgproc.hpp"#include <iostream>using namespace std;using namespace cv;/** Function Headers */void detectAndDisplay( Mat frame );/** Global variables */CascadeClassifier face_cascade;CascadeClassifier eyes_cascade;/** @function main */int main( ){if(!face_cascade.load("haarcascade_frontalface_alt.xml")) //opencv自带的人脸识别{cout << "--(!)Error loading face cascade\n";return -1;};if(!eyes_cascade.load("haarcascade_eye_tree_eyeglasses.xml")){cout << "--(!)Error loading eyes cascade\n";return -1;};Mat frame = imread("lena.jpg");//输入图片if (frame.empty()){cout << " wrong" << endl;}detectAndDisplay(frame);return 0;}/** @function detectAndDisplay */void detectAndDisplay( Mat frame ){Mat frame_gray;cvtColor( frame, frame_gray, COLOR_BGR2GRAY );equalizeHist( frame_gray, frame_gray );//-- Detect facesstd::vector<Rect> faces;face_cascade.detectMultiScale( frame_gray, faces );for ( size_t i = 0; i < faces.size(); i++ ){Point center( faces[i].x + faces[i].width/2, faces[i].y + faces[i].height/2 );ellipse( frame, center, Size( faces[i].width/2, faces[i].height/2 ), 0, 0, 360, Scalar( 255, 0, 255 ), 4 );Mat faceROI = frame_gray( faces[i] );//-- In each face, detect eyesstd::vector<Rect> eyes;eyes_cascade.detectMultiScale( faceROI, eyes );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( frame, eye_center, radius, Scalar( 255, 0, 0 ), 4 );}}//-- Show what you gotimshow( "Face detection", frame );waitKey(0);}

总结

7. CascadeClassifier face_cascade;8. face_cascade.load("训练好的xml模型");9. std::vector<Rect> faces;//人脸的矩阵数据10. face_cascade.detectMultiScale( frame_gray, faces );//输入人脸的照片； 输出人脸的矩形数据11. Point center( faces[i].x + faces[i].width/2, faces[i].y + faces[i].height/2 );ellipse( frame, center, Size( faces[i].width/2, faces[i].height/2 ), 0, 0, 360, Scalar( 255, 0, 255 ), 4 );//画12. imshow( "Face detection", frame );//显示