Provided are systems and methods to filter infrared spectrum radiation that can be integrated with a compact optical system for an infrared imaging system. The optical system includes an objective lens element configured to receive and transmit infrared (IR) radiation from a scene, where the IR radiation from the scene includes a particular range of wavelengths corresponding to an absorption spectrum or a transmission spectrum of a gas. The optical system also includes a spectral lens element configured to receive the IR radiation transmitted through the objective lens element, where the spectral lens element comprises a first interference filter disposed on a first surface of the spectral lens element. The interference filter is configured to filter the IR radiation transmitted through the objective lens element to a narrower wavelength band that includes the particular range of wavelengths.

A method and system for detecting sulfur fires that comprises a remote infrared or microwave sensor to detect sulfur dioxide gas and provide an unsupervised remote daytime and nighttime sulfur fire-watch, hot spot detection, early sulfur fire prevention, sulfur fire detection, or sulfur fire control of unattended combustible sulfur blocks, sulfur stockpiles, sulfur plants, or equipment using remote sensing devices that includes detection, measurement and analysis of electromagnetic radiation to determine the presence of sulfur dioxide gas.

A system for monitoring a petrochemical installation is disclosed. The system can include an optical imaging system comprising an array of optical detectors. The system can comprise processing electronics configured to process image data detected by the optical imaging system. The processing electronics can be configured to detect a target species based at least in part on the processed image data. The processing electronics can further be configured to, based on a detected amount of the target species, transmit an alarm notification to an external computing device over a communications network indicating that the target species has been detected at the petrochemical installation.

Systems and methods disclosed herein, in accordance with one or more embodiments, provide for indicating gas movement in a scene having a background and an occurrence of gas, and comprise obtaining a sequence of at least two thermal image frames of said scene recorded at different points of time, automatically identifying, in each image frame of said sequence of thermal image frames, a set of pixel coordinates representing gas above a predetermined concentration threshold present in the imaged scene at the point of time at which the image frame was recorded, and automatically determining the location of each of said sets of pixel coordinates in the imaged scene. The systems and methods further comprise at least one of automatically generating a visual presentation image of said scene in which the location of each of said sets of pixel coordinates in relation to the location of each of said other sets of pixel coordinates is visualized, and/or automatically determining a direction of gas movement based on the location of each of said sets of pixel coordinates in relation to the location of each of said other sets of pixel coordinates.

There is provided a gas sensing device for sensing a certain gas that is associated with a certain spectral band, the gas sensing device may include a passive gas sensor that is configured to generate passive gas sensor detection signals that are responsive to the certain spectral band; a passive dummy sensor that is configured to generate passive dummy sensor detection signals that are indifferent to the certain spectral hand; and at least one circuit that is configured to detect a presence or absence of the certain gas within a certain volume that is located within the fields of view of the passive gas sensor and the passive dummy sensor based on a comparison between the passive gas sensor detection signals and the passive dummy sensor detection signals.

Provided is a simulation spectrum apparatus including: a background image acquisition unit that acquires a background image of a target region and an infrared signal corresponding to each pixel of the background image; a spectrum acquisition unit that acquires a background radiation intensity spectrum from the infrared signal acquired for the each pixel; a simulation spectrum generation unit that generates a model of a linear combination of a radiation intensity spectrum of a contamination cloud and a background radiation intensity spectrum on the basis of a difference in radiation intensity; a controller that generates a simulation spectrum of the contamination cloud by applying the information on the at least one toxic substance and the atmosphere transmittance to the model of the linear combination; and an imaging unit that generates a spectrum image, combines the generated spectrum image and the background image, and thus generates a simulation contamination cloud image.

The present invention relates to a computationally compact and efficient method for determining physical characteristics of remote targets of interest from hyperspectral image scenes. Ground-based as well as space-borne hyperspectral imaging in the 7-14 microns region, also known as Thermal InfraRed (TIR) Hyperspectral imaging, is assuming increasing importance in military and civilian remote sensing. However, converting large hyperspectral imaging datasets into useable data products is complex and often requires long processing times. In-situ, field and on-board TIR hyperspectral imaging data processing is desirable for immediate detection, but currently very limited. Additionally, retrieving physical information of a target, seen against a background of clouds, is currently not possible. The present method creates a way to significantly improve the efficiency of analyzing hyperspectral imaging data to retrieve characteristics of remote targets of interest in the presence of both clear and cloudy sky background conditions. The present method uses a supervised machine learning Partial Least Squares Regression (PLSR) algorithm, which was trained from a library of simulated radiative transfer spectra. The radiative transfer library included a large number of complex conditions, which are difficult to implement in traditional lookup table methods, but become amenable in the present method. This invention is computationally compact and efficient and can be employed for on-board sensor data processing on the ground and in space. Various tests have shown the efficiency and reliability of the present method.

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.

A detection system with a two-step homogenizing device (1) and with a receiver (42). Viewed in a field direction (54) of a photon field, the homogenizing device (1) is located between a measurement area (44) and the receiver (42). The homogenizing device (1) includes a first diffuser (10) and a second diffuser (12). The first diffuser (10) generates an intermediate photon field from an input photon field. The second diffuser (12) generates an output photon field from the intermediate photon field. The receiver (42) generates signals depending on the incident photon field.

Improved techniques for infrared imaging and gas detection are provided. In one example, a system includes a sensor array configured to receive infrared radiation from a scene comprising a background portion and a gas. The sensor array includes a first set of infrared sensors configured with a first spectral response corresponding to a first wavelength range of the infrared radiation associated with the background portion. The sensor array also includes a second set of infrared sensors configured with a second spectral response corresponding to a second wavelength range of the infrared radiation associated with the gas. The system also includes a read out integrated circuit (ROIC) configured to provide pixel values for first and second images captured by the first and second sets of infrared sensors, respectively, in response to the received infrared radiation. Additional systems and methods are also provided.