Evaluation of an optical correlator automatic target recognition system for acquisition and tracking in densely cluttered natural scenes

Paul C. MillerMichael RoycePeter VirgoMerrilyn FiebigGarry HamlynSurveillance Systems DivisionDefence Science and TechnologyOrganisation, SalisburyP.O. Box 1500Salisbury, South Australia 5108AustraliaE-mail: paul.miller@dsto.defence.gov.auAbstract. We describe a real-time automatic target recognition (ATR)system that employs a state-of-the-art optical correlator. The system’sability to acquire and track a moving vehicle target against a denselycluttered natural background is investigated using six test image se-quences obtained from a scanning IR sensor array mounted on an air-borne platform. The approach adopted for the evaluation is to first opti-mize a number of system parameters, using what we considered to beone of the better test sequences, and then to test the system with theoptimum configuration on the remaining sequences. The system perfor-mance is quantified by measuring its receiver-operating-characteristiccurves against each test image sequence. Although successful acquisi-tion and tracking of the target is demonstrated for some test sequences,there are numerous occasions on which the system acquired andtracked false alarms. This is primarily because edge features alone arean insufficient discriminator. We therefore conclude that the systemevaluated does not exhibit the desired robustness for the acquisition andtracking of vehicles in densely cluttered natural scenes. Finally, theseresults are compared with those produced using a digital simulation ofthe ATR system’s algorithmic processing chain. Comparison shows thatfor all practical purposes the performances are equivalent.