1. TENNIS STROKE DETECTION
CS365
Mentor: Prof. Amitabh Mukherjee Khushdeep Singh (10351) Aakash Verma (10002)

2. Applications of human activity recognition
Khushdeep Singh and Aakash Verma

3. OUR task can be divided into the following subtasks
Player Tracking
Optical Flow Analysis
Using Motion Descriptors
Adaptive Boosting
Khushdeep Singh and Aakash Verma

4. Player Tracking
Using Particle Filter

5. What must be specified:
Prior Distribution: p(x0)
- Describes initial distribution of object states
Transition Model: p(xt | xt-1)
- Specifies how objects move between frames
- A simple model: sample next state from a Gaussian window around current state
- We used second order auto regressive model.
xt = Axt-1 + Bxt-2 +wt
Observation Model: p( yt | xt )
- Color Histogram
Object Tracking and Particle Filtering by Rob Hess [2006]
Khushdeep Singh and Aakash Verma

6. EXAMPLE OF PLAYER TRACKING
Khushdeep Singh and Aakash Verma

7. OPTICAL FLOW Using KL ALGORITHM 11-07-2019
Khushdeep Singh and Aakash Verma

8. OPTICAL FLOW estimation
SPARSE OPTICAL FLOW
Computed only at a subset of image points.
Quicker but less accurate results.
Example: Kanade-Lucas Algorithm
DENSE OPTICAL FLOW
Computed at each image pixel.
Slower but better results.
Example: Farneback Algorithm
Khushdeep Singh and Aakash Verma

9. EXAMPLE OF SPARSE OPTICAL FLOW ESTIMATION
Khushdeep Singh and Aakash Verma

10. ITERATIVE KL OPTICAL FLOW COMPUTATION
Khushdeep Singh and Aakash Verma

11. Feature DETECTION USING VOILA JONES ALGORITHM 11-07-2019
Khushdeep Singh and Aakash Verma

12. VOILA JONES algorithm
Efficient Visual Event Detection using Volumetric Features by Yan Ke, Rahul Suthankar, Martial Herbert [ICCV’05]
Khushdeep Singh and Aakash Verma

13. ADAPTIVE BOOSTING Meta machine learning algorithm 11-07-2019
Khushdeep Singh and Aakash Verma

14. Lecture on AdaBoost by Jan Sochman, Jiri Matas
Lecture on AdaBoost by Jan Sochman, Jiri Matas
Khushdeep Singh and Aakash Verma

15. For the given example
Khushdeep Singh and Aakash Verma

16. Comparison of adaboost with other methods
BoosTexter: A boosting-based system for text categorization by Robert E. Schapire and Yoram Singer.
Khushdeep Singh and Aakash Verma

17. Adaboost pseudocode
Khushdeep Singh and Aakash Verma

18. Some initial results using only 1000 weak classifiers
No. of Training Examples
No. of Features
Misses
False Alarms
200
2,00,000 3%
60%
19.58%
30%
500
1,00,000
12%
58%
* TRAINED ON THE KTH DATASET
Khushdeep Singh and Aakash Verma