Objectives

• To extract different types of ball in high speed camera
• To calculate the angle of rotation for such ball

• Complex background
• Gray scale video
• Small size of ball
• Blurring of ball texture
• Outdoor environment with different lighting condition

Foreground Extraction

• Background extraction by sampling different frames
• Background subtraction and morphological filtering
• Window searching for the ball

Lighting Condition Simulation

• Tracking the ball and averaging the ball intensity to get average lighting
• Subtracting the ball image with average lighting to get ball texture

Ball Rotation Calculation

• Mapping the ball texture to a virtual 3d ball
• Rotating the virtual ball and extract the rotated texture back
• Comparing the texture to that in previous frame to see if they match
• Using Kalman filter to smooth the value of rotation throughtout frames

Applications

• Ball rotation analysis
• Ball aerodynamic analysis
• Ball flight simulation