Trajectory plotting of a series of images

Hello Guys, I want to plot a trajectory of tennis ball thrown from one end of a table to another. This data is in the form of series of 18 images in a .mat file. This trajectory would be used to determine the final position of the ball's landing position. is there a way to overcome this problem? I shall send the .mat file if required. Thanks guys, Abhishek

Answer 1

[Joseph Areeda]

Well it seems to me the process is fairly straight forward but the implementation could be complicated depending on how fancy you wanted to get.

If I were given this problem it would be broken down into:

1) Determine the position of the ball in each frame.

2) Use some sort of calibration of frame time and image scaling to convert that position to (x,y,t)

3) Fit a linear function to x=f(t) and a quadratic function to y=f(t)

4) Determine when y(t) = 0 and calculate x at that time

Step 1 is a good image processing project to do automatically but for the first go aground I'd probably just display the image and ask the user to click on the center of the ball.

See the tech note http://www.mathworks.com/support/tech-notes/1500/1508.html for your curve fitting options. I'd probably go with a simple least squares fit.