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Face Tracking and Person Action Recognition - Update. Sascha Schreiber. Overview. Recapitulation of methodology for action recognition Face tracking with I-Condensation Recognition performance comparison on actions from the m4 dataset Kalman filtering of occluded gestures Outlook.
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Face Tracking and Person Action Recognition - Update Sascha Schreiber
Overview • Recapitulation of methodology for action recognition • Face tracking with I-Condensation • Recognition performance comparison on actions from the m4 dataset • Kalman filtering of occluded gestures • Outlook
Person Action Recognition Extraction of person locations Face detection/Blob tracking Feature calculation Global Motion Features Temporal segmentation Bayesian Information Criterion Classification of segments Hidden Markov Models Actions, timestamps
Person Action Recognition Extraction of person locations Face detection/Blob tracking Feature calculation Global Motion Features Temporal segmentation Bayesian Information Criterion Classification of segments Hidden Markov Models Actions, timestamps
Face Tracking • Sampling from importance function for reinitialisation • Importance sampling with weighting correction factor • Standard Condensation sampling • Nweighted particles • Updating using their likelihood Automatic initialization by pyramid sampling and MLP classification Particle filtering with ICondensation • Sampling from prediction density Introduction of importance function: skin color distribution
Performance of Face Tracking Demonstration of difference between: Standard Condensation ICondensation
Person Action Recognition Extraction of person locations Face detection/Blob tracking Feature calculation Global Motion Features Temporal segmentation Bayesian Information Criterion Classification of segments Hidden Markov Models Actions, timestamps
Recognition Performance m4 IDIAP training data (TRN 01-30), IDIAP test data (TST 01-30) Continuous HMMs (6 states, 3 mixtures)
Recognition Performance m4 IDIAP training data (TRN 01-30), IDIAP test data (TST 01-30) Discrete HMMs (6 states, codebook 1500)
Occluded Gestures Scenario: Person walking on front of a tracked object Video-stream Featurestream Feature- extraction Compensation of occlusion Occlusion Smoothed featurestream Segmented Featurestream Classification result Classification Stream- segmentation
Occluded Gestures Time update equation Measurement update equation Application for Kalman filtering: • Discrete-time process: • Calculation of an estimate
Occluded Gestures Kalman- filter • One general Kalman-Filter for the disturbed featurestream • N action-specialized Kalman-Filters, each trained for a special gesture to be recognized by the HMM Kalman- filter Kalman- filter Kalman- filter Improving featurestream by smoothing with :
Performance of Kalman filtering IDIAP training data (TRN 01-30), IDAP test data (TST 01-30) Continuous HMMs (6 states, 3 mixtures)
Outlook • Implementation of extended Kalman filter • Head orientation tracking • Integration of face recognition into particle filter • Further improvement of action detection on m4 data • Connection to Meeting Segmentation / Multimodal Recognizer
Face Tracking and Person Action Recognition - Update Sascha Schreiber