Thepurposeofthispaperistodevelopahighspeeddetectionschemeformovingand/orstationarypointtargetsinamultitargetenvironmentasregisteredinanIRimagesequence.Aniterativeapproximate3-Dlinesearchingalgorithmbaseduponthegeometricrepresentationoflines(fornon-maneuveringtargetsinspace)ina3-Dspaceisderived.Theconvergencyofthealgorithmisproved.Ananalysisisperformedofthetheoreticaldetectionperformanceofthealgorithm.ThestatisticalexperimentresultsshowhigheffectivenessandcomputationalefficiencyofthealgorithminthecaseoflowSNR.Theideamaybeemployedtosatisfythereal-timeprocessingrequirementofanIRsystem.