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Face detection and comparision

asked 2014-04-26 07:01:00 -0500

tejasunku gravatar image

HI, I need to detect a face from an image and need to compare to the faces which i m having and check whether they are same or not....I m new to opencv so i dont have any idea..i tried and able to identify the face from the image and had a problem to compare the obtained image from the other images so any one please help in thiss.... i am trying to in c++

this is the below code i tried

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

using namespace std;
using namespace cv;

// Function Headers
void detectAndDisplay(Mat frame);

// Global variables
// Copy this file from opencv/data/haarscascades to target folder
string face_cascade_name = "C:\\opencv\\data\\haarcascades\\haarcascade_frontalface_alt.xml";
CascadeClassifier face_cascade;
string window_name = "Capture - Face detection";
int filenumber; // Number of file to be saved
string filename;

// Function main
int main(void)
{
    // Load the cascades
    if (!face_cascade.load(face_cascade_name))
    {
        printf("--(!)Error loading\n");
        return (-1);
    };

    // Read the image file
    Mat frame = imread("images.jpg");

    for (;;)
    {
        // Apply the classifier to the frame
        if (!frame.empty())
        {
            detectAndDisplay(frame);
        }
        else
        {
            printf(" --(!) No captured frame -- Break!");
            break;
        }

        int c = waitKey(10);

        if (27 == char(c))
        {
            break;
        }
    }

    return 0;
}

// Function detectAndDisplay
void detectAndDisplay(Mat frame)
{
    std::vector<Rect> faces;
    Mat frame_gray;
    Mat crop;
    Mat res;
    Mat gray;
    string text;
    stringstream sstm;

    cvtColor(frame, frame_gray, COLOR_BGR2GRAY);
    equalizeHist(frame_gray, frame_gray);

// Detect faces
    face_cascade.detectMultiScale(frame_gray, faces, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(30, 30));

// Set Region of Interest
    cv::Rect roi_b;
    cv::Rect roi_c;

    size_t ic = 0; // ic is index of current element
    int ac = 0; // ac is area of current element

    size_t ib = 0; // ib is index of biggest element
    int ab = 0; // ab is area of biggest element

    for (ic = 0; ic < faces.size(); ic++) // Iterate through all current elements (detected faces)

    {
        roi_c.x = faces[ic].x;
        roi_c.y = faces[ic].y;
        roi_c.width = (faces[ic].width);
        roi_c.height = (faces[ic].height);

        ac = roi_c.width * roi_c.height; // Get the area of current element (detected face)

        roi_b.x = faces[ib].x;
        roi_b.y = faces[ib].y;
        roi_b.width = (faces[ib].width);
        roi_b.height = (faces[ib].height);

        ab = roi_b.width * roi_b.height; // Get the area of biggest element, at beginning it is same as "current" element

        if (ac > ab)
        {
            ib = ic;
            roi_b.x = faces[ib].x;
            roi_b.y = faces[ib].y;
            roi_b.width = (faces[ib].width);
            roi_b.height = (faces[ib].height);
        }

        crop = frame(roi_b);
        resize(crop, res, Size(128, 128), 0, 0, INTER_LINEAR); // This will be needed later while saving images
        cvtColor(crop, gray, CV_BGR2GRAY); // Convert cropped image to Grayscale

        // Form a filename
        filename = "";
        stringstream ssfn;
        ssfn << filenumber << ".png";
        filename = ssfn.str();
        filenumber++;

        imwrite(filename, gray);

        Point pt1(faces[ic].x, faces[ic].y); // Display detected faces on main window - live stream from camera
        Point pt2((faces[ic].x + faces[ic].height), (faces[ic].y + faces[ic].width));
        rectangle(frame, pt1, pt2, Scalar(0, 255, 0), 2, 8, 0);
    }

// Show image ...
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2 answers

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answered 2015-03-25 01:01:21 -0500

john_1282 gravatar image

The face detection looks well. However, If you want to compare (recognition), you must training the face first. You can use some database that is available such as AT. Let read that tutorial http://docs.opencv.org/modules/contri...

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answered 2015-01-06 04:13:24 -0500

Could you able to find the error? I am also using the same code. Thanks

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Asked: 2014-04-26 07:01:00 -0500

Seen: 848 times

Last updated: Mar 25 '15