Abstract: A system for acquiring both the spatial and spectral dimensions of a spectral image cube either simultaneously with a single frame acquisition, or sequentially with a small number of frames, using a sensor that uses an array of pixel-size, narrow wavelength bandpass filters placed in close proximity to a focal plane array (FPA), and for processing the acquired data to retrieve spectral image cubes at the pixel resolution of the FPA.

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 radiative transport band model method for prediction and analysis of high spectral resolution radiometric measurements. Atomic and molecular line center absorption is determined from finite spectral bin equivalent widths. A mathematically exact expansion for finite bin equivalent widths provides high accuracy at any desired spectral resolution. The temperature and pressure dependent Voigt line tail spectral absorption contributing to each spectral bin is pre-computed and fit to Padé approximants for rapid and accurate accounting of neighboring-to-distant lines. A specific embodiment has been incorporated into the MODTRAN™ radiation transport model.

Abstract: This invention discloses several improved methods of correcting for atmospheric effects on a remote image of the Earth's surface taken from above, wherein the image comprises a number of simultaneously acquired images of the same scene, each including a large number of pixels, each at a different wavelength band, and including infrared through ultraviolet wavelengths. One method is for retrieving the aerosol/haze amount (i.e., visible range) from an assumed ratio of in-band reflectances, rather than from an assumed reflectance value. Another method is for identifying cloud-containing pixels. This is used to improve the calculation of the spatially averaged radiance L*e and reflectance ?e images in standard equations. Another method greatly reduces the number of mathematical operations required to generate the reflectance values.

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.

Abstract: A method of automatically determining a measure of atmospheric aerosol optical properties using a multi- or hyper-spectral, multi-pixel image. A plurality of spectrally-diverse pixels are resolved from the image. A statistical spectral deviation of the spectrally-diverse pixels is determined, and then corrected for non-aerosol transmittance losses. One or more wavelength-dependent aerosol optical depths are derived from the statistical spectral deviation. Wavelength-dependent gaseous optical depths can be derived from the statistical spectral deviation.

Abstract: A method of automatically compensating a multi- or hyper-spectral, multi-pixel image for atmospheric effects, comprising resolving a plurality of spectrally-diverse pixels from the image, determining a spectral baseline from the spectrally-diverse pixels, determining a statistical spectral deviation of the spectrally-diverse pixels, normalizing the statistical spectral deviation by applying a scale factor, and compensating image pixels with both the spectral baseline and the normalized spectral deviation.

Abstract: A method of automatically compensating a multi- or hyper-spectral, multi-pixel image for atmospheric effects, comprising resolving a plurality of spectrally-diverse pixels from the image, determining a spectral baseline from the spectrally-diverse pixels, determining a statistical spectral deviation of the spectrally-diverse pixels, normalizing the statistical spectral deviation by applying a scale factor, and compensating image pixels with both the spectral baseline and the normalized spectral deviation.

Abstract: A leak detector for monitoring, in an area being investigated, the presence of a liquid having a characteristic fluorescence spectrum. The leak detector includes a radiation source, with the radiation provided to the area being investigated. The detector also includes a collector for collecting radiation, in the fluorescence emission band of the liquid being monitored, emitted from the area being investigated. The presence of this liquid is sensed by detection of a threshold level of collected radiation. The size of a stain of the liquid relative to the size of the field of view of the collector is then determined.