Abstract:
An intelligent electronic device (IED) may be configured to detect arc flash events within a power system using stimulus measurements acquired by detection devices communicatively coupled to the power system. An arc flash event may be detected using a time-intensity comparison metric, such as an inverse time-over-stimulus metric, a cumulative stimulus metric, or the like. The stimulus may include electro-optical (EO) radiation produced in the vicinity of the power system, current measurements, or the like. The IED may detect an arc flash event if one or more of the stimulus types are indicative of an arc flash event. Responsive to detecting an arc flash event, the IED, or other protective element, may take one or more protective actions, such as issuing trip commands, or the like.
Abstract:
A wireless battery-powered daylight sensor for measuring a total light intensity in a space is operable to transmit wireless signals using a variable transmission rate that is dependent upon the total light intensity in the space. The sensor comprises a photosensitive circuit, a wireless transmitter for transmitting the wireless signals, a controller coupled to the photosensitive circuit and the wireless transmitter, and a battery for powering the photosensitive circuit, the wireless transmitter, and the controller. The photosensitive circuit is operable to generate a light intensity control signal in response to the total light intensity in the space. The controller transmits the wireless signals in response to the light intensity control signal using the variable transmission rate that is dependent upon the total light intensity in the space. The variable transmission rate may be dependent upon an amount of change of the total light intensity in the space. In addition, the variable transmission rate may be further dependent upon a rate of change of the total light intensity in the space.
Abstract:
A high efficiency, environmentally friendly system comprising a plurality of photovoltaic solar collecting panels (PV panels) is disclosed. The system comprises an outer frame to which a plurality of inner frames are mounted to which the plurality of PV panels are attached. To minimize shadowing by the outer frame upon one or more PV panels, at least one PV panel may extend beyond an endpoint of the main frame. The system also comprises an outer frame rotation actuator that rotates the outer frame and an inner frame rotation actuator that rotates the inner frames and the plurality of PV panels. The solar tracking array frames disclosed herein help to improve the quality of the environment by conserving a variety of energy resources (e.g., fossil fuels, hydroelectric energy, etc.) The solar tracking array frames disclosed herein also help to reduce greenhouse gas emissions, as solar tracking array frames do not produce carbon dioxide byproducts.
Abstract:
A lighting device includes a pyroelectric sensor, a shutter and a lighting control unit. The lighting control unit is configured, when the lighting load is turned off, to turn the lighting load on if the pyroelectric sensor detects a change in infrared radiation. The lighting control unit is also configured, when the lighting load is turned on, to turn the lighting load off if a repetition count or time of a lighting retention time reaches a specified count or time, respectively, with no change in infrared radiation detected through the pyroelectric sensor within each lighting retention time per the passage of lighting retention time.
Abstract:
Machines and methods measure an unknown characteristic of an optical signal incident upon a detector characterized by one or more dynamic response parameters. One method receives an output signal from the detector and compares that output signal and a computationally determined response of the detector to a known optical signal incident upon the detector. The response is based on said one or more dynamic parameters. The method determines the unknown characteristic based on the comparison of the output signal and the computationally determined response of the detector. Another method receives an output signal from an optical detector detecting one or more optical signals, accesses a predetermined characteristic curve of detector response, compares the output signal from the detector to the predetermined characteristic curve of detector response, and calculates at least one unknown characteristic of one or more optical signals based on results of the comparing step.
Abstract:
Various embodiments related to monitoring for optical faults in an optical system are disclosed. For example, one disclosed embodiment provides, in an optical system comprising a light source, a light outlet, and an optical element disposed between the light source and the light outlet, a method of monitoring for optical system faults. The method includes detecting, via a light sensor directed toward an interface surface of the optical element closest to the light source, an intensity of light traveling from the interface surface of the optical element to the light sensor, and comparing an intensity of light detected to one or more threshold intensity values. The method further includes identifying an optical system fault condition based on comparing the intensity of light detected to one or more threshold values, and modifying operation of the optical system.
Abstract:
A photometric model includes at least one Gaussian model of a measurable physical magnitude in an image supplied by the camera and it is defined by the mean and the variance of the physical magnitude. A device comprises: means for computing the mean based on the current value of the physical magnitude, these means including a first summer mounted in a closed loop; means for measuring the difference between the mean and the current value of the physical magnitude, these means including a second summer; means for reducing the difference, these means including an automatic regulator. The first summer, the second summer and the automatic regulator are assembled in a closed-loop control of the first summer so as to update the model slowly in a period of stability of the observed scene and rapidly in a period of transition of the observed scene. Application: video surveillance, background subtraction.
Abstract:
A light sensor and light sensing system to detect an intensity of incident light and an angle of incidence of the incident light. The light sensor includes a dielectric layer, a plurality of photo detectors coupled relative to the dielectric layer, and a plurality of stacks of opaque slats embedded within the dielectric layer. The dielectric layer is substantially transparent to the incident light. The photo detectors detect the incident light through the dielectric layer. The stacks of opaque slats are approximately parallel to an interface between the dielectric layer and the photo detectors. The stacks of opaque slats define light apertures between adjacent stacks of opaque slats. At least some of the stacks of opaque slats are arranged at a non-zero angle relative to other stacks of the opaque slats.
Abstract:
This invention is related to a light measuring apparatus and a method of using the device. It is used to measure various photometric quantities of the light emanating from a distant source of light.
Abstract:
The detection device comprises a photodetector provided with first and second terminals. A readout circuit has an input coupled to the first terminal of the photodetector. A bias circuit imposes a bias on the terminals of the photodetector. A test circuit delivers a test current to the photodetector. The test circuit comprises a first transistor through which the test current flows. The first transistor presents a first main electrode connected to the input of the readout circuit and configured so as to have a junction diode opposing flow of the charge carriers when the photodetector is short-circuited.