Abstract: A gas detector for revealing a target gas includes an image capturing unit with multiple optical channels, an image processing unit and a calculation unit. The image processing unit is adapted for deducing a value of a radiation transmission coefficient which relates to an analysis spectral band, and which is attributable to a quantity of the target gas present in a part of the field-of-view. Preferably multiple analysis bands are used in parallel. The calculation unit is adapted for deducing an evaluation of the quantity of the target gas based on the value of the radiation transmission coefficient which relates to each analysis band. Such a gas detector may have small dimensions, be easily transportable, including on board a drone, and can provide evaluation results for the quantity of the target gas in real-time or nearly real-time.

Abstract: An imaging optical system including three mirrors has a configuration adapted to block stray rays which could otherwise reach an image sensor of the system, while permitting large fields, high apertures, and good system compactness. The system may also incorporate two entrance baffles which are arranged one on either side of an optical entrance of the system. Functions of the two entrance baffles may be limited to intercepting rays originating from fields which are angularly distant from the entrance field useful to each captured image. The two entrance baffles can thus have reduced lengths upstream, so that the system has a small size.

Abstract: Disclosed is an instrument including a multipath, monolithic optical component, made up of a portion of a transparent material between two opposite faces of the component. One of the two faces of the component is formed by a first refracting surface, and the other face includes several second refracting surfaces which are juxtaposed. Each optical path of the component is formed by one of the second refracting surfaces in combination with a corresponding portion of the first refracting surface. One such component is suited for being part, within the instrument, of a detection module with multiple optical paths arranged in parallel, with a matrix photodetector shared by the optical paths. Such a detection module may be compact enough in order to be integrated into a cryostat cold screen, improving cooling thereof, and may be combined with an objective in order to form an instrument with multiple optical paths.

Abstract: A gas detector for revealing a target gas includes an image capturing unit with multiple optical channels, an image processing unit and a calculation unit. The image processing unit is adapted for deducing a value of a radiation transmission coefficient which relates to an analysis spectral band, and which is attributable to a quantity of the target gas present in a part of the field-of-view. Preferably multiple analysis bands are used in parallel. The calculation unit is adapted for deducing an evaluation of the quantity of the target gas based on the value of the radiation transmission coefficient which relates to each analysis band. Such a gas detector may have small dimensions, be easily transportable, including on board a drone, and can provide evaluation results for the quantity of the target gas in real-time or nearly real-time.

Abstract: Disclosed is an instrument including a multipath, monolithic optical component, made up of a portion of a transparent material between two opposite faces of the component. One of the two faces of the component is formed by a first refracting surface, and the other face includes several second refracting surfaces which are juxtaposed. Each optical path of the component is formed by one of the second refracting surfaces in combination with a corresponding portion of the first refracting surface. One such component is suited for being part, within the instrument, of a detection module with multiple optical paths arranged in parallel, with a matrix photodetector shared by the optical paths. Such a detection module may be compact enough in order to be integrated into a cryostat cold screen, improving cooling thereof, and may be combined with an objective in order to form an instrument with multiple optical paths.

Abstract: A computer-implemented method for designing an electro-optical imaging system for estimating the distance of a source includes use of an optical subsystem, a detector subsystem and a digital image processing subsystem. The method includes the modelling of the propagation of radiation from its source through the optical subsystem, the detector subsystem and the digital image processing subsystem; the modelling being based on a spatial model of the source; the method including a joint step of simultaneously designing the optical subsystem and the digital image processing subsystem, the designing step being based at least on one performance metric depending on a comparison between the local estimation of the distance from the source and the actual distance from the source.

Abstract: An optical filtering device, in particular for remote gas detection, including a member comprising a tubular passage accommodating a plurality of reflective structures capable of reflecting infrared wavelengths, said structures being elongated along an axis of the tubular passage and arranged around the axis. The reflective structures comprise means of filtering by absorption of bands of different wavelengths located in the infrared spectral band.

Abstract: Some embodiments are directed to a wide-field imaging system for the infrared spectral range. The system can include a vacuum chamber that is optically open for the passage of the field rays originating from the scene to be imaged, a cooled dark chamber placed inside the vacuum chamber and provided with a cold diaphragm, an infrared detector placed inside the cooled dark chamber, and a device for optically conjugating the field rays with the detector.

Abstract: Some embodiments are directed to a wide-field imaging system for the infrared spectral range. The system can include a vacuum chamber that is optically open for the passage of the field rays originating from the scene to be imaged, a cooled dark chamber placed inside the vacuum chamber and provided with a cold diaphragm, an infrared detector placed inside the cooled dark chamber, and a device for optically conjugating the field rays with the detector.

Abstract: An optical filtering device, in particular for remote gas detection, including a member comprising a tubular passage accommodating a plurality of reflective structures capable of reflecting infrared wavelengths, said structures being elongated along an axis of the tubular passage and arranged around the axis. The reflective structures comprise means of filtering by absorption of bands of different wavelengths located in the infrared spectral band.

Abstract: A method for range imaging allows determining respective distances to multiple objects, based on a single image. The image is captured through a component having a transmittance function of which the Fourier transform is inscribed on a circle within a plane of spatial frequencies. A Fourier transform of the captured image is calculated in order to obtain a total spectrum for the image content. The distance to each object is then calculated based on several homothetic superimpositions of a reference spectrum with the total spectrum, so that said reference spectrum coincides with a portion of the total spectrum each time.

Abstract: The imaging system for imaging field rays comprises a detection surface, a device for focusing the field rays with said detection surface, and a diaphragm. Said device comprises a Fresnel lens comprising a first dioptre, the non-plane surface of which, called the active zone, makes it possible to focus the field rays towards said detection surface, and said diaphragm allows controlled distribution of the field rays over said active zone.

Abstract: A computer-implemented method for designing an electro-optical imaging system for estimating the distance of a source includes use of an optical subsystem, a detector subsystem and a digital image processing subsystem. The method includes the modelling of the propagation of radiation from its source through the optical subsystem, the detector subsystem and the digital image processing subsystem; the modelling being based on a spatial model of the source; the method including a joint step of simultaneously designing the optical subsystem and the digital image processing subsystem, the designing step being based at least on one performance metric depending on a comparison between the local estimation of the distance from the source and the actual distance from the source.

Abstract: Infrared imagery device with integrated shield against parasite infrared radiation, and method of manufacturing the device. This device comprises a support provided with an infrared radiation detector, at least one optical device facing the detector, and a shield against parasite radiation. The shield comprises at least two continuous beads, spaced from each other, extending from the support as far as the optical device, provided with vents and made of a material that significantly attenuates parasite radiation, penetrating laterally between the support and the optical device. The two beads with their vents 15 form a baffle. The device is manufactured using the flip chip technique.

Abstract: The imaging system for imaging field rays comprises a detection surface, a device for focusing the field rays with said detection surface, and a diaphragm. Said device comprises a Fresnel lens comprising a first dioptre, the non-plane surface of which, called the active zone, makes it possible to focus the field rays towards said detection surface, and said diaphragm allows controlled distribution of the field rays over said active zone.

Abstract: A method for range imaging allows determining respective distances to multiple objects, based on a single image. The image is captured through a component having a transmittance function of which the Fourier transform is inscribed on a circle within a plane of spatial frequencies. A Fourier transform of the captured image is calculated in order to obtain a total spectrum for the image content. The distance to each object is then calculated based on several homothetic superimpositions of a reference spectrum with the total spectrum, so that said reference spectrum coincides with a portion of the total spectrum each time.

Abstract: Infrared imagery device with integrated shield against parasite infrared radiation, and method of manufacturing the device. This device comprises a support (62) provided with an infrared radiation detector (40), at least one optical device (28) facing the detector, and a shield against parasite radiation. The shield comprises at least two continuous beads (c1, c2), spaced from each other, extending from the support as far as the optical device, provided with vents and made of a material that significantly attenuates parasite radiation, penetrating laterally between the support and the optical device. The two beads with their vents form a baffle. The device is manufactured using the flip chip technique.

Abstract: The present disclosure relates to a compact wide field imaging system for the infrared spectrum range, the system including a vacuum housing with a porthole, a cooled dark room arranged inside the vacuum housing and provided with an opening referred to as a cold diaphragm, an infrared detector arranged inside the cooled dark room, and a device for the optical conjugation of the field rays with the detector. In the system, the optical conjugation device does not include any element located outside the vacuum housing, and includes at least one cold lens located inside the cooled dark room, the pupil of the optical conjugation device coinciding with the cold diaphragm.