Patent ID: 6560545
Filing Date: 2003-05-06
Classification: G01N

Abstract:
A system for detecting components of the exhaust of a moving vehicle, comprising:a radiation source for producing radiation; a detector for receiving said radiation and generating at least one signal responsive to said radiation indicative of the radiation absorption of first and second vehicle exhaust components in first and second wavelength bands; optics for guiding said radiation through more than two passes through a detection space from said source to said detector, whereby said radiation passes through an exhaust plume of a moving vehicle in said detection space, and wherein a vertical height of the detection space is defined as the vertical distance between a horizontal surface and the location of an uppermost path of said radiation over said horizontal surface, and said optics are configured such that the radiation makes at least two passes through the detection space per foot of said vertical height; and a processor responsive to the at least one signal, said processor calculating a ratio of the radiation absorption of the first vehicle exhaust component to the radiation absorption of the second vehicle exhaust component to compensate for at least some dispersion of the exhaust plume.