Face-Dectection-using-Cpp

Face detection with C++ progamming with Qtcreator

install opencv C++ library using Cmake tool to work with project.

we use the Haar classifier in a cascade to detect faces in an image

create new project facedetect (Qt-widget)

... in section Sources open mainwindow.cpp

above MainWindow::MainWindow(QWidget *parent) :

delete all lines and change it to:

#include "mainwindow.h"
#include "ui_mainwindow.h"

//opencv
//#include "opencv2/imgcodecs.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/objdetect.hpp"
#include <opencv2/highgui.hpp>
#include <opencv2/video.hpp>
#include <opencv2/core.hpp>

//c++
#include <iostream>
#include <sstream>

using namespace std;
using namespace cv;

---

below ui->setupUi(this); we call our new function facedetect();

next, we define our new function at the end of our mainwindow.cpp file:

void MainWindow::facedetect() {

    //-- Note, either copy these two files from opencv/data/haarscascades to your current folder, or change these locations
    String face_cascade_name = "U://opencvProjSB//UE_8//haarcascade_frontalface_alt.xml";
    String eyes_cascade_name = "U://opencvProjSB//UE_8//haarcascade_eye_tree_eyeglasses.xml";
    CascadeClassifier face_cascade;
    CascadeClassifier eyes_cascade;
    std::vector<Rect> faces;
    namedWindow("Frame1",WINDOW_AUTOSIZE);   //create GUI window

    //-- 1. Load the cascades
    if( !face_cascade.load( face_cascade_name ) ){ printf("--(!)Error loading face cascade\n"); return; };
    if( !eyes_cascade.load( eyes_cascade_name ) ){ printf("--(!)Error loading eyes cascade\n"); return; };
    cout << "cascades loaded" << endl;


    /*
    VideoCapture capture;

    //if source is camera:
    capture.open(0); //>1 = external webcam

    if(!capture.isOpened()){
        cout<<"ERROR ACQUIRING VIDEO FEED\n" << endl;
        printf( "error video opening");
        return;
    }
   */
    Mat tmp, frame1;

    //check for keyboard input
    while( waitKey(10) != 27)
    {

        //read first frame
        //capture.read(tmp);  //uncomment this line if camera
        tmp = imread("U://opencvProjSB//UE_8//people1.jpg", IMREAD_COLOR);
        cv::resize(tmp, frame1, Size(640,480));
        //cv::resize(tmp, frame1,Size(),0.6,0.6,INTER_CUBIC);
        Mat frame_gray = Mat::zeros( frame1.size(), CV_8U );
        cvtColor( frame1, frame_gray, COLOR_BGR2GRAY );
        equalizeHist( frame_gray, frame_gray );
        //-- Detect faces
        face_cascade.detectMultiScale( frame_gray, faces );
        //   face_cascade.detectMultiScale( frame, faces, 1.1, 2, 0|CV_HAAR_SCALE_IMAGE, Size(30, 30) );

        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( frame1, center, Size( faces[i].width/2, faces[i].height/2), 0, 0, 360, Scalar( 255, 0, 255 ), 2, 8, 0 );

            Mat faceROI = frame_gray( faces[i] );

            //-- In each face, detect eyes
//            std::vector<Rect> eyes;

//            eyes_cascade.detectMultiScale( faceROI, eyes, 1.1, 2, 0 |CV_HAL_CMP_GE, Size(30, 30) );
//            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( frame1, eye_center, radius, Scalar( 255, 0, 0 ), 3, 8, 0 );
//            }
        }
        //-- Show what we got
        imshow( "Frame1", frame1 );

    }

    //destroy GUI windows
    destroyAllWindows();
    return;
}

---

in section Headers open mainwindow.h and declare our 2 new functions below the line ~MainWindow(); void facedetect();

---

save all specify the includepath of the dlls at the end of our .pro file:

INCLUDEPATH += U:\opencv401\include

LIBS += U:\opencv401\bin\libopencv_core401.dll
LIBS += U:\opencv401\bin\libopencv_highgui401.dll
LIBS += U:\opencv401\bin\libopencv_imgcodecs401.dll
LIBS += U:\opencv401\bin\libopencv_imgproc401.dll
LIBS += U:\opencv401\bin\libopencv_videoio401.dll
LIBS += U:\opencv401\bin\libopencv_video401.dll
LIBS += U:\opencv401\bin\libopencv_objdetect401.dll
 ----------------------

save all and build

if successful, open the folder build-facedetect-Desktop_Qt_5_12_1_MinGW_64_bit-Release on your USB flash drive copy all the dlls from opencv401/include into the release folder which includes the facedetect.exe

now the program should work and indicate the face.

comment out the second cascade for the eyes. build and run again

change the loaded image name to people3.jpg comment out cv::resize(tmp, frame1, Size(640,480)); comment in the next line as a different resize mode: cv::resize(tmp, frame1,Size(),0.6,0.6,INTER_CUBIC); build and run again