Finding 3D coordinate by using triangulation

I am going to find the real 3D coordinate of a target point in an image with respect to world coordinate system. It is supposed that the XY world coordinate plane is attached to the target plane in parallel and the Z world coordinate axis is perpendicular to the target plane. I also use the stereo camera system to record the image data. Also I have done the stereo camera calibration and rectified images through a stereo rectification process by using the calibration results. Then I utilized the bellow formulas to determine the 3d coordinate of the target points with respect to camera coordinate system: Z=Bf/(Xr-Xl), Y= uZ/f, X=vZ/f

But these coordinates are with respect to camera coordinate system. If I want to convert these 3d coordinates to the 3d world coordinate system that I have described above, what shall I do to perform this job?