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Human action recognition using spatio-temporal features Nikhil Sawant (2007MCS2899) Guide : Dr. K.K. Biswas
Human activity recognition Higher resolution Longer Time Scale Courtesy : Y. Ke,  Fathi and Mori, Bobick and Davis, Schuldt  et al,  Leibe  et al,  Vaswani  et al.   Pose Estimation Action Recognition Action Classification Tracking Activity Recognition
Use Action recognition? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Goals…. ,[object Object],[object Object],[object Object],[object Object],[object Object]
Goals…. ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Existing Approaches ,[object Object],[object Object],[object Object]
Tracking interest points ,[object Object],[object Object],[object Object],Images Courtesy : P. Correra Tracking 5 crucial points i.e. Head, 2 hands, 2 feet. Mostly present at the local maxima on the plot of geodesic distance
Tracking interest points ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Flow based approaches ,[object Object],[object Object],[object Object],[object Object]
Shape based Approaches ,[object Object],[object Object],[object Object],[object Object],[object Object],Images Courtesy : M. Blank
Our Approach ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Optical flow and motion features
Target Localization ,[object Object],[object Object],[object Object],[object Object],[object Object],Original Video Silhouette Original Video with ROI marked
Motion estimation ,[object Object],[object Object],[object Object],[object Object],[object Object]
Noise removal ,[object Object],[object Object],[object Object],[object Object],Noisy Optical flows After noise removal
Organizing optical flow ,[object Object],[object Object]
Organizing optical flow (Local oriented Histogram) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
[object Object],Organizing optical flow (Local oriented Histogram) C (0,0) d 2 d 1 O 1 O 2 O e O e
Organizing optical flow (Weighted Averaging) ,[object Object],[object Object]
Organizing optical flows
Formation of motion descriptor ,[object Object],[object Object],[object Object],[object Object],[object Object]
Learning with Adaboost Strong  classifier Weak classifier Weight Features vector
Classification Example  taken from Antonio Torralba @MIT Weak learners from the family of lines h => p(error) = 0.5  it is at chance Each data point has a class label: w t  =1 and a weight: + 1 (  ) -1 (  ) y t  =
Classification Example  This one seems to be the best This is a ‘ weak classifier ’: It performs slightly better than chance. Each data point has a class label: w t  =1 and a weight: + 1 (  ) -1 (  ) y t  =
Classification Example  We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t  w t  exp{-y t  H t } We update the weights: +  1 (  ) - 1 (  ) y t  =
Classification Example  We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t  w t  exp{-y t  H t } We update the weights: +  1 (  ) - 1 (  ) y t  =
Classification Example  We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t  w t  exp{-y t  H t } We update the weights: +  1 (  ) - 1 (  ) y t  =
Classification Example  We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t  w t  exp{-y t  H t } We update the weights: +  1 (  ) - 1 (  ) y t  =
Classification Example  The strong (non- linear) classifier is built as the combination of all the weak (linear) classifiers. f 1 f 2 f 3 f 4
Our Dataset ,[object Object],[object Object],ACTION SUBJECTS VIDEOS Walking 8 34 Running 8 20 Flying 5 25 Waving 5 25 Pick up 6 24 Stand up 6 48 Sitting down 6 24
Our Dataset (Tennis actions) ,[object Object],ACTION SUBJECTS VIDEOS Forehand 3 11 Backhand 3 10 Service 2 9
Training and Testing Dataset ,[object Object],[object Object],[object Object],ACTION TRAINING TESTING Walking 1184 1710 Running 183 335 Flying 182 373 Waving 198 317 Pick up 111 160 Stand up 128 187 Sitting down 230 282
Classification result ( framewise ) ,[object Object],Walking Running  Flying  Waving  Pick up  Sit down  Stand up  Error  Walking 1644  46  0  17  1  2  3.86%  Running 35  295  3  2  11.94%  Flying  1  2  349  11  9  1  6.43%  Waving  11  8  269  29  15.14%  Pick up 8  7  1  120  23  1  25%  Sit down  1  1  26  179  14.97%  Stand up 23  282  8.15%
Classification results ( clipwise ) ,[object Object],Walking Running Waving1 waving2 bending Sit-down Stand-up Error Walking 10 0.0% Running 10 0.0% Waving1 9 1 10.0% waving2 10 0.0% bending 9 1 10.0% Sit-down 10 0.0% Stand-up 1 9 10.0%
Action classification
Classification results (Tennis events) ,[object Object],Forehand Backhand Service Error Forehand 54 7 11 21.95% Backhand 11 53 10.75% Service 8 49 14.04%
Event Detection ,[object Object],[object Object],Current frame ‘ f’ Next  n  frames Previous  n  frames f f+1 f+2 f+3 f+4 … … f-1 f-2 f-3 f-4 … … f-n f+n
Event Detection Without using prediction logic With prediction logic
Weizmann Dataset ACTION SUBJECTS VIDEOS Bend 9 9 Jack 9 9 Jump 9 9 Pjump 9 9 Run 9 10 Side 9 9 Skip 9 10 Walk 9 10 Wave1 9 9 Wave2 9 9
Standard Dataset (Weizmann Dataset) Walk Side Skip Wave1 Wave2 Bend Run Jack Jump Pjump
confusion matrix ( framewise ) ,[object Object],Bend  Jack Jump Pjump Run Side Skip Walk Wave1 Wave2 Bend  271 1 1 20 3 30 11 Jack 18 368 8 48 3 2 3 9 16 Jump 9 3 157 8 2 26 19 7 Pjump 36 26 237 22 6 Run 4 2 5 158 3 50 6 1 2 Side 11 9 77 1 1 84 3 58 2 1 Skip 3 9 76 43 5 109 24 1 7 Walk 2 5 16 2 13 5 395 Wave1 47 2 12 238 27 Wave2 30 6 1 4 1 55 269
Weizmann dataset ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Use of MV + Shape Info(SI) ,[object Object],[object Object],[object Object],[object Object]
Use of MV + Differential SI  ,[object Object],[object Object],[object Object],[object Object]
confusion matrix ( framewise ) Bend  Jack Jump Pjump Run Side Skip Walk Wave1 Wave2 Bend  326 7 2 2 Jack 6 418 39 1 3 8 Jump 18 1 189 1 5 4 13 Pjump 11 55 243 6 1 11 Run 2 2 173 2 45 7 Side 8 30 11 1 152 12 33 Skip 1 20 32 83 4 121 13 1 2 Walk 1 1 2 1 1 432 Wave1 43 1 10 10 232 30 Wave2 13 25 328
Spatio-temporal features TSPAN TLEN
Spatio-temporal descriptor ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Event classification ( clipwise ) ,[object Object],[object Object],bend  Jack Jump Pjump Run Side Skip Walk Wave1 Wave2 Error bend  9 0.0% Jack 9 0.0% Jump 9 0.0% Pjump 9 0.0% Run 9 1 10.0% Side 9 0.0% Skip 10 0.0% Walk 10 0.0% Wave1 8 1 11.1% Wave2 9 0.0%
Action recognition in cluttered background
Cluttered environment ,[object Object],[object Object],[object Object],[object Object],[object Object]
Training ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Training data drinking
Training data bending
Template length ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Single template formation ,[object Object],[object Object],[object Object],[object Object],[object Object],1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 3 4 5 6 8 9 10 11 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12
Optical flow and Adaboost ,[object Object],[object Object],[object Object],[object Object],[object Object]
Testing ,[object Object],[object Object],Height Width Length
t x y
Testing ,[object Object],[object Object],[object Object],[object Object],[object Object],Height Width Length
Confidence matrix ,[object Object],[object Object],[object Object],[object Object],[object Object]
Confidence matrix
Results
Results
Results
Results
Results
Results
Key References ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

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Action Recognition (Thesis presentation)

  • 1. Human action recognition using spatio-temporal features Nikhil Sawant (2007MCS2899) Guide : Dr. K.K. Biswas
  • 2. Human activity recognition Higher resolution Longer Time Scale Courtesy : Y. Ke, Fathi and Mori, Bobick and Davis, Schuldt et al, Leibe et al, Vaswani et al. Pose Estimation Action Recognition Action Classification Tracking Activity Recognition
  • 3.
  • 4.
  • 5.
  • 6.
  • 7.
  • 8.
  • 9.
  • 10.
  • 11.
  • 12. Optical flow and motion features
  • 13.
  • 14.
  • 15.
  • 16.
  • 17.
  • 18.
  • 19.
  • 21.
  • 22. Learning with Adaboost Strong classifier Weak classifier Weight Features vector
  • 23. Classification Example taken from Antonio Torralba @MIT Weak learners from the family of lines h => p(error) = 0.5 it is at chance Each data point has a class label: w t =1 and a weight: + 1 ( ) -1 ( ) y t =
  • 24. Classification Example This one seems to be the best This is a ‘ weak classifier ’: It performs slightly better than chance. Each data point has a class label: w t =1 and a weight: + 1 ( ) -1 ( ) y t =
  • 25. Classification Example We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t w t exp{-y t H t } We update the weights: + 1 ( ) - 1 ( ) y t =
  • 26. Classification Example We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t w t exp{-y t H t } We update the weights: + 1 ( ) - 1 ( ) y t =
  • 27. Classification Example We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t w t exp{-y t H t } We update the weights: + 1 ( ) - 1 ( ) y t =
  • 28. Classification Example We set a new problem for which the previous weak classifier performs at chance again Each data point has a class label: w t w t exp{-y t H t } We update the weights: + 1 ( ) - 1 ( ) y t =
  • 29. Classification Example The strong (non- linear) classifier is built as the combination of all the weak (linear) classifiers. f 1 f 2 f 3 f 4
  • 30.
  • 31.
  • 32.
  • 33.
  • 34.
  • 36.
  • 37.
  • 38. Event Detection Without using prediction logic With prediction logic
  • 39. Weizmann Dataset ACTION SUBJECTS VIDEOS Bend 9 9 Jack 9 9 Jump 9 9 Pjump 9 9 Run 9 10 Side 9 9 Skip 9 10 Walk 9 10 Wave1 9 9 Wave2 9 9
  • 40. Standard Dataset (Weizmann Dataset) Walk Side Skip Wave1 Wave2 Bend Run Jack Jump Pjump
  • 41.
  • 42.
  • 43.
  • 44.
  • 45. confusion matrix ( framewise ) Bend Jack Jump Pjump Run Side Skip Walk Wave1 Wave2 Bend 326 7 2 2 Jack 6 418 39 1 3 8 Jump 18 1 189 1 5 4 13 Pjump 11 55 243 6 1 11 Run 2 2 173 2 45 7 Side 8 30 11 1 152 12 33 Skip 1 20 32 83 4 121 13 1 2 Walk 1 1 2 1 1 432 Wave1 43 1 10 10 232 30 Wave2 13 25 328
  • 47.
  • 48.
  • 49. Action recognition in cluttered background
  • 50.
  • 51.
  • 54.
  • 55.
  • 56.
  • 57.
  • 58. t x y
  • 59.
  • 60.
  • 68.