1. A method for registering a first sensor and a second sensor in a measurement system, the method comprising the steps of: sensing with the first sensor a first set of measurements from a first plurality of objects; sensing with the second sensor a second set of measurements from a second plurality of objects; generating a likelihood function associating a data element from the first set of measurements with a data element from the second set of measurements; generating a systematic error function based at least in part on the likelihood function; minimizing the systematic error function; and, assigning an object from the first plurality of objects to an object from the second plurality of objects, based at least in part on the minimized systematic error function.