Patent ID: 8804119

Claim:
A particle detection system including; at least one light source adapted to illuminate a volume being monitored at two or more wavelengths; an image sensor having a field of view and including plurality of sensor elements which receive light from respective regions within the field of view of the image sensor, said images sensor being adapted to generate respective signals indicative of the intensity of light received from said respective regions; the image sensor and at least one light source being arranged so that the image sensor receives light projected from at least one light source after said light has traversed the volume being monitored, a processor associated with the image sensor and being adapted to, process the signals generated by sensor elements within a region of interest, the region of interest including those sensor elements that receive light from a region or regions containing the light source, generate an output indicative of the relative level of light received at the two wavelengths in the region of interest, and to provide an output indicative of whether particles of interest are detected in said volume being monitored based on the relative light level.