Optics: measuring and testing – For light transmission or absorption – Of fluent material
Reexamination Certificate
2006-07-11
2006-07-11
Toatley, Jr., Gregory J. (Department: 2877)
Optics: measuring and testing
For light transmission or absorption
Of fluent material
C356S432000, C250S339110, C250S338500, C073S04050A, C073S861270
Reexamination Certificate
active
07075653
ABSTRACT:
A method and apparatus for remote laser-based detection of gas at levels exceeding natural background levels preferably utilizing wavelength modulated tunable diode laser absorption spectroscopy. In a preferred embodiment, background gas and noise are estimated using statistical moving average and variance calculations. Gas concentration length measurements resulting from the spectroscopy are preferably compared in real-time or near-real-time to the sum of the background and noise estimates and an alarm limit to detect gas presence of concern. Gas levels exceeding this detection threshold are preferably indicated by a prolonged output tone with a pitch indicative of the magnitude of the gas measurement, and gas levels below the detection threshold are preferably indicated by silence.
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Andrews & Kurth LLP
Bush, Esq. Gary L.
Heath Consultants Incorporated
Nguyen Sang H.
Toatley , Jr. Gregory J.
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