FACE DETECTION

Pritam Banerjee

The University of Texas at Tyler

Department of Computer Science

Tyler, TX, 75799

pbanerjee@patriots.uttyler.edu

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

What is Face Detection ?

Face detection is to identify and detect all imageregions in an image which contain a face regardlessof its three-dimensional position, orientation, andlighting conditions, and if there is a face present inthe image, return its location and extent of the face.The process is complex and challenging because itneeds to detect faces which are non-rigid and have ahigh degree of variability in size, shape, color, andtexture.

Face Detection

What is face detection ?

Why is face detection important

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Why is Face Detection Important ?

1) Face detection algorithms are used in a widerange of applications, such as security control, videoretrieving, biometric signal processing which is oftenmixed with face recognition, human computerinterface, face recognition and image databasemanagement.

2) Modern digital cameras automatically focus on thefaces when those are detected. Some of thecameras can also detect facial expressions such asa smile and then automatically captures thephotograph without the actual need of aphotographer pressing the shutter.

Why is Face Detection Important ?

3) Face detection is getting immensely

important for marketers as well. A webcam can

be integrated into a television which can detect

the face of any person who walks by. Then the

system can calculate the race, gender, and an

approximate age of the person by analyzing the

person’s facial features. Once the information is

collected, a series of advertisements can be

played that is specific toward the detected race

or gender or age.

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection techniques

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Classification of Face Detection Techniques

Image based techniques

1. Eigenface 1. Template Matching

2. Distribution based 2. Skin Color based detections

3. Support Vector Machines 3. Facial feature based detections

4. Bayes Decision Rule

Knowledge based techniques

Face detection techniques

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection techniques

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Image based techniques

Image-Based methods use training/learning methods

to make comparisons between face and non-face

images. For these methods, a large number of images

of faces and non-faces should be trained to increase

the accuracy of the system. Eigenface, Neural

Networks and Support Vector Machines are kinds of

methods that are used commonly in image based face

detection algorithms.

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based Face Detection

Comparison between Image based & Knowledge based methods

Open Issues

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Knowledge based techniques

Knowledge based techniques use information aboutfacial features, skin color or template matching.Facial features include eyes, mouth, nose or otherfacial features to detect the human faces. Skin coloris different from other colors, and its characteristicsdo not change with respect to changes in pose andocclusion. Because of this, skin color detection isoften the first step of a knowledge based facedetection algorithm.

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Comparison between Image based &

Knowledge based methods

Image Based Knowledge BasedPhases of the

systems

The system usually contains two

phases a. Training phase b.

Detection phase

The system usually contains two

phases a. Skin Detection b.Face

detection from the segmented skin

Desigining

Complexity

These systems are more complex as

this involved designing neural

networks to predict the face.

These systems are comparitively

simpler than Image based

techniques

Speed Computationally complex Usually faster than Image based

techniques.

Performance Performance Depends on the

training or learning images

Performance depends on the

criterion used to detect skin, face,

facial features etc

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Face Detection

What is face detection ?

Why is face detection important ?

Classification of face detection

Image based face detection

Knowledge based face detection

Comparison between Image based & Knowledge based methods

Open Issues

Open Issues1. There can be insufficient luminance in the image i.e. the image might be too

dark. Skin color cannot be detected in these cases and hence most of thealgorithms fail. And there is not enough difference between the pixelsbelonging to the facial region of the image and those belonging to non facialregion of the image.

2. Cases where the face is entirely covered with beard and the eyes are hiddenbehind sunglasses have not yet been addressed. In that case neither the skindetection will work nor will the facial feature detection work.

3. If the background is of skin color and there is a face in front of that wherethere is hardly any difference between the skin color of the face and thebackground there are no algorithm which can detect it. Though the facialfeatures might be detected but the exact face will be almost impossible todetect.

4. Also if the face is rotated to such an extent that the nose cannot be spottedanymore, then also it would be impossible to identify the facial region withthe existing systems.

Questions

Thank You