Abstract:
A disinfection system for liquids is provided that features an irradiation chamber for accommodating a liquid to be disinfected. A UV-radiator with a cladding that is transparent to UV-light is arranged in the irradiation chamber such that the UV-radiation emitted by the UV-radiator may penetrate the liquid. A first UV-sensor is arranged in the irradiation chamber such that a first attenuation characteristic with respect to the UV-light emitted by the UV-radiator may be measured with the first UV-sensor, wherein the first attenuation characteristic comprises a first aging characteristic and a first liquid attenuation characteristic. A second UV-sensor is arranged in the irradiation chamber such that a second attenuation characteristic with respect to the UV-light emitted by the UV-radiator may be measured with the second UV-sensor, wherein the second attenuation characteristic comprises a second aging characteristic and a second liquid attenuation characteristic and differs from the first attenuation characteristic.
Abstract:
Particular embodiments of the present disclosure relate systems and methods for evaluating visible light sources. According to one embodiment, a method of evaluating a visible light source including a semiconductor laser having a gain section, a wavelength selective section, and a phase section includes applying a gain drive signal to the gain section of the semiconductor laser at a gain modulation frequency, and applying a triangular wave drive signal to the wavelength selective section of the semiconductor laser at a wavelength selective modulation frequency that is greater than the gain modulation frequency. The light source emits a plurality of optical output pulses. Output power values of the optical output pulses at a selected wavelength are detected. The output power value of one or more selected output pulses is compared with an output power threshold value to generate an indication of whether the visible light source satisfies an output power specification.
Abstract:
An LED-based radiance source that is compact, temporally stable and uniform, and particularly useful in applications such as calibration and characterization of radiation thermometers, night vision devices, environmental remote sensing systems, biological agent detection, and any radiometer which needs a stable radiance source. The LED-based radiance source is a suitable replacement of lamp-based integrating sphere sources where they are used as stable and uniform radiance sources. The LED-based radiance source includes an array of LEDs having substantially similar radiance output wavelengths and a radiation detector such as a photodiode that detects and monitors radiation directed from the LEDs. Temperature of the LEDs can be controlled by feedback from the photodiode, thereby allowing for control and stabilization of temperature-dependent radiation output.
Abstract:
A method and apparatus are provided for testing a photodetector (20) that has a narrow field of view (A) and an alignment surface (50), to determine whether the field of view and the axis (52) of the field of view are precisely what is expected or deviates therefrom. While the photodetector views a region or zone (102), a narrow spot of light (82) is moved into and out of the zone and across the zone, while the output of the photodetector is monitored. The narrow spot of light is generated by focusing a small spot of light onto a surface. The small spot of light can be a spot of light on an oscilloscope monitor (80) which scans the spot back and forth in a raster pattern. To create a very small spot, the image on the oscilloscope monitor is focused to a greatly reduced size spot image (124) onto the surface that the photodetector views.
Abstract:
A device for controlling an amount of light of a lighting unit for use in an endoscope, used to view an image of an object. The device includes a light shield for shielding light generated by a light source and transmitted to the endoscope. A stepping motor drives the light shield for a series of predetermined time intervals. Brightness of the image is detected during each of the time intervals and pulses are generated during each of the time intervals. The number of pulses generated is determined in accordance with a difference between the brightness of the image detected during each of the time intervals and a desired brightness of the image. The pulses generated are used to drive the stepping motor in each of the plurality of time intervals.
Abstract:
A light source for examining leak detection sites in heating, ventilating, and air conditioning systems using a flourescent dye is described. The light source can include a parabolic reflector or a low voltage lamp.
Abstract:
An instrument and method for optically calibrating and balancing low level luminances of lighted instrument panel displays within the operator station of a vehicle is described which comprises a self-contained, calibrated luminance source and a beamsplitter for combining and juxtaposing an image of the calibrated luminance source with an image of the luminance from a lighted instrument panel display to be calibrated or balanced, whereby the images may be compared in luminance, the lighted instrument panel display being adjustable in intensity using the vehicle instrument panel light trim capability.
Abstract:
Apparatus and method for radiometrically calibrating an imaging sensor array using the sun as a calibration light source in an optical system of the type having an accessible real conjugate of the entrance pupil, includes a flux concentrator for concentrating the sunlight. A flux modulator modulates the intensity of the concentrated sunlight and a flux relay for relaying the intensity modulated sunlight to the real conjugate of the entrance pupil of the optical system. A flux diffuser located at the real conjugate of the entrance pupil of the optical system illuminates the imaging sensor array with diffuse intensity modulated sunlight for calibrating the imaging sensor. A radiometric calibration assembly is proposed to calibrate an imaging sensor array of an earth imaging system. The calibration assembly comprises a flux concentrator, a flux modulator, a flux relay lens and a flux diffuser located within a conjugate pupil of the earth imaging system. The flux concentrator transfers solar flux to the flux modulator, which modulates the flux to a number of controlled, deterministic levels. The flux relay lens transfers the modulated flux to the flux diffuser. The diffused flux illuminates the imaging sensor array, resulting in electrical signals that provide information to allow accurate calibration for use in imagery.
Abstract:
Multichannel infrared detector assemblies for use in the detection and monitoring of gas concentrations are provided. The detector assemblies include a detector housing having a port for receiving infrared radiation therethrough; a substrate mounted within the detector housing, the substrate having three apertures therein to transmit radiation entering the detector assembly therethrough; a first, a second and a third thermopile detector fabricated on the bottom side of the substrate, the hot junctions of each thermopile detector positioned over one of the apertures in the substrate so as to receive radiation transmitted through the aperture, and the cold junctions of each thermopile detector positioned over the substrate; a first interference bandpass filter mounted on the top side of the substrate so that the first filter covers the aperture above the first detector and the first filter is interposed between the port and the first detector, the first interference bandpass filter designed to pass incident radiation at a first spectral band; a second interference bandpass filter mounted on the top side of the substrate so that the second filter covers the aperture above the second detector and the second filter is interposed between the port and the second detector, the second interference bandpass filter designed to pass radiation at a second spectral band; and a third interference bandpass filter mounted on the top side of the substrate so that the third filter covers the aperture above the third detector and the third filter is interposed between the port and the third detector, the third interference bandpass filter designed to pass radiation at a third spectral band. The disclosed infrared detector assemblies can be used in traditional NDIR gas sensors having an active source or in passive infrared analysis gas sensors which use a passive infrared temperature source and the space between the detector assembly and the source as the sample chamber.
Abstract:
A high fidelity dual source solar simulator that provides a higher fidelity spectral match to the Air Mass Zero (AM0) solar spectrum and is derived from ultraviolet (UV) and visual light from a xenon arc lamp which is band pass filtered by a hot reflective mirror and slope filtered by a color glass filter, with the infrared (IR) light from a tungsten lamp which is band pass filtered by a cold reflective mirror and slope filtered by a thin film filter, so that, when the xenon and tungsten light components are combined as spectral segments, the spectra of the simulator matches both the curve shape and integral energy of the AM0 spectra while attenuating optical spikes so as to provide high fidelity over the entire AM0 spectrum.