Patent ID: 7242009
Filing Date: 2007-07-10
Classification: G01N

Abstract:
1. A method of using laser-induced fluorescence to distinguish (a) a presence of threat particles interspersed with background particles from (b) an absence of threat particles, the threat particles representing fluorescent biological substances, comprising: using a multiple-wavelength detection-band laser-induced fluorescence sensor to acquire a measurement set of particles for laser-induced fluorescence analysis, the sensor providing threat-present and threat-absent particle signals in response to the acquired measurement set of particles; defining a grey-scale weighting function formulated on competing sensitivity and false positive rate factors, the sensitivity factor representing sensitivity of detecting threat particles against non-threat particles and the false positive rate factor representing a probability of falsely concluding that the acquired measurement set of particles contains threat particles; using the weighting function to assign weights to particles in the measurement set, based on a numerical characterization of a particle and a weight associated with that characterization; assigning weights to each particle in the measurement set, based on the weighting function; and processing the weights assigned to the particles and producing an indication whenever a result obtained from the processing of the weights represents a likelihood of concluding correctly that the measurement set of particles contains threat particles.