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Face and Eyes Detection Using OpenCV

, 7 Aug 2008
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This article demonstrates how to perform human face and eyes detection on images using OpenCV in .NET
Cascades

Introduction

This article is an extension of an article that I posted on CodeProject earlier. This project demonstrates how to perform human face and eye detection using OpenCV in .NET. The detection is performed using Haar Cascades that I acquired from two different sources (see References).

Background

While working on a face recognition project, I stumbled across a huge problem; the preprocessing phase required face alignment for improved result. This step required eye coordinates in order to stretch/rotate the image to a standard size before performing actual face recognition training/projection. For experimentation, the eye-coordinates could be entered manually but that would never be a practical solution. Exploring my options, I found OpenCV and the Haar Cascades to perform this task for me.

Using the Code

The project is mainly a managed VC++.NET class library, that can be consumed from C#/VC++ .NET. A Test application demonstrates the typical use of this library. It is to be noted that Version 2 requires the 'Cascades' folder in the Current Execution Path folder.

There are mainly two functions that are used to perform face and eye detection. Observe the following code:

// the variable faces contains the number of detected faces in the image
int faces = objFaceDetector.WrapDetectFaces(lastPic);

int lx, ly, rx, ry, res;

for(int f = 0; f < faces; f++)
{ 
    //The face coordinates are indexed, max index == 4
    objFaceDetector.WrapGetFaceCordinates(f, &lx, &ly, &rx, &ry);
<< Source Code For Drawing Face Rectangle >>
    //returns -1 if cannot detect eyes for this face index
    res = objFaceDetector.WrapGetEyeCordinates(f, &lx, &ly, &rx, &ry);
<< Source Code For Drawing Eye Crosses >>
}

The use of this library is quite simple and may find its application in face recognition and human interaction projects. Someone suggested to use this for detecting if the driver is dozing while driving, BUT let me remind you that there are no guarantees from me, Opencv, Opencv developer community or any other party for the results of this code. The author will not be liable for any harm, injury and/or loss caused directly or indirectly by using this code in any way.

Points of Interest

The accuracy of Eye cascades was further corrected by a writing a code snippet that simply checks if the suggested eye coordinates really fall in the face region. Furthermore, the face region is logically divided into four equal height horizontal strips, the second strip from the top contains the eyes. This strip can be divided into two halves vertically so that each eye will fall in one half. If the detected eye coordinates do not fall in their respective halves, they are discarded. In case of multiple detections in the same region, the object with smaller size is preferred because of empirical reasons. The eye detection is performed using two different Cascades, this proved to give better results than using the Cascade that claims to detect both eyes in one go. Further research may lead you to differ from my suggested approach, you can always provide a feedback.

References

Other Articles by This Author

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Zeeshan Ejaz Bhatti
Web Developer
Pakistan Pakistan
BCSE - Software Engineering (2000 - 2004)
Foundation University Institute of Management and Computer Sciences.
Pakistan.
 
MS - Computer Sciences (2004 - 2005)
Lahore Univeristy of Management Sciences
Pakistan.

Comments and Discussions

 
Questiondll PinmemberMember 1081470614-May-14 0:33 
GeneralEmotion Detection Software Pinmembershane007117-Apr-14 7:16 
QuestionNeed more explaination PinmemberLogicPlayer18-Mar-14 21:04 
QuestionPlease provide FaceDetection.dll Pinmemberjeffy6653-Feb-14 2:40 
QuestionCompiling Error : error C1083: Cannot open include file: 'cv.h': No such file or directory PinmemberNehal4Monto25-Oct-13 3:09 
QuestionFacedetection dll PinmemberVishal Raje19-Oct-13 21:22 
Questioncannot find faceDetection.dll PinmemberMember 1033630414-Oct-13 17:56 
GeneralMy vote of 5 PinmemberMember 1023866828-Aug-13 11:21 
Questionfacedection.dll Pinmembernilooofar13-May-13 21:04 
QuestionEye detection in VB.net PinmemberZahid Gul10-Mar-13 19:16 
QuestionI want to FaceDetection.dll PinmemberSorum31-Oct-12 21:32 
Questionfacedection.dll Pinmembergsmsdn29-Oct-12 21:35 
QuestionPlease I need Facedetection.ddl Pinmemberrichmasua3-Oct-12 8:50 
QuestionX64 Pinmemberprogrammerdon24-Sep-12 10:32 
Questionfacedetection.dll PinmemberCerber24052-Sep-12 9:38 
AnswerRe: facedetection.dll PinmemberMember 1030893021-Dec-13 23:02 
Question[My vote of 2] face detect though MFC? PinmemberMember 842634320-Aug-12 22:00 
QuestionAdaboost PinmemberFadol31-Jul-12 23:42 
QuestionThis code in not working on my system PinmemberAhmad Usman8-Jul-12 16:02 
QuestionWhen Building the project ObjectLocator.h(63) : error C2440: 'return' : cannot convert from 'schar *' to 'char *' PinmemberHashan Randev Fernando2-Mar-12 20:42 
AnswerRe: When Building the project ObjectLocator.h(63) : error C2440: 'return' : cannot convert from 'schar *' to 'char *' PinmemberMahendranG3-May-12 0:42 
GeneralRe: When Building the project ObjectLocator.h(63) : error C2440: 'return' : cannot convert from 'schar *' to 'char *' Pinmemberskingomez13-Aug-12 4:22 
Questionnot found the facedetection.dll Pinmemberwudrans27-Feb-12 22:30 
Questionnot found FaceDetection.dll Pinmemberhamedyar222-Dec-11 7:52 
Questioneye detection Pinmemberboragökova20-Nov-11 0:57 

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