How to use a matrix of data of B field in a 3D space to calculate the induced current in a closed loop on xy plane

Dear all:

Any one could help me with this problem:

I want to use a matrix of data which describes the magnetic field(Bx, By, Bz) at point(x, y, z) in a column of space to calculate the the induced current in a closed loop on xy plane. Is there a way to do that?

Any one could help please as soon.

Thanks a lot! Ruming