tracking moving surface with time from sequence of images to get vector field for the powder surface velocity

i am doing tracking moving surface for powder with time to get an idea of the poder surface velocity with time. does anyone have any idea from where i have to start inorder to get the velocity from different time steps. i got that surace from boundary detection of the powder surface with time using images taken by high speed camera. the issue is that the surface is so random , and numer of point the decribe the powder surface is changing with time

[KSSV]

YOu have multiple..images......pick boundary from each image sequentially....and save them into a cell with increasing order of time....I hope you got it already looking at your jpg file.

[khalid Elserfy]

yes i got it, but i was trying to get velocity vector field of that moving surface with time. may be by subtracting successive surface in x, and y position to be velocity in x and y direction for different points on the moving surface

[KSSV]

Yes...pick two sucessive boundaries......get dx, dy..and divide them with dt.

[khalid Elserfy]

the issue that the coordinate are not the same at each time step also sometimes there is more than on point in x or y direction. so it is hard to subtract two succesive curves from each other