A system and method for exploiting spectral absorption properties of water is disclosed. The system and method use spectral absorption properties of water to improve Short Wave InfraRed (SWIR) sensor (camera) performance in the presence of clouds. This is achieved partly by limiting the spectral passband of a sensor to a water absorption band, thereby improving Signal to Noise Ratio (SNR). Higher SNR permits improved CSO resolution. Further, higher SNR reduces the uncertainty in matching observations in one sensor to the epipolar lines of another sensor thus reducing the time needed to achieve unambiguous matches.

A spectral imaging system configured to obtain spectral measurements in a plurality of spectral regions is described herein. The spectral imaging system comprises at least one optical detecting unit having a spectral response corresponding to a plurality of absorption peaks of a target chemical species. In an embodiment, the optical detecting unit may comprise an optical detector array, and one or more optical filters configured to selectively pass light in a spectral range, wherein a convolution of the responsivity of the optical detector array and the transmission spectrum of the one or more optical filters has a first peak in mid-wave infrared spectral region between 3-4 microns corresponding to a first absorption peak of methane and a second peak in a long-wave infrared spectral region between 6-8 microns corresponding to a second absorption peak of methane.

Embodiments include a method for retrieving atmospheric aerosol based on statistical segmentation. Firstly a multi-band remote sensing image including an apparent reflectance and an aerosol optical thickness look-up table corresponding to a retrieval band is obtained, then pixels are partitioned and screened according to apparent reflectance segments of a mid-infrared 2.1 micrometer band. After that the retained pixel sets are further partitioned and screened according to the apparent reflectance segments of the mid-infrared 1.6 micrometer band. Finally the obtained pixel sets are partitioned into two categories according to the pixel number, one category including pixels having more pixels, the other including those with less pixels. The category with more pixels is taken as the reference part for retrieval.

Various embodiments disclosed herein describe a divided-aperture infrared spectral imaging (DAISI) system that is adapted to acquire multiple IR images of a scene with a single-shot (also referred to as a snapshot). The plurality of acquired images having different wavelength compositions that are obtained generally simultaneously. The system includes at least two optical channels that are spatially and spectrally different from one another. Each of the at least two optical channels are configured to transfer IR radiation incident on the optical system towards an optical FPA unit comprising at least two detector arrays disposed in the focal plane of two corresponding focusing lenses. The system further comprises at least one temperature reference source or surface that is used to dynamically calibrate the two detector arrays and compensate for a temperature difference between the two detector arrays.

A laser-heterodyne combustion-efficiency monitor captures light emitted from a combustion zone during combustion and determines combustion efficiency based on the captured light. The monitor includes an optical detector that generates an electrical response by mixing the captured light with an optical local-oscillator signal, and a signal filter that filters the electrical response to isolate a beat-note that is proportional to a target-species concentration in the combustion zone. The frequency of the local-oscillator signal determines the target species, which may be carbon monoxide, carbon dioxide, or another emission or absorption line that can be detected using laser-heterodyne radiometry. A laser generates the local-oscillator signal. The monitor may be extended to operate with several lasers emitting several local-oscillator signals at different frequencies, thereby allowing multiple target species to be detected simultaneously.

An environmental emission monitoring system may include satellites configured to sense GHG emissions data for an AOI, and a server. The server may be configured to obtain the sensed GHG emissions data from the satellites, obtain geospatial positions of stationary GHG emitting point sources within the AOI, and generate expected stationary GHG emission data for the stationary GHG emitting point sources within the AOI and based upon the geospatial positions. The server may also be configured to obtain geospatial path data for GHG emitting vehicles moving within the AOI, generate expected vehicle GHG emission data for the GHG emitting vehicles moving within the AOI and based on the geospatial path data, and compare a sum of the expected stationary GHG emission data and expected vehicle GHG emission data with the sensed GHG emissions data to identify any stationary GHG emitting point source and any GHG emitting vehicle outside of a respective GHG emission threshold.

An infrared (IR) imaging system for determining a concentration of a target species in an object is disclosed. The imaging system can include an optical system including a focal plane array (FPA) unit behind an optical window. The optical system can have components defining at least two optical channels thereof, said at least two optical channels being spatially and spectrally different from one another. Each of the at least two optical channels can be positioned to transfer IR radiation incident on the optical system towards the optical FPA. The system can include a processing unit containing a processor that can be configured to acquire multispectral optical data representing said target species from the IR radiation received at the optical FPA. One or more of the optical channels may be used in detecting objects on or near the optical window, to avoid false detections of said target species.

An infrared (IR) imaging system for determining a concentration of a target species in an object is disclosed. The imaging system can include an optical system including a focal plane array (FPA) unit behind an optical window. The optical system can have components defining at least two optical channels thereof, said at least two optical channels being spatially and spectrally different from one another. Each of the at least two optical channels can be positioned to transfer IR radiation incident on the optical system towards the optical FPA. The system can include a processing unit containing a processor that can be configured to acquire multispectral optical data representing said target species from the IR radiation received at the optical FPA. One or more of the optical channels may be used in detecting objects on or near the optical window, to avoid false detections of said target species.

A thermal imaging system includes an infrared camera, a user interface, and a processor. While an actuation of the user interface is detected, the processor is configured to apply non-uniformity correction (NUC) values to infrared image data in infrared images of a target scene; register the corrected infrared images using image stabilization; perform an image-stabilized optical gas imaging process using the registered infrared images to generate optical gas image data indicating a change in the target scene; and generate a display image including the optical gas image data. Actuation of the user interface may be detected while a depressible trigger is depressed, and no longer detected when the depressible trigger is released. Upon detecting the actuation of the user interface, the processor may perform a NUC process to establish the NUC values. A drift indicator in the display image may indicate movement of the infrared camera from a reference position.

An integrated optical sensor enables the detection and identification of one or more remote gases using a transmission filter that matches specific absorption features of a remote gas and is detected using a single photodetection element. The sensor comprises an integrated optical component that is characterized by its transmission spectrum which corresponds to absorption or emission features of a target gas over a defined spectral bandpass, and the ability to have a reversibly tunable transmission spectrum. The change in the optical power output from the sensor as the transmission spectrum is tuned is proportional to the optical depth of the target gas absorption lines when viewed with a background light source. The optical power output from the integrated optical component is therefore related to the absorption spectrum of the input light Physical properties of the sensor are tailored to produce a quasi-periodic transmission spectrum that results in a stronger signal contrast for a specific gas. The sensor is preferably a waveguide ring resonator with a free spectral range that matches the absorption spectrum of a gas over a finite spectral bandpass.