根据检测出来的脸部而划定眼睛范围的检测

铜过打开摄像头，然后加载脸部检测器，来抓取头像，然后根据头像的比例进行确定眼睛的位置

#include "cv.h"
#include "highgui.h"
#include"iostream"
#include"cstring"
using namespace std;

using namespace cv;

static string xml = "G:\Opencv\sources\data\haarcascades\haarcascade_frontalface_alt.xml";
CvMemStorage* storage = 0;
CascadeClassifier facedectector;

CvCapture *capture = 0;
CvRect righteye;
CvRect lefteye;
Mat GetMatFrom(int choice, char* filename1);
Rect GetLargerFace(Mat face);
void GetFaceDetectionArea(Mat face);
Mat DrawEyeContours(Mat faceimg, Rect left, Rect right);
int main()
{
    facedectector.load(xml);//人脸检测
    Mat img = GetMatFrom(0,NULL);
    cvNamedWindow("test");
    while (true)
    {
        img = GetMatFrom(0, NULL);
        
        Mat grayimg;
        cvtColor(img,grayimg,CV_BGR2GRAY);
        imshow("linshi",img);
        imshow("linshi2", grayimg);
        Rect rect = GetLargerFace(grayimg);
        Mat img2 = grayimg(rect);
        GetFaceDetectionArea(img2);
        imshow("cishi",img2);
        Mat img3 = img(rect);
        DrawEyeContours(img3,lefteye,righteye);
        
        imshow("test",img3);
        if (cvWaitKey(15) == 27)
            break;
        
    }
    
    
    return 0;
}

//封装好的获取图片的函数
//choice=0是从摄像机中获取。
//choice!=0从文件获取，必须指定filename
Mat GetMatFrom(int choice, char* filename1 = NULL)
{
    Mat back_img = cvCreateImage(cvSize(640,480),8,3);
    if (choice == 0)//代表摄像机
    {
        if (capture == NULL)
            capture = cvCaptureFromCAM(0);
        back_img = cvQueryFrame(capture);
    }
    
    else if (filename1!=NULL)
    {
    if (capture==NULL)
    try{
    capture = cvCaptureFromAVI(filename1);
    }
    catch (cv::Exception){
    printf("视屏文件%s加载出错！
",filename1);
    }
    back_img = cvQueryFrame(capture);
    }
    else
    {
    printf("没有输入文件名！
");
        }    
    return back_img;
}

//得到最大脸区域的矩形
Rect GetLargerFace(Mat face)//利用灰度图像
{
    Rect rect;
    std::vector<Rect> rects;
    
    double scale = 0.5;
    int  scalewidth = cvRound(face.cols*scale);
    int scaleheight = cvRound(face.rows*scale);
    Mat smallimg;
    resize(face,smallimg,cvSize(scalewidth,scaleheight));

    facedectector.detectMultiScale(smallimg, rects, 1.1, 3, CASCADE_FIND_BIGGEST_OBJECT | CASCADE_DO_ROUGH_SEARCH, cvSize(10, 10));
    if (rects.size() < 1)
    {
        rect.x = 0;
        rect.y = 0;
        rect.width = 10;
        rect.height = 10;
    }
    else
        rect = rects[0];
    //恢复图像原来大小
    rect.x = cvRound(rect.x/scale);
    rect.y =cvRound(rect.y/scale);
    rect.width = cvRound(rect.width/scale);
    rect.height = cvRound(rect.height/scale);
    //判断矩形是否越界
    rect.x = rect.x < 0 ? 0 : rect.x;
    rect.y = rect.y < 0 ? 0 : rect.y;
    if (rect.width + rect.x>face.cols)rect.x = face.cols - rect.width;
    if (rect.y + rect.height>face.rows)rect.y = face.rows - rect.height;
    return rect;
}

//得到要可检测眼睛的矩形
void GetFaceDetectionArea(Mat face)//使用的是脸部灰度图像
{
    //计算眼睛的区域
    int leftx = cvRound(face.cols*0.16);
    int topy = cvRound(face.rows*0.26);
    int eye_width = cvRound(face.cols*0.3);
    int eye_height = cvRound(face.rows*0.28);
    int rightx = cvRound(face.cols*(1 - 0.16 - 0.3));

    //得到左右眼睛的矩形
    lefteye.x = leftx;
    lefteye.y = topy;
    lefteye.width = eye_width;
    lefteye.height = eye_height;

    righteye.x = rightx;
    righteye.y = topy;
    righteye.width = eye_width;
    righteye.height = eye_height;
    cout << righteye.x<<endl;
    cout << righteye.y<<endl;
    cout << righteye.width<<endl;
    
}
//画出眼睛轮廓
Mat DrawEyeContours(Mat faceimg, Rect left, Rect right)
{
    rectangle(faceimg, cvPoint(left.x, left.y), cvPoint(left.x + left.width, left.y + left.height), cvScalar(50, 50, 50));
    rectangle(faceimg, cvPoint(right.x, right.y), cvPoint(right.x + right.width, right.y + right.height), cvScalar(50, 50, 50));

    return faceimg;
}    

窗口的大小跟着人离屏幕的距离而改变。也许这个特点能有点其他用处。