Abstract: An improved fire detector unit has a plastic base defining a smoke chamber for detection of a smoke density in terms of light scattering due to the smoke particles in the smoke chamber. The base carries a circuit board mounting a light emitting element, a light receiving element, and other components forming a fire detecting circuit responsible for generating a fire warning signal based upon the detected smoke density. A metal-made electromagnetic shield is molded into the base to protect the light receiving element from electromagnetic radiation noises. The electromagnetic shield includes a ground terminal for connection with a ground line of the circuit board. In addition, terminal pins are molded into the base for electrical and physical connection of the circuit board to the base.

Abstract: An identification system for use in controlling the operation of a device comprises comparing fingerprint data with stored data to identify both an individual and which of the individual's fingerprints has been input, and using the identity of the individual and the finger in controlling the operation of the device.

Abstract: This device comprises at least one sensor of a CCD camera of very short spectral band lying between 0.4 &mgr;m and 1.1 &mgr;m, fitted with an infrared filter eliminating the spectral band lying between around 0.4 &mgr;m and 0.8 &mgr;m, this sensor being associated with a computer catering in particular for image processing, at least one display screen and a control board. It is thus possible, with the aid of a single type of sensor, to detect hot spots, flames, smoke and the shifting of objects, and to provide a visualization of the inside of the enclosure.

Abstract: A fire detection device that is inexpensive, capable of monitoring a wide range of area, and efficiently detecting a fire with high accuracy without necessitating a complicated image processing. Luminance data extraction means extracts luminance data from an input image. Resampling means carries out resampling of the luminance data over a time period longer than a repetition period of swaying of a flame, to generate resampled data. Fire detection means calculates an average value of N (natural number equal to or larger than 2) items of the resampled data, and determines that the input image is an image of a flame, by comparison between a count of sampled data items larger than the average value or a count of sampled data items smaller than the average value and a predetermined value.

Abstract: An imminent icing condition detector employs an infrared sensor with a focusing element to receive ambient infrared energy from a surface, particularly a road surface, and the output of the sensor is processed to provide an indication of the likelihood of icing conditions and to accordingly control a traction control substance deployment system, such as a truck that dispenses a de-icing, anti-icing, or traction substance, such as sand, salt, or other material or mixture of materials in solid granular, liquid, or mixed form.

Abstract: A road surface friction detector for use in a vehicle. The detector provides information regarding the integrity of a road surface to an operator of the vehicle. The detector is made up of three main parts, a sensor unit, a display unit and a microprocessor unit. The sensor unit is made up of a first sensor unit and a second sensor unit. The first sensor unit contains a first light source which directs light at the road surface to be reflected back to a first light receiver. The amount of light that returns to the first light receiver corresponds to various conditions on the road. The second sensor unit is made up of a second light source, second light receiver and a reflective element. The second light source directs light at the reflective element which is located between the second light source and the road. The light from the second light source is then reflected off of the reflective element to the second light receiver.

Abstract: An automatic, dynamic window anti freezing system for the windshield and the rear window of a motor vehicles parked in cold weather, connected to a battery, comprises a temperature range control-switch unit, an optic frost-monitor, and a sweeping time (frequency)- control to drive a wiper system to work for preventing frost accumulating on the window glass. The temperature unit sets up a certain working range to turn on the system, covering the real freezing stage of the windows. The sweeping time control sets up predetermined sweeping timely manner for the wipers to sweep. The monitor emits light signals to monitor the frost accumulating on the window glass, and actuates the sweeping control to drive wipers to sweep it off when detecting it. The energy consumption is generally exceptional low due to that working is effectively controlled and easily done. Thus a related window is substantially able to avoid freezing on.

Abstract: An optical device on board an aircraft for detecting icing conditions including an optical beam emitter to create at least one illuminated external volume of measurement through which there circulates a flow of air charged with water particles; a collector optical system for the collection of at least a part of the light beam back-scattered by the water particles (the external volume of measurement being located on the optical axis of said collector optical system); a photodetector for detecting back-scattered optical beams; a signal processor for processing the signal delivered by the photodetector to compute the severity of the icing conditions; an information provider for providing information on the calculated severity of the icing conditions. Advantageously, the optical means for the differentiation of device includes a differentiation for differentiating between liquid water particles and solid water particles, based on analysis of the polarization.

Abstract: A presence of a polarization altering substance on a specular surface is detected by transmitting light from a single strobed light source to the surface over a transmitting path and receiving the transmitted light from the surface. An intensity of the light is measured in both an optical non-isolator state and an isolator state by a same detector by delaying the non-isolated return light for a definite period of time before measuring it with the detector. The measured isolated and non-isolated intensities are converted to logarithmic form, range corrected, and compared to reference data established for the specific specular surface being investigated to detect the presence or absence of the polarization altering substance. Attenuation and backscattering effects of scattering and/or absorbing interference in the transmitted light are compensated so that the reference table is entered at the correct point. Using different intensities of transmitted light increases the dynamic range of the system.

Abstract: The intelligent alarm system of the present invention provides a reliable, low cost system for alerting a user to the presence of snow outside of a building. The system includes a sensor and an intelligent alarm clock for use inside a building or dwelling. The system can be set by a user to signal an alarm a programmable amount of time earlier or later than the user's normal waking time if an accumulation of snow is detected. The system is capable of processing preprogrammed data, user entered data and data accumulated from the sensor to determine whether a true snow condition exists and to generate an appropriate alarm signal.

Abstract: A modulated light source (31) transmits light pulses through an optical channel (20) to an optical sensor (10) remotely located from the cockpit and mounted proximate an aerodynamic surface (14) of an aircraft. In the absence of ice a baseline amount of light is returned inward via the optical channel. When water, ice, or de-icing fluid covers the light sensor, a detectable variable amount of light pulses are returned by the sensor inward through the optical channel, and are detected by a light detector (34) which generates an electrical output signal that varies as a function of the type, amount, and rate of substance accretion. The output signal is visually displayed (37) and the pilot may also be audibly warned.

Abstract: In a process and apparatus for determining the condition of a road surface, light backscattered from a road surface is divided into spectral components and the spectral intensity distribution of the backscattered light is analyzed. The wavelength-dependent backscattered light spectrum of a dry road surface is arranged with a mathematical function with free parameters. This function is multiplied by an exponential absorption term which describes the light transmission of a water layer of a defined thickness in order to obtain a mathematical function for the wavelength-dependent distribution of the backscatter intensity (as it impinges on the receiver). Using the actual measured values, the free parameters of the function can then be calculated to obtain a best possible approximation. This among other things, results in a determination of the thickness of the water layer.

Abstract: The present invention provides a method and apparatus for in situ measuring thicknesses of ice buildup on airfoil. The method and device uses a probe including a radioactive .sup.241 Am gamma ray source producing 60 keV gamma ray photons which penetrate through the airfoil substrate and a photodetector mounted behind the source for detection of backscattered gamma rays. The probe is mounted on the interior of the airfoil and secondary radiation is backscattered within the ice layer and back through the airfoil substrate to the photodetector. The shape and density of the source holder in addition to the geometrical arrangement of the source and detector with respect to the airfoil substrate are used to block a substantial fraction of gamma rays backscattered in the airfoil substrate thereby favoring scattering in the ice layer over that in the airfoil material.

Abstract: According to the invention, there is provided an icing detector for detecting presence of both rime ice and clear ice in air comprising an ice collecting surface facing an oncoming air stream; light emitting apparatus for emitting a light beam crossing the ice collecting surface, having a prismatic light refracting window for refracting the light beam in a first direction, when no ice is present on the ice collecting surface; light sensing apparatus in a path of the second direction, and annunciating apparatus coupled to the light sensing apparatus for annunciating presence of ice when light is sensed by the light sensing apparatus.

Abstract: A device for improving vehicle driving safety and comfort is disclosed. The main road sign information encountered during a journey is transmitted to the vehicle, the position of the vehicle on the driving surface is continuously monitored, and the road surface is checked for the presence of foreign matter such as mud, snow, ice, etc. A set of transmitting-receiving sensors (C1, C2) suitably arranged on the vehicle and facing the driving surface continuously observes changes in the reflective properties of the observed areas within the sensitivity range thereof. Markings defining lanes and shoulders lined with grassy, gravelly or sandy areas are sensed by the sensors (C1, C2) as soon as the vehicle approaches or drives over them. The signals from the sensors (C1, C2) are processed by an electronic unit (1) controlling an on-board signalling system (2) linked to an alarm system (3) for warning the driver of road hazards and possible unsafe driving (straying off-course, speeding, etc.).

Abstract: In a method of detecting ice on surfaces of an aircraft, a surface of an aircraft is scanned with laser light operating at different wavelength regions in a manner whereby the surface scatters the laser light. Laser light scattered from the surface is detected. Radiation outside the wavelength bands of interest is removed prior to detection. The detected, filtered, scattered laser light is processed to reconstruct images of the surface, thereby indicating areas of ice and water on the surface. The processing takes into account the directions of scanned continuous wattage laser beams relative to the surface, laser beam geometry factors due to changing distance between the laser beams and the surface while scanning, relative signal levels, normalizations and returns from other detectors. The material of the windows of the aircraft blocks the laser beam and any stray laser light. Also, the windows of the aircraft could be treated to block the laser beam and the laser light.

Abstract: An audio label comprising a circuit board substrate with a sound-generating microchip and a photovoltaic cell both attached to the substrate such that the microchip is electrically connected to the photovoltaic cell so that power is provided to the sound-generating microchip. A sound reproduction unit is also attached to the substrate and is connected to the sound-generating microchip communicates signals to the sound reproduction unit which are then converted by the sound reproduction unit to audible sounds. A system for audio label operation is also disclosed. The system includes a separate transmitter which transmits electromagnetic waves, such as light, infrared or radio waves to one or more audio labels which have electromagnetic wave receiving circuit elements, such as phototransistors disposed thereon. The transmitter thus sends wave signals to each label each of which then converts the wave signals to electric signals which each sound reproduction unit then converts to audible sounds.

Abstract: A method and apparatus for preventing and/or minimizing the formation of ice dams and icicles on a roof of a building having an unheated attic under said roof, which involves the steps of: (1) determining if there is an accumulation of snow on the roof, (2) determining ambient outdoor air temperature, (3) determining the temperature of air in the attic and (4) if there is an accumulation of snow on the roof and if the ambient outdoor air temperature is at or below freezing and if the attic air temperature is sufficient to cause melting of the snow on the roof, exhausting air from the attic.

Abstract: An apparatus for detecting a polarization altering substance, such as ice, on a surface includes a polarizing filter on the surface between the surface and the polarization altering substance. When the polarizing filter includes alternating regions having orthogonal polarizing properties, only one viewing of the surface through a blocking filter is required. When light, either polarized or unpolarized, reflects off the surface, it passes through the polarizing filter and becomes polarized. Reflected light that additionally passes through ice after leaving the polarizer becomes unpolarized. When viewed through a blocking polarizer filter, polarized light passing through ice appears bright due to the unpolarizing effect of ice. On the other hand, polarized light not passing through ice retains its polarization and appears dark when viewed through a blocking filter.

Abstract: An apparatus for detecting a polarization altering substance, such as ice, on a surface includes a polarizing filter on the surface between the surface and the polarization altering substance. When the polarizing filter includes alternating regions having orthogonal polarizing properties, only one viewing of the surface through a blocking filter is required. When light, either polarized or unpolarized, reflects off the surface, it passes through the polarizing filter and becomes polarized. Reflected light that additionally passes through ice after leaving the polarizer becomes unpolarized. When viewed through a blocking polarizer filter, polarized light passing through ice appears bright due to the unpolarizing effect of ice. On the other hand, polarized light not passing through ice retains its polarization and appears dark when viewed through a blocking filter.

Abstract: A presence of a polarization altering substance on a specular surface is detected by transmitting light from a single strobed light source to the surface over a transmitting path and receiving the transmitted light from the surface. An intensity of the light is measured in both an optical non-isolator state and an isolator state by a same detector by delaying the non-isolated return light for a definite period of time before measuring it with the detector. The measured isolated and non-isolated intensities are converted to logarithmic form, range corrected, and compared to reference data established for the specific specular surface being investigated to detect the presence or absence of the polarization altering substance. Attenuation and backscattering effects of scattering and/or absorbing interference in the transmitted light are compensated so that the reference table is entered at the correct point. Using different intensities of transmitted light increases the dynamic range of the system.

Abstract: The present invention provides a method and apparatus for in situ measuring thicknesses of ice buildup on airfoil. The method and device uses a probe including a high energy radioactive gamma ray source .sup.241 Am producing 60 keV photons which penetrate through the airfoil substrate and a photodetector mounted behind the source for detection of backscattered photons. The probe is mounted on the interior of the airfoil and secondary radiation is backscattered within the ice layer and back through the airfoil substrate to the photodetector. The shape and density of the source holder in addition to the geometrical arrangement of the source and detector with respect to the airfoil substrate are used to block photons backscattered in the airfoil substrate thereby favoring scattering in the ice layer over that in the aluminum.

Abstract: An apparatus for detecting the presence of ice or smooth packed snow on a road surface has a source of electromagnetic radiation, for example, a light emitting diode. This is mounted to illuminate an area of the road surface. It is driven by a modulating circuit at a known frequency. A detector is mounted adjacent the light source to receive radiation reflected back from the road surface, to generate a detector signal. This signal is demodulated by a demodulator to generate an intermediate signal. This is preferably compared with a fixed value, to determine whether the reflectivity of the road surface exceeds a set value, indicative of the presence of ice.

Abstract: The present invention relates to a method and apparatus for measuring road surface conditions. In the method of measuring road surface conditions, the conditions prevailing on the surface of a road are measured by a sensor head mounted in the pavement of the road with the top surface of the sensor head aligned substantially flush with the pavement of the road. According to the invention, an optical signal is impinged from below the road to the top surface of the road, the reflection/backscatter of the optical signal is measured inside the pavement layer of the road, and weather/driving conditions prevailing on the road top surface are determined from the reflected and backscattered signal values.

Abstract: An imminent icing condition enunciator employs an infrared sensor with a focusing element to receive ambient infrared energy from a surface, particularly a road surface, and the output of the sensor is processed to provide an indication of imminent icing to the operator of, for example, an automobile or other vehicle. The device is suitably mounted to a vehicle, within a mirror enclosure so as to provide an unobstructed view of the roadway surface.

Abstract: A modulated light source (31) transmits light pulses via a prism (27) through a monofilament optical fiber light channel (20) to an optical sensor (10) remotely located and flush mounted to an aerodynamic surface (14) of the aircraft most likely to accrete ice. In the absence of ice little to no light is reflected inward via the light channel. When water, ice, or de-icing fluid covers the light sensor, an increased amount of light pulses are reflected inward through the single fiber optic light channel and prism assembly where they are detected by a light detector (34) which generates an electrical output signal indicative of the type, amount, and rate of ice accretion. The output signal is visually displayed (37) and the pilot may be audibly warned.

Abstract: The thickness of a semi transparent layer, such as ice, is determined by supporting the layer atop or above a light transmissive window and directing multiple light beams through the light transmissive window and into the layer. The light transmissive window has a higher index of refraction than the layer or any intermediate layer directly above the semi-transparent layer. Light beams are directed at an angle to the surface that results in total internal reflection from the outer surface of the supported semi-transparent layer. The light reflected to the rear of the window at the same but opposite angle is monitored and correlates to the thickness of the monitored layer. The spatial distribution of reflected light along the longitudinal axis of the window changes in dependence upon the thickness of the supported layer. Quantitative indications of that thickness are displayed and should that thickness exceed a prescribed level an alarm may be generated.

Abstract: An improved visibility detector and method emit infrared radiation away from an infrared emitter; detect an amount of infrared radiation backscattered by an airborne visibility impeding agent; and generate a backscatter signal in response to the amount detected. In one embodiment, the detector detects an amount of the infrared radiation that is not backscattered; generates a reference signal in response thereto; determines an actual amount of the infrared radiation backscattered; determines whether the actual amount exceeds a prescribed threshold; and generates an alarm signal in event the actual amount is determined to exceed the prescribed threshold.

Abstract: An apparatus and method are provided for remotely detecting ice on a polarization preserving surface. A target location on the surface is irradiated with two cross-polarized beams of coherent light. A determination is then made as to whether the speckle patterns from each of the two beams interfere with one another. If interference of the speckle patterns from the two beams is detected, ice or some other birefringent material is said to be present on the surface.

Abstract: A method and apparatus for detecting a presence of a polarization altering substance on a specular surface includes transmitting light to the surface over a transmitting path and receiving the transmitted light from the surface and from the polarization altering substance. An intensity of the light is measured in an optical non-isolator state and in an isolator state. The isolator and non-isolator state measurements are performed either sequentially or simultaneously. A difference in intensity between isolator and non-isolator states indicates an absence of the substance. A sameness in intensity between isolator and non-isolator states indicates a presence of the substance.

Abstract: Ice in particular and also other substances such as water and glycol-containing anti-icing fluids can be detected and distinguished by means of differences in their optical index of refraction. A plurality of beams at different angles of incidence are multiplexed onto the reverse side of an optical surface which is embedded in a surface to be monitored or otherwise positioned in a sampling environment. The reflected beams at the different angles are measured and refractive indexes calulated form the measured reflected beams. If the calculated refractive indexes are the same at all angles, then the substance is positively identified. If the values do not agree, then there is partial coverage, and the substance may be identified by comparison with predetermined values. The system is applicable to aircraft, where in-flight and pre-flight monitoring of icing conditions and surface contamination is needed.

Abstract: A method and apparatus for detecting a presence of a polarization altering substance on a specular surface includes transmitting light to the surface over a transmitting path and receiving the transmitted light from the surface and from the polarization altering substance. An intensity of the light is measured in an optical non-isolator state and in an isolator state before being compared to reference data established for various specular surfaces. The reference data are preferably established by measuring an intensity of the light in both an optical non-isolator state and in an isolator state for a known surface when the polarization altering substance is absent from the known surface.

Abstract: An ice monitoring and detection system for determining the presence and thickness of ice on a surface is provided. The system includes an imaging device which includes at least one lens for providing image signals of the surface. The imaging device is operable in a predetermined portion of the electromagnetic spectrum. Image signals from the surface are polarized into discrete polarization changes responsive to the camera receiving image signals proportional to amplitude modulated signals generated by the presence of ice. A processor is provided for converting the modulated signals into discrete polarization changes and for obtaining the difference between the discrete polarization changes which is proportional to the amount of ice on the surface. An indication device provides an output corresponding to the difference between the discrete polarization changes. The difference is indicative of the presence and amount of ice on said surface.

Abstract: A system for detecting the presence of an energy polarization altering dielectric material, such as ice or snow, on a surface, such as a part of an aircraft, which normally specularly reflects incident energy, such as light, when there is no such dielectric present. The energy is conveyed from a transmitter along a path to the surface and the incident energy is reflected from the surface along a path to a receiver with a dielectric on the surface destroying any polarization, such as circular, of the energy and that reflected from a specular portion maintaining the polarization. An optical system in one or both of the paths operates in an isolator state to produce an image of the dielectric portion having a first intensity level and that of the specular portion passing through the optical system having a different intensity level.

Abstract: An optical weather identification system employing a light beam source that transmits a partial coherent beam of light along a prescribed path to detect precipitation and distinguish rain from snow is improved by the provision of another channel that is further able to distinguish solidified precipitation, namely sleet and hail. The additional output is derived from an acoustic, rather than an optical input. An acoustic receiver is positioned at a remote site to be monitored, along with an optical transmitter and receiver. The acoustic receiver employs a microphone located beneath the center of the underside of a domed top of the acoustic receiver casing. Falling precipitation is optically detected using prior optical precipitation detection techniques. However, if the particles of precipitation are solidified, as in the case of sleet and hail, the microphone will detect the impact of the sleet and hail on the domed receiver casing as an audible input.

Abstract: To determine whether ice is present on an aircraft wing, the intensity of light in a band between 1.16 and 1.20 microns is determined as is the intensity in a band between 1.24 and 1.28 microns. The contrast, defined as the difference between the intensities over the sum of these intensities, is determined. Because of the peculiar characteristics of the reflectivity of ice, water, Type I de-icing fluid, and Type II anti-icing fluid, if the contrast is positive, it is an indication of ice on the wing whereas if it is negative it is an indication there is no ice present.

Abstract: A safety system for detecting ice on the external surfaces of aircraft that are awaiting take-off from airports is disclosed. Multiple optical sensors mounted flush with the craft skin emit coded radiation signals away from the craft's skin. If a layer of ice is present on a sensor, light is reflected back to a corresponding detector, generating an electrical signal. Reflection from water or antifreeze or from environmental or endogenous noise yield distorted signals that are rejected by the code-reading circuitry. Relevant signals are sent to the cockpit, where the location of the ice on the aircraft is displayed for the crew, as well as to the airport tower via standard communication link, and to the flight data recorder. The invention assures that ice is detected at all critical times while the craft proceeds from the terminal to when it is airborne. Visual and audible alarms inform the pilot if unacceptable conditions prevail.

Abstract: A system for detecting the presence of an energy polarization altering dielectric material, such as ice or snow, on a surface, such as a part of an aircraft, which normally specularly reflects incident energy, such as light, when there is no such dielectric present. The energy is conveyed from a transmitter along a path to the surface and the incident energy is reflected from the surface along a path to a receiver with a dielectric on the surface destroying any polarization, such as circular, of the energy and that reflected from a specular portion maintaining the polarization. An optical system in one or both of the paths operates in an isolator state to produce an image of the dielectric portion having a first intensity level and that of the specular portion passing through the optical system having a different intensity level.

Abstract: A warning system for vehicles detects actual road surface temperature and advises the driver of surface temperatures which indicate the vehicle may be approaching possible ice formation on roadways. The warning system comprises an infrared detector mounted externally on the vehicle and aimed at the road surface, the detector arranged to read only the infrared temperature wavelength emissions associated with concrete and asphalt to eliminate confusing and erroneous readings inadvertently received through infrared emission from other objects in the vicinity. The detector is connected to a processing unit which translates the electric signals from the detector into a temperature readout display for the driver and the processing unit may include an alarm which is activated to attract the driver's attention when road temperatures are detected that are below a set minimum temperature that is selected by the driver's manual adjustment of a temperature select control knob on the unit.

Abstract: There is described a method and apparatus for detection and thickness evaluation of a buildup of ice or liquid on a solid surface, especially on a body of an aircraft. The apparatus comprises a source of a narrow beam of radiation and a means for remote evaluation of the size of a luminous area created on the solid surface by the beam. The method of the invention involves measuring the size of the luminous area and determining the thickness of any built-up layer, if sufficiently transparent, using a formula which uses the dependency of the size of the luminous are on the thickness of the layer and the refraction index of the medium. Differentiation between ice and a liquid is possible by evaluating regularity of illumination of the luminous area.

Abstract: A moisture content measuring apparatus and method wherein a sensor station produces calibration data corresponding to measurements of light at two different wavelengths reflected from a material, and the calibration data is then transferred to a hand held computer. The moisture content of a sample of the material is measured and input to the hand held computer. The process is repeated after changing the wetness of the material, and the hand held computer creates a table correlating reflection data to moisture content. The table is transferred to the sensor station which then continuously generates signals representing moisture content in response to real time reflection data and the table. The cost effectiveness of the sensor stations readily facilitates the use of a dedicated sensor station at each of a plurality of conveyors carrying different materials to be combined into a composite of predetermined proportions by weight.

Abstract: A detector system for detecting the formation of ice on an aircraft outer surface, e.g. wing skin. The ice detector system utilizes a light source, light detector and temperature sensor coupled together for providing signals representative of icing which may be utilized to provide an alarm to the cockpit of the aircraft. Built In Test Equipment (BITE) is also included in the detector system for system failure indication to the pilot of the aircraft.

Abstract: An apparatus and method that accurately and reliably detects ice on a target surface (20). Intrinsic birefringent properties of hexagonal ice crystals are used to detect ice by analyzing elliptically-polarized reflection of linearly-polarized radiation from ice. A linearly-polarized radiation beam (15) is focused on the target surface (20), and returned radiation (25) is filtered (30) as a function of its elliptical polarization. Filtered radiation (35) is directed to a sensor (40) and quantified according to the intensity of radiation received at various points (41.sub.1 -41.sub.n) on the filter (30), and an output signal for each point is produced (45.sub.1 -45.sub.n). The presence or formation of ice is determined by a signal processor (50) that detects the variance among the output signals (45.sub.1 -45.sub.n)--a variance (55) reaching a threshold value being indicative of ice.

Abstract: The condition of the roadway with respect to dryness, wetness, or icing is determined, contact-free by way of reflection measurements of light in the infrared range. The reflected light is measured selectively and simultaneously by a receiver in at least two wavelength regions with the wavelength ranges to be determined being in spectral dependence from the surface condition. Formation of a quotient of the detected signals makes possible an unequivocal statement regarding the respective condition of the roadway surface.

Abstract: The invention provides an apparatus and method for detecting the presence of ice on a surface. The invention uses cameras to allow ice detection over a large area instead of a single point. The detecting apparatus provides an improved deicing apparatus.

Abstract: A source sends light towards a receiver through an optical channel, a part of which has an interface with the external environment. The light that reaches this interface is reflected towards the receiver when the external environment is in contact with air and is refracted towards the external environment in the presence of water or ice. In streaming down the interface, the rain creates a modulation, not created by ice, in the signal of the receiver. The circuits downline of the receiver search for this modulation to determine whether the modifications of the signal of the receiver are due to rain or to ice.

Abstract: A system for automatic and real time detection of the presence or absence of a substance in an environment by monitoring variations in light energy transmitted through an optical fiber having a specially processed sensitive probe area. The sensitive probe area is positioned on, about or within the environment where a substance is to be detected. Because of differences in optical indices of refraction and energy absorption characteristics of different substances, the presence of different substances at the processed sensitive area will cause different proportional and characteristic attenuation of the light energy passing through the optical fiber. Changes in light energy transmission can be interpreted automatically to provide an indication of the condition of an environment.

Abstract: An apparatus for detecting a liquid-vapor change of phase in a fluid substance traveling through a conduit comprises a detector housing providing a path of travel for fluid and interposed in a portion of the fluid-carrying conduit in which the change of phase is to be detected, a source of radiation disposed for directing radiation into the path of travel and a detector for detecting radiation disposed generally at an opposite side of the path of travel from the said source. The arrangement is such that radiation from the source will pass through the fluid in the path of travel prior to reaching the detector. The detector is responsive to radiation detected thereat for producing a corresponding electrical signal. A detector circuit is responsive to the electrical signal produced by said detector for producing an output signal indicative of a liquid-vapor change of phase of the fluid in the conduit.

Abstract: A fiber optic frost sensor for use in a refrigerating apparatus having evaporator coils is used to determine when ice or frost has accumulated on the evaporator coils to an extent that the air around the evaporator coils cannot be cooled efficiently. The frost sensor includes a fiber optic cable located adjacent to the evaporator coils, the fiber optic cable extending between a light transmitter and a light receiver. As ice and frost accumulate on the evaporator coils, the ice and frost also accumulate on the outer surface of the fiber optic cable resulting in a change in the amount of light traveling from the transmitter to the receiver through the fiber optic cable. When the amount of light received by the receiver changes a preselected amount, the receiver determines that a defrost cycle needs to be initiated to melt the accumulated ice or frost. In one embodiment, a serpentine fiber optic cable is looped along the evaporator coils.

Abstract: A system for automatic and real time detection of water and icing on surfaces by monitoring variations in light energy transmitted through an optical fiber having a specially processed sensitive area probe. The sensitive probe area is positioned on, about or within the surface on which icing is to be detected. Because of differences in optical indices of refraction and energy absorption characteristics of air, water and ice, the presence of each of these at the processed sensitive area will cause a proportional and characteristic attenuation of the light energy passing through the optical fiber. Changes in light energy transmission can be interpreted automatically to provide an indication of icing. A reference optical circuit may be used to provide compensation for variations in input energy levels.