A training algorithm for optimal margin classifiers
COLT '92 Proceedings of the fifth annual workshop on Computational learning theory
Feature extraction from faces using deformable templates
International Journal of Computer Vision
Fundamentals of speech recognition
Fundamentals of speech recognition
Active shape models—their training and application
Computer Vision and Image Understanding
Machine Learning
Coding, Analysis, Interpretation, and Recognition of Facial Expressions
IEEE Transactions on Pattern Analysis and Machine Intelligence
Recognizing Facial Expressions in Image Sequences Using Local Parameterized Models of Image Motion
International Journal of Computer Vision
Mixtures of probabilistic principal component analyzers
Neural Computation
Optical Flow Constraints on Deformable Models with Applications to Face Tracking
International Journal of Computer Vision
Recognizing Action Units for Facial Expression Analysis
IEEE Transactions on Pattern Analysis and Machine Intelligence
Analysis and Synthesis of Facial Image Sequences Using Physical and Anatomical Models
IEEE Transactions on Pattern Analysis and Machine Intelligence
ECCV '98 Proceedings of the 5th European Conference on Computer Vision-Volume II - Volume II
Comprehensive Database for Facial Expression Analysis
FG '00 Proceedings of the Fourth IEEE International Conference on Automatic Face and Gesture Recognition 2000
Facial expression recognition from video sequences: temporal and static modeling
Computer Vision and Image Understanding - Special issue on Face recognition
Automatic Sign Language Analysis: A Survey and the Future beyond Lexical Meaning
IEEE Transactions on Pattern Analysis and Machine Intelligence
Multiview Facial Feature Tracking with a Multi-modal Probabilistic Model
ICPR '06 Proceedings of the 18th International Conference on Pattern Recognition - Volume 01
Spatio-Temporal Context for Robust Multitarget Tracking
IEEE Transactions on Pattern Analysis and Machine Intelligence
Recent developments in visual sign language recognition
Universal Access in the Information Society
Facial movement analysis in ASL
Universal Access in the Information Society
Dynamic Tracking of Facial Expressions Using Adaptive, Overlapping Subspaces
ICCS '07 Proceedings of the 7th international conference on Computational Science, Part I: ICCS 2007
An iterative image registration technique with an application to stereo vision
IJCAI'81 Proceedings of the 7th international joint conference on Artificial intelligence - Volume 2
A Unified Probabilistic Framework for Spontaneous Facial Action Modeling and Understanding
IEEE Transactions on Pattern Analysis and Machine Intelligence
Manifold based analysis of facial expression
Image and Vision Computing
Real-time 2D+3D facial action and expression recognition
Pattern Recognition
Adjusted pixel features for robust facial component classification
Image and Vision Computing
Coupled Prediction Classification for Robust Visual Tracking
IEEE Transactions on Pattern Analysis and Machine Intelligence
IEEE Transactions on Pattern Analysis and Machine Intelligence
LIBSVM: A library for support vector machines
ACM Transactions on Intelligent Systems and Technology (TIST)
Tracking facial features using mixture of point distribution models
ICVGIP'06 Proceedings of the 5th Indian conference on Computer Vision, Graphics and Image Processing
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This paper presents work towards recognizing facial expressions that are used in sign language communication. Facial features are tracked to effectively capture temporal visual cues on the signers' face during signing. Face shape constraints are used for robust tracking within a Bayesian framework. The constraints are specified through a set of face shape subspaces learned by Probabilistic Principal Component Analysis (PPCA). An update scheme is also used to adapt to persons with different face shapes. Two tracking algorithms are presented, which differ in the way the face shape constraints are enforced. The results show that the proposed trackers can track facial features with large head motions, substantial facial deformations, and temporary facial occlusions by hand. The tracked results are input to a recognition system comprising Hidden Markov Models (HMM) and a support vector machine (SVM) to recognize six isolated facial expressions representing grammatical markers in American sign language (ASL). Tracking error of less than four pixels (on 640x480 videos) was obtained with probability greater than 90%; in comparison the KLT tracker yielded this accuracy with 76% probability. Recognition accuracy obtained for ASL facial expressions was 91.76% in person dependent tests and 87.71% in person independent tests.