Abstract: A system for controlling the uniformity of combustion over a range of operating conditions in a combustor with a plurality of fuel nozzles. The system includes a number of optical sensors, each sensor comprising an optical probe that collects naturally occurring optical radiation emanating from a segment of the combustor or combustor exhaust, and at least one transducer that receives the radiation collected by the probes, compares the intensity of collected radiation from each sensor in a plurality of spectral pass-bands that are indicative of the fuel/air ratio in the combustor segments, and produces output signals that are indicative of the state of combustion in the combustor segments. A control system receives the output signals from the transducers and in response controls the fuel flow to the fuel nozzles to achieve an output from each of the sensors that has been determined to be indicative of a predetermined state of combustion.

Abstract: An adaptive spectral sensor, and methods of using the sensor. The sensor uses a programmable band pass transmission filter to produce both contrast signals, which discriminate specific target materials from background materials by comparing spectral signatures in hardware, and scene radiance spectra. The adaptive spectral sensor may measure one or more scene spectra and may form a spectral image. The sensor may automatically adjust to changing spectral, spatial and temporal conditions in the environment being monitored, by changing sensor resolution in those dimensions and by changing the detection band pass. The programmable band pass can be changed on-the-fly in real time to implement a variety of detection techniques in hardware or measure the spatial or spectral signatures of specific materials and scenes.

Abstract: A spectral encoder for producing spectrally selected images of a radiation field containing multiple spectral components. An imaging spectrograph defines a first optical path that produces from the input radiation field a spectrally dispersed image comprising multiple spectral components displaced along a dispersion direction. Spectral pass bands are encoded on the dispersed image by a programmable spatial light modulator using one or more spatial masks. The imaging spectrograph further defines a second optical path that reverses the spectral dispersion of the first path and produces a spectrally-encoded polychromatic output image containing only those spectral components encoded by the spatial mask. The first and second optical paths share a common dispersing element. A detector records at least one spatial region of the spectrally encoded output image.