基于眼睛宽高比的眨眼检测
在开始之前，电脑需要配置Opencv和Dlib
OpenCV配置流程请参考这篇博客：博客链接 Dlib配置过程请参考这篇博客：博客链接 Dlib有一个十分强大的功能就是能够定位人脸的68个关键点，其关键点的分布如下：
基于眼睛宽高比的方法即运用眼睛宽高比的变化来判断是否眨眼，以左眼为例：
以x_36表示点36(在上面的图中，应该是点37，实际上在程序中，关键点是从0到67，上图中用的1到68)的横坐标，y_36表示点36(上图中的点37)的纵坐标，以此类推
眼睛的宽度为定位点36-39的距离记为L=x_39 - x_36
眼睛的高度为定位点37-41的距离记为h1=y_41-y_37
以及定位点38-40的距离记为h2=y_40-y_38
取h1和h2的平均距离作为眼睛的高度h，即H=(h1+h2)/2
记EAR为眼睛宽高比的比值，则有：
EAR=L / H
我们用0.2代表睁眼（闭眼）的阈值，即：
EAR>0.2 睁眼
EAR<0.2 闭眼
眨眼的条件为：EAR从大于0.2到小于0.2到大于0.2的过程算做为一次眨眼
正常人的眨眼频率为10-15次/min
运行结果如下：
其中勾勒的波形图中瞬间下降非常显著的部分（箭头标注）为眨眼
PS：68个关键点检测要用到的dlib检测模型放到我的百度网盘了网盘链接 密码: 5j6g
若链接失效请留言
源码如下：
#include <dlib\opencv.h>
#include <opencv2\opencv.hpp>
#include <dlib\image_processing\frontal_face_detector.h>
#include <dlib\image_processing\render_face_detections.h>
#include <dlib\image_processing.h>
#include <dlib\gui_widgets.h>
#include <iostream>
#include <vector>
#include <cmath>
#include<time.h>
using namespace std;
using namespace dlib;
using namespace cv;
int main() {
//画坐标轴
Mat Eye_Waveform = Mat::zeros(900, 900, CV_8UC3); //用于记录眨眼的波形图
Point p1 = Point(10, 0);
Point p2 = Point(10, 900);
Point p3 = Point(0, 890);
Point p4 = Point(900, 890);
Scalar line_color = Scalar(255, 255, 255);
cv::line(Eye_Waveform, p1, p2, line_color, 1, LINE_AA);
cv::line(Eye_Waveform, p3, p4, line_color, 1, LINE_AA);
//存储眼睛的上一个点的坐标
int eye_previous_x = 10; //原点横坐标
int eye_previous_y = 890; //原点纵坐标
int eye_now_x = 1;
int eye_now_y = 1;
//存储眨眼的次数
unsigned int count_blink = 0; //眨眼次数
//每次眨眼EAR都要经历从 大于0.2-小于0.2-大于0.2 的过程
float blink_EAR_before =0.0; //眨眼前
float blink_EAR_now =0.2; //眨眼中
float blink_EAR_after = 0.0; //眨眼后
try {
VideoCapture cap(0);
if (!cap.isOpened()) { //打开摄像头
printf("Unable to connect a camera");
return 1;
}
frontal_face_detector detector = get_frontal_face_detector();
shape_predictor pos_modle;
//下面用到的shape_predictor_68_face_landmarks/shape_predictor_68_face_landmarks.dat 文件已经放到网盘里，上边有链接
deserialize("D:/shape_predictor_68_face_landmarks/shape_predictor_68_face_landmarks.dat") >> pos_modle;
while (waitKey(30) != 27) {
Mat temp;
cap >> temp;
//将图像转化为dlib中的BGR的形式
cv_image<bgr_pixel> cimg(temp);
std::vector<dlib::rectangle> faces = detector(cimg);
std::vector<full_object_detection> shapes;
unsigned int faceNumber = faces.size(); //获取容器中向量的个数即人脸的个数
for (unsigned int i = 0; i < faceNumber; i++) {
shapes.push_back(pos_modle(cimg, faces[i]));
}
if (!shapes.empty()) {
int faceNumber = shapes.size();
for (int j = 0; j < faceNumber; j++)
{
for (int i = 0; i < 68; i++)
{
//用来画特征值的点
cv::circle(temp, cvPoint(shapes[j].part(i).x(), shapes[j].part(i).y()), 1, cv::Scalar(0, 0, 255), -1);
//参数说明 图像 圆心 线条宽度 颜色 线的类型
//显示数字
cv::putText(temp, to_string(i), cvPoint(shapes[0].part(i).x(), shapes[0].part(i).y()), cv::FONT_HERSHEY_PLAIN, 1, cv::Scalar(0, 0, 255));
}
}
//左眼
//点36的坐标
unsigned int x_36 = shapes[0].part(36).x();
unsigned int y_36 = shapes[0].part(36).y();
//点37的坐标
unsigned int x_37 = shapes[0].part(37).x();
unsigned int y_37 = shapes[0].part(37).y();
//点38的坐标
unsigned int x_38 = shapes[0].part(38).x();
unsigned int y_38 = shapes[0].part(38).y();
//点39的坐标
unsigned int x_39 = shapes[0].part(39).x();
unsigned int y_39 = shapes[0].part(39).y();
//点40的坐标
unsigned int x_40 = shapes[0].part(40).x();
unsigned int y_40 = shapes[0].part(40).y();
//点41的坐标
unsigned int x_41 = shapes[0].part(41).x();
unsigned int y_41 = shapes[0].part(41).y();
/*
//把左眼的轮廓画出来,为了证明眼睛上的取点没有取错
Point pts[1][6];
pts[0][0] = Point(x_36, y_36);
pts[0][1] = Point(x_37, y_37);
pts[0][2] = Point(x_38, y_38);
pts[0][3] = Point(x_39, y_39);
pts[0][4] = Point(x_40, y_40);
pts[0][5] = Point(x_41, y_41);
const Point* ppts[] = { pts[0] };
int npt[] = { 6 };
Scalar eye_color = Scalar(0, 0, 255);
fillPoly(temp, ppts, npt, 1, eye_color, LINE_AA); //在眼睛上勾勒多边形
*/
int height_left_eye1 = y_41 - y_37; //37到41的纵向距离
//cout << "左眼高度1\t" << height_left_eye1 << endl;
int height_left_eye2 = y_40 - y_38; //38到40的纵向距离
//cout << "左眼高度2\t" << height_left_eye2 << endl;
float height_left_eye = (height_left_eye1 + height_left_eye2) / 2; //眼睛上下距离
//cout << "左眼高度\t" << height_left_eye << endl;
int length_left_eye = x_39 - x_36;
//cout << "左眼长度\t" << length_left_eye << endl;
if (height_left_eye == 0) //当眼睛闭合的时候，距离可能检测为0，宽高比出错
height_left_eye = 1;
float EAR_left_eye; //眼睛宽高比
EAR_left_eye = height_left_eye / length_left_eye;
/*
//在屏幕上显示眼睛的高度及宽高比
cout << "左眼宽高比" << EAR_left_eye << endl;
显示height_left_eye、length_left_eye以及ERA_left_eye
把hight_left_eye从float类型转化成字符串类型
char height_left_eye_text[30];
char length_left_eye_text[30];
char ERA_left_eye_text[30];
_gcvt_s(height_left_eye_text, height_left_eye, 10); //把hight_left_eye从float类型转化成字符串类型
_gcvt_s(length_left_eye_text, length_left_eye,10);
_gcvt_s(ERA_left_eye_text, EAR_left_eye, 10);
putText(temp, height_left_eye_text, Point(10, 100), FONT_HERSHEY_COMPLEX, 1.0, Scalar(12, 255, 200), 1, LINE_AA);
putText(temp,height_left_eye_text, Point(10, 200), FONT_HERSHEY_COMPLEX, 1.0, Scalar(12, 255, 200), 1, LINE_AA);
putText(temp, height_left_eye_text, Point(10, 300), FONT_HERSHEY_COMPLEX, 1.0, Scalar(12, 255, 200), 1, LINE_AA);
*/
//右眼
//点42的坐标
unsigned int x_42 = shapes[0].part(42).x();
unsigned int y_42 = shapes[0].part(42).y();
//点37的坐标
unsigned int x_43 = shapes[0].part(43).x();
unsigned int y_43 = shapes[0].part(43).y();
//点38的坐标
unsigned int x_44 = shapes[0].part(44).x();
unsigned int y_44 = shapes[0].part(44).y();
//点39的坐标
unsigned int x_45 = shapes[0].part(45).x();
unsigned int y_45 = shapes[0].part(45).y();
//点40的坐标
unsigned int x_46 = shapes[0].part(46).x();
unsigned int y_46 = shapes[0].part(46).y();
//点41的坐标
unsigned int x_47 = shapes[0].part(47).x();
unsigned int y_47 = shapes[0].part(47).y();
unsigned int height_right_eye1 = y_47 - y_43; //37到41的纵向距离
unsigned int height_right_eye2 = y_46 - y_44; //38到40的纵向距离
float height_right_eye = (height_right_eye1 + height_right_eye2) / 2; //眼睛上下距离
if (height_right_eye == 0) //当眼睛闭合的时候，距离可能检测为0，宽高比出错
height_right_eye = 1;
unsigned int length_right_eye = x_45 - x_42;
float EAR_right_eye; //眼睛宽高比
EAR_right_eye = height_right_eye / length_right_eye;
//取两只眼睛的平均宽高比作为眼睛的宽高比
float EAR_eyes = (EAR_left_eye + EAR_right_eye) / 2;
//cout << "眼睛的宽高比为" << EAR_eyes << endl;
//画眼睛的波形图
eye_now_x = eye_now_x + 1; //横坐标（每10个像素描一个点）
eye_now_y = 900 - ( EAR_eyes * 900 ); //纵坐标
Point poi1 = Point(eye_previous_x, eye_previous_y); //上一个点
Point poi2 = Point(eye_now_x, eye_now_y); //现在的点
Scalar eyes_color = Scalar(0, 255, 0);
cv::line(Eye_Waveform, poi1, poi2, eyes_color,1, LINE_AA); //画线
eye_previous_x = eye_now_x;
eye_previous_y = eye_now_y;
namedWindow("Blink waveform figure", WINDOW_AUTOSIZE);
//计算眨眼次数
if (blink_EAR_before < EAR_eyes) {
blink_EAR_before = EAR_eyes;
}
if (blink_EAR_now > EAR_eyes) {
blink_EAR_now = EAR_eyes;
}
if (blink_EAR_after < EAR_eyes) {
blink_EAR_after = EAR_eyes;
}
if (blink_EAR_before > 0.2 && blink_EAR_now <= 0.2 && blink_EAR_after > 0.2) {
count_blink = count_blink + 1;
blink_EAR_before = 0.0;
blink_EAR_now = 0.2;
blink_EAR_after = 0.0;
}
//显示height_left_eye、length_left_eye以及ERA_left_eye
//把hight_left_eye从float类型转化成字符串类型
char count_blink_text[30];
_gcvt_s(count_blink_text, count_blink, 10); //把hight_left_eye从float类型转化成字符串类型
putText(temp, count_blink_text, Point(10, 100), FONT_HERSHEY_COMPLEX, 1.0, Scalar(0, 0, 255), 1, LINE_AA);
}
//Display it all on the screen 展示每一帧的图片
cv::imshow("Dlib标记", temp);
cv::imshow("Blink waveform figure", Eye_Waveform);
//计时一分钟（60秒）
clock_t start = clock();
clock_t finish = clock();
double consumeTime = (double)(finish - start);//注意转换为double的位置
if (count_blink >= 25 ) {
if (consumeTime / 1000 < 60) {
cout << "您已疲劳，请休息！！" << endl;
count_blink = 0;
return 0;
}
}
}
}
catch (serialization_error& e) {
cout << "You need dlib‘s default face landmarking file to run this example." << endl;
cout << endl << e.what() << endl;
}
catch (exception& e) {
cout << e.what() << endl;
}
}
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