Adam Yeh

1
Adam Yeh

• UCF Computer Vision REU
• Week 2

2
Facial Expressions

• Problem given a face image, determine which of 7
  basic facial expressions is displayed
• Neutral, Anger, Disgust, Fear, Joy, Sadness,
  Surprise
• FACS (Facial Action Coding System)
• Identifies 44 basic facial actions
• Each expression
• Basic object recognition problem

3
Current Research

• Wang et al. 1
• Adaboost with Haar wavelet features
• Similar to Viola-Jones approach except train for
  specific expressions, not just faces
• gt90 precision, real-time
• Other similar research, but slight modifications
• Different classifiers
• Different learning algorithm

4
Current Research

• Using FACS Kotsia, Pitas 1
• Asks user to identify certain features in one
  control frame of face
• Charts movement of features and looks up which
  FACS action(s) are present
• Uses machine learning to determine actions
• Achieves gt95 performance
• Problem not full automated because of user input

5
Current Research

• Tong et al. 3
• Uses expert knowledge
• Trains on specific action units, not the entire
  facial expression
• Uses Gabor filters as features, Adaboost for
  feature selection
• Use Bayesian network to combine AUs into facial
  expressions
• 93 recognition

6
Machine Learning Techniques

• Support Vector Machines
• Map data into higher dimensional space
• Find hyperplane to separate/classify data
• K-nearest neighbors
• Group test sample with class that has most
  neighbors within a certain distance
• Adaboost

7
Project Possibility

• Expand on Tong et al.
• AdaSVM?
• Has shown improvements over just Adaboost and SVM
  in other applications
• Different classifiers?
• Try different filters
• Use knowledge of AUs
• Different feature combination techniques

8
Progress

• This week
• Background research
• Coding parts of Viola-Jones (for specific parts
  needed)
• Next week
• Finish coding and test on current images
• Try different features
• Hopefully filter and modify training data as
  needed

9
References

• 1 Yubo Wang Haizhou Ai Bo Wu Chang Huang .
  Real time facial expression recognition with
  AdaBoost Pattern Recognition, 2004. ICPR 2004.
  Proceedings of the 17th International Conference
  on, Vol.3, Iss., 23-26 Aug. 2004. Pages 926- 929
  Vol.3
• 2 Kotsia, I. Pitas, I. Real time facial
  expression recognition from image sequences using
  support vector machines. Image Processing, 2005.
  ICIP 2005. IEEE International Conference on,
  Vol.2, Iss., 11-14 Sept. 2005 Pages II- 966-9
• 3 Yan Tong, Wenhui Liao , and Qiang Ji, Facial
  Action Unit Recognition by Exploiting Their
  Dynamic and Semantic Relationships, accepted by
  IEEE Transactions on Pattern Analysis and Machine
  Intelligence (PAMI).