Patent ID: 6590661
Filing Date: 2003-07-08
Classification: G01H,G01N

Abstract:
An optical method for remotely sensing vocal sounds produced by a selected person, comprising:a) utilizing one or more sources of light, each of which produces a broad spectrum of wavelengths of light including wavelengths which are highly attenuated by carbon dioxide gas, said selected person exhaling as part of producing vocal sound, and said exhaling producing a cloud of air with a higher concentration of carbon dioxide gas than is found generally in atmospheric air, c) providing one or more light detectors, each of which is paired with a corresponding one of said one or more sources of light, d) said one or more light detectors, over said broad spectrum of wavelengths of light, is sensitive only to light received in a predetermined narrow range of wavelengths of light, said predetermined narrow range of wavelengths of light being among those which are highly attenuated by carbon dioxide gas, e) directing said one or more sources of light along a path through said cloud of air to said corresponding one of said one or more light detectors, f) said one or more light detectors each producing an output signal which varies according to the intensity of said light received in said predetermined narrow range of wavelengths, whereby sound waves in said cloud of air and crossing a said path have a greater effect on said intensity of said light received by said corresponding one of said one or more light detectors than do sound waves outside of said cloud of air, and whereby vocal sound waves can be remotely and selectively sensed according to said light received.