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Human Capabilities on Video-based Facial Expression Recognition. Motivation. Facial Expression Recognition goal: human-like man-machine communication six universal facial expressions [Ekman]: anger, disgust, fear, happiness, sadness, surprise minimal muscle activity
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Human Capabilities on Video-based Facial Expression Recognition
Motivation • Facial Expression Recognition • goal: human-like man-machine communication • six universal facial expressions [Ekman]:anger, disgust, fear, happiness, sadness, surprise • minimal muscle activity -> reliable recognition is difficult • recognition rate of state-of-the-art approaches: ~ 70% • Question • How reliable do humans specify facial expressions? -> survey to determine human capabilities Technische Universität München Ursula Zucker
The Facial Expression Database Cohn-Kanade AU-Coded Facial Expression Database • 488 image sequences (containing 4 up to 66 images) • each showing one of the six universal facial expressions • no natural facial expressions (simulated ground truth) • no context information Technische Universität München Ursula Zucker
Description of Our Survey • Execution of the Survey • participants are shown randomly selected sequences • 250 participants • 5413 annotations -> approx. 11 per sequence Technische Universität München Ursula Zucker
Evaluation • Evaluation of the Survey • no ground truth -> comparison of the annotations to one another • annotation rate for each sequence and each facial expression • relative agreement for an expression • confusion between facial expressions • Comparison to algorithms • recognition rate Technische Universität München Ursula Zucker
Annotation Rate for Each Sequence • Explanation: • 488 rows • 1 row = 1 sequence • darker regions denote a higher annotation rate • sorted by similar annotation • Result: • happiness:best annotation rates • surprise and fear: get confused often • fear: difficult to tell apart Technische Universität München Ursula Zucker
Relative Agreement • Explanation: • example: annotating the sequences as happiness ~ 350 sequences annotated as happiness by nobody, ~ 50 sequences annotated as happiness by everybody • well-recognized facial expressions have peaks at “0” and at “1” Technische Universität München Ursula Zucker
Confusion Between Facial Expressions • fear and surprise: high confusion • happiness and disgust: low confusion confusion rate Technische Universität München Ursula Zucker
Comparison: humans vs. algorithms • ground truth: provided by Michel et. al. • Results: • Michel et. al.: worse at recognizing anger • Schweiger et. al.: worse at recognizing disgust, fear, happiness and on the average Technische Universität München Ursula Zucker
Conclusion • Survey applies similar assumptions as algorithms: • consideration of visual information only • no context information • no natural facial expressions • Summary of our results: • poor recognition rate of humans – worse than expected • some facial expressions get confused easily • Conclusion & Outlook: • integration of more sources of information is highly recommended, e. g. audio/language, context, ... Technische Universität München Ursula Zucker
Thank you Technische Universität München Ursula Zucker