Provided is a reliable or accurate optical detection method or such an optical imaging method. Also provided is an application technique using such a method. At least a part of an optical path starting from a light-emitting source or reaching a photodetector includes a plurality of optical paths. At a predetermined position of the optical path, beams of light after passing through the plurality of optical paths are mixed. This mixed light is used for optical detection or optical imaging. An optical-length difference among beams of light passing through the plurality of optical paths may be longer than the coherence length. Means for feed-backing predetermined characteristics of a target to the optical characteristics to be used for optical detection or optical imaging may be included. Such means may be used separately from the above. Such means may be applied to another technique, an application material or an application program.

Provided is a reliable or accurate optical detection method or such an optical imaging method. Also provided is an application technique using such a method. At least a part of an optical path starting from a light-emitting source or reaching a photodetector includes a plurality of optical paths. At a predetermined position of the optical path, beams of light after passing through the plurality of optical paths are mixed. This mixed light is used for optical detection or optical imaging. An optical-length difference among beams of light passing through the plurality of optical paths may be longer than the coherence length. Means for feed-backing predetermined characteristics of a target to the optical characteristics to be used for optical detection or optical imaging may be included. Such means may be used separately from the above. Such means may be applied to another technique, an application material or an application program.

A system and method for calibrating a melt pool monitoring system of an additive manufacturing machine includes installing a calibration system on the machine and performing a calibration process. Specifically, the calibration system includes a calibration platform removably mountable to a build platform of the additive manufacturing machine and having calibrated electromagnetic energy sources mounted thereon for defining a measurement standard. The electromagnetic energy generated is measured by the melt pool monitoring system and compared to the known measurement standard to determine whether system adjustments would improve process tolerances or uniformity.

Multi-spectrum imaging systems and methods are provided for imaging in multiple spectrums, e.g., thermal IR (infrared) at wavelengths of 4 microns and 11 microns, near-IR, and visible light, all on a same optical centerline. For example, an imaging system includes a first imager and a second imager. The first imager includes an array of thermal IR detectors, wherein the first imager is configured to receive incident photonic radiation and generate a thermal IR image, wherein each thermal IR detector comprises a photon absorber member that is configured to absorb thermal IR photonic radiation from the incident photonic radiation, and reflect remaining photonic radiation in the incident photonic radiation along an optical path of the imaging system. The second imager is disposed in said optical path of the imaging system, wherein the second imager is configured to receive the remaining photonic radiation reflected from the first imager and generate a second image.

There is provided a method of tuning a resonant cavity and a cavity ring-down spectroscopy system using the same. A first mirror is actuated at a first end of a resonant cavity to move in a direction between a first position relative to a second mirror at a second end of the resonant cavity, at which a cavity length between the first mirror and the second mirror is less than a resonance length for a laser beam, and a second position relative to the second mirror, at which the cavity length is greater than the resonance length. An event is triggered when the cavity length is proximal to the resonance length. The first mirror is continuously actuated in the direction between the first position and the second position during the event.

A method for retrieving a corrected spectrum from a measured spectrum (e.g., retrieving a top-of-water spectrum from a measured top-of-atmosphere spectrum) includes creating a scene-specific model of a region of interest and performing a ray-tracing simulation to simulate rays of light that would reach an airborne (or spaceborne) sensor. The region of interest can be an optically complex area such as an inland or coastal body of water. Based on the ray-tracing simulation, a scene-specific correction for unwanted effects (e.g., adjacency effects, variable atmospheric conditions, and/or other suitable effects) is obtained. A corrected spectrum is obtained by correcting the measured spectrum using the scene-specific correction. The ray-tracing simulation may be performed using a graphical processing unit, allowing the scene-specific correction to be performed in real time or near real time.

Present invention provides a spectrometer including a first unit spectral filter configured to absorb or reflect light in a part of a wavelength band of a light spectrum of an incident target, a second unit spectral filter configured to absorb or reflect light in a wavelength band different from the part of the wavelength band, a first light detector configured to detect a first light spectrum passing through the first unit spectral filter, a second light detector configured to detect a second light spectrum passing through the second unit spectral filter, and a processing unit configured to perform a function of restoring a light spectrum of the target incident from spectra of light detected from the first light detector and the second light detector.

A monitoring system for a power grid includes one or more power transformer monitors. Each power transformer monitor includes a plurality of optical sensors disposed on one or more optical fibers that sense parameters of the power transformer. Each optical sensor is configured to sense a power transformer parameter that is different from a power transformer parameter sensed by at least one other sensor of the plurality of optical sensors. An optical coupler spatially disperses optical signals from the optical sensors according to wavelength. A detector unit converts optical signals of the optical sensors to electrical signals representative of the sensed power transformer parameters.

A monitoring system for a power grid includes one or more power transformer monitors. Each power transformer monitor includes a plurality of optical sensors disposed on one or more optical fibers that sense parameters of the power transformer. Each optical sensor is configured to sense a power transformer parameter that is different from a power transformer parameter sensed by at least one other sensor of the plurality of optical sensors. An optical coupler spatially disperses optical signals from the optical sensors according to wavelength. A detector unit converts optical signals of the optical sensors to electrical signals representative of the sensed power transformer parameters.

Systems and methods for color selection are provided. A web server stores a lookup table that associates room types and types of feelings with paint colors such that each possible combination of room type and type of feeling is associated with a subset of paint colors. A user device displays the room types, receives a room type selection indicating a particular room type, displays the types of feelings, receives a type of feeling selection indicating a particular type of feeling, accesses the lookup table and determines the associated subset of paint colors in the lookup table for the combination of the particular room type and the particular type of feeling, and displays the associated subset of paint colors as recommended paint colors for the combination of the particular room type and the particular type of feeling on the display of the user device.