Get a real pinball game to play on its own Have: Need: Web-camera PC DSP-Card Ball Detection Ball Movement Prediction Flipper Activate
Creation of a difference image
Ball Detection Difference image Previous Image Difference image Current Image
Using background image
Ball Detection Reference image Background Image Difference image Current Image (shifted 2 pixels) (Hard to find ball)
Ball Detection reference image Reference Image(t) =α × Current Image(t) + (1-α) × Reference Image(t-1) α=0.1 α=0.9 α=0.5 Creation of a reference image
Using reference image
Ball Detection Reference image Reference Image Difference image Current Image
Ball Detection reference image Finding the ball the position of the ball = the brightest
pixel in the image the brightest pixel Finding the ball in the image LP-filter
Ball movement prediction Prediction Difference image Finding the ball = Time DSP should predict Total System Delay Future
Activation delay real world Present DSP Past
Ball movement prediction Linear prediction Ball in previous position Ball in present position Travel distance = Current position – previous position So for a total delay of 3 frames:
Predicted position = current position+3xTraveled Distance Difference image Finding the ball Linear prediction
Ball movement prediction Kalman overview Time update Measurement update Difference image Finding the ball Linear prediction Kalman filter
Ball movement prediction Kalman space model ex ey ez c G x z y M W ß Hypothesis:
The sphere rolls without slipping
The plane is inclined with a constant angle
Difference image Finding the ball Linear prediction Kalman filter
Ball movement prediction Kalman vs. Linear Prediction Difference image Finding the ball Linear prediction Kalman filter Kalman vs. LP
Flipper activation Difference image Finding the ball Linear prediction Kalman filter Kalman vs. LP Decision Regions Decision Regions Ball inside region Activate flipper
Flipper activation Difference image Finding the ball Linear prediction Kalman filter Kalman vs. LP Decision Regions Activation Ball moves fast Interpolate position of ball between frames Decision Regions
Conclusion
Ball movement prediction Kalman space model ex ey ez c G x z y M W ß Hypothesis: the sphere rolls without slipping Difference image Finding the ball Linear prediction Kalman filter
Flipper activation Difference image Finding the ball Linear prediction Kalman filter Kalman vs. LP Ahead prediction more than three frames ahead prediction.
(Ball not hit by flipper) less than three frames ahead prediction.
(Can hit the ball a moment later) Decision Regions Activation Ahead prediction
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