Calculating the velocity (vector) from a 2-Dline

Hi all I have a line (path) which is drawn by mouse on the screen. The line is 3 column vector [X Y T] where x is the x position along x-axis, y is the y position along Y-axis and T is the time (second) that x,y are registered.

ex. line = [10, 1, 1.2; 12, 2, 1.3; ...]

Since the data (line) is discrete I am confused in calculating the velocity vector. further in calculating the acceleration vector (if needed)

can you help me in resolving this issue?

thanks, P

Answer 1

[Azzi Abdelmalek]

You can calculate the average velocity between two points (x1,y1) and (x2,y2), from time t1 to t2

 S=sqrt((x2-x1)^2+(y2-y1)^2)/(t2-t1)

You can, also use interpolation.

[tafteh]

Thanks Azzi, for the interpolation, if you mean to have the timing equidistance, should I do the cubic interpolation once for vector x and once for the vector y?

[Azzi Abdelmalek]

If you want, but I think, you can interpolate the vector velocity. But from the result you can't get the position. For how to choose interpolation, I'm not good with that

[tafteh]

thanks again, I guess the S=sqrt((x2-x1)^2+(y2-y1)^2)/(t2-t1) should be fine for me now.

cheers,

Answer 2

[Kubugha Bunonyo]

What if we are dealing with and image ?