Post on 04-Jul-2015
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