opencv 图片中的 人脸检测

haarcascade_eye.xml

haarcascade_frontalface_alt2.xml

放在程序目录下：

 

#include <opencv\cv.h>
#include <opencv\highgui.h>
#include <opencv\cxcore.h>
#include <stdio.h>

 

#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/ml/ml.hpp"
#include <iostream>

 

using namespace std;
 
using namespace cv;
 

void detectAndDraw( Mat& img,
 
                    CascadeClassifier& cascade, CascadeClassifier& nestedCascade,
 
                    double scale);
 

String cascadeName = "haarcascade_frontalface_alt2.xml";//人脸的训练数据
 
//String nestedCascadeName = "./haarcascade_eye_tree_eyeglasses.xml";//人眼的训练数据
 
String nestedCascadeName = "haarcascade_eye.xml";//人眼的训练数据
 

int main( int argc, const char** argv )
 
{
 
     Mat image;
 
     CascadeClassifier cascade, nestedCascade;//创建级联分类器对象
 
     double scale = 1.3;
 

     image = imread( "lena.jpg", 1 );//读入lena图片
 
     //image = imread("people_with_hands.png",1);
 
     namedWindow( "result", 1 );//opencv2.0以后用namedWindow函数会自动销毁窗口
 

     if( !cascade.load( cascadeName ) )//从指定的文件目录中加载级联分类器
 
     {
 
          cerr << "ERROR: Could not load classifier cascade" << endl;
 
          return 0;
 
     }
 

     if( !nestedCascade.load( nestedCascadeName ) )
 
     {
 
          cerr << "WARNING: Could not load classifier cascade for nested objects" << endl;
 
          return 0;
 
     }
 

     if( !image.empty() )//读取图片数据不能为空
 
     {
 
         detectAndDraw( image, cascade, nestedCascade, scale );
 
         waitKey(0);
 
     }
 

     return 0;
 
}
 

void detectAndDraw( Mat& img,
 
                    CascadeClassifier& cascade, CascadeClassifier& nestedCascade,
 
                    double scale)
 
{
 
     int i = 0;
 
     double t = 0;
 
     vector<Rect> faces;
 
     const static Scalar colors[] =  { CV_RGB(0,0,255),
 
         CV_RGB(0,128,255),
 
         CV_RGB(0,255,255),
 
         CV_RGB(0,255,0),
 
         CV_RGB(255,128,0),
 
         CV_RGB(255,255,0),
 
         CV_RGB(255,0,0),
 
         CV_RGB(255,0,255)} ;//用不同的颜色表示不同的人脸
 

     Mat gray, smallImg( cvRound (img.rows/scale), cvRound(img.cols/scale), CV_8UC1 );//将图片缩小，加快检测速度
 

     cvtColor( img, gray, CV_BGR2GRAY );//因为用的是类haar特征，所以都是基于灰度图像的，这里要转换成灰度图像
 
     resize( gray, smallImg, smallImg.size(), 0, 0, INTER_LINEAR );//将尺寸缩小到1/scale,用线性插值
 
     equalizeHist( smallImg, smallImg );//直方图均衡
 

     t = (double)cvGetTickCount();//用来计算算法执行时间
 


//检测人脸
 
//detectMultiScale函数中smallImg表示的是要检测的输入图像为smallImg，faces表示检测到的人脸目标序列，1.1表示
 
//每次图像尺寸减小的比例为1.1，2表示每一个目标至少要被检测到3次才算是真的目标(因为周围的像素和不同的窗口大
 
//小都可以检测到人脸),CV_HAAR_SCALE_IMAGE表示不是缩放分类器来检测，而是缩放图像，Size(30, 30)为目标的
 
//最小最大尺寸
 
     cascade.detectMultiScale( smallImg, faces,
 
         1.1, 2, 0
 
         //|CV_HAAR_FIND_BIGGEST_OBJECT
 
//|CV_HAAR_DO_ROUGH_SEARCH
 
         |CV_HAAR_SCALE_IMAGE
 
         ,
 
         Size(30, 30) );
 

     t = (double)cvGetTickCount() - t;//相减为算法执行的时间
 
     printf( "detection time = %g ms\n", t/((double)cvGetTickFrequency()*1000.) );
 
     for( vector<Rect>::const_iterator r = faces.begin(); r != faces.end(); r++, i++ )
 
     {
 
         Mat smallImgROI;
 
         vector<Rect> nestedObjects;
 
         Point center;
 
         Scalar color = colors[i%8];
 
         int radius;
 
         center.x = cvRound((r->x + r->width*0.5)*scale);//还原成原来的大小
 
         center.y = cvRound((r->y + r->height*0.5)*scale);
 
         radius = cvRound((r->width + r->height)*0.25*scale);
 
         circle( img, center, radius, color, 3, 8, 0 );
 

         //检测人眼，在每幅人脸图上画出人眼
 
         if( nestedCascade.empty() )
 
             continue;
 
         smallImgROI = smallImg(*r);
 

         //和上面的函数功能一样
 
         nestedCascade.detectMultiScale( smallImgROI, nestedObjects,
 
             1.1, 2, 0
 
             //|CV_HAAR_FIND_BIGGEST_OBJECT
 
//|CV_HAAR_DO_ROUGH_SEARCH
 
//|CV_HAAR_DO_CANNY_PRUNING
 
             |CV_HAAR_SCALE_IMAGE
 
             ,
 
             Size(30, 30) );
 
         for( vector<Rect>::const_iterator nr = nestedObjects.begin(); nr != nestedObjects.end(); nr++ )
 
         {
 
             center.x = cvRound((r->x + nr->x + nr->width*0.5)*scale);
 
             center.y = cvRound((r->y + nr->y + nr->height*0.5)*scale);
 
             radius = cvRound((nr->width + nr->height)*0.25*scale);
 
             circle( img, center, radius, color, 3, 8, 0 );//将眼睛也画出来，和对应人脸的图形是一样的
 
         }
 
     }
 
     cv::imshow( "result", img );
 
}

 

效果：