A commonly used and somewhat simple method for registering two point clouds (that presumably are of the same object or have significant similar structure), is to use what is called Iterative Closest Point (ICP). Read up on ICP, then implement in Matlab.
MORE DESCRIPTION NEEDED HERE.
/* For Matlab folks, an exemplar implementation of ICP can be found here. Try to implement your own version of ICP.
For PCL folks, you may refer to the sample code. Try to implement your own version of ICP. */