Abstract: A flame sensor for combustion flame temperature determination comprises elongated extensions that are positioned with parallel interdigitated longitudinal axis with respect to one another. An optical spectrometer comprises the sensor and a system comprises the sensor. A method for combustion flame temperature determination comprises obtaining a first photodiode signal and a second photodiode signal by using photodiode devices comprising photodiodes with elongated extending interdigitated digits. A method of fabricating a flame sensor for combustion flame temperature determination, comprises forming first and second photodiodes with elongated extending interdigitated digits.

Abstract: A flame sensor comprises a filter which blocks light in an infrared ray region, a filter which blocks stray light, a narrow band filter which passes only light of a band corresponding to a line spectrum of carbonic acid gas resonance radiation generated by a flame, and a broad band filter which passes light of a band which is broader than the band corresponding to the line spectrum, and a plurality of light reception elements which convert lights passing through the narrow and broad band filters to electric signals, the flame sensor judging flame when a difference between intensities of the electric signals is equal to or more than a predetermined value and a ratio between the intensities of the electric signals is within a predetermined range, by assuming that transmission band widths of the narrow and broad band filters are equal, is provided.

Abstract: An optical spectrometer for combustion flame temperature determination includes at least two photodetectors positioned for receiving light from a combustion flame, each of the at least two photodetectors having a different, overlap ping bandwidth for detecting a respective output signal in an ultraviolet emission band; and a computer for subtracting a respective output signal of a first one of the at least two photodetectors from a respective output signal of a second one of the at least two photodetectors to obtain a segment signal, and using the segment signal to determine the combustion flame temperature.

Abstract: A turbulent fluid, such as a flame, is examined using an array of infrared detector elements. The relationship between the thermal emissions received by different elements at different times is analysed, for example using correlation functions. This enables existence of a flame to be verified and the nature of the flame to be identified.

Abstract: A fire detection device luminance data over a time period longer than a repetition period of movement of a flame, to generate resampled data, and a device that 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 comparing a count of sampled data items larger than the average value, or a count of sampled data items smaller than the average value, with a predetermined value.

Abstract: A flame sensor capable of being easily produced and accurately detecting a flame includes a broadband filter having a transmission band inclusive of a line spectrum of resonance radiation of a carbonic acid gas, a narrowband filter permitting the passage of only the line spectrum of the resonance radiation of the carbonic acid gas and having its band center not coincident with that of the broadband filter, a light reception device, amplifiers, a circuit for computing the difference of mean intensities of spectrums transmitting through the filters and passing through the amplifiers, and a circuit for raising an alarm when the output of the computation circuit exceeds a predetermined value.

Abstract: An elongated heat detection device identifies heat sources based upon infrared radiation. The device includes a purged and sealed instrumentation chamber and a rugged and shock absorbing case. The case surrounds and protects the chamber and includes anti-roll features. The instrumentation is provided in a forward end of the device and is capable of being plugged into the balance of the device for rapid repair and replacement. The power supply is contained in a rear end of the device and the case forms a portion of the power supply circuit. The device employs a startup test of the sensor and the power supply. Also, the power supply is continuously monitored. The device also employs a lost device locator such that the device can be readily located after being misplaced. Moreover, the device has a signal expanding feature that allows a heat source that is rapidly passed over to be relocated on subsequent sweeps of the device.

Abstract: A solid state optical spectrometer for combustion flame temperature determination comprises: a first photodiode device for obtaining a first photodiode signal, the first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band; a second photodiode device for obtaining a second photodiode signal, the second photodiode device comprising a silicon carbide photodiode and a filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device; and a computer for obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature.

Abstract: A flame detection device for detecting a flame caused by a fire, including a light attenuation filter for attenuating 90% or greater of light with wavelengths in a visible to near-infrared band radiated from the flame. The flame detection device further includes an imager for photographing an image of the attenuated light incident thereon, and a processing section for deciding the flame from the image obtained by the imager.

Abstract: A method of detecting a fire in a scene by infrared (IR) radiation image processing comprises the steps of: receiving a sequential plurality of IR radiation images of the scene, each image including an array of picture elements (pixels), each pixel having a value that is representative of the pixel's portion of IR radiation intensity in the array of the scene image; identifying a region of pixels in one image based on pixel values; tracking the region through images subsequent the one image to determine a change of the region that meets predetermined IR radiation criteria; and detecting the fire in the scene based on the determined change of the region. In one embodiment, the step of tracking includes the steps of: identifying the region in images subsequent the one image; and comparing the identified regions of the one and subsequent images to determine a change of the region that meets the predetermined IR radiation criteria.

Abstract: A flame sensor comprises a filter which blocks light in an infrared ray region, a filter which blocks stray light, a narrow band filter which passes only light of a band corresponding to a line spectrum of carbonic acid gas resonance radiation generated by a flame, and a broad band filter which passes light of a band which is broader than the band corresponding to the line spectrum, and a plurality of light reception elements which convert lights passing through the narrow and broad band filters to electric signals, the flame sensor judging flame when a difference between intensities of the electric signals is equal to or more than a predetermined value and a ratio between the intensities of the electric signals is within a predetermined range, by assuming that transmission band widths of the narrow and broad band filters are equal, is provided.

Abstract: A flame sensor for combustion flame temperature determination, comprising a first photodiode formed with elongated extending digits, and having a range of optical responsivity within an OH band for producing a first output signal; and a second photodiode formed with for receiving light from a combustion flame and having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device OH band for producing a second output signal; wherein the elongated extensions are positioned with parallel interdigitated longitudinal axis with respect to one another. An optical spectrometer comprises the sensor and a system comprises the sensor.

Abstract: A flame sensor capable of being easily produced and accurately detecting a flame includes a broadband filter having a transmission band inclusive of a line spectrum of resonance radiation of a carbonic acid gas, a narrowband filter permitting the passage of only the line spectrum of the resonance radiation of the carbonic acid gas and having its band center not coincident with that of the broadband filter, a light reception device, amplifiers, a circuit for computing the difference of mean intensities of spectrums transmitting through the filters and passing through the amplifiers, and a circuit for raising an alarm when the output of the computation circuit exceeds a predetermined value.

Abstract: A process and system for flame detection includes a microprocessor-controlled detector with an array of sensors for sensing radiant energy from a fire or other heat source. A wide band infrared sensor is used as the primary detector, with near band and visible band sensors serving to detect false-alarm energy from nonfire sources. A narrow band sensor, such as a 4.3-micron sensor, is also employed in the sensor array, and assists in the detection of hydrocarbon fires. Digital signal processing is used to analyze sensed data and discriminate against false alarms. A multistage alarm system can be provided, which is selectively triggered by the microprocessor. Spectral recording and analysis of prefire data is provided for. The detector can be housed in an enclosed, sealed, removable, plastic housing that may include an integral plastic window lens.

Abstract: A process and system for flame detection includes a microprocessor-controlled detector with an array of sensors for sensing radiant energy from a fire or other heat source. A wide band infrared sensor is used as the primary detector, with near band and visible band sensors serving to detect false-alarm energy from non-fire sources. A narrow band sensor, such as a 4.3-micron sensor, may also be employed in the sensor array, and assists in the detection of hydrocarbon fires. Digital signal processing is used to analyze sensed data and discriminate against false alarms. A modulation index of one of the sensors (preferably the wideband IR sensor) is calculated by the microprocessor using measurements of the signal extremes (i.e., maxima and minima). A fire situation is not declared unless the modulation index falls within a prespecified range, such as between 5% and 85%. A multistage alarm system can be provided, which is selectively triggered by the microprocessor.

Abstract: A process and system for flame detection includes a microprocessor-controlled detector with a first sensor for sensing temporal energy in a first optical frequency range, and a second sensor for sensing temporal energy in a second optical frequency range. The temporal energy sensed in the respective first and second optical frequency ranges are transformed into respective first and second spectra of frequency components. A compensated spectrum of frequency components is generated by performing a frequency bin subtraction of the first and second spectra of frequency components. The compensated spectrum of frequency components represents the energy emitted from the environment with energy emitted from false alarm sources. An average amplitude and centroid of the compensated spectrum of frequency components are obtained and used to determine if a monitored phenomenon represents an unwanted fire situation.

Abstract: The present invention is a device for detecting modulated or active infrared light comprises a photodiode mounted on the base aperture of a wave guide for focusing infrared light onto the photodiode. The wave guide is preferably pyramid shaped and has a reflective surface on the inner surface. The apex of the wave guide comprises an acute angle from about 5 degrees to about 10 degrees. Units to process the signal and amplify the signal are attached thereto. The device may also include a Fresnel lens and a means to adjust the voltage of the active infrared signal processing means to improve detection capabilities.

Abstract: A flame detection apparatus has a focused array based sensor which is responsive to radiation having a predefined wavelength for generating an image of the infrared radiation emitted within a monitored region, and means for measuring the spectral ratio of the intensity of radiation having a first wavelength emitted within the monitored region to the intensity of radiation having a second wavelength emitted within the monitored region. Processing means analyses the output of the focused array based sensor and the spectral ration measuring means for responses indicative of the presence of a flame within the monitored region.

Abstract: An elongated heat detection device identifies heat sources based upon infrared radiation. The device includes a purged and sealed instrumentation chamber and a rugged and shock absorbing case. The case surrounds and protects the chamber and includes anti-roll features. The instrumentation is provided in a forward end of the device and is capable of being plugged into the balance of the device for rapid repair and replacement. The power supply is contained in a rear end of the device and the case forms a portion of the power supply circuit. The device employs a startup test of the sensor and the power supply. Also, the power supply is continuously monitored. The device also employs a lost device locator such that the device can be readily located after being misplaced. Moreover, the device has a signal expanding feature that allows a heat source that is rapidly passed over to be relocated on subsequent sweeps of the device.

Abstract: A method and apparatus for detecting and classifying an object, including a human intruder. The apparatus includes one or more passive thermal radiation sensors that generate a plurality of signals responsive to thermal radiation. A calculation circuit compares the plurality of signals to a threshold condition and outputs an alarm signal when the threshold condition is met, indicating the presence of the object. The method includes detecting thermal radiation from an object at a first and second wavelength and generating a first and second responsive signal. The signals are compared to a threshold condition that indicates whether the object is an intruder.

Abstract: A method and apparatus for an event detector using an array of passive infrared detector elements, which uses interchangeable spectral filters and lenses to permit detection of a range of event types, which normally each require individual detectors with specific spectral/optical designs.

Abstract: A fire detection device comprises a detection element to convert the infrared ray energy into the electric signal, a first extracting unit to extract the signal of a first prescribed frequency range including the flicker frequency of a fire from the output signal of the detection element, a second extracting unit to extract the signal of a second prescribed frequency range including no flicker frequency of a fire but including the frequency on the higher frequency side than that of the first prescribed frequency range from the output signal of the detection element, and a judging unit to judge a fire based on the output signal of the first extracting unit and the output signal of the second extracting unit. The fire detection device is capable of surely discriminating and detecting the flame from other infrared ray energy generation source. A band pass filter or the like need not be increased in number, and the increase in the product price can be prevented.

Abstract: A passive ranging system measured spectra of solar radiation off an adjacent spot and a distal target. Reflected solar radiation and differential attenuation are used to estimate target range. A comparison of absorption spectra from the solar illuminated distal target compared to the adjacent location is performed. Since the sun's position is always known, the increased absorption due to a distant target is derived from the differential between the adjacent spot and the distal target.

Abstract: An optical spectrometer for combustion flame temperature determination includes at least two photodetectors positioned for receiving light from a combustion flame and having different overlapping optical bandwidths for producing respective output signals; and a computer for obtaining a difference between a first respective output signal of a first one of the at least two photodetectors with and a second respective output signal of a second one of the at least two photodetectors, dividing the difference by one of the first and second respective output signals to obtain a normalized output signal, and using the normalized output signal to determine the combustion flame temperature.

Abstract: A flame detector with a radiation sensor (1) sensitive in the ultra-violet and/or visible range of the electro-magnetic spectrum, forms from the signal U1 at the output of the radiation sensor, a first signal U2 which is proportional to the direct voltage portion of the signal U1, and a second signal U3 which is proportional to the alternating voltage portion of the signal U1. The output signal UA of the flame detector is formed such that UA=U2−U3. Ignition sparks can thereby be effectively suppressed.

Abstract: A process and system for flame detection includes a microprocessor-controlled detector with at least three sensors. A wide band infrared sensor is used as the primary detector, with near band and visible band sensors serving to detect false-alarm energy from nonfire sources. Digital signal processing is used to analyze sensed data and discriminate against false alarms. A multistage alarm system can be provided, which is selectively triggered by the microprocessor. Spectral recording and analysis of prefire data is provided for. The detector can be housed in an enclosed, sealed, removable, plastic housing that may include an integral plastic window lens.

Abstract: A system for airborne detection of fires and transmission of fire location and characteristic data to the system ground station. The system includes an airborne pod and an associated ground station. The pod uses a passive infrared (IR) scanning system which employs a rotating and nutating mirror within an air slipstream driven propeller/spinner and is optically coupled to an infrared detector. A computer in the pod receives fire pod GPS position, IR detector fire spot detection pulse or ‘hit’ plus fire spot characteristics, spinner/mirror rotation and nutation angle at the ‘hit’ time and pod platform attitude relative to North-East-down using an on board Inertial Measurement Unit (IMU). The computer then calculates the firespot GPS location, and processes associated firespot characteristic data and downlinks this data to the ground station. Onboard pod video scene cameras also provide operational video that is also downlinked to the ground station.

Abstract: A passive ranging optical system is coupled to an active radar system. The passive ranging optical system provides range and rate information to the active radar system. After receiving the range and rate information, the active radar system uses fewer transmission pulses but achieves higher resolution of the range of the target because of improved range gate information.

Abstract: A solid state optical spectrometer for combustion flame temperature determination comprises: a first photodiode device for obtaining a first photodiode signal, the first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band; a second photodiode device for obtaining a second photodiode signal, the second photodiode device comprising a silicon carbide photodiode and a filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device; and a computer for obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature.

Abstract: There is described a detector which is suitable for use as a fire detector. The detector has two channels which allow for discrimination between energy received from a fire and a “false fire”. False fires are sometimes detected as a result of radiation from a so called “cold”, black body radiation source which flickers at a frequency of between 1 and 20 Hz. In the past, these gave rise to false alarms being triggered. The invention overcomes the problem by having a notch filter which when used in combination with another filter, ensures that detected radiation at, or around, 4.3 &mgr;m is transmitted to a sensor. A processor then compares the received value with a value computed by interpolating between signals received from two other channels. If a threshold value is exceeded an alarm is triggered. The invention thus overcomes disadvantages with prior art systems as signals from cold black body sources are rejected as false.

Abstract: A process and system for flame detection includes a microprocessor-controlled detector with at least three sensors. A wide band infrared sensor is used as the primary detector, with near band and visible band sensors serving to detect false-alarm energy from nonfire sources. Digital signal processing is used to analyze sensed data and discriminate against false alarms. A multistage alarm system can be provided, which is selectively triggered by the microprocessor. Spectral recording and analysis of prefire data is provided for. The detector can be housed in an enclosed, sealed, removable, plastic housing that may include an integral plastic window lens.

Abstract: An optical spectrometer for combustion flame temperature determination includes at least two photodetectors positioned for receiving light from a combustion flame, each of the at least two photodetectors having a different, overlapping bandwidth for detecting a respective output signal in an OH emission band; and a computer for subtracting a respective output signal of a first one of the at least two photodetectors from a respective output signal of a second one of the at least two photodetectors to obtain a segment signal, and using the segment signal to determine the combustion flame temperature.

Abstract: Sensors using detector arrays (1) are intended for identifying events within a scene (12). A sensor comprising an array of pyroelectric infrared detectors (1) is mounted directly onto an integrated readout circuit (2) so that each of its elements is in electrical contact with one of the inputs to the readout circuit. The detector array (1) on its readout circuit (2) is positioned at the focus of an infrared transmitting lens (11) so that an image of a scene (12) is formed on the array. The readout circuit (2) and array (1) are enclosed in a package (18) which is connected via a circuit board (19) to a microprocessor (20). The microprocessor (20) and readout circuit (2) work together to detect the occurrence and position of events within a scene (12). Application examples are the detection and identification of location of flames or intruders within the field of view.

Abstract: A system and method of passive ranging for a luminous target which employs a prior knowledge of atmospheric attenuation of spectral frequencies to determine range by comparing the intensities of a frequency component, that is attenuated by propagation through the atmosphere, with a frequency component that is not.

Abstract: The present invention provides a method and apparatus for detecting fire in a monitored area.

Abstract: An automated fire extinguishing apparatus includes a turret with a nozzle connected to a water supply. A plurality of sensors are used to detect a fire monitored by the apparatus. The signals from the sensors are used to aim the nozzle toward the fire and to initiate water ejection therefrom. After the fire is extinguished the water is turned off.