  This paper proposes and evaluates a new metric. This metric will overcome a
limitation of the Optimal Subpattern Assignment (OSPA) metric mentioned by
Schuhmacher et al.: the OSPA distance between two sets of points is insensitive
to the the case where one is empty. This proposed metric called Complete OSPA
(COSPA), retains all the advantages of the OSPA metric for evaluating the
performance of multiple target filtering algorithms while also allowing
separate control over the threshold of physical distance errors and cardinality
errors.
