A camera system includes one or more spectral illuminators, a tunable optical filter, and a sensor array. Active spectral light emitted from the one or more spectral illuminators towards a scene is dynamically tuned to an illumination sub-band selected from a plurality of different illumination sub-bands. Sequentially for each of a plurality of fluorescing light sub-bands different than the selected illumination sub-band, the tunable optical filter is adjusted to block light from being transmitted from the scene to the sensor array in all but a tested fluorescing light sub-band from the plurality of different fluorescing light sub-bands, and the sensor array is addressed to acquire one or more image of the scene in the tested fluorescing light sub-band.

Systems and methods for verifying that light absorption is caused by a targeted gaseous chemical compound. A first transmittance of light, either generated at, or filtered to, a first wavelength range and a second transmittance of light, either generated at, or filtered to, a second wavelength range are measured by first and second photon detectors. A ratio of the first and second measured transmittance is determined and that ratio is compared to a transmittance ratio associated with a targeted gaseous chemical compound to verify that the light absorption is caused by the targeted gaseous chemical compound.

Disclosed is an illumination source apparatus comprising a high harmonic generation medium, a pump radiation source and a spatial filter. The pump radiation source emits a beam of pump radiation having a profile comprising no pump radiation in a central region of the beam and excites the high harmonic generation medium so as to generate high harmonic radiation. The pump radiation and the generated high harmonic radiation are spatially separated beyond the focal plane of the beam of pump radiation. The spatial filter is located beyond a focal plane of the beam of pump radiation, and blocks the pump radiation. Also disclosed is a method of generating high harmonic measurement radiation optimized for filtration of pump radiation therefrom.

An imaging device includes a camera, light sources, an optical bandpass filter, and a conversion unit. The camera includes an image sensor including a N-band color filter (where N is a natural number greater than or equal to 3). The M types of light sources (where M is a natural number that satisfies 2MN) have the emission spectral characteristics of having respective peaks in mutually different wavelength ranges within a visible light range and a near-infrared range. The conversion unit generates image signals of M bands each having spectral sensitivity to the corresponding one of the mutually different wavelength ranges by performing a matrix operation on an N-band imaging signal obtained by the image sensor when an article is photographed with the camera. The light application direction and the emission intensity are individually selected for each of the light sources.

This disclosure provides a highly accurate NDIR gas sensor and a highly accurate optical device even using a simplified optical filter. The NDIR gas sensor and the optical device include: an optical filter having a substrate and a multilayer film on the substrate; and an infrared light emitting and receiving device; where the multilayer film has a structure in which a first layer and a second layer are alternately stacked; the active layer contains Al.sub.xIn.sub.1-xSb or InAs.sub.ySb.sub.1-y; and the optical filter includes a wavelength range having an average transmittance of 70% or more with a width of 50 nm or more in 2400-6000 nm, and has a maximum transmittance of 5% or more in 6000-8000 nm and an average transmittance of 2% or more and 60% or less in 6000-8000 nm.

This invention relates to a method of and system for facilitating detection of a particular predetermined gas in a scene under observation. The gas in the scene is typically associated with a gas leak in equipment. To this end, the system comprises an infrared camera arrangement; a strobing illuminator device having a strobing frequency matched to a frame rate of the camera; and a processing arrangement. The processing arrangement is configured to store a prior frame obtained via the infrared camera arrangement; and compare a current frame with the stored prior frame and generate an output signal in response to said comparison. The system also comprises a display device configured to display an output image based at least on the output signal generated by the processing arrangement so as to facilitate detection of the particular predetermined gas, in use.

An optical device comprises an optical filter having a substrate and a multilayer film having layers with different refractive indexes formed on at least one side of the substrate; and an infrared light emitting and receiving device having a first conductive-type semiconductor layer, an active layer, and a second conductive-type semiconductor layer. The multilayer film has alternatively stacked first second layers each having refractive indexes of 1.2 or more and 2.5 or less, and 3.2 or more and 4.2 or less, respectively, in a wavelength range of 2400 nm to 6000 nm. The optical filter includes a wavelength range having an average transmittance of 70% or more with a width of 50 nm or more in a wavelength range of 2400 nm to 6000 nm, and has a maximum transmittance of 5% or more in a wavelength range of 6000 nm to 8000 nm.

A device (1) for determining the concentration of a gas component is configured with a radiation source (30) for emitting (31) a light radiation or heat radiation in an infrared wavelength range. A detector array (40) has at least two detector elements (50, 60), configured to detect the radiation generated by the radiation source (30), in an angular arrangement (52, 62) and with filter elements (51, 61). At least one of the two detector elements (50, 60) is oriented in an angular arrangement (52, 62) in relation to a vertical axis (32), so that a range of overlap (65) is obtained due to the angular arrangements (52, 62). The range of overlap (65) causes attenuations in the propagation of light, which attenuations may be due, for example, to gas molecules or moisture (400), affect both detector elements (50, 60) and are thus compensated concerning the concentration determination.

A device and system for optically analyzing food products is provided. The device comprises first and second imaging devices respectively sensitive to first and second wavelengths; the imaging devices include a line-scan camera to acquire images of food products at a line in a food-path-facing direction, and a line-scan spectrometer to acquire spectroscopic images at the line. The device includes an optical filter configured to: convey the first wavelengths from the line to the first imaging device; and convey the second wavelengths from the line to the second imaging device. The device includes a frame to align the optical filter and respective optical axes of the first and second imaging devices, relative to each other and the food-path-facing direction, such that the first imaging device and the second imaging device are optically aligned via the optical filter to image the line.

An optical device includes an optical filter having a substrate and a multilayer film having a plurality of layers with different refractive indexes formed on at least one side of the substrate, and an infrared light emitting and receiving device. The optical filter includes a wavelength range having an average transmittance of 70% or more with a width of 50 nm or more in a wavelength range of 2400 nm to 6000 nm, and has a maximum transmittance of 5% or more in a wavelength range of 6000 nm or more of the mid-infrared range.